Medial Meniscus Posterior Root Tear Research Articles

Is it possible to use stress radiographs as a tool to diagnose medial meniscus posterior root tears?

Aim:Medial meniscus posterior root tear (MMPRT) causes meniscal extrusion, loss of meniscus function, arthritic changes. Clinical history, physical examination and magnetic resonance imaging (MRI) findings are useful for the diagnosis of MMPRT. The aim of this study is to evaluate the utility of stress X-rays in the diagnosis of MMPRT.Methods:Twenty patients who had undergone high tibial osteotomy between March 2015 and May 2016 and whose preoperative bilateral varus and valgus stress x-rays (Telos device) along with weight bearing x-rays were available were included. These patients were grouped into two according to integrity of posterior roots of their medial menisci; there were ten patients both in the study and control groups. Lateral joint space width (LJW) on varus stress x-rays, medial joint space width (MJW) on valgus stress x-rays as well as LJW and MJW on weight bearing x-rays were measured bilaterally. Intragroup comparisons of joint space widths between index and opposite knees were performed. Differences of MJW and LJW between index and opposite knees were calculated. Differences of joint space widths between stress x-rays and weight bearing x-rays were also calculated. The changes in joint space widths between the two groups were compared. Statistical analyses were performed utilizing SPSS 18.0. Significance level was set at 0.05.Results:In MMPRT group, opening of LJ space of index knees under varus stress was greater than that of opposite knees (Index: (mean±SD) 10,27±1,17 mm, opposite: 8,61±1,37 mm; p<0,0001). In the control group the difference was not significant (Index: 9,29±2,55 mm, opposite: 9,68±1,44 mm; p=0,566). The difference in the opening of LJW (under varus stress) between index and opposite knees was significantly greater in the study group (p=0,013). The difference between LJW under weight-bearing and varus stress conditions was significantly greater in the study group. (Study: 3,64±0.217 mm, control:2,28±0,182 mm, p=0.018).Conclusions:The findings of this study showed that in patients who had MMPRTs, an increased opening in the LJW was observed under varus stress conditions. This may be relevant with the fact that when varus stress is applied, meniscal extrusion is increased in case of a MMPRT. Stress x-rays could be a useful tool in the diagnosis of MMPRTs. Further studies are needed to determine the sensitivity and specificity of this diagnostic tool.

Meniscus morphology: Does tear type matter? A narrative review with focus on relevance for osteoarthritis research

To give a narrative overview of meniscal tears with a radiologic emphasis on the morphologic type, technical considerations, and on the relevance of the type of meniscal tear in the context of osteoarthritis (OA) research. Total 20 years of the PubMed database were searched for epidemiological, radiological, arthroscopic and biomechanical reports, and review articles focusing on meniscal tears in middle-aged and older individuals, in the setting of OA. Case reports, publications on meniscal tears in young active individuals, and publications not in English were excluded. Meniscal intra-substance signal abnormalities are associated with an increased risk of a degenerative meniscal tear in the same segment. Posterior radial tears of the medial meniscus appear to be a highly relevant event in OA of the knee, with associated cartilage loss and meniscal extrusion. Radial tears are more commonly missed on MRI than other types, and should be carefully looked for on coronal and axial images. While medial meniscus posterior root tears are of "radial" morphology, there is growing interest in looking at them as a separate entity, mainly because they require a different therapeutic approach. There is a lack of data on the relevance of different morphologic types of meniscal tears to the natural history of knee OA, both cross-sectionally and-especially-longitudinally. Further epidemiologic studies should focus on specific meniscal tears based on their morphology to better understand their relevance in the genesis and progression of knee OA.

Lésion de la racine postérieure du ménisque médial : réparation transtibiale par le système FasT-Fix®

A medial meniscus posterior root tear (MMPRT) may increase the tibiofemoral contact pressure by decreasing the tibiofemoral contact area. Meniscal dysfunction induced by posterior root injury may lead to the development of osteoarthritic knees. Repair of a MMPRT can restore medial meniscus function and prevent knee osteoarthritis progression. Several surgical procedures have been reported for treating a MMPRT. However, these procedures are associated with several technical difficulties. Here, we describe a technique to stabilize a torn MM posterior root using the FasT-Fix® all-inside meniscal suture device and a new aiming device. The uncut free-end of the FasT-Fix® suture can be used as a thread for transtibial pullout repair. Our procedure might help overcome the technical difficulties in arthroscopic treatment of a MMPRT.

