Transtibial pullout repair of medial meniscus posterior root tear restores physiological rotation of the tibia in the knee-flexed position

Establishment of a Posttraumatic Osteoarthritis Model in Mice Induced by Noninvasive Anterior Cruciate Ligament Tear

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.

Editorial Commentary: Anatomic Morphologies of the Femur and Tibia and the Femorotibial Interactions Affect the Development of Medial Meniscus Posterior Root Tear

Medial meniscus posterior root tears (MMPRTs) occur frequently in middle-aged and older individuals. Female sex, increased body mass index, lower sports activity level, chondral lesions of the far posterior femoral condyles, anterior cruciate ligament degeneration, greater varus mechanical axis angle, steeper posterior slope of the medial tibial plateau, shallow concave shape of the medial tibial plateau, narrower intercondylar distance and notch width, bony spur formation, and medial meniscus posterior root impingement have been reported as significant risk factors for MMPRT development. Orthopaedic surgeons should recognize that the anatomic morphologies of the femur and tibia and the femorotibial interactions can affect the development of MMPRTs by increasing pathologic mechanical stresses on the medial meniscus posterior root.

Concomitant posterior anchoring further reduces posterior meniscal extrusion during pullout repair of medial meniscus posterior root tears: a retrospective study

PURPOSE

Transtibial pullout repair improves the clinical outcomes of medial meniscus (MM) posterior root tears (PRTs); however, reducing MM extrusion remains challenging. Thus, the purpose of this study was to examine the role of additional posterior anchoring (PA) during pullout repair in reducing the severity of MM extrusion compared to pullout repair alone.

METHODS

Patients who underwent pullout repair with two-cinch stitches (TCS) only or TCS combined with PA (TCS-PA)-deployment of an additional suture anchor in the posteromedial corner of MM-were included retrospectively. MM medial and posterior extrusion (MMME and MMPE), MM extrusion and remaining volume (MMEV and MMRV), and corresponding ratios were evaluated pre-operatively and three months post-operatively using a three-dimensional meniscal model at 10° and 90° of knee flexion and compared within and between groups.

RESULTS

A total of 15 and 16 patients treated with TCS and TCS-PA, respectively, were enrolled. At 90° knee flexion, both techniques significantly reduced MMPE (TCS: 4.2 ± 0.7 mm to 3.5 ± 0.6 mm, p < 0.05; TCS-PA: 3.7 ± 0.8 mm to 2.8 ± 0.7 mm, p < 0.05) at three months post-operatively. TCS-PA reduced MMPE more significantly than TCS alone (p < 0.05). Only TCS-PA significantly improved the MMEV and MMRV ratios (39.6 ± 8.9% to 28.1 ± 6.0%, p < 0.05 and 60.4 ± 8.9% to 71.9 ± 6.0%, p < 0.05, respectively). Significance was not found in all other comparisons.

CONCLUSIONS

Both techniques improved MMPE at knee flexion at the three month follow-up, with TCS-PA providing significantly superior results. Our findings support the evidence that the application of PA may be an effective surgical option for alleviating persistent MMPE.

Clinical outcomes of medial meniscus posterior root repair: A midterm follow-up study

BACKGROUND

Transtibial pullout repair of medial meniscus posterior root tears (MMPRTs) cannot prevent the progression of knee osteoarthritis. Conversions of knee arthroplasties are occasionally required following MMPRT repair. However, other knee-related surgical treatments following MMPRT repair are unclear. This study was aimed at investigating the midterm clinical outcomes and knee-related surgical events following MMPRT repair.

METHODS

Patients with MMPRT underwent pullout repair using FasT-Fix modified Mason-Allen (F-MMA) suturing with an all-inside meniscal repair device. Thirty-two patients with follow-up duration >2 years were enrolled. We assessed the clinical outcomes and postoperative surgical treatment of both knees.

RESULTS

F-MMA pullout repair improved all clinical evaluation scores in patients with MMPRT at a mean follow-up of 36.1 months. Postoperative arthroscopic debridement was required for one patient. An additional MMPRT repair was performed in one patient on second-look arthroscopy. None of the patients required ipsilateral knee arthroplasty. In the contralateral knees, one pullout repair of a newly developed MMPRT and two knee arthroplasties were performed.

