Radiological outcome of early surgical fixation versus cast immobilization for adults with a scaphoid waist fracture:five-year follow-up of the Scaphoid Waist Internal Fixation for Fractures Trial

Aims In the Scaphoid Waist Internal Fixation for Fractures Trial (SWIFFT), surgical fixation was compared with cast immobilization, with the primary endpoint being the outcomes at one year. The aim of the current study was to assess the radiological outcomes (union and the development of osteoarthritis (OA)) of the two forms of treatment at five years. Methods Patients who remained in the trial at five years after randomization were invited to have plain radiographs and a CT scan of the injured wrist, and a posterior-anterior radiograph of the contralateral wrist. This imaging was reviewed by three observers independently for union of the fracture and the distribution and severity of OA. This analysis followed a pre-specified statistical analysis plan. The relationship between OA and the Patient-Rated Wrist Evaluation (PRWE) scores at five years was assessed. Results Of the 439 patients who were randomized, 267 (60.8%) provided imaging at five years. Their characteristics were similar to those of the original cohort. A total of 182 patients (68.2%) (n = 92 fixation, n = 90 cast) had complete union and seven had a nonunion (2.6%; n = 3 fixation, n = 4 cast). Fractures with a minimum of 20% union at one year consolidated with the passage of time without intervention. Progression of OA in the joints around the scaphoid was seen in both groups from baseline to five years. By five years, 140 patients (52.4% of those with imaging at five years) had OA in at least one joint with similar prevalences in both groups. The prevalence of OA, the number of arthritic joints and the maximum severity of OA, was similar in the two groups. A total of 344 of the initial cohort of 439 patients (78.4%) provided a valid PRWE score at five years and the mean score was higher in those with more severe OA, indicating worse pain and function. Conclusion Between one and five years after randomization, union consolidated in those with > 20% bridging without intervention. The proportion of patients with full, almost full, partial, slight, and nonunion for the two forms of treatment remained similar at five years. The prevalence and severity of OA increased during the five years but was similar in both groups. Cite this article: Bone Joint J 2026;108-B(1):87–95.