Non-operative management of medial meniscus posterior horn root tears is associated with worsening arthritis and poor clinical outcome at 5-year follow-up

Medial meniscus posterior root tears (MMPRTs) are a significant source of pain and dysfunction, but little is known about the natural history and outcome and for non-operative management of these lesions. The purpose of this study was to evaluate (1) the mid-term clinical and radiographic outcomes of non-operative treatment of MMPRTs and (2) risk factors for worse outcomes. A retrospective review was performed for patients with symptomatic, unrepaired MMPRTs and a minimum 2-year follow-up for IKDC and Tegner outcome scores. Baseline and final radiographs were reviewed and graded according to Kellgren-Lawrence scores. Baseline MRIs were reviewed for the presence of meniscal extrusion, subchondral oedema, and insufficiency fractures. Failure was defined as conversion to arthroplasty or severely abnormal patient subjective IKDC score. Fifty-two patients (21M:31F) with a mean age of 58±10years were diagnosed with symptomatic MMPRTs clinically and confirmed by MRI and followed for a mean of 62±30months. Sixteen patients (31%) underwent total knee arthroplasty at a mean of 30±32months after diagnosis with higher Kellgren-Lawrence grades associated with increased rates of arthroplasty (p=0.01). Mean IKDC scores for the remaining patients were 61.2±21 with significantly lower scores in females compared to males (75±12 vs. 49±20; p=0.03). Mean Kellgren-Lawrence grades and rates of arthritis progressed over time on radiographs (1.5±0.7 vs. 2.4±1.0; p<0.001 and 78% vs. 51%; p=0.01). Overall, 87% of patients failed non-operative treatment. Non-operative treatment of medial meniscus posterior horn root tears is associated with poor clinical outcome, worsening arthritis, and a relatively high rate of arthroplasty at 5-year follow-up. Female gender was associated with lower subjective scores and higher rate of arthroplasty. The current study provides a natural history benchmark for clinical outcomes that can be expected in patients with medial meniscus posterior horn root tears undergoing non-operative treatment and helps in counselling patients with these types of injuries. IV.

Pullout Fixation of Posterior Medial Meniscus Root Tears: Correlation Between Meniscus Extrusion and Midterm Clinical Results

Background: Medial meniscus posterior root tears (MMPRTs) lead to extrusion of the meniscus during weightbearing as well as loss of the ability of the meniscus to generate hoop stress. This loss of load-sharing ability leads to progressive arthritic changes. However, there have been no studies that correlate the correction of meniscus extrusion with clinical outcomes. Hypothesis: Decreased meniscus extrusion is associated with better clinical and radiographic outcomes compared with increased meniscus extrusion after MMPRT pullout fixation. Study Design: Case-control study; Level of evidence, 3. Methods: A total of 39 patients who underwent MMPRT pullout fixation and had been observed for more than 5 years were recruited for this study. The mean follow-up period was 69.8 months. Participants were categorized into 2 groups according to the direction of meniscus extrusion: group A (increased extrusion; 23 patients) and group B (decreased extrusion; 16 patients). Meniscus extrusion was assessed in the coronal plane on magnetic resonance imaging preoperatively and at 1 year postoperatively. The postoperative clinical outcomes (Lysholm and International Knee Documentation Committee [IKDC] scores) and radiographic results (Kellgren-Lawrence [K-L] grade and medial joint space) were compared between groups. Results: Meniscus extrusion in group A increased significantly from a mean (±SD) of 3.5 ± 0.9 mm preoperatively to 5.1 ± 1.4 mm at 1 year postoperatively (P < .001), whereas in group B, it decreased significantly from 4.1 ± 1.3 mm preoperatively to 3.5 ± 1.4 mm at 1 year postoperatively (P < .001). The K-L arthritis grade (0/1/2/3/4) significantly progressed in group A (from 2/12/9/0/0 preoperatively to 0/1/14/8/0 postoperatively, respectively; P = .009) but not in group B (from 1/11/4/0/0 preoperatively to 0/6/8/2/0 postoperatively, respectively; P = .274). The mean final Lysholm and IKDC scores in group B (88.1 ± 12.1 and 79.0 ± 11.4, respectively) were significantly better than those in group A (81.0 ± 9.0 and 71.1 ± 7.8, respectively) (P < .05). There was less medial joint space narrowing at final follow-up in group B (0.6 ± 0.8 mm) than in group A (1.1 ± 0.6 mm) (P = .015). Progression of the K-L arthritis grade was seen in 50% (8/16) of the patients in group B compared with 87% (20/23) of the patients in group A (P = .027). Conclusion: The current study demonstrates that in patients with MMPRTs, pullout fixation leads to favorable midterm outcomes, regardless of meniscus extrusion at 1-year follow-up. However, patients with decreased meniscus extrusion at postoperative 1 year have more favorable clinical scores and radiographic findings at midterm follow-up than those with increased extrusion at 1 year. This study indicates that one of the main goals of the repair of MMPRTs is to reduce meniscus extrusion as much as possible.

