Surgical fixation compared with cast immobilisation for adults with a bicortical fracture of the scaphoid waist: the SWIFFT RCT

Background: Scaphoid fractures account for 90% of carpal fractures and occur predominantly in young men. Immediate surgical fixation of this fracture has increased. Objective: To compare clinical and cost-effectiveness of surgical fixation with cast treatment and early fixation of those that fail to unite for scaphoid waist fractures in adults. Design: Multicentre, pragmatic, open-label, parallel two-arm randomised controlled trial with an economic evaluation and nested qualitative study. Setting: Orthopaedic departments of 31 hospitals in England and Wales recruited from July 2013 with final follow-up in September 2017. Participants: Adults (aged ≥ 16 years), presenting within two weeks of injury with a clear bicortical fracture of the scaphoid waist on plain radiographs. Interventions: Early surgical fixation using CE marked headless compression screws. Below elbow cast immobilisation for six to ten weeks, and urgent fixation of confirmed non-union. Main outcome measures: The primary outcome and end-point was the Patient Rated Wrist Evaluation (PRWE) total score at 52 weeks, with a clinically relevant difference of six points. Secondary outcomes included PRWE pain and function subscales, Short Form 12-item questionnaire (SF-12), bone union, range of movement, grip strength, complications and return to work. Results: The mean age of 439 participants was 33 years, 363 were male (83%) and 269 had an undisplaced fracture (61%). The primary analysis was on 408 participants providing valid PRWE outcome data for at least one post-randomisation time-point (surgery n=203 of 219; cast n=205 of 220). There was no clinically relevant difference in the total PRWE at 52 weeks: cast group mean 14.0 [95% confidence interval (CI) 11.3 to 16.6] and surgery group mean 11.9 (95% CI 9.2 to 14.5); adjusted mean difference of -2.1 in favour of surgery (95% CI -5.8 to 1.6, p=0.27). Non-union rate was low (surgery group n=1; cast group n=4). Eight participants in the surgery group had 11 re-operations, and one participant in the cast group required a re-operation for non-union. The base-case economic analysis at 52 weeks found the cost of surgery was £1,295 more per patient (95% CI £1,084 to £1,504) than cast treatment. The base-case analysis of a lifetime extrapolated model confirmed that the cast treatment pathway was the most cost-effective option. The nested qualitative study identified patients desire to have a “sense of recovering” which surgeons should address at the outset. Limitation: There were 17 participants who had initial cast treatment and surgery for confirmed non-union, 14 within six months from randomisation and three after six months. Three of four participants in the cast group, who had a non-union at 52 weeks, were not offered surgery. Conclusions: Adult patients with an undisplaced or minimally displaced scaphoid waist fracture should have cast immobilisation and suspected non-unions immediately confirmed and urgently fixed. Future work: Patients will be followed-up at five years to investigate the effect of partial union, degenerative arthritis, malunion and screw problems on their quality of life