記述言語：英語   掲載種別：研究論文（学術雑誌）  

PURPOSE: The effect of quadriceps muscle strength on medial joint space (MJS) narrowing after repair for medial meniscus (MM) posterior root tears (MMPRTs) has not yet been determined. This study aimed to evaluate the effect of preoperative and postoperative quadriceps muscle strength on the change in MJS (ΔMJS) in MMPRTs. METHODS: Thirty patients who underwent pullout repair for MMPRTs were retrospectively evaluated. The MJS width using fixed-flexion view radiographs, MM extrusion (MME) using magnetic resonance imaging, quadriceps muscle strength using the Locomo Scan-II and clinical scores were measured and compared preoperatively and 1 year postoperatively. Correlations between the ΔMJS, change in MME (ΔMME), and preoperative and postoperative quadriceps muscle strength were evaluated using Spearman's rank correlation coefficient. RESULTS: MJS narrowing and MME progressed significantly at 1 year postoperatively (p < 0.001). Quadriceps muscle strength in MMPRT knees and all clinical scores significantly improved at 1 year postoperatively (p < 0.001). ΔMJS and ΔMME showed a significant positive correlation (0.50 ± 0.70 and 1.22 ± 0.92 mm, respectively; r = 0.516, p = 0.004). Both preoperative and postoperative quadriceps muscle strength in MMPRT knees showed significant negative correlations with ΔMJS (preoperative: r = -0.529, p = 0.003; postoperative: r = -0.477, p = 0.008) and ΔMME (preoperative: r = -0.431, p = 0.018; postoperative: r = -0.443, p = 0.014). CONCLUSIONS: In pullout repair for MMPRTs, preoperative and postoperative quadriceps muscle strength in MMPRT knees was negatively correlated with the progression of MJS narrowing and MME. Rehabilitation with a focus on quadriceps muscle strengthening, including preoperative rehabilitation, may delay knee-osteoarthritis progression after pullout repair for MMPRTs. LEVEL OF EVIDENCE: Level IV.

DOI： 10.1002/jeo2.70057

PubMed

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掲載種別：研究論文（学術雑誌）   出版者・発行元：SAGE Publications  

Background:

Animal models that use open surgical transection of the anterior cruciate ligament (ACL) do not accurately simulate the clinical condition regarding the pivot-shift mechanism and the associated inflammatory response that occurs before reconstruction.

Purpose/Hypothesis:

The purpose was to characterize a reproducible manual, nonsurgical method to mimic an isolated ACL tear in a clinically relevant model and to evaluate the development of progressive posttraumatic osteoarthritis due to ACL injury. It was hypothesized that the ACL could be reproducibly torn with minimal damage to other ligaments and that there would be progressive development of degenerative joint disease after ACL injury.

Study Design:

Controlled laboratory study.

Methods:

A total of 37 mice (strain C57BL/6) were used to compare the manual procedure with sham surgery (sham group; n = 10) and with the established surgical ACL transection (ACLT) procedure (surgical group; n = 27). In the sham group, a closed manual procedure was performed on the right knee and sham surgery on the left knee. In the surgical group, the closed manual procedure was performed on the right knee and surgical ACLT on the left knee. Dissection using India ink, histological assessment with safranin O and hematoxylin-eosin staining, radiological evaluation through radiographs and microfocus computed tomography scans, and gait analyses were performed to assess cartilage/ligament status. Osteoarthritis Research Society International (OARSI) and synovitis scores, anterior tibial translation, range of motion, bone microstructure, osteophyte volume, and pain were assessed at 2, 4, and 8 weeks postoperatively.

Results:

The manual procedure successfully resulted in an ACL rupture and associated meniscal injury. The posterior cruciate, lateral collateral, and medial collateral ligaments were intact in all dissected knees. Two weeks after ACL tear, the surgical group showed a significantly higher synovitis score, whereas 8 weeks after ACL tear, the manual group showed a significantly higher volume of osteophytes. No significant differences were found between the groups in terms of OARSI score, anterior tibial translation, range of motion, bone microstructure computed tomography values, and stride distance/irregularity.

Conclusion:

This procedure can be used to create an ACL tear model without causing grossly evident injuries to other ligaments and avoiding the risk of cartilage damage from surgical instruments.

Clinical Relevance:

This procedure offers a more clinically relevant ACL tear model and facilitates simple, inexpensive, and reproducible development of posttraumatic osteoarthritis.

DOI： 10.1177/03635465241253225

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その他リンク： https://journals.sagepub.com/doi/full-xml/10.1177/03635465241253225

掲載種別：研究論文（学術雑誌）   出版者・発行元：Wiley  

Abstract

Purpose

This study aimed to evaluate the association between the progression of medial joint space (MJS) narrowing, medial meniscus extrusion (MME) and clinical scores and the tibial tunnel position in pullout repairs for medial meniscus posterior root tears (MMPRTs).

Methods

This retrospective study examined 54 patients. Changes in MJS (ΔMJS), MME (ΔMME) and clinical scores and their relationship with the tibial tunnel position were evaluated using correlation coefficients. The distance from the anatomical to technical attachment position in the tibial tunnel position was measured in the anterior and medial directions, and the direct distance was measured using the Pythagorean theorem.

Results

The mean ΔMJS and ΔMME were 0.6 ± 0.8 and 1.3 ± 1.3 mm, respectively, and the mean anterior, medial and direct distances were 1.4 ± 2.3, 2.2 ± 1.7 and 3.4 ± 1.7 mm, respectively. ΔMJS had a significant positive correlation with the medial (r = 0.580, p &lt; 0.001) and direct (r = 0.559, p &lt; 0.001) distances, while ΔMME had a significant positive correlation with direct distance (r = 0.295, p = 0.030). Several clinical scores were significantly negatively correlated with these distances.

Conclusion

In transtibial pullout repair for MMPRTs, accurate tibial tunnel position delayed the progression of MJS narrowing and MME, leading to improved clinical outcomes. The progression of MJS narrowing was associated with the mediolateral direction of the tibial tunnel position, while the clinical scores were associated with the anteroposterior direction of the tibial tunnel position. These findings indicate the need to orient the tip of the guide in a more posterolateral direction when creating the tibial tunnel.

Level of Evidence

Level IV.

DOI： 10.1002/ksa.12229

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

Sarcopenia and malnutrition are increasing in older adults and are reported risk factors for functional impairment after hip fracture surgery. This study aimed to investigate the associations between skeletal muscle mass loss, malnutrition, and postoperative walking ability in patients with hip fracture. We retrospectively reviewed patients who underwent intertrochanteric fracture surgery at our institute. The psoas muscle index, controlling nutritional status score, and functional ambulation category (FAC) were used to evaluate skeletal muscle mass, nutritional status, and walking ability, respectively. Six months after surgery, walking ability was assessed as either "gait disturbance" or "independent gait". Multivariate binomial logistic regression analysis, with skeletal muscle mass, nutritional status, and other factors, was used to predict the risk of being assigned to the gait disturbance group. This study included 95 patients (mean age, 85.2 years; 70 women). Sixty-six patients had low skeletal muscle mass, 35 suffered from malnutrition, and 28 had both. Malnutrition and low skeletal muscle mass were significantly associated with postoperative gait disturbance (FAC < 3). Preoperative low skeletal muscle mass and malnutrition were risk factors for postoperative poor walking ability. Further preventive interventions focusing on skeletal muscle mass and nutritional status are required.

DOI： 10.18926/AMO/65973

PubMed

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掲載種別：研究論文（学術雑誌）   出版者・発行元：Springer Science and Business Media LLC  

Abstract

Background

This study aimed to assess quadriceps muscle strength after medial meniscus (MM) posterior root repair and determine its relationship with clinical scores and MM extrusion (MME).

Methods

Thirty patients who underwent pullout repair for MM posterior root tear and were evaluated for quadriceps muscle strength preoperatively and at 1 year postoperatively were included in this study. Quadriceps muscle strength was measured using the Locomo Scan-II instrument (ALCARE, Tokyo, Japan). MME and clinical scores (i.e., Knee Injury and Osteoarthritis Outcome Score [KOOS], International Knee Documentation Committee score, Lysholm score, Tegner score, and visual analog scale pain score) were evaluated preoperatively and at 1 year postoperatively, and second-look arthroscopy was performed at 1 year postoperatively. Wilcoxon's signed-rank test was used to compare each measure pre- and postoperatively. Pearson's correlation coefficient was used to assess the correlation with quadriceps muscle strength values. Multiple regression analysis was performed to identify factors associated with the change in MME (ΔMME).

Results

Second-look arthroscopy confirmed continuity of the posterior root in all patients. The quadriceps muscle strength measured at 1 year postoperatively (355.1 ± 116.2 N) indicated significant improvement relative to the quadriceps muscle strength measured preoperatively (271.9 ± 97.4 N, p &lt; 0.001). The MME at 1 year postoperatively (4.59 ± 1.24 mm) had progressed significantly relative to the MME preoperatively (3.63 ± 1.01 mm, p &lt; 0.001). The clinical scores at 1 year postoperatively were improved significantly relative to the scores preoperatively (p &lt; 0.001). The postoperative quadriceps muscle strength was correlated with ΔMME (correlation coefficient = -0.398, p = 0.030), and the change in quadriceps muscle strength was correlated with the KOOS-Quality of Life (correlation coefficient = 0.430, p = 0.018). Multiple regression analysis showed that the postoperative quadriceps muscle strength had a significant effect on ΔMME even when the body mass index and time from injury to surgery were included.

Conclusions

After MM posterior root repair, patients with greater quadriceps muscle strength showed less MME progression. In addition, patients with greater improvement in quadriceps muscle strength had better clinical scores; therefore, continued rehabilitation aimed at improving quadriceps muscle strength after MM posterior root repair is recommended.

Level of evidence

IV

DOI： 10.1186/s12891-023-06858-0

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その他リンク： https://link.springer.com/article/10.1186/s12891-023-06858-0/fulltext.html

掲載種別：研究論文（学術雑誌）   出版者・発行元：Elsevier BV  

DOI： 10.1016/j.jos.2022.08.005

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掲載種別：研究論文（学術雑誌）   出版者・発行元：Springer Science and Business Media LLC  

Abstract

Purpose

Untreated or overlooked medial meniscus posterior root tears (MMPRTs) induce sequential knee joint degradation. We evaluated epidemiological features of acute MMPRT for its early detection and accurate diagnosis.

Methods

Among 330 MMPRT patients from 2018 to 2020, those who underwent arthroscopic pullout repairs were enrolled. Patients who underwent non-operative treatment or knee arthroplasty, those with a cruciate ligament-deficient knee or advanced osteoarthritis of the knee, and those with insufficient data were excluded. Finally, we retrospectively evaluated data from 234 MMPRTs (female: 79.9%, complete tears: 92.7%, mean age: 65 years). Welch’s t-test and Chi-squared test were used for pairwise comparisons. Spearman’s rank correlation analysis was performed between age at surgery and body mass index (BMI). Multivariable logistic regression analysis with stepwise backward elimination was applied to the values as risk factors for painful popping events.

Results

In both sexes, there were significant differences in height, weight, and BMI. In all patients, there was a significant negative correlation between BMI and age (ρ =  − 0.36, p &lt; 0.001). The BMI cutoff value of 27.7 kg/m² had a 79.2% sensitivity and a 76.9% specificity for detecting MMPRT patients aged &lt; 50 years. A painful popping event was confirmed in 187 knees (79.9%), and the frequency was significantly reduced in partial tears as compared to complete tears (odds ratio: 0.080, p &lt; 0.001).

Conclusion

Higher BMI was associated with a significantly younger age of MMPRT onset. Partial MMPRTs had a low frequency of painful popping events (43.8%).