Does Release of the Superficial Medial Collateral Ligament Result in Clinically Harmful Effects After the Fixation of Medial Meniscus Posterior Root Tears?

To investigate pain and tenderness, stress testing, clinical outcome scores, complications, and operation time at 24months and magnetic resonance imaging (MRI) analysis at 12months after the release of the distal attachment of thesuperficial medial collateral ligament (sMCL) during medial meniscus posterior root tear (MMPRT) fixation. Patients who received MMPRT fixation with a follow-up of at least 2years were included. During fixation, the release of the distal attachment of the sMCL on the proximal tibia was performed to improve visualization and provide sufficient working space. Pain and tenderness at the released area, manual valgus stress tests of 30° and 0° flexion (grade 0/1/2/3), and subjective instability during weight bearing were evaluated serially at postoperative 3, 6, 12, and 24+ months. The contour of detachment area was assessed using MRI 12months postoperatively. As a subgroup analysis, tourniquet time (minutes) and final clinical scores were compared between release and nonrelease groups. The numbers of participants in the release and nonrelease groups were 118 and 20 patients, and their mean follow-up durations were 42.4 ± 19.3 (24-95) and 37.2 ± 7.8 (30-55) months, respectively. In the release group, percentages of patients with pain and tenderness at 3months were 15% and 18%, respectively; however, no patients had symptoms at 12months. In valgus stress tests (30°, 0°), 12% and 2% of patients showed grade 1 laxity at 3months, and 7% had grade 1 laxity in only 30° flexion at the final follow-up. However, no patients had subjective valgus laxity. An intact contour was confirmed in all cases among 94 patients checked by performing follow-up MRI. Tourniquet time was significantly shorter in the release group (42.4 ± 19.3) than in the nonrelease group (58.5 ± 9.5; P < .001). Between release and nonrelease groups, Lysholm (84.4 ± 12.1, 88.1 ± 12.8; P = .117) and International Knee Documentation Committee scores (73.6 ± 11.2, 77.5 ± 11.9; P = .112) did not differ. The release of the distal attachment of the sMCL during fixation of MMPRT did not result in pain and tenderness, residual instability, and complication. An intact contour of the sMCL was confirmed in all cases with MRI. This procedure reduced operation time and showed similar clinical results when compared between the release and nonrelease groups. However, this study had low power to detect the difference for clinical scores between the 2 groups. Level IV, therapeutic case series.

Pullout repair of a medial meniscus posterior root tear using a FasT-Fix® all-inside suture technique

A medial meniscus posterior root tear (MMPRT) may increase the tibiofemoral contact pressure by decreasing the tibiofemoral contact area. Meniscal dysfunction induced by posterior root injury may lead to the development of osteoarthritic knees. Repair of a MMPRT can restore medial meniscus (MM) function and prevent knee osteoarthritis progression. Several surgical procedures have been reported for treating a MMPRT. However, these procedures are associated with several technical difficulties. Here, we describe a technique to stabilize a torn MM posterior root using the FasT-Fix® all-inside meniscal suture device and a new aiming device. The uncut free-end of the FasT-Fix® suture can be used as a thread for transtibial pullout repair. Our procedure might help overcome the technical difficulties in arthroscopic treatment of a MMPRT.

