RESUMO
BACKGROUND: The primary goal after open reduction and internal fixation of an established scaphoid nonunion is to achieve union. Low-intensity pulsed ultrasound (LIPUS) has been reported to increase the rate of union and to decrease the time to union for multiple fractures and nonunions in clinical and animal models. The evidence for LIPUS in the treatment of scaphoid nonunion, however, is sparse. The aim of this study was to assess whether active LIPUS (relative to sham LIPUS) accelerates the time to union following surgery for scaphoid nonunion. METHODS: Adults with a scaphoid nonunion indicated for surgery were recruited for a multicenter, prospective, double-blinded randomized controlled trial. After surgery, patients self-administered activated or sham LIPUS units beginning at their first postoperative visit. The primary outcome was the time to union on serial computed tomography (CT) scans starting 6 to 8 weeks postoperatively. Secondary outcomes included patient-reported outcome measures, range of motion, and grip strength. RESULTS: A total of 142 subjects completed the study (69 in the active LIPUS group and 73 in the sham group). The average age was 27 years, and the cohort was 88% male. There was no difference in time to union (p = 0.854; hazard ratio, 0.965; 95% confidence interval, 0.663 to 1.405). Likewise, there were no differences between the active LIPUS and sham groups with respect to any of the secondary outcomes, except for wrist flexion at baseline (p = 0.008) and at final follow-up (p = 0.043). CONCLUSIONS: Treatment with LIPUS had no effect on reducing time to union in patients who underwent surgical fixation of established scaphoid nonunions. LEVEL OF EVIDENCE: Therapeutic Level I. See Instructions for Authors for a complete description of levels of evidence.
RESUMO
BACKGROUND: Between 2014 and 2020, candidates for scaphoid non-union (SNU) surgery were enrolled in a prospective randomized trial (Scaphoid Nonunion and Low Intensity Pulsed Ultrasound [SNAPU] trial) evaluating the effect of low-intensity pulsed ultrasound on postoperative scaphoid healing. At trial completion, 114/134 (85%) of these patients went on to union, and 20/134 (15%) went on to persistent SNU (PSNU). The purpose of this study was to use this prospectively gathered data to identify patient-, fracture-, and surgery-specific risk factors that may be predictive of PSNU in patients who undergo surgery for SNU. METHODS: Data were extracted from the SNAPU trial database. The inclusion and exclusion criteria of this study were the same as that of the SNAPU trial. Nineteen patient-, fracture-, and surgery-specific risk factors were determined a priori. A stepwise multivariable logistic regression model was used to identify independent risk factors for PSNU. RESULTS: Three risk factors were found to be independently significant predictors of PSNU: age at the time of surgery, dominant hand injury, and previous surgery on the affected scaphoid. With every decade of a patient's life, dominant hand injury, and previous scaphoid surgery, the odds of union are reduced by 1.72 times, 7.35 times, and 4.24 times, respectively. CONCLUSION: We identified three independent risk factors for PSNU: age at SNU surgery, dominant hand injury, and previous surgery on the affected scaphoid. The findings of this study are significant and may contribute to shared decision-making and prognostication between the patient, surgeon, and affiliated members of their care team.