CONCLUSIONS

This study demonstrated that F-MMA pullout repair yielded satisfactory clinical outcomes. However, subsequent knee-related surgeries were observed in 6.3% of the pullout-repaired knees and 9.4% of the contralateral knees. Our results suggest that surgeons should be aware of the worsening and/or occurrence of contralateral knee joint disease, even when the postoperative clinical outcomes are satisfactory following MMPRT repair.

LEVEL OF EVIDENCE

IV.

Arthroscopic Meniscal Healing following Medial Meniscus Posterior Root Repair: A Comparison between Two Suture Materials

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 < 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.

Medial meniscus posterior root repair influences sagittal length and coronal inclination of the anterior cruciate ligament: a retrospective study

PURPOSE

Medial meniscus (MM) posterior root tears (PRTs) lead to abnormal kinematic changes in the knee and may induce pathological external rotation of the tibia during knee flexion. This study aimed to investigate changes in the length and inclination of the anterior cruciate ligament (ACL) after MM posterior root repair using magnetic resonance imaging (MRI).

METHODS

This retrospective study included 44 patients who underwent MM posterior root repair between 2016 and 2019. Clinical outcomes were evaluated before and after surgery. MRI examinations were performed at 10°/90° of knee flexion preoperatively and 3 months postoperatively. The ACL length, proximal angle, and distal angle were determined using the sagittal view. MM extrusion and ACL inclination angle were determined using the coronal view.

RESULTS

Clinical outcomes significantly improved 1 year after surgery. The postoperative ACL length (29.7 ± 2.4 mm) and proximal angle (47.0 ± 7.4°) at 90° of knee flexion decreased relative to the preoperative values (31.5 ± 2.3 mm and 51.8 ± 8.7°, P < 0.01). The postoperative ACL inclination (64.9 ± 5.6°) at 10° of knee flexion decreased relative to the preoperative value (69.7 ± 5.6°, P < 0.01).

CONCLUSION

Pathologically-stretched linear ACL at 90° of knee flexion and a steep ACL inclination at 10° of knee flexion could be reduced after MM posterior root repair. This suggests that pullout repair could restore MM function as a secondary stabilizer, thereby preventing meniscal and cartilage degeneration.

Examining the Efficacy of Medial Meniscus Posterior Root Repair: A Meta-analysis and Systematic Review of Biomechanical and Clinical Outcomes

BACKGROUND

Medial meniscus posterior root (MMPR) injuries accelerate the progression of osteoarthritis. While partial meniscectomy was once considered the gold standard for treatment, meniscus root repair has become increasingly utilized with reported improvements in clinical and biomechanical outcomes.

PURPOSE

To perform a systematic review of biomechanical outcomes and a meta-analysis of clinical and radiographic outcomes after MMPR repair.

STUDY DESIGN

Meta-analysis and systematic review; Level of evidence, 4.

METHODS

The PubMed, Embase, and Cochrane databases were queried in August 2021 for studies reporting biomechanical, clinical, and radiographic outcomes after MMPR repair. Biomechanical studies were assessed for main results and conclusions. Data including study characteristics, cohort demographics, and outcomes were extracted. Included clinical studies were analyzed with a random-effects meta-analysis of proportions for binary outcomes or continuous outcomes for mean differences between preoperative and postoperative time points. Subgroup analysis for studies reporting repair outcomes with concomitant high tibial osteotomy (HTO) was performed where appropriate.

RESULTS

A total of 13 biomechanical studies were identified and reported an overall improvement in mean and peak contact pressures after MMPR repair. There were 24 clinical studies, consisting of 876 patients (877 knees), identified, with 3 studies (106 knees) reporting outcomes with concomitant HTO. The mean patient age was 57.1 years (range, 23-74 years), with a mean follow-up of 27.7 months (range, 2-64 months). Overall, clinical outcomes (Lysholm, Hospital for Special Surgery, International Knee Documentation Committee, visual analog scale for pain, Tegner, and Knee injury and Osteoarthritis Outcome Score scores) were noted to improve postoperatively compared with preoperatively, with improved Lysholm scores in patients undergoing concomitant HTO versus MMPR repair alone. Meniscal extrusion was not significantly improved after MMPR repair compared with preoperative measurements. The progression in Kellgren-Lawrence grades from grade 0 to grades 1 to 3 occurred in 5.9% (21/354) of patients after repair, with no patients progressing from grades 1 to 3 to grade 4.