DOI： 10.1007/s00264-023-05848-0

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その他リンク： https://link.springer.com/article/10.1007/s00264-023-05848-0/fulltext.html

掲載種別：研究論文（学術雑誌）   出版者・発行元：Elsevier BV  

DOI： 10.1016/j.asmart.2023.03.001

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掲載種別：研究論文（学術雑誌）   出版者・発行元：Springer Science and Business Media LLC  

Abstract

Background

This study aimed to determine the predictors of tight extension gap (EG) compared with the flexion gap (FG) during navigational posterior stabilized-type total knee arthroplasty using the pre-cut technique.

Methods

Nineteen patients with tight EG (defined as FG-EG ≥2 mm after pre-cut; group T) and 84 patients with an approximately equal gap (defined as FG-EG = 0–1 mm after pre-cut; group E) were enrolled. Medial tibial slope angle, hip knee ankle angle, flexion contracture angle, and active maximum flexion angle were compared between the two groups.

Results

The multivariate logistic regression model indicated that the probability of tight EG increased with flexion contracture angle (odds ratio, 1.13; 95% confidence interval 1.05–1.20; P ≤ 0.001). According to the receiver operating characteristic analysis, the flexion contracture angle cut-off value associated with tight EG was 15.0° (sensitivity, 85%; specificity, 78%).

Conclusion

This study demonstrated that a large flexion contracture angle (cut-off 15.0°) was associated with tight EG after pre-cut osteotomy during posterior stabilized-type total knee arthroplasty. Awareness of this risk factor may help improve preoperative predictability of tight EGs and preparedness for additional procedures, such as soft tissue release or capsulotomy, to correct them.

Level of evidence

Level III.

DOI： 10.1186/s12891-022-05035-z

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その他リンク： https://link.springer.com/article/10.1186/s12891-022-05035-z/fulltext.html

記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Springer Science and Business Media LLC  

Abstract

Background

There are no recommendations for specific suture materials in transtibial pullout repair of medial meniscus posterior root tears. This study aimed to evaluate the clinical outcomes of transtibial pullout repair of medial meniscus posterior root tears using ultrahigh-molecular-weight polyethylene sutures and suture tape.

Methods

We retrospectively reviewed the data of 36 patients (27 women and 9 men, mean age 64.1 years) who had undergone transtibial pullout repair of medial meniscus posterior root tears between November 2018 and December 2019. Two groups of 18 patients each received either two different cord-like sutures or suture tape. Clinical parameters were assessed preoperatively and on second-look arthroscopy (mean postoperative period 12 months). The meniscal healing status was assessed using a previously published scoring system (ranging from 0 to 10), and the incidence rate of suture cut-out was assessed on second-look arthroscopy.

Results

All clinical scores significantly improved in both groups, with no significant between-group differences on second-look arthroscopy. The arthroscopic meniscal healing scores significantly differed between sutures (mean 6.7 points) and suture tape (mean 7.4 points; p = 0.044). No significant between-group difference in the suture cut-out rate was observed.

Conclusions

This study found no significant differences in the clinical outcomes between ultrahigh-molecular-weight polyethylene sutures and suture tape. Favorable clinical outcomes were obtained using both types of suture; however, the usefulness of suture tape appears to be limited.

DOI： 10.1186/s43019-022-00167-x

PubMed

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その他リンク： https://link.springer.com/article/10.1186/s43019-022-00167-x/fulltext.html

掲載種別：研究論文（学術雑誌）   出版者・発行元：Elsevier BV  

DOI： 10.1016/j.knee.2022.08.010

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掲載種別：研究論文（学術雑誌）   出版者・発行元：Wiley  

DOI： 10.1007/s00167-022-07095-z

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その他リンク： https://link.springer.com/article/10.1007/s00167-022-07095-z/fulltext.html

掲載種別：研究論文（学術雑誌）   出版者・発行元：Georg Thieme Verlag KG  

Abstract

Recently, transtibial pullout repair of the medial meniscus (MM) posterior root tear (PRT) has become widely accepted and provides satisfactory clinical outcomes. Widening after cyclic loading or ultimate failure load using different suture materials and configurations has been studied. However, no study has compared the clinical outcomes using different suture materials. This study aimed to evaluate the clinical outcomes after performing MMPRT pullout repair using different suture materials. We hypothesized that better clinical outcomes would be achieved using ultra-high molecular weight polyethylene (UHMWPE) tape compared with a normal polyester suture. Thirty-seven patients who underwent MM posterior root repair between November 2019 and May 2020 were retrospectively investigated. Pullout repair was performed using a hollow no. 0 polyester suture (n = 14) and UHMWPE tape (n = 23). Clinical outcomes were assessed preoperatively and at 1 year postoperatively, using the Lysholm knee score, Knee Injury and Osteoarthritis Outcome Score, and visual analogue scale (VAS) pain score. The meniscal healing status was assessed using an arthroscopic scoring system (range: 0–10). All clinical scores were improved significantly in both groups. However, significantly higher meniscal healing scores and decreased VAS pain scores were observed in the UHMWPE group (7.3 ± 0.9 and 7.7 ± 11.3, respectively) than in the polyester group (5.6 ± 2.1 and 18.4 ± 18.6, respectively; p &lt; 0.01). Suture cut-out and loss of the root continuity were observed in some cases (three cases [21.4%] in the polyester suture group and one case [4.3%] in the UHMWPE tape group). Both suture materials led to satisfactory clinical outcomes at 1 year postoperatively, whereas the UHMWPE tape was useful for obtaining good meniscal healing and decreasing the VAS pain score.

DOI： 10.1055/s-0042-1750047

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掲載種別：研究論文（学術雑誌）   出版者・発行元：Springer Science and Business Media LLC  

DOI： 10.1007/s00590-022-03285-0

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その他リンク： https://link.springer.com/article/10.1007/s00590-022-03285-0/fulltext.html

記述言語：英語   掲載種別：研究論文（学術雑誌）  

Bone marrow edema (BME) after meniscus injury and risk factors for subchondral insufficiency fracture of the knee (SIFK) have been reported. However, their association with medial meniscus posterior root tear (MMPRT) remains unknown. We investigated the association of BME volume (BME-V), posterior shinycorner lesion (PSCL), and SIFK with MMPRT to examine the correlations between BME-V and medial meniscus extrusion (MME), PSCL and duration from injury to the time of magnetic resonance imaging (duration), and SIFK and duration. Twenty-nine patients who underwent surgery for MMPRT were included (mean age, 59.2; range, 39-84). The presence of PSCL, femoral BME-V (cm3), and SIFK grade (1-4) were evaluated. Preoperative factors, such as MME (mm) and duration (weeks), were investigated using multivariate linear/ logistic regression analyses. Multivariate linear regression analysis revealed duration as a significant factor for high-grade SIFK (p<0.01). Multivariate logistic regression analysis revealed duration as a significant factor for the presence of PSCL (odds ratio=0.94, p<0.05). A long duration of MMPRT leads to severe MME and highgrade SIFK (3 and 4), often resulting in knee arthroplasty. Early diagnosis of MMPRT and pullout repair can prevent severe MME and high-grade SIFK.

DOI： 10.18926/AMO/63405

PubMed

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掲載種別：研究論文（学術雑誌）   出版者・発行元：Elsevier BV  

DOI： 10.1016/j.knee.2022.02.004

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掲載種別：研究論文（学術雑誌）   出版者・発行元：Springer Science and Business Media LLC  

<title>Abstract</title><sec>
<title>Background</title>
Diagnosing partial tears of the medial meniscus (MM) posterior root is difficult. The aim of this study was to evaluate diagnostic values involved in conventional magnetic resonance imaging (MRI) features of MM posterior root tears (MMPRTs) and find other MRI-based findings in patients with partial MMPRTs.


</sec><sec>
<title>Methods</title>
Eighteen patients who had arthroscopically confirmed partial MMPRTs were included. As a control, 18 patients who underwent partial meniscectomy for other types of MM tears were evaluated. Isolated partial MMPRTs were classified into the following three types: type A, accurate partial stable tear (cleavage &lt; 1/2 of root width); type B, bridged unstable root tear (cleavage ≥ 1/2 of root width); type C, complex horn tear expanded to the root. Conventional MRI-based findings of MMPRTs were evaluated between two groups (<italic>n</italic> = 23). Posterior root irregularity, bone marrow spot, and ocarina-like appearance showing several condensed circles in triangular meniscal horn (ocarina sign) were also evaluated.


</sec><sec>
<title>Results</title>
Posterior root irregularity and bone marrow spot were frequently observed in the partial MMPRTs (47.8%), compared with the other MM tears (<italic>P</italic> = 0.007 and 0.023, respectively). The ocarina sign was detected in 69.6% of patients with partial MMPRTs. A significant difference between two groups was observed in a positive ratio of ocarina sign (<italic>P</italic> &lt; 0.001). Types A, B, and C of the partial tear/damage were observed in three, eight, and seven patients, respectively. The ocarina sign was the most common MRI finding in each type of partial MMPRT.


</sec><sec>
<title>Conclusions</title>
This study demonstrated that a characteristic MRI finding, “ocarina sign,” was frequently observed in patients with partial tear/damage of the MM posterior root. The ocarina sign was the most common MRI finding in several types of partial MMPRTs. Our results suggest that the ocarina sign may be useful to diagnose unnoticed partial MMPRTs.


<italic>Level of evidence:</italic> IV, retrospective comparative study.


</sec>

DOI： 10.1186/s43019-021-00120-4

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その他リンク： https://link.springer.com/article/10.1186/s43019-021-00120-4/fulltext.html

記述言語：英語   掲載種別：研究論文（学術雑誌）  

Background: Cartilage degradation progresses rapidly following medial meniscus posterior root tear (MMPRT). Unicompartmental knee arthroplasty (UKA) has been performed for medial compartmental osteoarthritis following MMPRT. We evaluated the clinical and radiographic outcomes of UKA for medial compartmental osteoarthritis after an untreated MMPRT. Methods: Twenty-one patients who underwent UKA for isolated medial compartment osteoarthritis following MMPRT were retrospectively investigated. Clinical outcomes were assessed using the Knee Injury and Osteoarthritis Outcome Score and knee range of motion. The posterior tibial slope and tibial component inclination were evaluated using plain radiographs. Results: The mean follow-up periods were 25.5 ± 13.8 months. Clinical outcomes improved significantly postoperatively. The mean postoperative knee extension angle was -1.1° ± 2.1°, and the knee flexion angle was 134.3° ± 4.9°. The posterior tibial slope angle decreased from 9.0° ± 2.0° preoperatively to 5.4° ± 1.8° postoperatively, and postoperative tibial component inclination at the final follow-up was 2.9° ± 1.1° varus. No aseptic loosening or deep infections were observed. Conclusion: UKA significantly improved clinical outcomes and could be a viable surgical option for treating isolated medial compartmental osteoarthritis accompanied by untreated MMPRT.

DOI： 10.1016/j.asmart.2021.07.005

PubMed

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掲載種別：研究論文（学術雑誌）   出版者・発行元：SAGE Publications  

Purpose: Medial meniscus (MM) posterior root (PR) tear leads to severe MM posterior extrusion (PE), resulting in rapid knee cartilage degeneration. MMPR repairs are recommended to reduce MMPE, especially during knee flexion. However, the difference in MMPE between different repair techniques remains unknown. This study aimed to investigate preoperative and postoperative MMPE following several pullout repair techniques. We hypothesized that a technique using two simple stitches (TSS) would be more useful than FasT-Fix-dependent modified Mason-Allen suture (F-MMA) to prevent the progression of MMPE in knee extension. Methods: This retrospective study included 35 patients who underwent MMPR repair. To compare MMPE, patients were divided into two groups according to the use of F-MMA while grasping the posterior capsule and TSS without grasping it. Open magnetic resonance imaging was performed at 10° and 90° knee flexion preoperatively, and at 3 and 12 months postoperatively, and the MMPE of both groups was evaluated. Results: A significant difference was observed between preoperative and 3-month postoperative MMPE at 90° knee flexion in both groups ( p &lt; .01). A significant difference was observed in 3- and 12-month postoperative MMPE at 10° knee flexion between both groups ( p = .04/.02), whereas no significant difference in the preoperative MMPE at 10° knee flexion was observed between them ( p = .45). Conclusions: Both repairs were found to be useful to reduce MMPE in knee flexion. Further, F-MMA repair increased MMPE in knee extension, unlike TSS repair. These findings suggest that TSS might have more advantages for load distribution when standing or walking.

