Correlation of factors affecting correction of meniscal extrusion and outcome after medial meniscus root repair

Accurate tibial tunnel position in transtibial pullout repair for medial meniscus posterior root tears delays the progression of medial joint space narrowing

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 < 0.001) and direct (r = 0.559, p < 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.

Clinical outcomes following transtibial medial meniscal root repair are maintained at long-term follow-up

PURPOSE

To evaluate long-term outcomes of patients treated with posterior medial meniscal root tear (PMMRT) repair through assessment of functional outcome scores and to identify patient surgical and magnetic resonance imaging (MRI) characteristics associated with improved outcomes.

METHODS

This was a single-centre, retrospective study evaluating patients who had undergone a PMMR repair using a transtibial suture pullout technique with two locking cinch sutures. This was performed as a follow-up to previously published 2-year and 5-year outcome studies, using the same cohort. All patients from the prior short-term and midterm studies were invited to participate. Patient-reported outcome (PROs) scores, including the International Knee Documentation Committee (IKDC) and Lysholm scores, were collected. Previously collected demographic data were updated based on review of the electronic medical record. Patient outcomes were assessed preoperatively, as well as at 2-year, 5-year and 8-year postoperatively. MRI outcome measurements were assessed at 2-year and 5-year follow-ups. All statistical analysis was performed using SPSS version 26.

RESULTS

Seventeen patients of the original 18 patients (94.4%) were included in the final analysis. Additionally, three patients who had additional ipsilateral surgery were excluded from the analysis of PROs. The IKDC score significantly increased from 44.7 ± 11.6 at preoperative baseline to 71.2 ± 21.3 at 8-year post-operation (p = 0.001). There were no significant differences in IKDC score between 2-year and 8-year follow-ups (p = n.s.) or 5-year and 8-year follow-ups (p = n.s.). The Lysholm score significantly increased from 49.6 ± 7.3 at preoperative baseline to 76.4 ± 17.2 at 8-year follow-up (p < 0.001). There was no significant difference in Lysholm scores between 2-year and 8-year follow-ups (p = n.s.) or 5-year and 8-year follow-ups (p = n.s.). A linear regression analysis found that 5-year IKDC scores were significantly correlated with 8-year IKDC scores (β = 0.681, p = 0.038). At 8-year follow-up, four (23.5%) patients required additional procedures on their operative knee (one total knee arthroplasty conversion).

CONCLUSION

Patients treated with repair of PMMRT had maintenance of clinical outcome improvements at long-term follow-up despite worsening MRI outcomes at short-term and medium-term follow-ups. While a high proportion of patients required additional procedures on their operative knee at 8-year follow-up, few of these patient's additional procedures were related to failure of their primary surgery. Providers and patients may expect durable clinical outcomes following the repair of PMMRT, irrespective of radiographic appearance.

LEVEL OF EVIDENCE

Level IV.

Signal intensity of repaired posterior roots after transtibial pullout repair for medial meniscus posterior root tears in stable knees: Magnetic resonance imaging evaluations at 3 years postoperatively

BACKGROUND

Only a few studies have assessed signal intensity after pullout repair for medial meniscus posterior root (MMPR) tears (MMPRTs) based on mid-term magnetic resonance imaging (MRI) evaluations. Therefore, this study aimed to assess the quantitative signal intensity of repaired posterior roots over time, up to 3 years postoperatively, and the related factors.

METHODS

This study included 36 patients who underwent pullout repair for MMPRTs and MRI examinations using the same MRI system. The signal intensity of the repaired posterior roots was quantitatively evaluated using the signal-to-noise quotient (SNQ). Medial meniscus extrusion (MME), the SNQ for MMPR, and clinical scores were assessed over 3 years postoperatively.

RESULTS

MME progressed over time until 3 years postoperatively, and its progression during this period was 1.61 ± 1.44 mm. The SNQ for MMPR decreased over time until 3 years postoperatively, and the change in the SNQ from 3 months to 3 years postoperatively (ΔSNQ) was 2.69 ± 1.69. All clinical scores significantly improved (p < 0.001). ΔSNQ was significantly correlated with body weight (correlation coefficient = -0.424, p = 0.010) and body mass index (correlation coefficient = -0.330, p = 0.050). However, ΔSNQ was not significantly correlated with preoperative or postoperative clinical scores.

CONCLUSION

After pullout repair for MMPRTs, MME progressed to 3 years postoperatively. However, the signal intensity of the repaired posterior roots decreased, and clinical scores improved over time until 3 years postoperatively. Patient weight and body mass index were significantly correlated with the reduced signal intensity of the repaired posterior roots, suggesting that weight assessment in patients with MMPRTs is crucial.

LEVEL OF EVIDENCE

IV.

