Meniscal Translation Under Loaded Motion After Posterior Horn Medial Meniscal Root Repair: A Cadaveric Biomechanical Evaluation

Background: Biomechanical evidence for adjustable posterior medial meniscal root (PMMR) fixation has shown promising results for meniscal root repair. Adjustable suture anchor (ASA) fixation has yet to be evaluated through the loaded knee range of motion. Hypothesis: The ASA PMMR repair would restore meniscal translation similar to the native meniscus and maintain those parameters through the knee flexion arc during cyclical axial loading. Study Design: Controlled laboratory study. Methods: Eight cadaveric knees from 6 donors (4 men, 2 women; mean age, 44.9 years) were tested. Each knee was tested for meniscal translation in 3 conditions: intact, posterior root released, and root repair. The repairs were fixed with an ASA device in a Mason-Allen configuration with knotless repair sutures. In each condition, the knees were axially loaded with 30 N through a range of motion to test meniscal excursion, extrusion, and hoop strain at 0°, 30°, 60°, 90°, and 100° of flexion for 10 cycles. Each parameter was compared for statistical significance using repeated-measures analysis of variance (ANOVA) or 1-way ANOVA, followed by Tukey post hoc tests. Results: Extrusion was significantly elevated in the PMMR released group compared with the native and repaired conditions at full extension ( P = .0008), 30° ( P = .007), 60° ( P = .0008), 90° ( P = .00006), and 100° ( P = .0005). Extrusion in the ASA repaired condition was similar to, or less than, the native condition across every position. Meniscal hoop strain in the repaired and intact groups was significantly increased compared with the released group ( P = .0009). Meniscal excursion was significantly greater with root release compared with intact and repaired groups at 30° ( P = .001), but less in the native condition at 60° ( P = .021) and 100° ( P = .018). Conclusion: PMMR ASA repair resulted in decreased excursion and extrusion compared with the meniscal root tear condition, extrusion, and hoop strain approximated that of native, intact meniscus through axial loading and knee range of motion in a human cadaveric model. Clinical Relevance: ASA PMMR demonstrated meniscal translation similar to that of the native meniscus under loading during knee motion, which could potentially enable more accelerated postsurgical rehabilitation. Future studies may define the clinical significance of healing rates and long-term outcomes.