Monoaxial distraction of ulna to second metacarpal followed by single bone forearm in massive post infective radial bone loss

Abstract

Introduction: Radial bone loss associated with gross manus valgus deformity can be managed by open reduction internal fixation using intervening strut bone graft, callus distraction using ring or monoaxial fixator, and achieving union by distraction histogenesis. These methods are particularly suitable when bone loss is small. Single or staged procedure is described for congenital as well as in acquired extensive bone loss of radius. Distraction through radial proximal to distal segments, to achieve reduction of distal radio-ulnar joint (DRUJ), is also described in acquired cases. In the present series, functional results of distraction through ulna to 2(nd) metacarpal is studied alongwith, functional status of hand, stability of wrist, level of patient's satisfaction are also studied.

Materials and methods: 7 unilateral cases of radial loss (M = 5, F = 2) affecting 4 right hands of mean age 17 years (range 9 to 24 years) were included in this study. They were treated by distracting through ulna to 2(nd) metacarpal to achieve DRUJ alignment in first stage. Subsequently ulna was osteotomised and translated to distal stump of radius. It was then fixed to the distal radial remnant in 30° pronation in dominant and 30° supination non dominant hands.

Results: Union was achieved in all cases associated with beneficial cross union of distal ulna. Hand functions improved near to normal, with fully corrected stable wrist joint, hypertrophied ulna and without recurrence. All of them had practically complete loss of forearm rotations, however patients were fully satisfied.

Conclusion: This method is particularly suitable when associated with 6 cm or more radial bone loss. But when loss is small, sacrifice of one bone may not be justifiable.

Keywords: Massive radial shaft loss; monoaxial distractor; single bone forearm; ulna to metacarpal distraction.

Figure 1

X rays images (a) showing gap between segments and amount of DRUJ dislocation (b) showing after applying distractor (c) Post fusion X-ray image when longitudinal K-wire in position (d) Post operated X-ray after complete fusion

Figure 2

Clinical photographs (a) showing radial deviation (b) with attempted ulnar deviation (c) during writing at final followup (d) during eating at final followup