Initial tension at suture fixation affects the suture breakage following medial meniscus posterior root repair: A retrospective cohort study

OBJECTIVES

This study aimed to investigate whether the initial suture tension when pullout sutures are fixed affects postoperative clinical outcomes following medial meniscus posterior root repair.

METHODS

The data of 48 patients who underwent transtibial pullout repair using two simple stitches (outer and inner sutures) with an additional all-inside posteromedial pullout were retrospectively investigated. The patients were sequentially divided into two groups to compare the clinical efficacy of the initial pullout tension (N) when pullout sutures were fixed: the 30 N Group (April 2019 to September 2019, 24 patients) and the 15 N group (October 2019 to February 2020, 24 patients). The rate of suture breakage (suture cutout or rupture) at the second-look arthroscopy at 1 year postoperatively and clinical outcomes at 2 years postoperatively were compared between the two groups.

RESULTS

In both groups, each clinical score significantly improved at 2 years postoperatively. At the second-look arthroscopy, the rate of posteromedial suture breakage was significantly higher in the 30 N group (19 patients, 79 ​%) than in the 15 N group (10 patients, 42 ​%); the rate of outer suture breakage was also higher in the 30 N group (five patients, 21 ​%) than in the 15 N group (no patients). On comparing 2 years of preoperative clinical scores between the groups categorized according to posteromedial suture breakage, the pain score was significantly higher in the suture breakage group.

CONCLUSIONS

The initial tension of pullout repair of the medial meniscus posterior root tear is related to suture breakages. To prevent suture breakage, 15 N is a more initially suitable condition than 30 N.

LEVEL OF EVIDENCE

Level III.

Meniscal healing status after medial meniscus posterior root repair negatively correlates with a midterm increase in medial meniscus extrusion

PURPOSE

The second-look arthroscopic score of pullout repair for medial meniscus posterior root tears (MMPRTs) is associated with contemporaneous clinical scores and progression of cartilage damage. However, the relationship among these scores, midterm clinical scores and magnetic resonance imaging (MRI) evaluations is unknown. The relationship between the second-look arthroscopic score at 1 year and the clinical scores or MRI at 3 years was evaluated.

METHODS

Sixty-three patients were included. Medial meniscus extrusion (MME) was evaluated preoperatively and at 3 years postoperatively. Clinical scores were evaluated preoperatively, and 1 and 3 years postoperatively. Meniscal healing status was assessed using the semiquantitative second-look arthroscopic score at 1 year postoperatively. Correlation coefficients between patient characteristics, postoperative clinical scores or second-look arthroscopic score and the change in MME (ΔMME) were evaluated. Multiple regression analysis was performed on the ΔMME to evaluate the effects of patient characteristics and second-look arthroscopic scores.

RESULTS

No significant correlation was observed between patient characteristics and ΔMME. In contrast, a significant correlation was found between the second-look arthroscopic score and ΔMME (p < 0.001) and visual analogue scale pain score (p = 0.016) at 3 years postoperatively. In the subitems of the second-look arthroscopic score, width (p < 0.001) and stability (p = 0.009) scores also showed significant correlations with ΔMME. Multiple regression analysis showed a significant association between the second-look arthroscopic score and ΔMME (p = 0.001).

CONCLUSIONS

The second-look arthroscopic score at 1 year postoperatively correlated with the ΔMME and clinical score at 3 years postoperatively. Second-look arthroscopic scores predict midterm meniscal function after pullout repair of MMPRTs.

LEVEL OF EVIDENCE

Level IV.

Seven tesla knee MRI T2*-mapping detects intrasubstance meniscus degeneration in patients with posterior root tears

Background

Medial meniscus root tears often lead to knee osteoarthritis. The extent of meniscal tissue changes beyond the localized root tear is unknown.

Purpose

To evaluate if 7 Tesla 3D T2*-mapping can detect intrasubstance meniscal degeneration in patients with arthroscopically verified medial meniscus posterior root tears (MMPRTs), and assess if tissue changes extend beyond the immediate site of the posterior root tear detected on surface examination by arthroscopy.

Methods

In this prospective study we acquired 7 T knee MRIs from patients with MMPRTs and asymptomatic controls. Using a linear mixed model, we compared T2* values between patients and controls, and across different meniscal regions. Patients underwent arthroscopic assessment before MMPRT repair. Changes in pain levels before and after repair were calculated using Knee Injury & Osteoarthritis Outcome Score (KOOS). Pain changes and meniscal extrusion were correlated with T2* using Pearson correlation (r).