CONCLUSION

MMPR repair generally improved biomechanical outcomes and led to improved patient-reported outcomes with greater improvements noted in patients undergoing concomitant HTO. Repair did not significantly improve meniscal extrusion, while only 5.9% of patients were noted to progress to low-grade osteoarthritis. The high level of heterogeneity in the included biomechanical and clinical investigations emphasizes the need for more well-designed studies that evaluate outcomes after MMPR repair.

Postoperative external tibial rotation is correlated with inferior meniscal healing following pullout repair of a medial meniscus posterior root tear

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.

Comparison of two simple stitches and modified Mason-Allen suture for medial meniscus posterior root tear based on the progression of meniscal posterior extrusion: A retrospective cohort study

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 < .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.

A posterior anchoring method decreases pullout suture translation of the medial meniscus posterior root repair during knee flexion

BACKGROUND

The medial meniscus (MM) translates posteriorly and extrudes severely from the medial tibial plateau (MTP) during knee flexion in the MM posterior root tear (PRT) knee. Transtibial pullout repair of the MMPRT has been performed to regulate MM extrusion. This study aimed to evaluate pullout suture translation during knee flexion before and after posterior anchoring during pullout repair. We hypothesized that suture translation after posterior anchoring would be significantly decreased relative to that before posterior anchoring.

METHODS

Thirty-five patients who underwent MM posterior root repair were prospectively investigated. Pullout repair was performed using two cinch sutures (outer and inner sutures) and posterior anchoring through the MM posterior horn and an additional bone tunnel on the MTP. The translation of the outer suture from 0° to 90° of knee flexion was measured and compared before and after posterior anchoring intraoperatively. The MM morphologic features were measured using preoperative magnetic resonance imaging, and the correlation between these values and outer suture translation was evaluated.

RESULTS

The average outer suture translation after posterior anchoring (1.6 ± 1.5 mm) was significantly decreased relative to that before posterior anchoring (2.5 ± 1.7 mm, P < 0.01). No significant correlations were observed between the MM morphological features and outer suture translation.

CONCLUSIONS

The posterior anchoring method with an MM posterior root repair is useful in decreasing posterior translation of the pullout suture during knee flexion, which might have an advantage in preventing suture pullout from the repaired MM, leading to good clinical outcomes.

High body mass index is a risk factor for unfavorable clinical outcomes after medial meniscus posterior root repair in well-aligned knees

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.

Does intermeniscal ligament tenodesis affect meniscal allograft extrusion? Retrospective comparative study at a minimum follow-up of 2 years

INTRODUCTION

Meniscal allograft transplantation (MAT) is indicated for the treatment of post-meniscectomy syndrome in young patients who do not have severe cartilage loss. While its clinical effectiveness is well established in the short- and mid-term, it does not appear to stop the progression of osteoarthritis. Meniscal extrusion often occurs early on and is irreversible. The aim of this study was to evaluate results of arthroscopic MAT combined with reconstruction of the intermeniscal ligament (IML).

HYPOTHESIS

Concurrent reconstruction of the IML decreases the incidence of early allograft extrusion when compared to conventional soft-tissue techniques.

MATERIALS AND METHODS

This was a retrospective single-centre comparative study of 55 patients operated between 2011 and 2018. The 34 patients who met the inclusion criteria were divided into two subgroups: the IML group (MAT with IML repair, n=14) and the non-IML group (MAT without IML repair, n=20). Clinical outcomes consisted of the KOOS at the last follow-up visit and the surgical revision rate. MRI was performed at a minimum of 12 months (mean 34±25 months) to determine absolute and relative meniscal extrusion, sagittal anterior and posterior extrusion, and cartilage coverage in the frontal and sagittal planes.

RESULTS

The KOOS score was not significantly different between the two groups. There were no reoperations in the IML group, but there were four in the non-IML group (13%) (p=0.13). Meniscal extrusion of the allograft occurred in 43% of patients (6/14) in the IML group versus 85% (17/20) in the non-IML group (p<0.03). Absolute meniscal extrusion was 2.9mm ([2.2-3.6] SD=1.2) in the ILM group versus 5.4 mm ([4.1-6.7] SD=2.9) (p=0.004) in the non-ILM group.

