Clinical effectiveness 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 using the Patient-Rated Wrist Evaluation (PRWE) score at one year as the primary endpoint. The aim of this longer-term study was to assess the clinical effectiveness of the two treatment pathways at a five-year follow-up. Methods: Patients who had not withdrawn from the trial were invited for a clinical assessment at five years after randomization and asked to complete a patient-reported questionnaire in the clinic, or by post or telephone. The PRWE was collected along with the grip strength, range of motion (ROM), imaging data, EuroQol five-dimension three-level questionnaire (EQ-5D-3L) score, and the use of health resources. The repeated measures analysis model used at one year was repeated to include the five-year timepoint. Results: A total of 344 patients provided a valid PRWE score at five years (78.4% of the original cohort). There was no significant difference between the groups at five years (mean difference 0.6 (95% CI -2.4 to 3.6); p = 0.709). These results were robust to sensitivity analyses, restricting data collection windows. Neither the pain and function subscales of the PRWE score nor the overall estimate of the treatment effect showed a significant difference between the groups. Neither non-compliance with allocation of treatment, the displacement of the fracture, nor the patient's preferred treatment at baseline had an effect on the PRWE scores between groups. Only seven patients for whom imaging was collected at five years had a nonunion, three of 146 (2.1%) in the fixation group and four of 121 (3.3%) in the immobilization group. Grip strength and ROM were similar between the groups. Conclusion: The clinical effectiveness of the two forms of treatment remained similar at five years. The recommendation that adult patients with a fracture of the waist of the scaphoid which is displaced by ≤ 2 mm should be treated inially with immobilization in a cast, followed by early fixation of a nonunion, is further corroborated by these findings.