Results

Twenty patients (mean age 53 ± 8; 16 females) demonstrated significantly higher T2* values across the medial meniscus (anterior horn, posterior body and posterior horn: all P < .001; anterior body: P = .007), and lateral meniscus anterior (P = .024) and posterior (P < .001) horns when compared to the corresponding regions in ten matched controls (mean age 53 ± 12; 8 females). Elevated T2* values were inversely correlated with the change in pain levels before and after repair. All patients had medial meniscal extrusion of ≥2 mm. Arthroscopy did not reveal surface abnormalities in 70% of patients (14 out of 20).

Conclusions

Elevated T2* values across both medial and lateral menisci indicate that degenerative changes in patients with MMPRTs extend beyond the immediate vicinity of the posterior root tear. This suggests more widespread meniscal degeneration, often undetected by surface examinations in arthroscopy.

Short-term results of tibial interference screw fixation for transtibial medial meniscus posterior root pull-out repair

Background

To evaluate the technique of transtibial pull-out repair with tibial interference screw fixation for medial meniscus posterior root (MMPR) tear by reporting on short-term outcomes and complications.

Methods

All MMPR repairs performed between January 2019 and August 2021 (n = 70) were retrospectively screened regarding demographic data and surgical parameters. The patients were questioned for performed revision surgery, symptoms and complications. The Numeric Rating Scale (NRS) for pain, Lysholm Knee Score and International Knee Documentation Committee Subjective Knee Form (IKDC) questionnaires were used to evaluate clinical outcome. In cases of revision surgery for re-tear the mode of failure was intraoperatively classified (patients with re-tear were excluded from the clinical follow-up examination). The influence of demographic and treatment parameters (surgical and rehabilitation) on the incidence and mode of re-tear and clinical scores was evaluated.

Results

After 2.3 ± 0.7 years, 62 patients (88.6 %) were available for follow-up. There were no direct intra- or postoperative complications. No revision was performed due to symptoms related to the tibial fixation material. The mean surgery time was 33.5 ± 10.8 min. The overall re-tear rate was 17.7 % (11 patients) of whom 10 were treated surgically and one conservatively. Primary mode of failure was suture cut-out from the meniscus (70 %). The NRS, Lysholm Knee Score and subjective IKDC were obtained in 38 patients and improved from 6.8 ± 2.4, 40.1 ± 23.9 and 32.8 ± 16.3 to 2.2 ± 2.2, 80.5 ± 16.3 and 63.0 ± 13.9, respectively (all p < 0.001). No influence was observed from demographic and treatment parameters on re-tear rates or clinical Scores.

Conclusions

Tibial interference screw fixation is a fast and promising technique for MMPR transtibial pull-out repair. In the presented technique, utilizing non-absorbable locking sutures alongside tibial interfenrence screw fixation, the primary mode of failure was suture cut-out from the meniscus.

Superior outcomes of pullout repairs for medial meniscus posterior root tears in partial tear compared to complete radial tear

PURPOSE

To reveal the outcomes of partial medial meniscus posterior root tears following transtibial pullout repair compared with the outcomes of complete radial meniscus posterior root tears.

MATERIALS AND METHODS

We retrospectively evaluated 15 consecutive patients (male/female, 5/10; average age, 64.4 years) who underwent transtibial pullout repair for partial medial meniscus posterior root tears and compared their results with those of 86 consecutive patients who underwent the same surgery for complete medial meniscus posterior root tears. All patients underwent second-look arthroscopy on average 1 year postoperatively, and a semi-quantitative meniscal healing score (anteroposterior width, stability, and synovial coverage, total 10 points) was evaluated. Medial meniscus extrusion was evaluated preoperatively and at second-look arthroscopy.

RESULTS

Postoperative clinical scores were not significantly different in the short term. However, second-look arthroscopy revealed a significant difference in repaired meniscal stability (partial tear; 3.3 points, complete tear; 2.3 points, p < 0.001) and total meniscal healing scores (partial tear; 8.3 points, complete tear; 7.1 points, p < 0.001). Medial meniscus extrusion progression was significantly different (partial tear; 0.4 mm, complete tear; 1.0 mm, p < 0.001).

CONCLUSION

Partial medial meniscus posterior root tears showed better meniscal healing and less medial meniscus extrusion progression following pullout repair than complete medial meniscus posterior root tears.

The meniscal extrusion index is a reliable indirect sign of different meniscal lesion patterns: a classification based on percentage of meniscal extrusion

PURPOSE

This study's goal is to propose a straightforward classification system based on the MEI (Meniscal Extrusion Index), a measure of meniscal extrusion, that relates to various meniscal lesion patterns and has clinical and biomechanical significance. The study's secondary goal is to determine whether the standard 3 mm meniscal extrusion parameter still has value by correlating the MEI with it.

METHODS

1350 knee MRIs that were performed over the course of 2 years made up the study cohort. Following the application of inclusion and exclusion criteria, 200 of those patients were qualified to participate in the study. All the measurements examined for this study underwent an interobserver reliability test.