DOI： 10.1177/23094990211049569

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その他リンク： http://journals.sagepub.com/doi/full-xml/10.1177/23094990211049569

掲載種別：研究論文（学術雑誌）   出版者・発行元：Elsevier BV  

DOI： 10.1016/j.jos.2021.07.023

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

PURPOSE: To assess the effects of transtibial pullout repair for medial meniscus posterior root tears (MMPRTs) among patients with early osteoarthritis of the knee as measured by the meniscus healing score and to determine whether the meniscus healing score correlates with the International Cartilage Repair Society (ICRS) grade progression. METHODS: Forty-seven patients with mild osteoarthritic knees (Kellgren-Lawrence grade ≤ 2 and varus alignment < 5°) who underwent transtibial pullout repair less than 3 months after MMPRT onset were assessed. The association between meniscus healing scores at 1 year postoperatively and cartilage damage of the medial compartment (medial femoral condyle [MFC] and medial tibial plateau [MTP]) were evaluated. The MFC was divided into six zones (A to F) and the MTP into two zones (G and H). The mean ICRS grade for each zone was compared between the primary surgery and second-look arthroscopy. The correlation between cartilage damage and meniscus healing status at the time of second-look arthroscopy in each zone was analysed. RESULTS: The mean time interval from injury to surgery was 63 days, and all clinical scores showed significant improvement. There were no significant differences in the extent of cartilage damage in areas B, C, E, or F (n.s.) for MFC or in areas G and H (n.s.) for MTP. The meniscus healing score and cartilage damage were correlated in the loading areas (B, C, E, and H; - 0.53, - 0.45, - 0.33, and - 0.38, respectively; p < 0.05). CONCLUSION: Transtibial pullout repair of MMPRTs among patients with mild osteoarthritic knees improved the clinical outcomes and showed a negative correlation between high meniscus healing scores and ICRS grades in the medial compartment loading area. This study suggests that early surgery should be undertaken for patients with mild osteoarthritic knee who develop MMPRTs. LEVEL OF EVIDENCE: Level IV.

DOI： 10.1007/s00167-020-06332-7

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

The treatment of medial meniscus posterior root tears (MMPRTs) has evolved to include a variety of repair strategies. This study investigated the location of the articular cartilage degeneration during second-look arthroscopy after transtibial pullout repair with a modified Mason-Allen suture using FasT-Fix (F-MMA) in 22 patients with MMPRTs. Second-look arthroscopy was performed approximately 1 year postoperatively to eval-uate the healing status of the medial meniscus (MM). Articular cartilage degeneration was assessed using the International Cartilage Repair Society grade at primary surgery and again at second-look arthroscopy. Articular surfaces of the medial/lateral femoral condyles, the medial/lateral tibial plateaus, the patella and the trochlea were divided into several subcompartments (MF 1-9, LF 1-9, MT 1-5, LT 1-5, P 1-9, T 1-3). Clinical evaluations used the Japanese Knee Injury and Osteoarthritis Outcome, Lysholm, and International Knee Documentation Committee scores. Second-look arthroscopic findings showed complete healing of the MM posterior root in all patients. Significant differences between pullout repair and second-look arthroscopy were observed for MF 2 and 4, LF 7, and P 7. All clinical outcomes were improved. Our results indicate that this technique improves clinical outcomes postoperatively and may prevent the progression of cartilage degenera-tion on the loading surface of the medial knee compartment.

DOI： 10.18926/AMO/62380

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

PURPOSE: Medial meniscus posterior root tears (MMPRTs) can cause severe medial extrusion of the medial meniscus (MMME) and the progression of knee degenerative changes, inducing a high signal intensity of the meniscus on magnetic resonance imaging (MRI). Although MMME and intrameniscal signal intensity (IMSI) reportedly decreased within 3 months after MMPRT repair, no previous studies have reported these changes after a 1-year follow-up. This study aimed to investigate the 1-year postoperative changes in MMME and IMSI on MRI after using different suture techniques. METHODS: Overall, 33 patients with MMPRT were evaluated, 22 underwent FasT-Fix-dependent modified Mason-Allen suture (F-MMA) repair, and 11 underwent two simple stitches (TSS) repair. MRI examinations were performed preoperatively and 1 year postoperatively. MMME and IMSI were determined using MRI. RESULTS: A significant decrease in postoperative MMME was observed in the TSS group (4.1 ± 1.0) relative to that in the F-MMA group (5.1 ± 1.4, P = 0.03). A significant decrease in postoperative IMSI (0.75 ± 0.14) was observed relative to preoperative IMSI in the TSS group (P < 0.01), whereas postoperative IMSI (0.94 ± 0.25) was similar to preoperative IMSI in the F-MMA group (P = 0.06). Furthermore, a significant decrease in postoperative IMSI was observed in the TSS group relative to that in the F-MMA group (P < 0.01). CONCLUSIONS: The most important finding of this study is that TSS repair yielded a greater decrease in MMME and IMSI than F-MMA repair in patients with MMPRT. These results suggest that TSS repair is more useful for restoring loading stress to the posterior horn of the medial meniscus.

DOI： 10.1007/s00590-020-02830-z

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

PURPOSE: The purpose of this study was to evaluate the influence of tibial rotation on the postoperative healing status of the medial meniscus (MM) following pullout repair of the MM posterior root tear (MMPRT). METHODS: Ninety-one patients (68 women and 23 men; mean age 63.3 ± 8.8 years) who had undergone transtibial pullout repair of MMPRT were enrolled in the study. The tibial external rotation angle (ERA) in each patient was measured postoperatively using computed tomography in the extended knee position. The meniscal healing status following transtibial pullout repair was assessed by second-look arthroscopy (mean postoperative period 12 months) using a previously published scoring system (range 0-10). The association between the ERA and the meniscal healing score was investigated using univariate linear regression models. The ERA cut-off for improved meniscal healing score (≥ 7) was determined using receiver-operating characteristic analysis. RESULTS: The ERA and the meniscal healing score were significantly associated, confirming that increased ERAs were correlated with worse meniscal healing status (R =  - 0.28; P < 0.001). The optimum ERA cut-off value was 0.5°, with a sensitivity of 68% and a specificity of 63%. The mean meniscal healing scores were 7.3 and 6.2 among patients with ERAs < 0.5° and those with ERAs ≥ 0.5°, respectively (P < 0.001). CONCLUSION: This study demonstrated that the ERA was significantly correlated with the postoperative meniscal healing status. Postoperative tibial rotation could be one of the factors affecting postoperative outcomes of pullout repair of MMPRT. Controlling the tibial rotation may possibly improve meniscal healing. LEVEL OF EVIDENCE: III.

DOI： 10.1007/s00167-021-06656-y

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

PURPOSE: Transtibial pullout repairs using two simple stitches (TSS) and a combination of TSS with posteromedial pullout repair (TSS + PMP) using an all-inside meniscal repair device have been reported previously for the treatment of medial meniscus (MM) posterior root tears. This study aimed to investigate the postoperative clinical outcomes of these techniques including MM extrusion (MME). METHODS: Fifty-two patients who underwent transtibial pullout repair were investigated and divided into TSS (n = 27) and TSS + PMP (n = 25) groups. The clinical outcomes were assessed using the Lysholm knee score and Knee Injury and Osteoarthritis Outcome Score 1 year postoperatively and compared between two groups. MME was measured using magnetic resonance imaging at 1 year postoperatively and compared between two groups. RESULTS: A significant improvement in each clinical score was observed in both groups, and no significant difference was seen in clinical outcomes. Moreover, no significant difference in postoperative MME was observed in both groups (TSS and TSS + PMP: 3.5 mm and 3.8 mm, respectively). Though no significant progression of MME was observed in TSS group, a significant progression of it was observed in TSS + PMP group postoperatively. CONCLUSIONS: This study demonstrated that both techniques improved clinical outcomes in the short-term postoperative period. However, MME was progressed significantly in TSS + PMP group 1 year postoperatively, which indicated that PMP might not be a useful additional procedure for reducing the postoperative MME.

DOI： 10.1007/s00590-021-03035-8

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

BACKGROUND: During transtibial pullout repair of medial meniscus (MM) posterior root tears (MMPRTs), accurate tibial tunnel creation within the anatomic MM posterior root attachment seems critical. This study aimed to evaluate the tibial tunnel position created by a newly-developed Precision guide during pullout repair of MMPRTs. METHODS: In 40 patients who underwent transtibial pullout repairs, the tibial tunnel was created using the Unicorn Meniscal Root (UMR) (n = 20) or Precision guide (n = 20). Three-dimensional computed tomography images of the tibial surface were evaluated postoperatively, using Tsukada's measurement method. The expected anatomic center of the MM posterior root attachment was defined as the center of three tangential lines corresponding to anatomic bony landmarks. The expected anatomic center (AC) and the tibial tunnel center (TC) were evaluated using the percentage-based posterolateral location on the tibial surface. The difference in the mediolateral and anteroposterior percentage distance between the AC and TC was calculated, as was the absolute distance between the AC and TC. RESULTS: The mean AC was located 77.4% posterior and 40.1% lateral. The mean TC was similar in the UMR and Precision guide groups. There was no significant difference in the mediolateral percentage distance (UMR 3.9% vs. Precision 3.6%, p = 0.405), but a significant difference was observed in the anteroposterior percentage distance (UMR 3.5% vs. Precision 2.6%, p = 0.031). The mean absolute distance between the AC and TC was 3.9 mm and 3.5 mm (UMR and Precision guide groups, respectively) (p = 0.364). CONCLUSIONS: The new Precision guide can create tibial tunnel in an optimal and stable position during pullout repair of MMPRTs.

DOI： 10.1016/j.jos.2021.04.002

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

Purpose/Aim of the study: Previous studies have noted distinctions between medial meniscus posterior root and horn cells. However, the characteristics of root remnant cells have not been explored in detail. The purpose of this study was to evaluate the gene expression levels, proliferation, and resistance to mechanical stress of remnant and horn cells.Materials and Methods: Medial meniscus tissue samples were obtained from patients who underwent total or uni-compartmental knee arthroplasty. Cellular morphology, sry-type HMG box 9, type II collagen, and chondromodulin-I gene expression levels were analyzed. Collagen synthesis was assessed by immunofluorescence staining. Proliferation analysis after 4 h-cyclic tensile strain was performed.Results: Horn cells displayed triangular morphology, whereas root remnant cells appeared fibroblast-like. sry-type HMG box 9 mRNA expression levels were similar in both cells, but type II collagen and chondromodulin-I mRNA expressions were observed only in horn cells. The ratio of type II collagen-positive cells in horn cells was about 10-fold higher than that in root remnant cells, whereas the ratio of sry-type HMG box 9-positive cells was similar. A significant increase in proliferation was observed in root remnant cells compared to that in horn cells. Further, under cyclic tensile strain, the survival rate was higher in root remnant cells than in horn cells.Conclusions: Medial meniscus root remnant cells showed higher proliferation and resistant properties to cyclic tensile strain than horn cells and showed no chondromodulin-I expression. Preserving the medial meniscus posterior root remnant during pullout repair surgery might maintain mechanical stress-resistant tissue and support healing.