Clinical Outcomes of Medial Meniscus Posterior Root Tears

Objectives:Medial meniscus posterior root tears (MMPRTs) present a unique challenge for both patients and surgeons as these tears have shown to be biomechanically equivalent to complete meniscectomy. However, little is known about the natural history of these lesions. Therefore, the purpose of this study is to describe the clinical course of MMPRTs with respect to subsequent operative and non-operative treatments, and associated comorbidities.Methods:Over 2600 MRIs were identified by searching radiologist reads for the terms “root” or “root tear” from 2005-2013. Presence or absence of MMPRTs and other associated boney, meniscal, or ligamentous injuries were identified and recorded. Of these MRIs, 102 MRIs from 102 patients who had unrepaired MMPRTs with minimum 2-year follow-up and no prior ligamentous surgery were followed. These MRIs were evaluated to confirm the presence of a meniscal root tear and the presence or absence of associated meniscal or ligamentous injuries, as well as meniscal extrusion, subchondral edema, or insufficiency fractures. Chart review was performed to obtain the treatment summary after diagnosis. Radiographs from before and after the diagnosis of MMPRT were reviewed and Kellgren-Lawrence scores were determined. Finally, the association between concomitant boney, ligamentous, or meniscal injuries, patient factors, and rate of arthroplasty, as well as final Kellgren-Lawrence scores were evaluated. Chi-square analysis was used for categorical variables, and Wilcoxon Rank-Sums was used for continuous variables. Kaplan-Meier analysis was used to evaluate the effect of meniscal extrusion on the time-dependant rate of arthroplasty.Results:104 patients (43 M:61F) were diagnosed with MMPRTs at a mean age of 54±13. These patients were followed for a mean of 66±26 months. 75 (74%) patients had associated meniscal extrusion, 64 (62%) had associated subchondral edema, and 14 (13%) had associated insufficiency fractures at the time of diagnosis. After initial diagnosis, 59 (58%) underwent subsequent surgical treatment. This included 52 (51%) patients undergoing arthroscopic partial meniscectomy, and 29 (28%) patients undergoing total knee arthroplasty at a mean 38±32 (range 3-107) months after MRI. Kellgren-Lawrence grades worsened from 1.3±0.7 before diagnosis to 2.2±1.0 after (p<0.001), with a mean 44±32 months between radiographs. There was a higher rate of radiographic arthritis (K-L grade 2+) after diagnosis (73%) than before diagnosis (36%) (p<0.001). The presence of meniscal extrusion on MRI was associated with the presence of arthritis on post-diagnosis radiographs (p=0.03). Meniscal extrusion, subchondral edema, and insufficiency fractures were not associated with increased rates of surgical treatment, or time to arthroplasty.Conclusion:Little information is available to guide patients and physicians on the clinical outcomes for MMPRTs. These injuries are associated with a relatively high rate of arthroplasty and worsening arthritis, especially with concomitant meniscal extrusion. More information is needed to determine the efficacy of meniscal root repair in preventing these unfavorable outcomes.

Prognostic Factors in the Midterm Results of Pullout Fixation for Posterior Root Tears of the Medial Meniscus

To identify predictors of unfavorable clinical and radiologic outcomes a minimum of 5years after pullout fixation for medial meniscus posterior root tears (MMPRTs). In total, 40 patients who were followed for >5years after pullout fixation in MMPRT were recruited. The mean follow-up duration was 71.1months. Clinical outcomes, including Lysholm score and International Knee Documentation Committee (IKDC) score, and radiographic results, including Kellgren-Lawrence (K-L; 0/1/2/3/4) grade and medial joint space width, were evaluated preoperatively and at final follow-up. Preoperative prognostic factors, including age, sex, body mass index, degree of varus alignment, K-L grade, medial joint space width, meniscal extrusion, and cartilage status, by the modified Outerbridge classification (grades 1 or 2 v 3 or 4), for relatively unfavorable (fair or poor grade) Lysholm or IKDC score, and progression of K-L grade were investigated by multivariate logistic regression analysis. The mean Lysholm score (52.1 ± 8.8 to 83.8 ± 11.9) and IKDC score (40.1 ± 7.6 to 73.3 ± 10.9) were improved significantly (P < .001), although the loss of medial joint space width (4.8 ± 1.1 to 3.9 ± 1.1mm) and K-L grade (6/25/9/0/0 to 0/11/20/9/0) progressed significantly (P < .001). Unfavorable prognostic factors of the Lysholm score were grade ≥3 chondral lesions (odds ratio [OR]= 5.993; P= .028) and varus mechanical alignment (OR= 1.644; P= .017), for IKDC score were grade ≥3 chondral lesions (OR= 11.146; P= .038) and older age (OR= 1.200; P= .017). Preoperative chondral lesion grade ≥3 increased the risk of K-L grade progression (OR= 11.000; P= .031). Clinically, modified Outerbridge classification grade ≥3 chondral lesions, varus alignment, and older age were found to predict a poor prognosis after MMPRT fixation. In terms of radiographic K-L grade progression, grade ≥3 chondral lesions were identified as a poor prognostic factor. Level IV, case series.