RESULTS

In the 1350 MRIs that were examined for this study, meniscal extrusion of any grade was present 18.9% of the time. The use of the MEI revealed three groups of patients: those with a MEI < 20%, who are likely para-physiological; those with a MEY between 20% and 40%, who are in a grey area; and those with a MEY > 40%, who have lesions that are impairing the proper meniscal function. According to the authors' findings, the percentage of meniscal extrusion did not correlate with the finite number (3 mm), making the 3 mm parameter an unreliable evaluation method.

CONCLUSIONS

This study is clinically relevant, because it proposes a simple and reproducible classification of meniscal extrusion that may aid in evaluating the severity of an extrusion and help in the diagnosis of lesions that might be difficult to identify on MRI.

LEVEL OF EVIDENCE

Level IV.

Meniscal Extrusion Measurements After Posterior Medial Meniscus Root Tears: A Systematic Review and Meta-analysis

BACKGROUND

Meniscal extrusion has become increasingly utilized when evaluating meniscus root abnormalities. However, no consensus definition or approach exists on how to measure extrusion.

PURPOSE/HYPOTHESIS

The purpose of this study was to evaluate the extent of heterogeneity in meniscal extrusion measurement techniques and reported extrusion values in knees with posterior medial meniscus root tears (PMMRTs). We hypothesized that meniscal extrusion measurement techniques would vary considerably throughout reported studies, with resultant wide-ranging published extrusion values.

STUDY DESIGN

Systematic review; Level of evidence, 4.

METHODS

A systematic review was conducted according to the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) statement. The inclusion criteria consisted of all clinical and cadaveric studies reporting on meniscal extrusion after PMMRTs, excluding studies lacking data in full extension, those presenting only semiquantitative analyses, articles reporting only differences in meniscal extrusion, and review articles.

RESULTS

A total of 45 studies were included. Imaging modality types included magnetic resonance imaging (89%), 3-dimensional reconstruction with computed tomography (7%), linear displacement transducers (2%), and a combination of magnetic resonance imaging and ultrasound (2%). The 3 most commonly used landmarks to acquire coronal images for meniscal extrusion measurements were the medial collateral ligament (38%), the midpoint of the anterior-posterior length of the medial meniscus (23%), and the middle of the medial femoral condyle (19%). The pooled mean extrusion values according to the measurement location were 3.5 ± 0.7 mm, 3.9 ± 0.8 mm, and 4.5 ± 2.1 mm, respectively, with no significant differences noted between the modality types (P = .23). The pooled mean meniscal extrusion from all included studies was 3.2 ± 2.0 mm.

CONCLUSION

Substantial variation exists in measurement techniques for meniscal extrusion, particularly as it relates to the coronal cross-sectional reference location. Further studies should aim to provide clear descriptions of the measurement method and have uniform measurement methodology to allow comparisons and pooling between studies.

Younger patients, lower BMI, complete meniscus root healing, lower HKA degree and shorter preoperative symptom duration were the independent risk factors correlated with the good correction of MME in patients with repaired MMPRTs

PURPOSE

To evaluate the clinical and radiological outcomes of arthroscopically assisted tendon graft anatomic reinforced reconstruction of the medial meniscus posterior root tears (MMPRTs) and identify relevant factors affecting the correction of medial meniscal extrusion (MME).

METHODS

Fifty-three MMPRTs patients who underwent arthroscopically assisted tendon graft reconstruction of the meniscal root between 2018 and 2020 were evaluated retrospectively. the patients were divided into 2 groups according to the correction of MME (maintained MME group: 32 cases vs. increased MME group: 21 cases). The clinical and radiological outcomes of arthroscopically assisted tendon graft reconstruction of the meniscal root, including postoperative correction of MME and functional recovery of the knee were assessed in this study, and potential independent risk factors that could influence the correction of MME were also evaluated.

RESULTS

The functional recovery of the knee was significantly improved at the end of follow-up (P < 0.001; respectively), furthermore, a comparison of the final functional outcomes between the groups showed that the mean Lysholm score and IKDC score of the maintained MME group were significantly improved than those of increased MME group. 60.4% had good correction of MME, and patients with complete healing had better extrusion correction than those with partial healing and non-healing. Binary logistic regression models analysis indicated that the age (OR = 1.053, P = 0.048), BMI (OR = 1.376, P = 0.004), meniscus root healing status (OR = 7.701, P = 0.005), HKA degree (OR = 1.891, P = 0.011) and preoperative symptom duration (OR = 1.055, P = 0.013) were the independent risk factors correlated with correction of MME. Additionally, the ROC curve demonstrated the cut-off values of the Age, BMI, HKA degree and preoperative symptom duration were 46.0 years, 22.5 kg/m2, 3.2° and 9.5 months, respectively, CONCLUSIONS: The arthroscopically assisted tendon graft anatomic reinforced reconstruction of the meniscal root showed clinical improvement and prevented the progression of postoperative MME. Additionally, younger patients, lower BMI, complete meniscus root healing, lower HKA degree and shorter preoperative symptom duration were the independent risk factors correlated with the good correction of MME in patients with repaired MMPRTs.

