Time-Dependent Anchor Hole Expansion May Associate with Meniscal Extrusion After Open-Wedge High Tibial Osteotomy Combined with Medial Meniscus Posterior Root Tear Repair and Meniscal Centralization

Background: This study evaluated time-dependent changes in anchor hole width (AHW) and their association with postoperative medial meniscus extrusion (MME) in patients undergoing open-wedge high tibial osteotomy (OWHTO) with medial meniscus posterior root tear (MMPRT) repair and meniscal centralization. Methods: Thirty knees treated with combined OWHTO and MMPRT repair using the centralization technique were retrospectively reviewed. MRI, CT, and second-look arthroscopy were performed preoperatively and postoperatively. AHW of the MMPRT anchor and two centralization anchors (midbody and midbody–posterior, M-anchor and MP-anchor) were measured on multiplanar reconstruction CT images at 1, 3, and 6 months, and 1 year, and their correlations with postoperative MME were analyzed. Results: AHW increased up to 3 months and gradually decreased with surrounding sclerosis by 1 year. The M-anchor showed significantly greater mediolateral (ML) expansion than the MP-anchor and demonstrated a moderate positive correlation between 1-year AHW and MME (r ≈ 0.5, p < 0.01). Second-look arthroscopy confirmed a 90% healing rate of the repaired root. Conclusions: Although OWHTO combined with MMPRT repair and centralization achieved favorable root healing, postoperative MME progression was not fully prevented. Time-dependent ML anchor hole expansion around the M-anchor may indicate persistent micromotion, elongation of the meniscotibial ligament, and degenerative stretch of the repaired meniscus following healing, suggesting that even after successful root healing, ML motion remains difficult to control, highlighting the need for biomechanically optimized fixation.