DOI： 10.1080/03008207.2021.1920935

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

BACKGROUND: Severe chondral lesions and varus knee alignment are associated with poor outcomes following transtibial pullout repair for medial meniscus posterior root tears and meniscus tear is strongly associated with body mass index. The prognostic factors in well-aligned knees (femorotibial angle < 180°) with mild chondral lesions are unknown. Therefore, we investigated the prognostic factors in these patients. We hypothesized that high body mass index would lead to poor clinical outcomes following pullout repair of medial meniscus posterior root tears. METHODS: We retrospectively reviewed the files of 28 patients who had undergone pullout repair of medial meniscus posterior root tears between October 2016 and December 2017. We recorded the baseline characteristics (age, gender, height, weight, and body mass index) and the time between injury and surgery. We recorded the International Knee Documentation Committee scores, Knee injury and Osteoarthritis Outcome Scores, and pain visual analog scale scores. Using magnetic resonance imaging preoperatively and 1 year after surgery, we measured the medial meniscus body width and absolute and relative medial meniscus extrusion. Pearson correlation and multivariate linear regression analyses were used to assess potential associations between these factors and clinical outcomes. RESULTS: Age positively correlated (coefficient = 0.49, P < 0.01) and body mass index negatively correlated with the postoperative International Knee Documentation Committee score (coefficient = -0.64, P < 0.01). In multivariate linear regression analysis, body mass index was a significant factor leading to poor postoperative International Knee Documentation Committee score (R2 = 0.29, P < 0.05). CONCLUSIONS: Body mass index > 30 kg/m2 is a risk factor for unfavorable clinical outcomes following pullout repair of medial meniscus posterior root tears in well-aligned knees. LEVEL OF EVIDENCE: III, Comparative retrospective study.

DOI： 10.1016/j.jos.2020.04.018

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

BACKGROUNDS: Medial meniscus (MM) posterior root tear (PRT) results in joint overloading and degenerative changes in the knee, and pullout repair is recommended to prevent subsequent osteoarthritis. Diagnosing MMPRT is sometimes difficult, especially in the case of an incomplete tear. A posterior shiny-corner lesion (PSCL) is reported to be useful for diagnosis, although the association between MMPRT and PSCL is unknown. This study aimed to investigate the properties of PSCL, such as the location, volume, and duration from injury to the time of MRI (duration). We hypothesized that PSCL is observed in the early phase after the MMPRT onset. METHODS: T2-weighted fat-suppression magnetic resonance imaging (MRI) was obtained from 55 patients with MMPRT preoperatively. The prevalence of the PSCL; giraffe neck, cleft, and ghost signs; severe MM extrusion (> 3 mm); and the PSCL volume were evaluated. The PSCL lesion elliptical volume (mm3) was calculated by measuring the anteroposterior, transverse, and craniocaudal dimensions. RESULTS: PSCL was observed in 34 (62%) cases. The mean volume of the PSCL was 102.0 mm3. A significantly shorter duration was observed in the PSCL-positive group (5.6 weeks) than that in the PSCL-negative group (40.9 weeks, P < 0.01), although no significant correlation was observed between the PSCL volume and duration. The sensitivity for the MMPRT was 90.5% when the cut-off duration value was 3 weeks and 81.8% when the cut-off value was 8 weeks. CONCLUSIONS: MRI examination may detect PSCL if it is performed early following MMPRT onset. Detecting PSCL may be useful in diagnosing MMPRT with high sensitivity.

DOI： 10.1007/s00590-021-02968-4

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

CASE: A 49-year-old woman injured her anterior cruciate ligament (ACL) as a high-school student. Double-bundle ACL reconstruction (DBACLR) using hamstring tendon grafts was performed because of recurrent instability. Eleven years after DBACLR, total knee arthroplasty was performed because of osteoarthritis progression. Histologic analysis was completed to observe the osteointegration of the tendon in the obtained proximal tibia. The tibial tunnel showed Sharpey-like fibers anteriorly, connecting the tendon graft and lamellar bone, whereas the intraarticular exit revealed well-aligned chondrocytes posteriorly, indicating chondral metaplasia of the tendon graft. CONCLUSION: Tendon-bone healing can regenerate both fibrous insertion and chondral metaplasia in DBACLR.

DOI： 10.2106/JBJS.CC.20.00509

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

A 65-year-old man presented with a left medial meniscus (MM) posterior root tear (PRT). Unicompartmental knee arthroplasty was performed 12 months after transtibial pullout repair of the MMPRT. Repaired MM posterior root tissue was subjected to histological analysis. Immunostaining and picrosirius red staining showed sufficient deposition of type I collagen, and hematoxylin-eosin staining using a polarized microscope showed well-aligned fiber orientation in the repaired tissue. The repaired posterior root (post-transtibial pullout repair) showed mature and well-aligned ligament-like tissue. Preserving the MM posterior root remnant to mimic the original posterior root tissue might be useful when performing pullout repair.

DOI： 10.18926/AMO/61905

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

BACKGROUND: The lengths of the anteromedial bundle (AMB) and posterolateral bundle (PLB) change during knee motion in double-bundle anterior cruciate ligament (ACL) reconstruction. However, the actual intraarticular graft length would be affected by the bone tunnel position and tunnel creation angle during ACL reconstruction. The aim of this study was to investigate the intraarticular length change of the AMB and PLB in patients who underwent anatomic double-bundle ACL reconstruction. HYPOTHESIS: We hypothesized that the PLB would show a more dynamic length change pattern than the AMB during knee flexion at ACL reconstruction. METHODS: Thirty-two patients (16 men and 16 women) who had isolated ACL injuries with intact menisci were investigated. Anatomic double-bundle ACL reconstructions were performed using semitendinosus tendon autografts at a mean age of 30.6 years. The graft and tunnel lengths were measured intraoperatively. Intraarticular graft lengths and length changes were calculated at 0° and 90° of knee flexion during ACL reconstruction. Intraoperative data were collected prospectively, and analyses were performed retrospectively. RESULTS: The intraarticular length of the AMB at 0° of knee flexion was 28.1±5.5mm. At 90° of knee flexion, the AMB intraarticular length decreased to 25.6±4.8mm. The intraarticular length of the PLB decreased to 17.7±4.6mm at 90° of knee flexion compared to 22.0±4.2mm at 0° of knee flexion. Changes in the intraarticular graft length during knee flexion were detected more in the PLB (4.1mm) than in the AMB (2.0mm, p=0.01). DISCUSSION: This study demonstrated that the intraarticular length change of the PLB during knee motion was larger than that of the AMB in anatomic double-bundle ACL reconstructions with semitendinosus tendon autografts and suspensory femoral fixation devices. LEVEL OF EVIDENCE: IV; retrospective cohort study.

DOI： 10.1016/j.otsr.2021.102816

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記述言語：英語  

DOI： 10.1007/s00167-020-06412-8

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

PURPOSE: Contralateral medial meniscus posterior root tear (MMPRT) can sometimes occur after primary surgeries for MMPRT and lead to unsatisfactory outcomes. The incidence rate and risk factors for contralateral MMPRT have not been well investigated, despite their clinical importance. Therefore, the incidence and predictors of bilateral MMPRT were aimed to be evaluated. METHODS: Fourteen patients with bilateral MMPRT (group B) and 169 patients with unilateral MMPRT (group U) were enrolled in this study. Sex, age, body mass index, time between injury and surgery, and medial tibial slope angle (MTSA) were compared between the groups. MTSA was measured using lateral radiographs. RESULTS: The incidence rate of bilateral MMPRT was 6.2% among all patients with MMPRTs. Multivariate logistic regression analysis showed that a prolonged time between injury and surgery (odds ratio [OR], 1.0; 95% confidence interval [CI] 1.00-1.01; P < 0.05) and steeper MTSA (OR, 1.85; 95% CI 1.21-2.64; P < 0.01) were significantly associated with the development of bilateral MMPRT. Receiver operating characteristic curve analysis showed that MTSA > 10.0° was associated with bilateral MMPRT, with a sensitivity of 93% and specificity of 69%. CONCLUSION: A longer time between injury and surgery and steeper MTSA were risk factors for the development of bilateral MMPRT. Surgeons need to pay close attention to the contralateral knee in addition to the primary injured knees when treating knees with steep MTSA. Besides, early meniscal repair of primary MMPRT would be important to prevent the events of contralateral MMPRT. LEVEL OF EVIDENCE: III.

DOI： 10.1007/s00167-020-06079-1

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

PURPOSE: The purpose of this study was to evaluate the influence of tibial tunnel position in pullout repair for a medial meniscus (MM) posterior root tear (MMPRT) on postoperative MM extrusion. METHODS: Thirty patients (median age 63 years, range 35-72 years) who underwent transtibial pullout repairs for MMPRTs were included. Three-dimensional computed tomography images of the tibial surface were evaluated using a rectangular measurement grid for assessment of tibial tunnel position and MM posterior root attachment. Preoperative and postoperative MM medial extrusion (MMME) and posterior extrusion (MMPE) at 10° and 90° knee flexion were measured using open magnetic resonance imaging. RESULTS: Tibial tunnel centers were located more anteriorly and more medially than the anatomic center (median distance 5.8 mm, range 0-9.3 mm). The postoperative MMPE at 90° knee flexion was significantly reduced after pullout repair, although there was no significant reduction in MMME or MMPE at 10° knee flexion after surgery. In the correlation analysis of the displacement between the anatomic center to the tibial tunnel center and improvements in MMME, and MMPE at 10° and 90° knee flexion, there was a significant positive correlation between percentage distance and improvement of MMPE at 90° knee flexion. CONCLUSION: This study demonstrated that the nearer the tibial tunnel position to the anatomic attachment of the MM posterior root, the more effective the reduction in MMPE at 90° knee flexion. Our results emphasize that an anatomic tibial tunnel should be created in the MM posterior root to improve the postoperative MMPE and protect the articular cartilage in a knee flexion position. Placement of an anatomic tibial tunnel significantly improves the MMPE at 90° of knee flexion after MM posterior root pullout repair. LEVEL OF EVIDENCE: IV.

DOI： 10.1007/s00167-020-06070-w

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

Medial meniscus posterior root tears (MMPRTs) have recently attracted considerable interest in orthopedics. To date, no in vivo human study has investigated suture translation changes in repaired MMPRTs with different degrees of knee flexion. This study examined suture translation at various degrees of knee flexion in 30 patients undergoing medial meniscus posterior root repair using the modified Mason-Allen suture technique between August 2016 and September 2017. Intraoperatively, sutures were provisionally fixed to an isometric positioner at the tibial site of the desired meniscal attachment, and the suture translation was measured at 0°, 30°, 60°, and 90° of knee flexion. The results showed significant increases in mean suture translation at the knee flexion positions from 0° to 30°, 30° to 60°, and 60° to 90° (p<0.01 for all). Our findings indicate that surgeons should carefully assess the degree of knee flexion at the moment when the meniscus is refixed by surgical sutures.