LEVEL OF EVIDENCE

Level IV.

The stability of repaired meniscal root can affect postoperative cartilage status following medial meniscus posterior root repair

BACKGROUND

Transtibial pullout repair yields beneficial clinical outcomes in patients with medial meniscus (MM) posterior root tear. However, the relationship between repaired meniscal root healing status and postoperative clinical outcomes remains unclear. We aimed to evaluate changes in articular cartilage damage and clinical scores after pullout repair using two simple stitches (TSS).

METHODS

Thirty-three patients who underwent pullout repair using TSS were assessed. Healing status was assessed by a semi-quantitative second-look arthroscopic scoring system comprising three evaluation criteria (width of bridging tissues, stability of the repaired root, and synovial coverage), 1 year postoperatively. MM medial extrusion (MMME) and cartilage damage were assessed preoperatively and 1 year postoperatively. The medial compartment was divided into 8 zones (A-H) for comparison of preoperative and 1-year postoperative cartilage damage. Clinical outcomes were evaluated using the Knee Injury and Osteoarthritis Outcome score, Lysholm score, International Knee Documentation Committee scores, and visual analogue scale pain score.

RESULTS

Although cartilage damage did not aggravate significantly in most medial compartment areas, MMME progressed at 1 year postoperatively. No statistical differences were observed in cartilage damage between the central-to-medial area of the medial femoral condyle and the medial tibial plateau area at 1 year postoperatively. Regarding semi-quantitative healing scores, the stability score was significantly correlated with the International Cartilage Repair Society grade at 1 year postoperatively. All 1-year and 2-year clinical scores significantly improved compared with the preoperative scores.

CONCLUSION

Regarding TSS repair, stability of repaired meniscal root negatively correlated with cartilage damage in the medial compartment loading area. All 1-year and 2-year clinical scores significantly improved than those of the preoperative scores. Achieving MM stability is crucial for suppressing cartilage degeneration.

LEVEL OF EVIDENCE

IV case series study.

Concomitant Medial Meniscal Root Repair with Extrusion Repair (Centralization Technique)

Background

Meniscal extrusion is a phenomenon in which a degenerative posterior horn tear, radial tear, or root tear results in displacement of the body of the meniscus medial to the tibial rim. The paramount function of the meniscus is to provide load distribution across the knee joint. Meniscal extrusion will prevent the meniscus from properly fulfilling this function and eventually leads to progression of osteoarthritis1. Thus, root repair accompanied by arthroscopic meniscal extrusion repair (by a centralization technique) has been suggested for restoration of meniscal function2-5. There are various techniques to correct meniscal extrusion, including a dual-tunnel suture pull-out technique2 (to address extrusion and root tear2), a knotless suture anchor4,6 technique, and an all-inside suture anchor repair7. The indications for extrusion repair are not consistently reported in the literature, and the procedure is not always easy to perform. Currently, there is no consensus regarding the ideal technique. In the present article, we describe the steps for successful combined medial meniscal root repair with extrusion repair and centralization.

Description

Place the patient in the supine position with the knee supported in 90° of flexion and the feet at the edge of the operating table with foot-positioner support. First, meniscal root repair is performed with use of the suture pull-out technique, utilizing a cinch suture configuration to hold the root in place, and the suture tapes are fixed over the anterior cortex of the tibia with a suture button. Next, the meniscal body is arthroscopically assessed for residual extrusion from the medial tibial rim. Extrusion repair is indicated in cases with >3 mm of extrusion7-9, as measured on magnetic resonance imaging. In our technique, any extrusion beyond the medial tibial rim is reduced and secured with use of a double-loaded 2.3-mm all-suture type of anchor.

Alternatives

Alternatives include surgical procedures in which the root repair is performed with use of suture-anchor fixation10,11 and the extrusion repair is performed with use of the transtibial suture pull-out method.

Rationale

Root repair performed with the most common fixation techniques does not always reduce meniscal extrusion or restore meniscal function12,13. Consequently, several augmentation techniques have been reported to address meniscal extrusion3,14, including those that use arthroscopy to centralize the midbody of the meniscus over the rim of the tibial plateau. The rationale for this combined procedure is to restore the hoop-stress distribution and maintain meniscal function by repairing the extrusion of the meniscus. Addressing all intra-articular pathologies in a single stage is a challenging situation, and the sequence of the repair is important to achieve optimal postoperative results.