Arthroscopic Medial Meniscus Posterior Root Fixation Using a Modified Mason-Allen Stitch

A complete radial tear of the meniscus posterior root, which can effectively cause a state of total meniscectomy via loss of hoop tension, requires that the torn root be repaired. Several methods have been used to repair medial meniscus posterior root tears, most of which are based on a simple stitch technique that is known to have stitch-holding strength. We applied a modified version of the Mason-Allen stitch technique, which is recognized as a method for rotator cuff repair surgery because its locking effect overcomes the potential weakness of simple stitches. This article introduces the medial meniscus posterior root tears repair procedure based on a modified Mason-Allen stitch technique in which 2 strands (i.e., 1 simple horizontal and 1 simple vertical stitch) are used.

A meta-analysis of clinical and radiographic outcomes of posterior horn medial meniscus root repairs.

Although interest in medial meniscus posterior root tear (MMPRT) repair has increased, few case series have been reported. This meta-analysis aimed to examine the clinical and radiological effects of MMPRT repair by pooling pre- and post-operative data from case-series reports. A literature search was performed using MEDLINE/PubMed, the Cochrane Central Register of Controlled Trials, and EMBASE databases. Pre- and post-operative data were pooled to investigate the effects of MMPRT repair, including the Lysholm score improvement, meniscal extrusion (mm) reduction, progression of the Kellgren-Lawrence (K-L) grade, and cartilage status according to the Outerbridge classification. Treatment effects included paired standardized mean differences (difference in the pre- and post-operative mean outcomes divided by the standard deviation) for the Lysholm score and meniscal extrusion, as well as the pooled event rates of progression of K-L grade and cartilage status. As treatment effects, the Lysholm score increased by as much as 3.675 (P<0.001), whereas meniscus extrusion was not reduced (n.s.). The overall pooled event rates of progression of K-L grade and cartilage status were 10.6 and 17.3% (P<0.001), respectively. According to the current literature, MMPRT repair resulted in significant improvements in the post-operative clinical subjective scores compared with the preoperative status. However, meniscus extrusion was not reduced. Considering the occurrence of progression of K-L grade and cartilage status, it did not prevent the progression of arthrosis completely. Based on these results, repair results in favourable outcomes for MMPRT. Meta-analysis, Level IV.

The Degeneration of Meniscus Roots Is Accompanied by Fibrocartilage Formation, Which May Precede Meniscus Root Tears in Osteoarthritic Knees

Background: Fibrocartilage metaplasia in tendons and ligaments is an adaptation to compression as well as a pathological feature during degeneration. Medial meniscus posterior roots are unique ligaments that resist multidirectional forces, including compression. Purpose: To characterize the degeneration of medial meniscus posterior root tears in osteoarthritic knees, with an emphasis on fibrocartilage and calcification. Study Design: Cross-sectional study; Level of evidence, 3. Methods: Samples of medial meniscus posterior roots were harvested from cadaveric specimens and patients during knee replacement surgery and grouped as follows: normal reference, no tear, partial tear, and complete tear. Degeneration was analyzed with histology, immunohistochemistry, and real-time polymerase chain reaction. Uniaxial tensile tests were performed on specimens with and without fibrocartilage. Quantifiable data were statistically analyzed by the Kruskal-Wallis test with the Dunn comparison test. Results: Thirty, 28, and 42 samples harvested from 99 patients were allocated into the no tear, partial tear, and complete tear groups, respectively. Mean modified Bonar tendinopathy scores for each group were 3.97, 9.31, and 14.15, respectively, showing a higher degree of degeneration associated with the extent of the tear (P < .05 for all groups). The characterization of root matrices revealed an increase in fibrocartilage according to the extent of the tear. Tear margins revealed fibrocartilage in 59.3% of partial tear samples and 76.2% of complete tear samples, with a distinctive cleavage-like shape. Root tears with a similar shape were induced within fibrocartilaginous areas during uniaxial tensile testing. Even in the no tear group, 56.7% of samples showed fibrocartilage in the anterior margin of the root, adjacent to the meniscus. An increased stained area of calcification and expression of the ectonucleotide pyrophosphatase/phosphodiesterase 1 gene were observed in the complete tear group compared with the no tear group (P < .0001 and P = .24, respectively). Conclusion: Fibrocartilage and calcification increased in medial meniscus posterior roots, associated with the degree of the tear. Both findings, which impair the ligament’s resistance to tension, may play a pivotal role during the pathogenesis of degenerative meniscus root tears in osteoarthritic knees. Fibrocartilage and calcification may be useful as diagnostic markers as well as markers of degeneration, which may aid in determining the treatment modality in meniscus root tears. The presence of fibrocartilage in intact roots may suggest an impending tear in osteoarthritic knees.