DOI： 10.18926/AMO/61881

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

Background: Medial meniscus (MM) tears are associated with both acute and chronic anterior cruciate ligament (ACL) insufficiency and can lead to degenerative changes in the knee. ACL reconstruction (ACLR) combined with the meniscal repair was reported to result in decreased anterior knee joint laxity with evidence of improved patient-reported outcomes in the long term. However, a subtle tear of the MM posterior segment, also known as a ramp lesion, is difficult to detect on conventional magnetic resonance imaging (MRI) and is frequently missed in ACL-deficient knees. However, there are few studies about the associations between bone geometry and ramp lesion of the MM. This study aimed to compare sagittal medial tibial slope (MTS), medial tibial plateau depth (MTPD), and coronal tibial slope (CTS) between ACL-injured knees with and without ramp lesion of the MM. We hypothesised that patients with ramp lesion of the MM and a concomitant ACL injury have a steeper MTS and shallower MTPD than those without ramp lesion of the MM. Methods: Twenty-seven patients who underwent ACLR (group A), and 15 patients with combined MM repair (group AM) were included in the study. Anterior tibial translation (ATT) was measured under general anaesthesia just before surgery using a knee arthrometer. MRI was performed in the 10°-knee-flexed position. The MTS and MTPD were measured on sagittal view, and the CTS was measured on coronal view. These parameters were compared between the groups. Differences in MRI measurements or patient demographics between the groups were evaluated using the Mann-Whitney U test. Results: No significant difference was observed in demographic data and post-operative side-to-side difference in ATT between both groups. Pre-operative ATT was significantly higher in group AM than in group A (P < 0.05), whereas post-operative ATT was similar in both groups. Further, Pre-operative ATT was significantly higher in patients with MTS ≥5.0° than in those with MTS <5.0° (P < 0.05). In groups A and AM, the MTS were 3.6° ± 1.8° and 6.2° ± 2.9°, the MTPD were 2.0 ± 0.5 mm and 2.1 ± 0.6 mm, and the CTS were 2.5° ± 1.8° and 2.4° ± 1.6°, respectively. Patients in group AM had a significantly steeper MTS compared to those in group A (P < 0.01), whereas MTPD and CTS were nearly the same in both groups. When the MTS cut-off value was set at 5.0°, the sensitivity and specificity for ACL injury with concomitant ramp lesion of the MM were 0.73 and 0.76, respectively. Conclusion: A steep posterior slope of the medial tibial plateau is a risk factor for ramp lesion of the MM associated with an ACL injury. Especially in patients with MTS ≥5.0°, an occult MM ramp lesion should be strongly suspected, and surgeons should prepare for MM repair in combination with ACLR.

DOI： 10.1016/j.asmart.2021.01.005

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

PURPOSE: The volume of medial meniscus (MM) extrusion at 10° and 90° knee flexions using three-dimensional (3D) magnetic resonance imaging (MRI) and assessed relevant clinical outcomes at 1-year follow-up were evaluated. METHODS: Twenty-four patients who underwent MM posterior root repair were retrospectively reviewed. At 10° and 90° knee flexions, the meniscal extrusion distance and volume were measured using 3D meniscus models constructed by SYNAPSE VINCENT®. The correlation between Knee Injury and Osteoarthritis Outcome Score, Lysholm, International Knee Documentation Committee scores, Tegner activity, and pain visual analog scales and changes in MM extrusion were assessed. RESULTS: No significant differences in the MM medial extrusion were observed between 10° and 90° knee flexions postoperatively. MM posterior extrusion (MMPE) decreased significantly at 10° and 90° knee flexions postoperatively. At 90° knee flexion, the meniscus volume at the intra-tibial surface increased at 3 and 12 months postoperatively. The MM extrusion volume increased slightly at 10° knee flexion; however, the volume decreased significantly at 90° knee flexion postoperatively. The change in MMPE significantly correlated with clinical scores. All 12-month clinical scores were significantly improved compared to preoperative scores. CONCLUSIONS: The progression of meniscus posterior extrusion and reduction of its volume at 90° knee flexion can be suppressed by MM posterior root repair. Postoperative clinical scores correlated with reductions of the posterior extrusion. Regarding clinical relevance, the dynamic stability of the meniscus can be maintained by MM posterior root repair, which is an effective therapeutic method for improving its clinical status. LEVEL OF EVIDENCE: Level IV.

DOI： 10.1007/s00167-021-06505-y

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

BACKGROUND: Medial meniscus (MM) posterior root repairs show favorable clinical outcomes in patients with MM posterior root tears (MMPRTs). However, there is no useful magnetic resonance imaging (MRI) finding to determine a functionally good meniscal healing following MM posterior root repairs. We hypothesized that a characteristic postoperative MRI finding can predict a good meniscal healing following pullout repairs. The aim of this study was to investigate a clinical usefulness of several MRI findings for estimating an actual meniscal healing following MMPRT repairs. METHODS: Fifty eight patients who had a posteromedial painful popping of the injured knee and underwent an arthroscopic pullout repair for the MMPRT were included. Arthroscopic meniscal healing was assessed according to the Furumatsu scoring system at 1 year postoperatively. We evaluated postoperative MRI-based meniscal healing using signal intensity, continuity, suspension bridge-like sign of the MM posterior root, and MM medial extrusion on coronal images. Postoperative clinical outcome evaluations were performed at second-look arthroscopy. RESULTS: Twenty three patients showed good arthroscopic healing scores (≥7 points). Thirty five patients had moderate/poor arthroscopic healing scores (<7 points). At 1-year follow-up period, clinical outcome scores were significantly higher in the good healing group than in the moderate/poor healing group. A characteristic meniscal shape, termed "suspension bridge sign", was highly observed in the good meniscal healing group (83%) compared with in the moderate/poor healing group (26%, P < 0.001). High signal intensity and continuity of the MM posterior root and MM medial extrusion showed no differences between both groups. CONCLUSIONS: Our study demonstrated that the MRI-based suspension bridge sign can predict an arthroscopically favorable meniscal healing following the MM posterior root repair. The suspension bridge-like MRI finding of the MM would be a useful indicator to evaluate the actual meniscal healing in patients who underwent pullout repairs for MMPRTs.

DOI： 10.1016/j.jos.2020.03.012

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

BACKGROUND: Medial meniscus (MM) posterior root repairs lead to favorable clinical outcomes in patients with MM posterior root tears (MMPRTs). However, there are few comparative studies in evaluating the superiority among several pullout repair techniques such as modified Mason-Allen suture, simple stitch, and concomitant posteromedial pullout repair. We hypothesized that an additional pullout suture at the MM posteromedial part would have clinical advantages in transtibial pullout repairs of the MMPRTs. The aim of this study was to compare the clinical usefulness among several types of pullout repair techniques in patients with MMPRTs. METHODS: Eighty-three patients who underwent arthroscopic pullout repairs of the MMPRTs were investigated. Patients were divided into three groups using different pullout repair techniques: a modified Mason-Allen suture using FasT-Fix all-inside meniscal repair device (F-MMA, n = 28), two simple stitches (TSS, n = 30), and TSS concomitant with posteromedial pullout repair using all-inside meniscal repair device (TSS-PM, n = 25). Postoperative clinical outcomes and semi-quantitative arthroscopic meniscal healing scores (0-10 points) were evaluated at second-look arthroscopies. RESULTS: No significant differences among the three groups were observed in patient demographics and preoperative clinical scores, except for preoperative Lysholm scores. At second-look arthroscopies, there were no significant differences among the three techniques in postoperative clinical outcomes and meniscal healing scores. CONCLUSIONS: This study demonstrated that the TSS-PM pullout repair technique did not show better scores in postoperative clinical outcomes and meniscal healings compared with the F-MMA and TSS techniques. Our results suggest that the concomitant posteromedial pullout suture may have no clinical advantage in the conventional pullout repairs for the patients with MMPRTs.

DOI： 10.1016/j.jos.2020.11.013

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

PURPOSE: A medial meniscus posterior root tear results in the loss of meniscal circumferential hoop stress and causes a pathological posteromedial extrusion of the medial meniscus. Although creating a tibial tunnel in the anatomic place improves postoperative medial meniscus posterior extrusion, no studies have evaluated the relationship between tibial tunnel position and clinical outcomes. This study aimed to evaluate how tibial tunnel positioning of medial meniscus posterior root pullout repair affects meniscal healing status and clinical outcomes. METHODS: Sixty-two patients with 64 medial meniscus posterior root tears (mean age 62.8 ± 7.9 years) who had undergone pullout repairs and second-look arthroscopies were included. All 62 patients were Lachman test negative. Three-dimensional computed tomography images of the tibial surface were evaluated using a rectangular measurement grid to assess the tibial tunnel centre and medial meniscus posterior root attachment centre. Spearman's rank correlation analysis was undertaken to determine displacement distance from the medial meniscus posterior root attachment centre to the tibial tunnel centre and a meniscal healing score, as well as clinical outcomes at 1 year post-repair. RESULTS: Tibial tunnel centres were located more anteriorly and medially than the medial meniscus posterior root attachment centre (mean distance 5.0 ± 2.2 mm). The mean meniscal healing score was 6.7 ± 1.8 of 10 possible points. The 1-year postoperative clinical scores showed significant improvement compared with preoperative scores for all the items. There was a significant negative correlation in the absolute distance between the medial meniscus posterior root attachment centre and the tibial tunnel centre with the meniscal healing score (ρ =  - 0.39, p = 0.002). Furthermore, there were significant positive correlations between the distance between the medial meniscus posterior root attachment centre and the tibial tunnel centre in the mediolateral direction and patient-based clinical outcomes (ρ = 0.25-0.43, p < 0.05). CONCLUSION: Accurate placement of a tibial tunnel, especially in the mediolateral direction, significantly improved meniscal healing and clinical outcomes at 1 year following medial meniscus posterior root repair. Surgeons should create a medial meniscus posterior root tibial tunnel at the anatomic attachment with particular attention to the mediolateral position. LEVEL OF EVIDENCE: Level IV.

DOI： 10.1007/s00167-020-06376-9

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

PURPOSE: Bone morphological factors are important for menisci. Their association with medial meniscus posterior root tears, however, has not yet been studied. This study aimed to compare sagittal medial tibial slope and medial tibial plateau depth between knees with and without medial meniscus posterior root tears. METHODS: Nine healthy volunteers, 24 patients who underwent anterior cruciate ligament reconstruction, and 36 patients who underwent medial meniscus posterior root pullout repair were included. Magnetic resonance imaging examinations were performed in the 10°-knee-flexed position. The medial tibial slope and medial tibial plateau depth were compared among the groups. RESULTS: In healthy volunteers, the anterior cruciate ligament reconstruction group, and the medial meniscus posterior root tear group, the medial tibial slopes were 3.5° ± 1.4°, 4.0° ± 1.9°, and 7.2° ± 1.9°, respectively, and the medial tibial plateau depths were 2.1 ± 0.7 mm, 2.2 ± 0.6 mm, and 1.2 ± 0.5 mm, respectively. Patients with medial meniscus posterior root tears had a significantly steep medial tibial slope and shallow medial tibial plateau concavity compared to those of healthy volunteers (P < 0.01) and the anterior cruciate ligament group (P < 0.01). In the multivariate logistic regression analysis, body mass index, medial tibial slope, and medial tibial plateau depth were significantly associated with medial meniscus posterior root tears. CONCLUSIONS: A steep posterior slope and a shallow concave shape of the medial tibial plateau are risk factors for medial meniscus posterior root tear. LEVEL OF EVIDENCE: Level III: Case-control study.

DOI： 10.1007/s00167-019-05590-4

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

BACKGROUND: Medial meniscus (MM) translates and extrudes posteriorly during knee flexion in MM posterior root tear (MMPRT) knees, and transtibial pullout repair of MMPRT has been performed to regulate the MM extrusion. This study aimed to calculate each suture translation during knee flexion in transtibial pullout repair of MMPRT, and to investigate the morphologic features of the MM that lead to longer suture translations during knee flexion. METHODS: Thirty patients with MMPRT who met the operative indication of pullout repair were enrolled and investigated prospectively. Pullout repair was performed by using two simple stitches (outer and inner sutures) and an all-inside suture in the posteromedial part of the MM. Each suture's translation from 0° to 90° of knee flexion was measured intraoperatively. The MM morphologic features, including MM medial extrusion (MMME) and MM posterior height (MMPH), were measured using preoperative magnetic resonance imaging, and the correlation between these values and each suture translation was evaluated. RESULTS: The average outer, inner, and all-inside suture translations were 4.8 mm, 3.9 mm, and 1.3 mm, respectively. Significant correlations were observed between the outer suture translation and MMME, and MMPH (p < 0.001 and <0.01, respectively). The thresholds for preoperative MMME and MMPH for longer outer suture translations (≥6 mm) were 2.1 mm and 5.4 mm, respectively. CONCLUSIONS: Preoperative longer MMME and higher MMPH were associated with longer meniscus translations during knee flexion during MMPRT repair.

