Can medial stability be preserved after open wedge high tibial osteotomy?

Purpose: This study evaluated the medial joint stability after high tibial osteotomy (HTO) releasing the superficial medial collateral ligament (sMCL) without cutting and repairing. Methods: Twenty-one patients who performed HTO were enrolled. After an L-shaped incision was made in the pes anserinus, the sMCL was released from the distal portion during surgery. After plate fixation, the sMCL was reattached and the pes anserinus was repaired underneath the plate. Plate removal was performed after 31.1 ± 14.2 months. Before HTO, a valgus force of 40 N was exerted at extension for reference values. Before and after plate removal, a valgus force of 40 N was exerted at extension and at a flexion position of 20°. Medial stability was evaluated by measuring the joint line convergence angle (JLCA). Results: The JLCAs in the extension state before HTO and plate removal were 1.64° ± 1.15° and 1.83° ± 1.36°, respectively; there was no significant difference (p = 0.198). There was also no significant difference in JLCA before HTO and after plate removal (p = 0.835). There was also no significant difference in JLCA before and after plate removal both at a knee extension and flexion position of 20° (p = 0.348 and p = 0.456, respectively). Conclusions: Releasing the sMCL without cutting and repairing the pes anserinus underneath the plate during medial open wedge HTO could facilitate the maintenance of medial joint stability.