Meniscus Radial Repair with the Transtibial Two Tunnel Technique: A Non-Inferiority Study with Vertical Mensical Tears Repair Comparison

OBJECTIVES: Radial meniscus tears disrupt the circumferential fibers and thereby compromise meniscal integrity. Historically, radial tears were often treated with meniscectomy due to an inunderstanding of the biomechanical consequences of these tears, limited information regarding the biomechanical performance of repairs, and the technical difficulty associated with repair. A paucity of studies on the outcomes of repair of radial meniscal tears are available. The purpose was to report early (minimum two-year follow-up) results of a two-tunnel transtibial repair of radial meniscus tears and compare these outcomes to the outcomes of patients who underwent repair of vertical meniscus tears. The hypothesis was that radial tear repair would be safe and efficacious and that there would be no difference between repair and repair of vertical meniscal tears. METHODS: The primary study group included patients that underwent a two-tunnel transtibial pullout repair for a radial meniscus tear. The compare group included patients that underwent inside-out repair of vertical meniscus tears. Subjective questionnaires were administered pre-operatively and at a minimum of two years follow-up, including the Lysholm score, the Western Ontario & McMaster Universities Osteoarthritis Index (WOMAC) score, the Short Form-12 (SF-12) physical component summary (PCS) and mental health component summary (MCS), the Tegner Activity scale and patient satisfaction. ANCOVA models were used to compare postop outcome scores between meniscus repair groups while accounting for baseline score. Adjusted mean effects relative to the radial repair group were reported with 95% confidence intervals. RESULTS: Twenty-seven patients that underwent two tunnel transtibial pullout repairs for radial meniscal tears and 33 patients who underwent inside-out vertical meniscus tear inside-out repair group were available for follow-up at a minimum of two-years. No baseline outcome scale significantly differed between the groups. In the radial repair group, the mean ± SD preoperative SF-12 PCS, WOMAC and Lysholm were 36.7 ± 9.4, 36.6 ± 20.5, and 47.4±22.1, respectively. In the vertical repair group the mean ± SD preoperative SF-12 PCS, WOMAC and Lysholm were 37.4 ± 10.2, 40.4 ± 23.5, and 45.6 ±22, respectively. There were no significant group differences for any of the two-year postoperative outcomes scores. Relative to radial repair, the repaired vertical tear group exhibited an adjusted average of +0.4 (95% CI: -4.2, 5.00), +0.6 (-4.9, 6.0) and -5.1 (-13.6, 3.5) points on the SF-12 PCS, WOMAC and Lysholm scales, respectively. CONCLUSION: The Two tunnel transtibial pullout repairs for radial meniscal tear technique is a safe and efficacious procedure and produces similar clinical outcomes when compared to repairs of vertical tears.