DOI： 10.1016/j.knee.2020.12.020

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

BACKGROUND: Medial meniscus posterior root tear (MMPRT) causes medial meniscus extrusion (MME) and leads to subchondral insufficiency fracture of the knee (SIFK). However, the progression of SIFK after MMPRT pullout repair remains unknown. This study aimed to investigate the progression of SIFK and compare clinical outcomes in patients with SIFK to those without SIFK after MMPRT pullout repair. We hypothesized that the progression of SIFK would be prevented by MMPRT pullout repair, and clinical outcomes would improve in all patients. METHODS: The SIFK grade (1-4) was evaluated using T2-fat suppression magnetic resonance imaging. Thirty-eight patients without SIFK (n = 22) and with low-grade SIFK (1 and 2; n = 16) who underwent MMPRT pullout repair were included. Preoperative factors, such as the duration from injury to the time of magnetic resonance imaging/surgery (weeks), femorotibial angle (degree), MME (mm), and clinical outcomes were evaluated, as well as the progression of SIFK. RESULTS: SIFK was identified in only 9 patients (grade 1) postoperatively. Significantly improved clinical outcomes were observed in all patients. Preoperative femorotibial angle, MME, and duration from injury to the time of magnetic resonance imaging/surgery were 177.1 ± 1.5°, 3.2 ± 1.6 mm, and 6.4 ± 7.0/10.1 ± 7.5 weeks, respectively. No significant difference in preoperative factors and clinical outcomes was observed between patients with SIFK and those without SIFK. CONCLUSIONS: MMPRT pullout repair prevented the progression of low-grade SIFK and improved clinical outcomes in all patients, although bone contusions (grade 1 SIFK) were not completely healed within 1 year. MMPRT pullout repair could be a good treatment option for optimizing clinical outcomes in patients with low-grade SIFK.

DOI： 10.1016/j.jos.2020.10.008

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

PURPOSE: Transtibial repair of a medial meniscus posterior root tear (MMPRT) can improve clinical outcomes, although meniscal extrusion remains. However, few studies have investigated the volume of meniscal extrusion. This study aimed to evaluate the effect of transtibial repair in reducing the volume using three-dimensional (3D) magnetic resonance imaging, at 10° and 90° knee flexion. METHODS: Twenty patients with MMPRTs and 16 volunteers with normal knees participated. The 3D models of meniscus were constructed using SYNAPSE VINCENT®. The meniscal extrusion and its volume were measured at 10° and 90° knee flexion. Differences between the pre- and postoperative examinations were assessed using the Wilcoxon signed-rank test. The postoperative parameters were compared to those in patients with normal knees. RESULTS: There were no significant pre- and postoperative differences in any parameter at 10° knee flexion. At 90° knee flexion, the posterior extrusion and its meniscal volume were decreased significantly after transtibial repair (p < 0.05), even though these parameters were larger than in the normal knees. On the other hand, intra-articular meniscal volume calculated by the extrusion volume was increased to the level of the normal knee. CONCLUSIONS: This study demonstrated that transtibial repairs improved the intra-articular/intra-tibial surface volume of the medial meniscus by reducing the posteromedial extrusion during knee flexion. This 3D analysis is clinically relevant in evaluating that, while transtibial root repair has a limited ability to reduce meniscal extrusion, it can restore the functional volume of the medial meniscus which contributes to the shock absorber postoperatively. LEVEL OF EVIDENCE: IV.

DOI： 10.1007/s00167-020-05953-2

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

PURPOSE: To investigate changes in meniscal extrusion during knee flexion before and after pullout fixation for medial meniscus posterior root tear (MMPRT) and determine whether these changes correlate with articular cartilage degeneration and short-term clinical outcomes. METHODS: Twenty-two patients (mean age 58.4 ± 8.2 years) diagnosed with type II MMPRT underwent open magnetic resonance imaging preoperatively, 3 months after transtibial fixation and at 12 months after surgery, when second-look arthroscopy was also performed. The medial meniscus medial extrusion (MMME) and the medial meniscus posterior extrusion (MMPE) were measured at knee 10° and 90° flexion at which medial meniscus (MM) posterior translation was also calculated. Articular cartilage degeneration was assessed using International Cartilage Research Society grade at primary surgery and second-look arthroscopy. Clinical evaluations included Knee Injury and Osteoarthritis Outcome Score, International Knee Documentation Committee subjective knee evaluation form, Lysholm score, Tegner activity level scale, and pain visual analogue scale. RESULTS: MMPE at 10° knee flexion was higher 12 months postoperatively than preoperatively (4.8 ± 1.5 vs. 3.5 ± 1.2, p = 0.01). MMPE at 90° knee flexion and MM posterior translation were smaller 12 months postoperatively than preoperatively (3.5 ± 1.1 vs. 4.6 ± 1.3, 7.2 ± 1.7 vs. 8.9 ± 2.0, p < 0.01). Articular cartilage degeneration of medial femoral condyle correlated with MMME in knee extension (r = 0.5, p = 0.04). All clinical scores significantly improved 12 months postoperatively. However, correlations of all clinical scores against decreased MMPE and increased MMME were not detected. CONCLUSIONS: MMPRT transtibial fixation suppressed the progression of MMPE and cartilage degeneration and progressed MMME minimally in knee flexion position at 1 year. However, in the knee extension position, MMME progressed and correlated with cartilage degeneration of medial femoral condyle. MMPRT transtibial fixation contributes to the dynamic stability of the MM in the knee flexion position. LEVEL OF EVIDENCE: IV.

DOI： 10.1007/s00167-019-05810-x

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

Purpose/Aim of the study: Posterior root injury of the medial meniscus often leads to articular cartilage degeneration due to altered biomechanics. To avoid dysfunction, the attachment must be repaired using the transtibial pullout technique. To guide appropriate placement of the tibial tunnel, additional details on the normal anatomy of the meniscus insertion are needed. Therefore, we performed a histological analysis of a tibial bone slice with the medial meniscus posterior insertion obtained during total knee arthroplasty surgery. Materials and methods: Horizontal slices of the proximal tibia were obtained from 7 patients with osteoarthritis who underwent total knee arthroplasty. After decalcification, the region of the posterior horn was cut out and segmented into four pieces (2.0 mm thickness; medial to lateral). Sagittal sections were evaluated by safranin O staining or immunohistochemistry with anti-type collagen antibody. Results: Safranin O staining showed that the insertion of the posterior root consisted primarily of fibrocartilaginous layers in segment 2. Anatomically, segment 2 corresponded to the sagittal plane passing through the peak of the medial intercondylar tubercle. In this section, safranin O staining and immunohistochemistry revealed that the anterior one-third of the posterior root insertion was richer in proteoglycans and type II collagen than the central and posterior one-third. Conclusions: Anatomical insertion of the posterior root of the medial meniscus was located at the sagittal plane passing through the peak of the medial intercondylar tubercle. The structure of the medial meniscus posterior insertion was mainly localized in the anterior one-third.

DOI： 10.1080/03008207.2019.1631298

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

PURPOSE: This study aimed to clarify the advantages of three-dimensional (3D) magnetic resonance imaging (MRI) over two-dimensional (2D) MRI in measuring the size of the medial meniscus (MM) and to analyse the volumes of MM and the extruded meniscus in patients with MM posterior root tear (MMPRT), at 10° and 90° knee flexion. METHODS: This study included 17 patients with MMPRTs and 15 volunteers with uninjured knees. The MMs were manually segmented for 3D reconstruction; thereafter, the extruded part separated from the tibial edge was determined. The length, width, height, and extrusion of MM were measured by the 2D and 3D methods, and compared. The MM volume, extruded meniscus volume, and their ratio were also calculated using 3D analysis software in the two groups. RESULTS: The estimated length and posterior height of MM were larger with 3D MRI than with 2D MRI measurements. The MM volume was significantly greater in MMPRT knees than in normal knees, with increasing MM height. In MMPRT knees, the mean volume of the extruded meniscus and its ratio significantly increased by 304 mm3 (p = 0.02) and 9.1% (p < 0.01), respectively, during knee flexion. CONCLUSIONS: This study demonstrated that 3D MRI could estimate the precise MM size and that MMPRT caused swelling of the meniscus due to the increased thickness in the posteromedial part. The clinical significance of this study lies in its 3D evaluation of MM volume, which should help the surgeon understand the biomechanical failure of MM function and improve MMPRT repair technique. LEVEL OF EVIDENCE: III.

DOI： 10.1007/s00167-019-05580-6

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

OBJECTIVES: To identify the diagnostic performance of magnetic resonance imaging (MRI) in the knee-flexed position for the detection of meniscal ramp lesions in patients with anterior cruciate ligament tears. MATERIALS AND METHODS: Forty-three patients (mean age 24.5 ± 9.5 years; 21 males, 22 females) with an arthroscopically proven anterior cruciate ligament tear were included in this retrospective study. The presence of the following two important features on MRI was recorded: irregularity of the medial meniscus at the posterior margin, and complete fluid filling between the posterior horn of the medial meniscus and the capsule margin. Findings obtained in arthroscopy served as the reference standard. The diagnostic sensitivity, specificity, and inter-observer agreement were calculated. RESULTS: Sixteen ramp lesions were noted on arthroscopy (37.2%). With an irregularity of the medial meniscus at the posterior margin on MRI, the sensitivity and specificity were 87.5 and 59.3% at 10° knee flexion and 93.8 and 85.2% at 90° flexion, respectively. The complete fluid filling sign on MRI showed sensitivity and specificity of 31.3 and 100% at 10° knee flexion and 87.5 and 100% at 90° flexion, respectively. The concordance between the two observers for the two MRI features was very good (k = 0.70-0.88). CONCLUSION: MRI with the knee in the flexed position improves the diagnostic performance of the detection of meniscal ramp lesions compared with MRI with the knee in the extended position.

DOI： 10.1007/s00256-020-03480-2

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

The aim of this study was to evaluate tunnel coalition and inter-tunnel distance by comparing the tibial tunnel position in double-bundle anterior cruciate ligament (ACL) reconstruction performed with a conventional guide versus a posterolateral (PL) divergence (PLD) guide. Subjects were 43 patients (ACL tip aimer: 20 knees; PLD guide: 23 knees) who underwent double-bundle ACL reconstruction between September 2014 and December 2017. In all cases, the tibial tunnel position, tunnel edge distance and tunnel angles were evaluated based on CT images. Clinical outcome was evaluated using the Lachman test, pivot-shift test, and Lysholm score. Tibial tunnel positions were similar between the conventional and PLD guide groups, while tibial tunnel edge distance was significantly less in the conventional group. Tunnel coalition was observed in 5 knees in the conventional and no knees in the PLD guide group. Distance between two tibial tunnel centers was 9.1 mm for the tip aimer, and 10.5 mm for the PLD guide. Creation of the PL tunnel tended to involve insertion from a more medial aspect for the PLD guide group than the conventional guide group. No differences in clinical outcomes were noted. The PLD guide can be used to create anatomically-positioned PL tunnels, and reduce the probability of occurrence of tunnel coalition.