Larger medial femoral to tibial condylar dimension may trigger posterior root tear of medial meniscus.

The major meniscal functions are load bearing, load distribution, and shock absorption by increasing the tibiofemoral joint (TFJ) contact area and dissipating axial loads by conversion into hoop stresses. The increased hoop strain stretches the meniscus in outward direction towards radius, causing extrusion, which is associated with the root tear and resultant degenerative osteoarthritis. Since the larger contact area of medial TFJ may increase the hoop stresses, we hypothesized that the larger medial femoral to tibial condylar dimension would contribute to the development of medial meniscus posterior root tear (MMPRT). Thus, the purpose of the study was to assess the relationship between MMPRT and medial femoral to tibial condylar dimension. A case-control study was conducted to compare medial femoral to tibial condylar dimensions of patients with complete MMPRT (n=59) with those of demography-matched controls (n=59) during the period from 2010 to 2013. In each patient, MRIs were reviewed and several parameters were measured including articulation width of medial femoral condyle (MFC) at 0°, 30°, 60°, and 90°, medial tibial condyle (MTC) width, degree of meniscal extrusion, and medial femoral to tibial condylar width ratio (MFC/MTC) at 0°, 30°, 60°, and 90°, respectively. Demographic and radiographic data were assessed. A larger medial femoral to tibial condylar dimension was associated with MMPRT at 0° and 30° knee angles. Patients with MFC/MTC greater than 0.9 at 0° also showed about 2.5-fold increase in the chance of MMPRT. Those with meniscal extrusion greater than 3mm also had about 17.1 times greater chance for the presence of MMPRT accordingly. A larger medial femoral to tibial condylar dimension may be considered as one of the regional contributors to the outbreak of MMPRT, and medial femoral to tibial condylar width ratio greater than 0.9 at 0° knee angle may be considered as a significant risk factor for MMPRT. III.

Comparison of Clinical and Radiologic Results Between Partial Meniscectomy and Refixation of Medial Meniscus Posterior Root Tears: A Minimum 5-Year Follow-up

To compare the clinical and radiologic results of partial meniscectomy with those of refixation in patients with medial meniscus posterior root tears (MMPRTs) at a minimum 5-year follow-up. Between 2005 and 2009, patients with MMPRTs who had been followed up for at least 5 years after a partial meniscectomy (group M, n= 20) or pullout repair (group R, n= 37) were recruited. The mean follow-up duration was 67.5 months in group M and 72.0 months in group R. Clinical assessments, including the Lysholm score and International Knee Documentation Committee (IKDC) Subjective Knee Form score, and radiographic assessments, including the Kellgren-Lawrence (K-L) grade and medial joint space width, were evaluated preoperatively and at final follow-up. We compared the preoperative results with the final results in each group, and we compared the final results of groups M and R. Five-year survival rates were also evaluated. The mean Lysholm score (P= .039) and IKDC score (P= .037) improved significantly. However, the width of the medial joint space (P < .001) and K-L grade (P < .001) worsened significantly in both groups. When we compared the final results, group R had significantly better Lysholm scores (P= .002) and IKDC scores (P<.001) than group M. Group R showed less K-L grade progression (P= .005) and less medial joint space narrowing (P<.001) than group M. The rate of conversion to total knee arthroplasty was 35% in group M, whereas there was no conversion to total knee arthroplasty in group R. The 5-year survival rates in groups M and R were 75% and 100%, respectively (P < .001). For MMPRTs, refixation was more effective than partial meniscectomy in terms of the clinical and radiologic outcomes and survival for at least 5 years' follow-up. Refixation slowed the progression of arthritic changes compared with partial meniscectomy, although it did not prevent the progression of arthrosis completely. Level III, retrospective comparative study.

