Minimum 5-Year Outcomes, Complication Rates, and Conversion to Total Knee Arthroplasty Following Isolated Medial Meniscus Posterior Root Repair.

Background: Medial meniscus posterior root tear (MMPRT) repair is indicated in patients with preserved articular cartilage to prevent rapidly progressive osteoarthritis. However, there is limited published data on midterm outcomes after MMPRT repair. Purpose: To report the patient-reported outcome measures (PROMs), complication, and failure rate for patients undergoing MMPRT repair at a minimum of 5-year follow-up. Study Design: Case series; Level of evidence, 4. Methods: A single-institution prospectively collected database was retrospectively queried for patients who underwent isolated MMPRT repair from January 2016 to March 2019. Exclusion criteria included Kellgren-Lawrence grade ≥3 osteoarthritis, concurrent ligamentous or realignment procedures, all-inside suture anchor repair, and concomitant lateral meniscal tears. The clinical outcome measures included conversion to knee arthroplasty, the shortened Knee injury and Osteoarthritis Outcome (KOOS) Jr, International Knee Documentation (IKDC), and Veterans RAND 12-Item Health Survey (VR-12) scores. Clinical failure was defined as failing to achieve the minimal clinically important difference (MCID) for ≥1 PROM. The MCID and Patient Acceptable Symptom State (PASS) thresholds were derived from a peer-reviewed study and were as follows: IKDC (MCID, 10.2; PASS, 67.8), KOOS Jr (MCID, 10.4; PASS, 71.9) and VR-12 Physical (MCID, 6.1; PASS, 47.8). Results: A total of 38 patients who met inclusion criteria and underwent transtibial root repair before March 2019 were retrospectively identified, of which 36 (94.7%) were available for follow-up at mean 65.8 ± 6.7 months (range, 60-81). Of this total, 5 patients (13.9%) converted to arthroplasty (mean ± SD, 41.8 ± 28.0 months). Transtibial pullout repair had an overall survivorship of 97.2%, 94.4%, and 91.6% at the 1-year, 2-year, and 5-year time points, while 2 patients failed after 60 months postoperatively, for an 86.1% arthroplasty-free survivorship at mean 65.8 months. MCID and PASS achievement rates at final follow-up for KOOS Jr were 74.2% and 51.6%, respectively. Three patients (8.3%) failed to achieve MCID for any 1 of the 3 PROMs while 28 patients (77.8%) achieved the MCID for ≥1 PROM. Conclusion: Clinically significant outcomes for KOOS Jr were achieved in 74.2% and 51.6% of patients undergoing transtibial pullout repair for isolated MMPRT at 5-year follow-up. There was an 86.1% survivorship free of arthroplasty at midterm follow-up.