Mallet Finger Autofusion in Adolescent Post-Pin Fixation Surgery – A Case Report

INTRODUCTION: Mallet finger is a common hand injury in sports in which the terminal extensor tendon is disrupted. This case report describes the rare occurrence of joint autofusion following surgical fixation of an unstable mallet finger injury. CASE REPORT: We present a case of a 13-year-old right-hand dominant boy who sustained a right long finger bony mallet injury while playing football. Treatment consisted of closed reduction, percutaneous pinning of the right long finger distal interphalangeal (DIP) joint. He went on to heal with residual DIP joint stiffness and only 20° of residual motion that were noted on the early follow-up. Seven years later, he presented with no motion at the right long finger DIP joint. X-rays of his right long finger showed a complete fusion of bone across the DIP joint. CONCLUSION: Autofusion as a complication of mallet finger surgery is an unprecedently rare finding, especially in the absence of any predisposing factors. This complication must be considered when treating mallet finger injuries through surgical intervention. Fortunately, the loss of DIP motion, complete in this case, had no long-term effect on the overall use of this patient’s hand.