DOI： 10.18926/AMO/60373

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

BACKGROUND: Two types of repair techniques, FasT-Fix modified Mason-Allen (F-MMA) and two simple stitches (TSS), for the treatment of a medial meniscus posterior root tear (MMPRT) were previously reported. However, whether these techniques could prevent postoperative medial meniscus extrusion (MME) progression is unknown. This study investigated and compared postoperative MME of the two repair techniques. METHODS: Forty-seven knees that had undergone pullout repair for MMPRT were retrospectively reviewed. These knees were divided into two groups as follows: In 26 knees, MMPRT was treated using the F-MMA technique and fixed with the knee flexed at 45° and 20 N of tension [F-MMA (45°-20 N) group], and in 21 knees, MMPRT was treated using the TSS technique and fixed with the knee flexed at 20° and 30 N of tension [TSS (20°-30 N) group]. The medial meniscus body width (MMBW), absolute MME (aMME), and relative MME (rMME = absolute MME/MMBW) were measured and compared using magnetic resonance imaging 3 months postoperatively. The Knee Injury and Osteoarthritis Outcome Score (KOOS) subscales for clinical outcomes were compared between the two groups at 6 months postoperatively. RESULTS: At 3 months postoperatively, the aMME and rMME significantly decreased in the TSS (20°-30 N) compared to the F-MMA (45°-20 N) group. The TSS (20°-30 N) group had better KOOS subscale scores than the F-MMA (45°-20 N) group at 6 months postoperatively. CONCLUSIONS: The TSS technique with appropriate tibial fixation can decrease MME soon after surgery. This may prevent osteoarthritis progression and improve clinical outcomes.

DOI： 10.1007/s00590-020-02647-w

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

BACKGROUND: Transtibial pullout repair of a medial meniscus posterior root tear (MMPRT) is a commonly used procedure, and several techniques have been reported. We hypothesised that pull-out repairs using two simple stitches (TSS) would have similar postoperative outcomes as those using the modified Mason-Allen suture with FasT-Fix (F-MMA). We aimed to investigate the clinical outcomes of these techniques, including the meniscal healing status and osteoarthritic change. METHODS: The data of 68 patients who underwent transtibial pull-out repair were retrospectively investigated. The patients were divided into two groups of 41 and 27 patients using F-MMA and TSS, respectively. The clinical outcomes were assessed preoperatively and at second-look arthroscopy (the mean period from surgery was one year) using the Knee injury and Osteoarthritis Outcome Score. The meniscal healing status, evaluated at second-look arthroscopy, was compared between the two groups. The cartilage damage was graded as per the classification of the International Cartilage Repair Society and compared at the primary surgery and second-look arthroscopy. RESULTS: Both groups showed significant improvement in each clinical score. No significant difference was seen in the clinical outcome scores and the meniscal healing status between the two groups at second-look arthroscopy. Moreover, no significant progression of cartilage damage was observed in both groups. Fourteen patients in the F-MMA group developed a complication of suture bar failures postoperatively; however, there were no complications in the TSS group. CONCLUSIONS: The TSS and F-MMA techniques showed favourable clinical outcomes and would be established as clinically useful techniques for the MMPRT treatment.

DOI： 10.1016/j.knee.2020.04.023

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

BACKGROUND: To investigate the relationship between tibial tunnel aperture location and postoperative meniscal healing. METHODS: We enrolled 25 patients (20 women and five men, mean age: 62.5 years) who underwent transtibial pullout repair for medial meniscus (MM) posterior root repair. The expected MM posterior root attachment center (AC) and tibial tunnel center (TC) were identified using three-dimensional computed tomography, and the minimum AC-TC distance was calculated. The meniscal healing status following transtibial pullout repair was assessed by second-look arthroscopy (mean postoperative period: 15 months) using a previously reported scoring system (meniscal healing score; range: 0-10). The association between AC-TC distance and meniscal healing score was investigated using univariate linear regression models. The optimal AC-TC distance cut-off for improved MM healing score (≥7) was determined using receiver operating characteristic analysis. RESULTS: The AC-TC distance and meniscal healing score were significantly associated (y = -0.42x + 9.48, R2 = 0.342; P = 0.002), with the optimum AC-TC distance being 5.8 mm. This cut-off had a sensitivity of 100% and specificity of 53%. CONCLUSIONS: This study demonstrates that AC-TC distance is significantly correlated with postoperative meniscal healing. Anatomical repair within 5.8 mm of the AC may result in improved meniscal healing.

DOI： 10.1016/j.knee.2020.02.025

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

BACKGROUND: Lateral meniscus (LM) posterior root tear (PRT) is often associated with anterior cruciate ligament (ACL) injury and can result in rotational instability, joint overloading, and degenerative changes in the knee. Improved rotational stability and kinematics have been reported after LMPRT repair. However, it is unclear what repair technique can achieve the greatest reduction in LM extrusion (LME). HYPOTHESIS: We hypothesized that transtibial pullout repair would decrease LME to a greater extent than other repair techniques. PATIENTS AND METHODS: Seventeen patients with ACL injury and complete LMPRT were evaluated. Nine underwent ACL reconstruction (ACLR) and transtibial pullout repair, and eight underwent ACLR and other repairs such as inside-out suturing. Double-bundle ACLR was performed using hamstring tendons, and LMPRT pullout repair was performed through the bone tunnel for the posterolateral bundle. Magnetic resonance imaging was performed immediately preoperatively and at>6 months postoperatively, and LME was measured from coronal images only. RESULTS: A significantly greater decrease in the value of LME from pre- to postoperative measurement was observed in the transtibial pullout repair group (-0.5±0.7mm) than in the other-repair group (1.0±0.9mm, p<0.01). Pre- and postoperative LME measurements were not significantly different between the two groups. DISCUSSION: The most important finding of this study was that transtibial pullout repair resulted in a greater decrease in LME than other repair techniques in patients with ACL injury and LMPRT. This technique might be useful for restoring hoop tension by decreasing LME. LEVEL OF EVIDENCE: III, comparative retrospective study.

DOI： 10.1016/j.otsr.2019.10.022

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

Background: Meniscal tears are commonly observed in patients with anterior cruciate ligament (ACL) injuries. Meniscal repair has become a common procedure for the injured meniscus, and good clinical outcomes have been reported in such cases when used concurrently with ACL reconstruction. However, it is unclear whether early chondral damage progression can be prevented following meniscal repair with ACL reconstruction, as meniscal damage is a potential risk factor for the development of osteoarthritis. The purpose of this study was to evaluate the zone-specific chondral damage that occurs after arthroscopic meniscal repair with concomitant ACL reconstruction. Our hypothesis was that meniscal repair with ACL reconstruction would not decrease the rate of progression of chondral damage compared to that observed in isolated ACL reconstruction with intact menisci. Methods: This study included 40 patients who underwent anatomic double-bundle ACL reconstruction. We divided the patients into the following two groups: Group A with an intact meniscus (20 knees) and Group M requiring meniscal repair (20 knees). Chondral damage was evaluated arthroscopically in six compartments and 40 sub-compartments, and these features were graded using the International Cartilage Repair Society lesion classification. The cartilage damage in each sub-compartment and compartment was compared between the two groups both at reconstruction and at second-look arthroscopy (average 16 months postoperatively). At the latest follow-up examination (average 37 months postoperatively), the International Knee Documentation Committee (IKDC) score was compared between the two groups. Results: Group M had a significantly worse cartilage status than Group A in five sub-compartments (mainly in the medial compartment) at reconstruction and in nine sub-compartments (mainly in the bilateral compartments) at second-look arthroscopy. The mean IKDC score was better in Group A than in Group M (Group A; 90 vs. Group M; 86). The overall success rate of meniscal repairs was 92% (23 of 25 menisci) at second-look arthroscopy. Conclusion: The progression of post-traumatic chondral damage may occur at a faster rate in patients who require ACL reconstruction and meniscal repair than in patients with intact menisci.

DOI： 10.1016/j.asmart.2020.01.001

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：SAGE Publications Ltd  

This report describes a novel arthroscopic technique for the treatment of anterior cruciate ligament (ACL) tibial eminence avulsion fractures. A 16-year-old boy who was diagnosed with a left ACL tibial eminence avulsion fracture was treated by arthroscopic fixation. Two bone tunnels were created from the anterior tibial cortex into the fracture bed, and a strong suture passed through the ACL just above its insertion was pulled out through them for reduction and fixation. A retrograde cannulated screw fixation was added for stronger fixation. Weight-bearing and range of motion exercises were started immediately after surgery. Radiographically, bone union was obtained 6 months postoperatively. During second-look arthroscopy (24 months postoperatively), there was no loss of reduction and no subsequent meniscal or cartilage injuries. At that point, the Lysholm score was 95, and the International Knee Documentation Committee score was 96.

DOI： 10.1177/2309499020918681

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

BACKGROUND: Medial meniscus (MM) medial extrusion in the coronal plane does not always improve, even after repair. This study aimed to determine the extent of posteromedial extrusion of the MM during knee flexion before and after MM pullout repair using three-dimensional magnetic resonance imaging (MRI). METHODS: Data from 14 patients (mean age, 63.4 years; 86% female) who had undergone MM pullout repair at the current institution between August 2017 and October 2018 were retrospectively reviewed. The MRIs were performed pre-operatively and ≥3 months postoperatively. Three-dimensional MRIs of the tibial surface and MM were evaluated using Tsukada's measurement method before and after pullout repair. The expected center of MM posterior root attachment (point A), the point on the extruded edge of the MM farthest away from point A (point E), and the point of intersection of a line through the posteromedial corner of the medial tibial plateau and a line connecting points A and E (point I) were identified. Subsequently, the pre-operative and postoperative AE and IE distances were calculated and compared. RESULTS: Point E was laterally shifted by the pullout repair, whereas point I showed no significant change. The postoperative IE distance (6.7 mm) was significantly shorter than the pre-operative one (9.1 mm, P < 0.01). The postoperative AE distance (29.3 mm) was significantly shorter than the pre-operative one (31.5 mm, P < 0.01). CONCLUSIONS: The AE and IE distances significantly decreased after MM posterior root repair, suggesting that transtibial pullout repair may be useful in reducing posteromedial extrusion of the MM.

DOI： 10.1016/j.knee.2019.09.005

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

Background: Medial meniscus (MM) posterior root tear (PRT) is often caused by meniscal degeneration, whereas lateral meniscus (LM) PRT is mainly caused by trauma, especially trauma associated with anterior cruciate ligament (ACL) injuries. Although there are a few reports on PRTs of both menisci with an ACL injury, to our knowledge, there is no report on those with an intact ACL. Thus, the purpose of this study was to describe a rare case of both meniscal PRTs with an intact ACL. Case Presentation. A 67-year-old woman complained of right knee pain during weeding in a deep knee flexion position. At presentation, three days after the injury, physical examination revealed signs of meniscal injury without ACL rupture. Magnetic resonance imaging showed PRTs of both menisci and damaged cartilage, especially on the medial femoral condyle and lateral tibial plateau. MM was sutured using the FasT-Fix dependent modified Mason-Allen suture technique, and LM by a single simple stitch using the Knee Scorpion suture passer. Referring to previous cadaveric studies, transtibial pullout repair using a single tibial tunnel for MM fixation was performed. The stability of the repaired menisci was checked by probing during second-look arthroscopy at one year after the primary surgery, and no meniscal signs and symptoms were present at the last follow-up one year after the surgery. Conclusions: This rare case showed PRTs of both menisci with an intact ACL. We speculated that, in this case, both roots tore because of the degenerative menisci. A good clinical outcome was achieved after single-transtibial pullout repair. This technique may be an effective surgical approach for PRTs of both menisci.

DOI： 10.1155/2020/8842167

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

INTRODUCTION: The effect of tranexamic acid (TXA) on the incidence of venous thromboembolic events (VTEs) in total knee arthroplasty (TKA) as assessed by contrast-enhanced computed tomography (CT) is unclear. Thus, we investigated the efficacy and safety profiles of TXA administration during TKA. We hypothesised that intra-articular 1 g TXA administration would have a sufficient effect on the reduction of blood loss and transfusion rates without increasing VTE risk. MATERIALS AND METHODS: We retrospectively analysed 86 patients who underwent primary TKA from January 2014 to September 2017. The study comprised control (n = 45) and TXA (n = 41) groups. All patients underwent navigation-assisted TKA via the medial parapatellar approach. In those who received TXA, 1 g of intra-articular TXA was injected via a drain immediately following wound closure. The drain was clamped for 2 h and then reopened. Contrast-enhanced CT was performed 5-6 days after surgery to detect deep venous thrombosis (DVT) and pulmonary embolism (PE). Blood loss was calculated using the haemoglobin balance method. RESULTS: The mean postoperative volume of blood loss was 900 ± 296 mL vs 1216 ± 445 mL in the TXA vs control group (p < 0.01). Allogeneic blood transfusion was required for 0 (0%) vs 6 (13.3%) patients in the TXA vs control group (p = 0.013). There were no significant inter-group differences regarding DVT and PE incidence (p > 0.05). No case of symptomatic PE occurred. CONCLUSIONS: This study demonstrated that intra-articular 1 g TXA administration during TKA is safe and effective for reducing blood loss and blood transfusion without increasing VTE risk.

