Improved range of motion in three cases following axillary nerve hydrorelease after reverse shoulder arthroplasty: a case series.

Introduction: Quadrilateral space syndrome following a reverse total shoulder arthroplasty may be underdiagnosed owing to the difficulty in recognizing its symptoms. However, quadrilateral space syndrome following a reverse total shoulder arthroplasty may cause postoperative limitation of range of motion and affect clinical outcomes. The study aimed to report three cases of quadrilateral space syndrome after a reverse total shoulder arthroplasty, resulting in limited range of motion, in which hydrorelease of the axillary nerve improved the limited range of motion. Case report: This study presents three cases of limited anterior elevation and abduction (<100 degrees) at 3 months following a reverse total shoulder arthroplasty, in which hydrorelease of the axillary nerve for quadrilateral space syndrome led to rapid improvement, sustained at 1 year postoperatively. Furthermore, the American Shoulder and Elbow Surgeons score, Constant score, and Subjective Shoulder Value improved in all three cases. All three cases involved small female patients, each <150 cm in height. Although upper limb lengthening was modest (14-19 mm), the patients' small body size may have led to proportionally greater traction on the axillary nerve, potentially contributing to quadrilateral space syndrome. Conclusion: Hydrorelease of the axillary nerve may be effective in alleviating early postoperative limitations in anterior elevation and abduction in patients with quadrilateral space syndrome following a reverse total shoulder arthroplasty.