Open surgery for isolated posterolateral corner injury with hypermobile lateral meniscus was successful at a minimum follow up of 2 years

Background: Isolated posterolateral corner (PLC) injuries classified as grade I/II or type B (Fanelli–Larson) may coexist with a hypermobile lateral meniscus (LM). Although lesions are often managed conservatively, residual rotational instability from LM hypermobility can persist, warranting surgery in patients. We evaluated outcomes of open repair for isolated PLC injury with hypermobile LM at a minimum 2-year follow up. Methods: Twenty-eight consecutive patients undergoing open repair were retrospectively evaluated at a minimum 2-year follow up (median, 2.8 years; interquartile range (IQR), 2.2–3.9). Conservative treatment was initiated in all patients, and surgery was considered after at least 3 months of persistent symptoms. Patient-reported outcomes (PROs) included the Lysholm score, subjective International Knee Documentation Committee (IKDC) score, Knee injury and Osteoarthritis Outcome Score (KOOS), and the Tegner activity scale. Rotational laxity was assessed with the dial test (30°/90°) and quantified bilaterally with the Rotameter. Results: Ninety-six per cent of patients were satisfied or very satisfied. Median postoperative Lysholm and subjective IKDC scores were 85 (IQR, 73–94 and 77–91, respectively); median KOOS was 85 (IQR, 71–93). The Tegner activity scale was unchanged (6 (IQR, 5–7) preinjury vs. 5 (IQR, 4–6) postoperatively). No side-to-side differences were detected on dial testing at 30° or 90°. Rotameter side-to-side differences were 0.6 ± 2.4° (internal rotation), 1.1 ± 4.5° (external rotation), and 1.7 ± 4.6° (total rotational laxity). Conclusions: Open repair for isolated PLC injury with a hypermobile LM yielded high patient satisfaction and favorable PROs, and restored rotational stability at mid-term follow up.