The value of MR in diagnosis of posterior root tear of the medial and lateral meniscus

Objective To determine the value of MR in the diagnosis of the medial and lateral meniscal posterior root tears.Methods One hundred and twenty one patients underwent arthroscopy and MR of knee examinations were retrospectively reviewed,and all of them did not have the history of knee surgery before the MR examination.MR images were double-blinded,independently,retrospectively scored by radiology residency (doctor 1) and attending radiologist (doctor 2).The likelihood of the meniscus posterior root tear was scored on basis of arthroscopic findings constituted the gold standard.Sensitivity,specificity and accuracy of MR diagnosis of the lateral and medial meniscus posterior root tear by two physicians were calculated,and the consistency of diagnosis results by two physicians was evaluated using the Kappa statistics.Reasons leading to misdiagnosis or missed diagnosis were discussed.Results Thirty three of the 121 patients were diagnosed with meniscus posterior root tears by arthroscopy,including 14 cases of lateral tears and 19 cases of medial tears.The sensitivity,specificity and accuracy in the diagnosis of posterior lateral meniscus root tears (PLMRT) for doctor 1 were 71.4％ (10/14),82.2％ (88/107) and 81.0％ (98/121),respectively,and for doctor 2 were 71.4％ (10/14),86.0％ (92/107) and 84.3％ (102/121).The sensitivity,specificity and accuracy in the diagnosis of posterior medial meniscus root tears (PMMRT) for doctor 1 were 100.0％ (19/19),88.2％ (90/102) and 90.1％ (109/121),respectively,and for doctor 2 were 100.0％ (19/19),95.1％ (97/102) and 95.9％ (116/121),respectively.The Kappa statistics for PLMRT and PMMRT were 0.67 and 0.81,respectively,demonstrating a good interobserver agreement (P＜0.05).The misdiagnosed cases of the PMMRT were 12 for doctor 1 and 5 for doctor 2.There were 4 cases being commonly misdiagnosed by the two doctors,and there were no any missed cases in this study.For the PLMRT,the misdiagnosed cases were 19 for doctor 1 and 15 for doctor 2.Eleven cases were misdiagnosed and 4 were missed by the two physicians.Conclusion MR is a reliable diagnostic tool for detecting posterior root tears of the medial and lateral meniscus. Key words: Magnetic resonance imaging; Knee joint; Menisci; Tibial

Traumatic posterior root tear of the medial meniscus in patients with severe medial instability of the knee.

To examine the incidence and diagnostic rate of traumatic medial meniscus posterior root tear associated with severe medial instability and to evaluate the effectiveness of pullout repair. From 2007 to 2011, 51 patients who underwent operation due to multiple ligament injuries including medial collateral ligament rupture were reviewed retrospectively. The International Knee Documentation Committee (IKDC) subjective and Lysholm score were evaluated pre- and postoperatively. Postoperative magnetic resonance imaging (MRI) was performed, and if indicated, a second-look arthroscopic examination was conducted. Fourteen out of 51 patients were associated with severe medial instability. Seven patients were diagnosed with traumatic medial meniscus posterior root tear and underwent arthroscopic pullout repair. Five of them were missed at initial diagnosis using MRI. In seven patients, the mean Lysholm and IKDC subjective scores improved from 74.6±10.3 and 47.6±7.3 to 93.0±3.7 and 91.6±2.6, respectively. All showed complete healing of meniscus root on follow-up MRI and second-look arthroscopy. Medial meniscus posterior root tear may occur in severe medial instability from trauma. It is a common mistake that surgeons may not notice on the diagnosis of those injuries using MRI. Therefore, a high index of suspicion is required for the diagnosis of medial meniscus posterior root tear in this type of injuries. The traumatic medial meniscus posterior root tear could be healed successfully using arthroscopic pullout repair technique. The possibility of the medial meniscus posterior root tear should be considered in severe medial instability and arthroscopic pullout repair can be an effective option for treatment. Case series with no comparison group, Level IV.