Expected Outcomes

Several surgical techniques have been described for the operative treatment of extrusion repair with use of centralization sutures2,3,5,6, and each has its own distinctive pearls and pitfalls for each. To combine root repair and extrusion repair presents a challenge for surgeons. From our clinical experience, a methodical approach to understanding the pathoanatomy and sequential execution of repair techniques would yield desired results. Extrusion correction through the use of a peripheral suture anchor over the medial rim of the tibia and knot tying are relatively easier to perform than some other published extrusion-repair techniques. Although no consensus has been achieved yet regarding the best technique, recent literature has suggested that the use of centralization sutures is effective to restore the native biomechanical properties of the medial meniscus5.Mochizuki et al. assessed the clinical and radiological outcomes of combined medial meniscal root repair and centralization in 26 patients with a minimum follow-up of 2 years. Both Lysholm scores and Knee injury and Osteoarthritis Outcome Scores improved significantly after surgery, with a significant reduction in extrusion distance from preoperatively to 2 years postoperatively20. Koga et al21 assessed the 2-year outcomes of lateral arthroscopic meniscal centralization, finding significantly reduced meniscal extrusion at both 3 months and 1 year postoperatively. Biomechanical studies have demonstrated that centralization can improve meniscal mechanics and potentially reduce the risk of osteoarthritis. The centralization suture technique for extrusion repair has the theoretical advantage of restoring meniscal function following meniscal root repair; however, there are also concerns regarding over-constraint of the meniscus. We believe that the medial meniscus, being less mobile than the lateral meniscus, can withstand the constraint created by the use of centralization. Meniscal centralization is a technically demanding surgical procedure, but with a systematic approach and meticulous technique, we have observed good short-term outcome in our patients.

Important Tips

A tight medial compartment is one of the most common problems encountered during a medial meniscal root repair. "Pie-crusting" of the superficial medial collateral ligament at the tibial insertion aids in improving the space, thereby reducing chondral damage during the root repair.It is challenging to achieve the correct inclination of insertion when inserting the suture anchor through a mid-medial portal. This limitation can be mitigated by utilizing a 16G or 18G needle before making the portal, as the needle direction, trajectory, and extent of accessibility within the joint will aid in proper portal placement and anchor insertion.Suture management is another technical challenge. Suture tape is first cinched to the root of the meniscus and then shuttled into the transtibial tunnel in order to discern the reducibility of the meniscus and the extent of possible extrusion correction. Then, extrusion repair is performed. This sequence allows the surgeon to avoid mixing of root-repair sutures and extrusion-repair sutures. Following insertion of the all-suture anchor, each suture limb is brought out through the anteromedial portal, passed through the nitinol loop from the lasso, and shuttled back through the mid-medial portal. Knot tying is performed through the mid-medial portal.

Acronyms and Abbreviations

ACL = anterior cruciate ligamentPCL = posterior cruciate ligamentICRS grading = International Cartilage Research Society system for classification of cartilage lesionsKL grade = Kellgren-Lawrence system for classification of osteoarthritisMRI = magnetic resonance imagingMC = medial femoral condyleMPTA = medial proximal tibial angleLC = lateral femoral condyleHTO = high tibial osteotomyMCL = medial collateral ligamentAM = anteromedialKOOS = Knee injury and Osteoarthritis Outcome ScoreMME = medial meniscus extrusion.

Arthroscopic Transtibial Medial Meniscus Posterior Root Repair Using the "Meniscal Track" to Locate the Anatomical Footprint

The medial meniscus posterior root tears are a common problem in early elder patients. From a biomechanical study, the anatomical repair demonstrated a restored contact area and contact pressure than the nonanatomical repair. Nonanatomical repair of the medial meniscus posterior root resulted in decreased tibiofemoral contact area and increased contact pressure. Various surgical repair techniques were reported in the literature. However, there was no reported precise arthroscopic landmark to define the anatomical footprint of the posterior root attachment of the medial meniscus. We propose the "meniscal track", an arthroscopic landmark to guide the location of the anatomical footprint of the medial meniscus posterior root attachment.

Repair of meniscus root tear - Is there a difference between medial meniscus root repair and lateral meniscus root repair? A systematic review and meta-analysis

PURPOSE

Complete meniscus root tear is associated with meniscus extrusion; this causes a loss of meniscus function and accelerated osteoarthritis of the knee. Existing small-scale retrospective case-control studies suggested that the outcomes were different between medial and lateral meniscus root repair. This meta-analysis aims to study whether such discrepancies exist via a systematic review of the available evidence in the literature.