DOI： 10.1007/s00590-019-02520-5

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

The medial meniscus (MM) posterior root has important functions in preventing an excessive loading stress during knee motion and degeneration of the articular cartilage. Although the transtibial pullout repair has become the gold standard for MM posterior root tears (MMPRTs), MM extrusion remains. In addition, during knee extension to deep flexion, the MM posterior segment in the MMPRT knee has been shown to translate toward the posteromedial direction, causing a notable MM posterior extrusion. Thus, the reduction in the MM posteromedial extrusion is one of the important postoperative outcomes to restore the meniscal function and eventually prevent the progression of knee osteoarthritis. The present technical note describes an arthroscopic technique addition to the pullout repair, in which an all-inside suture is inserted into the posteromedial part of the MM to reduce the MM posteromedial extrusion.

DOI： 10.1007/s00590-019-02513-4

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

The case of an individual with a bilateral anterior cruciate ligament (ACL) tear combined with a medial meniscus (MM) posterior root tear is described. A 34-year-old Japanese man with bilateral ACL rupture that occurred > 10 years earlier was diagnosed with bilateral ACL tear combined with MM posterior root tear (MMPRT). We performed a transtibial pullout repair of the MMPRT with ACL reconstruction. The tibial tunnels for the MM posterior root repair and ACL reconstruction were created separately. Postoperatively, a good clinical outcome and meniscal healing were obtained. Our surgical technique may thus contribute to anatomical MM posterior root repair and ACL reconstruction.

DOI： 10.18926/AMO/57717

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

Clinical studies have demonstrated that transtibial pullout repair led to favorable midterm outcomes in patients with medial meniscus posterior root tears (MMPRTs) although medial meniscal extrusion (MME) continued to be present. It has been unclear whether these residual postoperative MMEs existed after the pullout repair or had progressed at the very short-term evaluation after surgery. We sought to determine which characteristics of patients with MMPRTs influence the incidence of postoperative MME. The cases of 23 patients whose date of injury was known were analyzed. All patients underwent MMPRT pullout fixation. Preoperative and 3-month postoperative magnetic resonance imaging (MRI) examinations were performed. MME was retrospectively assessed on the mid-coronal plane of MRI scans. The preoperative and postoperative MME values were 4.2±1.2 mm and 4.3±1.5 mm, respectively (p=0.559). Pullout repair surgery was performed significantly earlier after the MMPRT-specific injury in patients whose postoperative MME improved compared to the patients whose MME did not improve (p<0.001). Our findings demonstrated that an early transtibial pullout repair of an MMPRT was more effective in reducing MME than a late repair. Surgeons should not miss the optimal timing for the pullout repair of an MMPRT, considering the period from the injury and the preoperative MME.

DOI： 10.18926/AMO/57714

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

Medial meniscus posterior root tear causes rapid knee cartilage degradation by inducing posteromedial displacement of the medial meniscus. We evaluated medial meniscus posterior extrusion before and after pullout repair for medial meniscus posterior root tear using magnetic resonance images. Twenty-eight patients with symptomatic medial meniscus posterior root tear were included. The inclusion criteria were: acute (< 3 months) or chronic (≥3 months) medial meniscus posterior root tear after painful popping events. The exclusion criteria were: other meniscus and anterior cruciate ligament injuries. We measured medial meniscus posterior extrusion and medial meniscus anteroposterior interval at knee flexion angles of 10° and 90° preoperatively and at 3 months postoperatively. The posterior extrusion at 90° knee flexion decreased from 4.42±1.38 mm preoperatively to 3.09±1.06 mm (p<0.001) postoperatively, while at 10° knee flexion it was -4.17±1.63 mm preoperatively and -3.77±1.72mm postoperatively, showing no significant change. The anteroposterior interval at 10° knee flexion increased from 19.74±4.27 mm preoperatively to 22.15±5.10 mm postoperatively (p<0.001); at 90° knee flexion, it increased from 16.81±4.51 mm preoperatively to 19.20±4.30 mm postoperatively (p<0.001). Medial meniscus posterior extrusion and movement decreased after pullout repair. Pullout repair for medial meniscus posterior root tear improves medial meniscus posterior extrusion, especially at 90° knee flexion.

DOI： 10.18926/AMO/57713

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

BACKGROUND: Several studies have demonstrated that posttraumatic knee osteoarthritis progresses even after anterior cruciate ligament reconstruction. Few reports described zone-specific cartilaginous damages after anterior cruciate ligament reconstruction. This study aimed to compare the status of articular cartilage at anterior cruciate ligament reconstruction with that at second-look arthroscopy. METHODS: This study included 20 patients (20 knees, 10 males and 10 females, mean age 22.4 years, Body mass index 24.4 kg/m2) that underwent arthroscopic anatomic double-bundle anterior cruciate ligament reconstruction and second-look arthroscopy. Mean periods from injury to reconstruction and from reconstruction to second-look arthroscopy were 3.4 and 15.3 months, respectively. Cartilage lesions were evaluated arthroscopically in the 6 articular surfaces and 40 articular subcompartments independently, and these features were graded with the International Cartilage Repair Society articular cartilage injury classification; comparisons were made between the grades at reconstruction and at second-look arthroscopy. Furthermore, clinical outcomes were assessed at reconstruction and at second-look arthroscopy, using the Lysholm knee score, Tegner activity scale, International Knee Documentation Committee score, Knee injury and Osteoarthritis Outcome Score, side-to-side difference of the KT-2000 arthrometer, and pivot shift test. RESULTS: Each compartment showed a deteriorated condition at second-look arthroscopy compared with the pre-reconstruction period. A significant worsening of the articular cartilage was noted in all compartments except the lateral tibial plateau and was also observed in the central region of the medial femoral condyle and trochlea after reconstruction. However, each clinical outcome was significantly improved postoperatively. CONCLUSIONS: Good cartilage conditions were restored in most subcompartments at second-look arthroscopy. Furthermore, posttraumatic osteoarthritic changes in the patellofemoral and medial compartments progressed even in the early postoperative period, although good knee stability and clinical outcomes were obtained. Care is necessary regarding the progression of osteoarthritis and the appearance of knee symptoms in patients undergoing anterior cruciate ligament reconstruction.

DOI： 10.1016/j.jos.2019.08.001

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

PURPOSE: Posterior root repair of the medial meniscus (MM) can prevent rapid progression of knee osteoarthritis in patients with a MM posterior root tear (MMPRT). The anatomic reattachment of the MM posterior root is considered to be critical in a transtibial pullout repair. However, tibial tunnel creation at the anatomic attachment is technically difficult. We hypothesized that a newly developed point-contact aiming guide [Unicorn Meniscal Root (UMR) guide] can create the tibial tunnel at a better position rather than a previously designed MMPRT guide. The aim of this study was to compare the position of the created tibial tunnel between the two meniscal root repair guides. MATERIALS AND METHODS: Thirty-eight patients underwent transtibial pullout repairs. Tibial tunnel creation was performed using the UMR guide (19 cases) or MMPRT guide (19 cases). Three-dimensional computed tomography images of the tibial surface were evaluated using the Tsukada's measurement method postoperatively. The expected anatomic center of the MM posterior root attachment was defined as the center of three tangential lines referring to three anatomic bony landmarks (anterior border of the posterior cruciate ligament, lateral margin of the medial tibial plateau, and retro-eminence ridge). The expected anatomic center and tibial tunnel center were evaluated using the percentage-based posterolateral location on the tibial surface. The distance between the anatomic center and tunnel center was calculated. RESULTS: The anatomic center of the MM posterior root footprint was located at a position of 79.2% posterior and 39.5% lateral. The mean of the tunnel center in the UMR guide was similar to that in the MMPRT guide (posterior direction, P = 0.096; lateral direction, P = 0.280). The mean distances between the tunnel center and the anatomic center were 4.06 and 3.99 mm in the UMR and MMPRT guide group, respectively (P = 0.455). CONCLUSIONS: The UMR guide, as well as the MMPRT guide, is a useful device to create favorable tibial tunnels at the MM posterior root attachment for pullout repairs in patients with MMPRTs. LEVEL OF EVIDENCE: IV.

DOI： 10.1186/s43019-019-0007-1

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

Anterior cruciate ligament (ACL) reconstruction (ACLR) after ACL rupture improves the instability of the knee joint and decreases mechanical stress to the meniscus and articular cartilage. However, there are reports that post-traumatic osteoarthritis (PTOA) is observed over time following ACLR. In this study, we assessed changes in cartilage lesions by arthroscopic findings following anatomical double-bundle ACLR and at post-operative second-look arthroscopy about 14 months later. We retrospectively evaluated 37 knees in cases with patients <40 years of age who had undergone an anatomical double-bundle ACL reconstruction <1 year after ACL rupture injury from March 2012 to December 2016. Clinical results and arthroscopic cartilage/meniscal lesion were evaluated and compared between a cartilage lesion-detected group and intact-cartilage group. Surgery improved anteroposterior laxity and other clinical measures; however, cartilage lesions were detected at 11 sites during ACLR and at 54 sites at second-look arthroscopy. The periods from injury to second-look arthroscopy and from ACLR to second-look arthroscopy were significantly longer in the cartilage-lesion group (n=23) than in the intact-cartilage group (n=14). Conversely, 96% of meniscal damage observed during ACLR was cured at the time of second-look arthroscopy. Knee articular cartilage lesions after ACL rupture cannot be completely suppressed, even using the anatomical ACL reconstruction technique. This study suggested that articular cartilage lesions can progress to a level that can be confirmed arthroscopically at approximately 17 months after ACL injury. Therefore, in ACLR patients, the possibility of developing knee articular cartilage lesions and PTOA should be considered.

DOI： 10.18926/AMO/56864

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Elsevier  

Background: A complete discoid lateral meniscus (DLM) has a high risk of horizontal tear. However, cellular phenotypes and extracellular matrix organizations in complete DLMs are still unclear. The aim of this study was to investigate histological and cellular biological characteristics in both the intercondylar and central regions of complete DLM. Materials and methods: Meniscal samples were obtained from the intercondylar and central regions of complete DLM (n = 6). Blood vessels and aggregated cell ratio were measured in each region. Depositions of type I/II collagens and safranin O-stained proteoglycans in the extracellular matrix were assessed. Experiments in gene expression, morphology, proliferation, and effect of mechanical stretch were performed using cultured cells derived from each region. Results: Blood vessel counts were significantly higher in the intercondylar region than in the central region. The ratio of aggregated cells was lower in the intercondylar region than in the central region. Deposition of type I collagen was comparable for both regions. The central region contained a larger quantity of type II collagen and safranin O staining density compared with the intercondylar region. Proliferation of the fibroblastic intercondylar cells was not affected by 5%-stretching. However, stretching treatments decreased relative proliferation of the chondrocytic central cells. Conclusions: This study demonstrated that the central region of complete DLM had different cellular properties and collagen components compared with the intercondylar region. Our results suggest that the central region of complete DLM may have a low healing potential like the inner avascular region of the meniscus.

DOI： 10.1016/j.jos.2018.05.006

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