Long-term outcomes following scaphoid nonunion surgery: the role of structural severity, avascular necrosis, and surgical timing.

backgroundThis study aimed to evaluate the long-term clinical and radiological outcomes of patients undergoing surgical treatment for scaphoid nonunion and to examine the independent effects of surgical timing and preoperative avascular necrosis (AVN) on postoperative recovery.

methodsThis retrospective cohort study included 71 adult patients who underwent surgical treatment for scaphoid nonunion between 2011 and 2020 and had a minimum follow-up of five years. Variables included demographic characteristics, surgical timing, pre-operative AVN, and radiographic severity. Clinical outcomes were assessed using the Visual Analog Scale (VAS), Patient-Rated Wrist Evaluation (PRWE), and Mayo Wrist Score (MWS). Radiological evaluation included scaphoid nonunion advanced collapse (SNAC) staging, scapholunate angle (SLA), radiolunate angle (RLA), and carpal height index. Multivariate linear and logistic regression analyses were performed to identify independent predictors of functional improvement, union, complications, and reoperation.

resultsThe mean patient age was 34.4±7.1 years, and the mean follow-up duration was 78.4±10.3 months. Preoperative AVN was present in 29.6% of patients. Union was achieved in 76.1% of patients, while complication and reoperation rates were 26.8% and 18.3%, respectively. In univariate analysis, surgery performed within 12 months of injury was associated with greater improvement in resting pain (p=0.046), and the absence of AVN was associated with greater improvement in pain scores and MWS (p<0.05). After adjustment for baseline pain and radiographic severity, surgical timing was no longer independently associated with pain improvement (p=0.056), whereas AVN remained an independent predictor of reduced symptomatic recovery (p<0.001). No variable independently predicted union. The preoperative SNAC stage was associated with complications (p=0.007), and Schernberg classification predicted reoperation (p=0.011). Radiographic parameters were not associated with functional outcomes. These findings suggest that biological and structural disease burden may have a greater influence on long-term recovery than surgical timing alone. Although vascular compromise appears to limit symptomatic improvement despite surgical intervention, structural severity influences the risk of adverse postoperative events. The absence of a correlation between radiographic healing and functional outcomes underscores the complex and multifactorial nature of recovery after scaphoid nonunion surgery.

conclusionSurgical timing and radiographic union were not independently associated with long-term functional recovery. In contrast, preoperative AVN predicted less symptomatic improvement, whereas structural severity, reflected by SNAC stage and Schernberg classification, was associated with postoperative complications and reoperation.