DISCUSSION

Adding ILM tenodesis or reconstruction can significantly limit early extrusion of the meniscal allograft. Clinical outcomes at a mean of 34 months are not different when compared to standard procedure. These patients should be re-evaluated in the long term to determine whether the incidence of osteoarthritis is lower with ILM tenodesis.

LEVEL OF EVIDENCE

III; case-control study.

Steep medial tibial slope and prolonged delay to surgery are associated with bilateral medial meniscus posterior root tear

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.

Meniscus transplantation-prospective assessment of clinical results in two, five and ten year follow-up

PURPOSE

The authors present clinical results in patients following transplantation of deep-frozen menisci within ten years following the surgery.

METHODS

A cohort of 46 patients who were transplanted altogether 49 menisci was subject to prospective study following six months, two, five and ten years after meniscus transplantation. For subjective assessment, we used KOOS, IKDC and Lysholm scores; objective assessment was based on load X-ray examination of the operated knee at two, five and ten years after the surgery, MRI examination of 34 patients in the interval of two and ten years after the operation, control arthroscopy was performed in 23 patients eight of whom suffered a new injury.

RESULTS

All 38 patients who have completed ten year follow-up without any new injury of the operated joint demonstrated statistically significant improvement of mobility in the period of six months and two, five and ten years following the meniscal transplantation. Further follow-up demonstrated different results in patients with a new injury and without a new injury of the operated knee joint. In eight patients (17.3%), the follow-up was disturbed by a new injury of the operated joint within three to eight years after the meniscal transplantation. In three patients with the damaged meniscal transplant, a cartilage deterioration from degree II to degree IIIa was found. In second-look arthroscopy, the patients with no injury showed signs of the improved condition of cartilage by one degree according to ICRS classification on average. The MRI imaging showed relatively frequent (47%) extrusion of the anterior and medial part of meniscus (2.5-3.8 mms) without the followed-up dynamics of changes at two and ten years after the surgery.

CONCLUSION

All patients in the selected cohort proved the positive benefit of meniscus transplant when it comes to the improvement of clinical symptoms and improvement of mobility of the operated knee joint. The higher mobility following the transplantation compared to the activity prior to the surgery could have contributed to a new injury of the operated joint in 17% of the patients in the cohort.

Medial meniscus posterior root repair decreases posteromedial extrusion of the medial meniscus during knee flexion

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.

Preliminary diagnosis of medial meniscus posterior root tears using the Rosenberg radiographic view

Purpose

To verify the effectiveness of detecting medial meniscus posterior root tears (MMPRTs) using weight-bearing posterior-anterior (PA) radiographs.

Materials and methods

Twenty-three patients were diagnosed with an MMPRT using magnetic resonance imaging (Group A), with 23 matched individuals forming the control group (Group B). The distance between medial tibial eminence and the lateral edge of the medial femoral condyle (MTE–MFC distance) and medial joint space (MJS) width were measured on weight-bearing PA radiographs, with the knee flexed at 45° (Rosenberg view). Absolute medial meniscus extrusion (MME) was measured on magnetic resonance images.

Results

The MTE–MFC distance was greater and the MJS width was smaller in Group A than Group B (7.7 ± 1.7 mm versus 6.0 ± 1.24 mm and 3.2 ± 0.8 mm versus 4.5 ± 0.7 mm, respectively; P < 0.05). The MTE–MFC distance and MJS width correlated with MME (r = 0.603 and 0.579, respectively; P < 0.05), and the extent of MME was greater in Group A than Group B (4.1 ± 1.1 mm versus 1.8 ± 1.5 mm, respectively; P < 0.05).

Conclusions

MMPRTs increase the MTE–MFC distance and decrease the MJS width, with these measurements correlating to the MME. Therefore, measurement of the MTE–MFC distance and MJS width on the Rosenberg view could be a useful preliminary method for the diagnosis of an MMPRT.

Level of evidence

IV

The accuracy of a newly developed guide system in medial meniscus posterior root repair: a comparison between two aiming guides

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