Preoperative Subchondral Insufficiency Fractures Are Associated With Decreased Clinically Significant Outcome Achievement, Higher Reoperation Rates, and Greater Osteoarthritis Progression After Medial Meniscus Posterior Root Repair at a Minimum 2‐Year Follow‐Up

PURPOSE: To evaluate the effect of preoperative subchondral insufficiency fracture of the knee (SIFK) on the outcomes of medial meniscus posterior root tear repair. METHODS: Patients undergoing repair of an isolated primary medial meniscus posterior root tear with ≥2-year follow-up were included. Data encompassed demographics, history, magnetic resonance imaging-confirmed SIFK, subsequent surgery, radiographic osteoarthritis progression, and patient-reported outcome measures: Knee Injury and Osteoarthritis Outcome Score, Joint Replacement; International Knee Documentation Committee; and Veterans RAND 12-Item Health Survey. Patients were stratified by SIFK status. Clinically significant improvement was assessed using cohort-specific minimal clinically important difference thresholds. RESULTS: Ninety-one patients (mean age: 56.5 ± 9.4 years, 73.6% women; mean body mass index: 32.5 ± 6.1) were included with a follow-up of 38.3 ± 15.3 months (range, 24-82), which did not differ between groups (P = .841). Thirty-four patients (37.4%) had SIFK, and 85% had SIFK grade 1 or 2. Baseline characteristics did not differ between groups. Compared with patients without SIFK, those with SIFK showed lower rates of achieving the minimal clinically important difference and patient-acceptable symptom state for Knee Injury and Osteoarthritis Outcome Score, Joint Replacement (80.7% vs 38.2%, P < .001; 61.4% vs 35.3%, P = .028, respectively). Patients with SIFK demonstrated higher rates of subsequent surgery (20.6% [95% confidence interval, 8.7%-37.9%] vs 5.3% [95% confidence interval, 1.1%-14.6%]; risk difference, 15.3% [95% confidence interval, 1.6%-31.9%]; P = .036) and a higher postoperative Kellgren-Lawrence grade (median [interquartile range], 3.0 [3.0-4.0] vs 2.0 [2.0-3.0]; P = .013), with smaller postoperative joint space (2.8 ± 0.6 mm vs 3.8 ± 1.0 mm, P = .002). CONCLUSIONS: Preoperative SIFK is associated with lower rates of achieving meaningful clinical improvement along with a higher likelihood of subsequent surgeries and inferior postoperative radiographic osteoarthritis outcomes after medial meniscus posterior root tear repair. LEVEL OF EVIDENCE: Level III, retrospective cohort study.