A randomized controlled trial of arthroscopic capsular release versus hydrodilatation in the treatment of primary frozen shoulder

Background Arthroscopic capsular release (ACR) and hydrodilatation (HD) have been developed for the management of frozen shoulder refractory to conservative treatment. To date no randomized trial has directly compared the efficacy of both interventions. The aim of this trial was to determine whether the Oxford Shoulder Score (OSS) differs between patients with frozen shoulder randomized to treatment with ACR or HD. Methods Patients presenting with severe idiopathic frozen shoulder deemed suitable for surgical intervention by a consultant shoulder surgeon were randomized to ACR or HD. The primary outcome measure was OSS at 6 months, with secondary outcomes measures of the EuroQol-5D visual analog scale, external rotation, complications, and crossover rate also recorded. Results Between June 2013 and December 2016, 50 patients were randomized to HD or ACR. The average age of the HD and ACR cohorts was 55.2 and 52.6 years, respectively ( P  = .36). At 6 months after the intervention, 20 patients were available for follow-up in the HD cohort and 19 in the ACR cohort. Both groups demonstrated significant improvements in OSS from baseline, but the OSS was significantly higher in the ACR cohort than the HD cohort (43.8 vs. 38.5, P  = .023). The OSS was noted to improve rapidly after the intervention, with 75% of improvement in OSS noted at 6 weeks after surgery in both groups. Conclusions Patients randomized to ACR reported a significantly higher OSS at 6 months than those randomized to HD. Both groups, however, showed a significant improvement.