METHODS

Studies evaluating the outcomes of surgical repair of posterior meniscus root tears, with reassessment MRI or second-look arthroscopy, were identified through a systematic search of PubMed, Embase, and Cochrane Library. The degree of meniscus extrusion, healing status of the repaired meniscus root, and functional outcome scores after repair were the outcomes of interest.

RESULTS

Among the 732 studies identified, 20 studies were included in this systematic review. 624 knees and 122 knees underwent MMPRT and LMPRT repair, respectively. The amount of meniscus extrusion following MMPRT repair was 3.8 ± 1.7 mm, which was significantly larger than the 0.9 ± 1.2 mm observed after LMPRT repair (p < 0.001). Significantly better healing outcomes were observed on reassessment MRI after LMPRT repair (p < 0.001). The postoperative Lysholm score and IKDC score was also significantly better after LMPRT than MMPRT repair (p < 0.001).

CONCLUSIONS

LMPRT repairs resulted in significantly less meniscus extrusion, substantially better healing outcomes on MRI, and superior Lysholm/IKDC scores, when compared to MMPRT repair. This is the first meta-analysis we are aware of that systematically reviews the differences in the clinical, radiographic, and arthroscopic results of MMPRT and LMPRT repair.

Radiographic OA, bone marrow lesions, higher body mass index and medial meniscal root tears are significantly associated with medial meniscus extrusion with OA or medial meniscal tears: a systematic review and meta-analysis

PURPOSE

Medial meniscus extrusion (MME) refers to the protrusion of the medial meniscus beyond the tibial edge by more than 3 mm, leading to a deficiency of the hoop strain. MME commonly occurs in conjunction with osteoarthritis (OA) or medial meniscal tears (MMT). However, factors associated with concomitant MME in patients with OA or MMT have not been systematically reviewed. This study aims to perform a systematic review and meta-analysis to identify factors associated with concomitant MME in OA or MMT.

METHODS

The systematic review of the literature was performed according to PRISMA. A literature search was conducted in 4 databases. All original human studies that reported the available evidence on factors associated with concomitant MME in patients with OA or MMT were included. Pooled binary variables were analyzed by odds ratios (OR) and 95% CIs, and pooled continuous variables were evaluated by mean difference (MD) and 95% CIs.

RESULTS

Ten studies on OA (5993 patients) and eight studies on MMT (872 patients) met the inclusion criteria. The overall pooled incidence of MME was 43% (95% CI, 37-50%) for OA, 61% (95% CI 43-77%) for MMT, and 85% (95% CI 72-94%) for medial meniscal root tears (MMRT). For the population with OA, Factors significantly associated with MME included radiographic OA [OR 4.24; 95% CI 3.07-5.84; P < 0.0001], bone marrow lesions [OR, 3.35; 95% CI 1.61-6.99; P = 0.0013], cartilage damage [OR, 3.25; 95% CI 1.60-6.61; P = 0.0011], and higher body mass index (BMI) [MD, 1.81; 95% CI 1.15-2.48; P < 0.0001]. Factors strongly associated with increased risk of MME for MMT included medial meniscal root [OR, 8.39; 95% CI 2.84-24.82; P < 0.0001] and radial tears [OR, 2.64; 95% CI 1.18-5.92; P < 0.0001].

CONCLUSION

Radiographic OA, bone marrow lesions, cartilage damage, and higher BMI were significantly associated with concomitant MME with OA. Furthermore, medial meniscal root and radial tears were significantly associated with an increased risk of MME in patients with MMT.

LEVEL OF EVIDENCE

IV.

Quantifying Meniscal Extrusion Using Ultrasound in the Setting of Concomitant Cadaveric Knee Lesions: Part I: The Medial Meniscotibial Ligament and Posterior Medial Meniscal Root

PURPOSE

1. Evaluate how the meniscotibial ligament (MTL) affects meniscal extrusion (ME) +/- concomitant posterior medial meniscal root (PMMR) tears. 2. Describe how ME varied along length of meniscus.

METHODS

ME was measured using ultrasonography in 10 human cadaveric knees in conditions: (1) control, either (2a) isolated MTL sectioning, or (2b) isolated PMMR tear, (3) combined PMMR + MTL sectioning, and (4) PMMR repair. Measurements were obtained 1 cm anterior to the MCL (anterior), over the MCL (middle), and 1 cm posterior to the MCL (posterior) +/- 1000N axial loads in 0° and 30° flexion.

