Intraoperative Lateral Hinge Fractures and Early Postoperative Pain Burden After Medial Opening Wedge High Tibial Osteotomy: Implications for Augmented Postoperative Analgesia.

Background Intraoperative lateral hinge fractures (LHFs) are common complications during medial opening wedge high tibial osteotomy (MOWHTO). While their radiological outcomes are well-studied, their impact on immediate postoperative pain remains underexplored. Purpose The aim of this study was to evaluate the relationship between LHFs and early postoperative pain intensity (visual analog scale [VAS] scores) following MOWHTO. Materials and methods We retrospectively reviewed 244 patients undergoing MOWHTO under spinal anesthesia. Patients were divided into a hinge fracture group (n = 95) and a non-hinge fracture group (n = 149). Fractures were classified using a novel MRI-based system. Preoperative pain sensitivity was balanced using needle-prick antibiotic sensitivity testing (AST) VAS scores. Postoperative day 1 (POD#1) VAS scores and analgesic use were compared under a standardized multimodal analgesic protocol. Results Baseline demographics and preoperative AST pain sensitivity were similar between groups (p = 0.1293). On POD#1, the hinge fracture group experienced significantly higher mean pain intensity than the non-fracture group (mean VAS: 3.82±1.97 vs. 3.30±1.85; p = 0.0411) and trended toward higher rates of moderate-to-severe pain (31.6% vs. 19.5%), though this categorical distribution did not achieve strict statistical significance (χ² = 4.95, p = 0.084). Importantly, multivariable regression confirmed that sustaining a hinge fracture remained an independent predictor of elevated pain regardless of age, sex, or BMI (β = 0.53, p = 0.036). Fracture morphology did not significantly influence pain levels (p = 0.434). Total analgesic consumption was uniform across both cohorts (p = 0.9981) Conclusion While intraoperative LHFs are associated with a statistically significant increase in early postoperative pain following MOWHTO, the mean difference (0.52 points) does not meet the commonly accepted minimal clinically important difference. This indicates that a rigorous, standardized multimodal analgesic protocol effectively neutralizes the excess nociceptive burden associated with the fracture. Clinicians utilizing robust multimodal pain pathways can proceed with early rehabilitation protocols without the need to drastically alter their postoperative management when an LHF occurs.