Abstract
Entrapment of the extensor indicis proprius (EIP) after open reduction and internal fixation (ORIF) of the distal ulna with a plate and screw construct is rare. By literature review, we found evidence of such complication associated with distal radius fracture, but no past reports relating to the distal ulna. ORIF of the distal ulna is a common procedure for both fracture treatment and deformity correction. Due to the EIP muscle originating primarily from the dorsoradial surface of the distal ulna and the adjacent interosseous membrane, the muscle may be damaged or compressed by a fixation plate during ORIF, resulting in entrapment. We present two case reports of this rare complication, describing the method of clinical diagnosis, surgical treatment, and outcome. Our accompanying cadaver dissection provides an explanation for proper plate positioning during ORIF of the ulna to reduce the risk of EIP entrapment.