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Comparable Midterm Survival After Medial Meniscus Root Repair for High and Low Intraoperative Outerbridge
Camila Grandberg1, Abigail N Boduch1, Robert E Bilodeau1
1Department of Orthopaedic Surgery, UPMC Freddie Fu Sports Medicine Center, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania, USA.
Background:
While medial meniscus posterior root repairs (MMPRRs) have been shown to reverse harmful biomechanical effects of medial meniscus posterior root tears, it is questionable whether meaningful improvement occurs in patients with advanced chondral loss.
Purpose/Hypothesis:
The objectives of this study were to compare midterm survival of MMPRR and to determine patient-reported outcomes (PROs) after MMPRR based on intraoperative Outerbridge grades (0-2 vs 3 and 4). It was hypothesized that patients undergoing MMPRR with Outerbridge grades 3 and 4 would have a decreased rate of MMPRR survival and inferior PROs compared to patients with Outerbridge grades 0 to 2.
Study Design:
Cohort study; Level of evidence, 3.
Methods:
Consecutive patients who underwent primary isolated MMPRR performed at a single institution between July 2003 and November 2022 with a minimum follow-up of 1 year were included and categorized according to medial compartment Outerbridge grade (0-2 or 3 and 4) based on diagnostic arthroscopy. Failure was defined as reoperation of the index knee. PROs collected included International Knee Documentation Committee (IKDC), visual analog scale (VAS) for pain, and Marx activity scale scores, which were compared to the previously established minimal clinically important difference (MCID) and/or clinically meaningful change. A minimum follow-up of 2 years was used for PRO analyses. Data were collected through electronic medical records and/or prospectively distributed surveys. A post hoc power analysis was performed, yielding a post hoc power of >0.99.
Results:
A total of 170 patients were included (74 in the Outerbridge grade 0-2 group and 96 in the Outerbridge grade 3 and 4 group). The mean follow-up time was 5 years. There were no significant descriptive differences between groups. The median survival was 11 years, and there were no significant differences between groups in the survival analysis. There was 80% survival at 8 years overall, with 80% survival at 8 years and 7 years for Outerbridge grades 0 to 2 and grades 3 and 4, respectively. The failure rate was 17.6%, with no significant differences between groups, and the mean time to reoperation was 5.3 years. The mean postoperative IKDC score was 64.1 ± 23.0. The mean IKDC change was 27.6 ± 29.7, reaching the MCID of 10.17, with no significant differences between groups. The VAS score decreased from 6.1 ± 2.2 preoperatively to 3.0 ± 3.0 postoperatively, with no significant differences between groups.
Conclusion:
Midterm survival and clinical outcomes after MMPRR were comparable between patients with intraoperative Outerbridge grades 0 to 2 and grades 3 and 4, with no significant differences in failure rate or survival. The overall median survival was 11 years, with an 80% survival rate at 8 years. The change in IKDC score exceeded the MCID in both groups. These findings indicate that MMPRR is durable and effective and intraoperative Outerbridge classification grades should not dissuade orthopaedic surgeons from performing MMPRR.
Insights
Medial meniscus posterior root repair (MMPRR) shows comparable midterm survival and patient outcomes regardless of advanced chondral damage (Outerbridge grades 3-4). These findings support MMPRR as a durable and effective treatment for various stages of knee injury.
Area of Science:
- Orthopedic Surgery
- Knee Biomechanics
- Meniscus Repair
Background:
- Medial meniscus posterior root repairs (MMPRRs) aim to mitigate biomechanical issues from root tears.
- The efficacy of MMPRR in patients with significant pre-existing chondral damage (advanced osteoarthritis) remains debated.
- Intraoperative assessment of chondral health using Outerbridge grading is crucial for surgical decision-making.
Purpose of the Study:
- To compare the midterm survival rates of MMPRR between patients with Outerbridge grades 0-2 and grades 3-4.
- To evaluate and compare patient-reported outcomes (PROs) following MMPRR based on intraoperative chondral damage severity.
- To test the hypothesis that advanced chondral damage negatively impacts MMPRR survival and patient outcomes.
Main Methods:
- A retrospective cohort study (Level of evidence, 3) included 170 patients undergoing primary isolated MMPRR.
- Patients were categorized into Outerbridge grades 0-2 (n=74) or 3-4 (n=96) based on arthroscopic findings.
- Midterm survival (defined by reoperation) and PROs (IKDC, VAS pain, Marx activity) were analyzed with a minimum 2-year follow-up.
Main Results:
- No significant differences in midterm survival or failure rates were observed between the Outerbridge grade groups.
- Overall median survival was 11 years, with 80% survival at 8 years for both groups.
- Postoperative International Knee Documentation Committee (IKDC) scores significantly improved, exceeding the minimal clinically important difference (MCID) in both groups.
Conclusions:
- Midterm survival and patient-reported outcomes after MMPRR are comparable, irrespective of intraoperative chondral damage severity (Outerbridge grades 0-4).
- MMPRR demonstrates durable efficacy, with overall 80% survival at 8 years.
- Intraoperative Outerbridge grade should not deter surgeons from performing MMPRR, as outcomes remain favorable.