RESULTS

At 0°, MTL sectioning demonstrated greater middle than anterior (P<0.001) and posterior (P<0.001) ME, while PMMR (P=0.0042) and PMMR+MTL (P<0.001) sectioning demonstrated greater posterior than anterior ME. At 30°, PMMR (P<0.001) and PMMR+MTL (P<0.001) sectioning demonstrated greater posterior than anterior ME, and PMMR (P=0.0012) and PMMR+MTL (P=0.0058) sectioning demonstrated greater posterior than anterior ME. PMMR+MTL sectioning demonstrated greater posterior ME at 30° compared to 0° (P=0.0320). MTL sectioning always resulted in greater middle ME (P<0.001), in contrast with no middle ME changes following PMMR sectioning. At 0°, PMMR sectioning resulted in greater posterior ME (P<0.001), but at 30°, both PMMR and MTL sectioning resulted in greater posterior ME (P<0.001). Total ME surpassed 3 mm only when both the MTL and PMMR were sectioned.

CONCLUSION

The MTL and PMMR contribute most to ME when measured posterior to the MCL at 30° of flexion. ME greater than 3 mm is suggestive of combined PMMR + MTL lesions.

CLINICAL RELEVANCE

Overlooked MTL pathology may contribute to persistent ME following PMMR repair. We found isolated MTL tears able to cause 2-2.99 mm of ME, but the clinical significance of these magnitudes of extrusion is unclear. The use of ME measurement guidelines with ultrasound may allow for practical MTL and PMMR pathology screening and pre-operative planning.

The clinical and radiographic outcomes of type 2 medial meniscus posterior root tears following transtibial pullout repair

PURPOSE

The aim of this study was to compare the clinical outcomes of different subtypes of type 2 medial meniscus posterior root tears following transtibial pullout repair.

METHODS

In total, 147 patients (mean age: 66.2 ± 8.3 years) who were diagnosed with type 2 medial meniscus posterior root tears and underwent transtibial pullout repair were included. Patients were divided into 2A (n = 31), 2B (n = 90), and 2C (n = 26) groups according to tear type. Clinical outcomes were assessed pre-operatively and at second-look arthroscopy using the Knee injury and Osteoarthritis Outcome Score. The meniscal healing status was evaluated at second-look arthroscopy. Medial meniscus extrusion was calculated using magnetic resonance imaging pre-operatively and at second-look arthroscopy.

RESULTS

No significant differences in pre-operative or post-operative clinical scores were observed between each subtype, although clinical scores improved post-operatively for each subtype. Significant differences were noted in the anteroposterior width of the bridging tissues at second-look arthroscopy (2A, 7.1 ± 1.2; 2B, 6.2 ± 1.7; and 2C, 6.2 ± 1.7 mm; p = 0.045); type 2A tears were the widest. There was a significant difference in post-operative medial meniscus extrusion (2A, 3.2 ± 0.9; 2B, 4.0 ± 1.2; and 2C, 4.0 ± 1.4 mm; p = 0.004) and its progression (2A, 0.7 ± 0.6; 2B, 1.2 ± 0.8; and 2C, 1.2 ± 0.8 mm; p = 0.008), and type 2A tears were the shortest.

CONCLUSION

Although there was no significant difference in the post-operative clinical scores among different type 2 tears in the short term, type 2A tears showed better healing and medial meniscus extrusion progression prevention, thus indicating the usefulness of classifying tear type in estimating post-operative outcomes.

LEVEL OF EVIDENCE

III.

An anatomical study of the meniscal roots of the knee: landmarks for its surgical reconstruction and implications for knee surgeons

PURPOSE

The aim of this anatomical study was to describe the anatomy of the meniscal roots and their relationships with respect to the main adjacent structures in order to improve their surgical reconstruction.

METHODS

Fourteen knees were included. The mean age of the donors was 92 years (range 89-96). We studied the general characteristics of the anterior and posterior roots of the medial meniscus and lateral meniscus by measuring their widths at their base and area. We investigated the relations between anterior and posterior roots of the medial and lateral menisci with respect to the anterior and posterior cruciate ligaments (ACL and PCL).

RESULTS

The mean width of the anterior root of the lateral meniscus was 10.5 ± 1.4 mm. The mean width of the anterior root of the medial meniscus was 10 ± 1.5 mm. The mean width of the posterior root of lateral meniscus was 11.4 ± 1.4 mm. The mean width of the posterior root of medial meniscus was 10.5 ± 1.0 mm. The mean distance between the anterior cruciate ligament and the anterior root of lateral meniscus was 9.8 ± 2.9 mm, for the medial meniscus it was 15.9 ± 3.4 mm. The mean distance between the posterior cruciate ligament and the posterior root of the lateral meniscus was 11.5 ± 2.7 mm, for the medial meniscus, it was 11 ± 2.6 mm.

CONCLUSION

The anterior and posterior meniscal roots have precise landmarks, and this article contributes to define the location of the meniscal roots with respect to their adjacent anatomical structures: ACL, PCL and intercondylar tubercle. Having precise measures of the distances between the meniscus roots and these structures allows knee surgeons to perform ACL reconstruction, meniscal root repair and meniscal allograft transplantation.

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.