SNAPU: A Randomized Controlled Trial Comparing Low-Intensity Pulsed Ultrasound to Sham in the Treatment of Operatively Managed Scaphoid Non-Unions
Neil J White, MD, FRCS(C)1, Gurpreet S Dhaliwal, MD, FRCS(C)1, Ethan D Patterson, Medical Student2 and Kevin A Hildebrand, MD, FRCS(C)1, (1)University of Calgary, Calgary, AB, Canada, (2)Queens University, Kingston, ON, Canada
The surgical problem of scaphoid non-union is complex, and achieving union, thus preventing progression to arthritis, is paramount. This study aims to assess whether adjunctive low intensity pulsed ultrasound (LIPUS) versus sham accelerates the rate of union after surgery for an established scaphoid non-union.
This was a national, multicentre, prospective, double-blinded randomized controlled trial. After surgery for an established scaphoid non-union (SNU) patients self-administered LIPUS over the scaphoid for 20 minutes once daily beginning at their first post-operative visit. Visually identical active and sham Exogen 4000 LIPUS units were randomly allocated to patients. The primary outcome was time to union as evidenced on serial CT scans. Secondary outcome measures were: Disability, Shoulder, Arm and Hand (DASH), SF-36, Pain Visual Analogue Scale (VAS), range of motion, and grip strength.
There were 69 patients in the LIPUS group, and 73 in the placebo group. Eighty-eight percent were male sex with an average age of 27 years at time of surgery. The hazard ratio for the primary analysis was 1.018 (95% CI = 0.691-1.5) (P=0.93), showing no difference in time to union between LIPUS and placebo groups. Subgroup analyses of proximal pole and scaphoid waist fractures revealed hazard ratios of 1.265 (95% CI = 0.574-2.788) (P=0.56) and 0.965 (95% CI = 0.605-1.539) (P=0.88), respectively. Analysis by device compliance also showed no differences between groups. Baseline and secondary outcomes demonstrated no statistically significant differences between treatment groups, though all subjects showed an improvement after surgery.
Treatment with LIPUS had no effect on reducing time to union in patients who underwent surgical fixation of established scaphoid non-unions.
Level of Evidence: Therapeutic Level I
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