Extensor Retinaculum Graft for Chronic Boxer’s Knuckle

PurposeBoxer’s knuckle is a tear of the metacarpophalangeal (MCP) joint capsule that occurs while punching. Because of the nature of boxing, boxer’s knuckle tends to be a chronic condition and often is associated with sagittal band rupture. Chronic cases often feature excessive scarring in the damaged area where the sagittal band and the MCP joint capsule become indistinguishable. The purpose of this study was to ascertain whether extensor retinaculum grafting to the defect is useful in treating chronic boxer’s knuckle when direct repair of a capsular tear is not possible.MethodsIn 5 professional boxers with chronic boxer’s knuckle in whom capsular repair could have impaired MCP joint flexion, scar tissue of the damaged capsule and the sagittal band—if ruptured—were removed and an oval extensor retinaculum graft was sutured in the capsule/sagittal band defect. The mean age of the patients was 22 years. In all patients, surgery was performed on the middle finger. The capsule was damaged on the ulnar side in 3 patients and on the radial side in 2 patients.ResultsAll boxers reported alleviation of pain when punching. The range of motion for the MCP joint was not restricted after surgery in any patient. Tendon dislocation did not occur after surgery in any patient. All 5 patients were able to return to professional competition.ConclusionsExtensor retinaculum grafting is useful in treating chronic boxer’s knuckle if the damaged capsule cannot be repaired directly.Type of study/level of evidenceTherapeutic, Level IV.