Mirror Hand Deformity: A Report of Two Cases.

Abstract

Mirror hand (ulnar dimelia) is an extremely rare congenital deformity in the upper extremity; only approximately seventy cases have been reported in the literature1,2 since the anomaly was first described in 1587 by Rueff3. The typical deformity consists of an absent radius, a duplication of the ulna, and polydactyly4,5. The elbow is generally stiff in extension, and the wrist is hyperflexed. The shoulder can be affected with instability and underdeveloped musculature1,6. The main functional problems that need to be resolved are the stiff elbow and the polydactylous hand. A resection of the olecranon process of one of the ulnae (usually the lateral “radial” one) is advised in order for the elbow7 to have improved flexion and pronation and supination. Early arthrolysis of the elbow joint has also been described8. For pollicization, the most normal finger is chosen to create a thumb9, and extensor tendons from the removed digits can be transferred to strengthen the new thumb7. We describe two patients who presented with mirror hand deformity. The patients and their parents were informed that data concerning their cases would be submitted for publication, and they provided consent. Case 1. A two-month-old girl presented with unilateral abnormalities to the left upper extremity (Fig. 1-A). There had been no perinatal medical problems, and the family history was negative for congenital anomalies. There was good movement in the shoulder. The elbow was extended with no sign of active flexion. The wrist was hyperflexed and could be passively extended to 0°. The hand had seven triphalangeal fingers. The most radial finger (number 1) did not show any sign of movement and was unstable. The other six fingers were active, but finger number 3 …