Medial meniscus posterior root tear: a comprehensive review.

Damage to the medial meniscus root, for example by a complete radial tear, destroys the ability of the knee to withstand hoop strain, resulting in contact pressure increases and kinematic alterations. For these reasons, several techniques have been developed to repair the medial meniscus posterior root tear (MMPRT), many of which have shown complete healing of the repaired MMPRT. However, efforts to standardize or optimize the treatment for MMPRT are much needed. When planning a surgical intervention for an MMPRT, strict surgical indications regarding the effect of pullout strength on the refixed root, bony degenerative changes, mechanical alignment, and the Kellgren-Lawrence grade should be considered. Although there are several treatment options and controversies, the current trend is to repair the MMPRT using various techniques including suture anchors and pullout sutures if the patient meets the indications. However, there are still debates on the restoration of hoop tension and prevention of arthritis after repair and further biomechanical and clinical studies should be conducted in the future. The aim of this article was to review and summarize the recent literature regarding various diagnosis and treatment strategies of MMPRT, especially focusing on conflict issues including whether repair techniques can restore the main function of normal meniscus and which is the best suture technique to repair the MMPRT. The authors attempted to provide a comprehensive review of previous studies ranging from basic science to current surgical techniques.

Risk Factors for Medial Meniscus Posterior Root Tear

Background: Medial meniscus posterior root tears (MMPRT) have a different clinical effect from other types of meniscal tears. These tears are very common among Asian people and may be related to the frequent use of postures such as the lotus position or squatting. Purpose: The present study was designed to identify the risk factors for MMPRT among an Asian sample. Study Design: Cohort study; Level of evidence, 3. Methods: An observational study was performed of 476 consecutive patients undergoing an arthroscopic procedure on their medial meniscus from January 2010 to December 2010. One hundred four patients had MMPRT (group 1), and the other patients had other types of medial meniscal tears (group 2). Demographic characteristics (age, sex, body mass index [BMI]), radiographic features (mechanical axis angle, tibia vara angle, tibial slope angle, Kellgren-Lawrence grade [KLG]), and environmental factors (occupation, trauma history, sports activity level, table use or not, bed use or not—variables that are representative of the oriental lifestyle of lotus position and squatting) were surveyed. We assessed the relation of these risk factors to the type of meniscal tear (group 1 or 2). Results: In group 1, there were 7 male and 97 female patients, with an average age of 58.2 years (range, 39-78 years) and BMI of 26.7 ± 3.4 kg/m2. In group 2, there were 136 male and 236 female patients (P < .01 compared with group 1), with an average age of 54.3 years (range, 17-77 years; P < .01) and a BMI of 24.9 ± 3.1 kg/m2 (P < .01). With regard to radiographic features, the mechanical axis angle demonstrated a significantly increased varus alignment in group 1 (4.5° ± 3.4°) compared with group 2 (2.4° ± 2.7°; P < .01), and the KLG was 1.4 ± 0.8 in group 1 and 0.9 ± 0.6 in group 2 (P < .01). Environmental factors showed no differences in occupation, table use or not, and bed use or not, except sports activity level. There were 41 patients (42.7%) in group 1 and 77 patients (20.6%) in group 2 who did not participate in any recreational activity (P < .01). Multiple logistic regression analysis showed that female sex was associated with a 5.9-fold increase in risk (95% confidence interval [CI], 2.138-16.575), a varus mechanical axis angle with a 3.3-fold increase (95% CI, 1.492-7.153), a BMI more than 30 kg/m2 with a 4.9-fold increase (95% CI, 1.160-20.955), and lower sports activity level with a 2.7-fold increase (95% CI, 1.011-7.163) for MMPRT. Conclusion: Persons with MMPRT had significantly increased age, female sex predominance, higher BMI, increased KLG, greater varus mechanical axis angle, and lower sports activity level compared with persons with other types of meniscal tear. After adjusting for other factors, sex, BMI, mechanical axis angle, and lower sports activity level remained strong determinants of MMPRT. Interestingly, oriental postural positions including the lotus position and squatting showed no contribution to increased risk of MMPRT. This suggests that intrinsic risk factors (similar to those that predispose to osteoarthritis) predispose to MMPRT.