A child with type I ulnar ray deficiency.

Ulnar ray deficiency is the least common type of congenital longitudinal deficiency, and it shows several distinct manifestations, including various finger deformities [1].

To date, no reports have been published describing ulnar ray deficiency with multiple finger deformities, including central polysyndactyly, ectrodactyly, and first-web space narrowing. We describe the case of a patient with type I multiple-finger deformities.

A 6-year-old girl had a shorter left arm and 3 digits, with central polysyndactyly on her left hand (Fig. 1). The radiographic findings are presented in Fig. 2. The extra digit interfered with her ability to grasp and pinch, and she was only able to use the thumb and middle finger for these purposes. Therefore, excision of the non-functional index finger was performed, and the web space was reconstructed to improve the range of motion (Figs. 3, 4).

Fig. 1.

Clinical photograph of the left hand. The index finger was present in the form of central polysyndactyly, and the ring and little fingers were absent.

Fig. 2.

Radiograph of the left extremities. The supernumerary digit on the index finger had a short proximal and distal phalanx and only the head of the metacarpal bone. The hamate, pisiform, triquetrum, and lunate were absent.

Fig. 3.

Operative design for reconstruction of web space and correction of syndactyly.

Fig. 4.

Findings at 1 day postoperatively. (A) Palmar side and (B) dorsal side.

At 1 year postoperatively, her index finger still had limitations of motion and joint function, and power had not recovered. She usually used her thumb and middle finger to grab, pinch, and grip (Fig. 5).

Fig. 5.

Findings at 1 year postoperatively. (A) Resting position and (B) grasping position.

Although the appropriate treatment of ulnar deficiency is not clear-cut, previous studies have emphasized the importance of operating upon hand deformities to improve functionality, and it has been stated that syndactyly should be released between 6 and 12 months of life [2,3]. In this case, the patient’s index finger did not have normal anatomy, and the operation was delayed until 6 years of age. At that time, it could be conducted in a way that would not affect her finger movement. Based on this case, the timing of surgical treatment of complicated hand deformities should be planned carefully in order to maximize function.