Digital Ray Reconstruction via Distraction Osteogenesis Lengthening

Abstract

Background: Adequate length is a prerequisite for a functional digit. Over the last 20 years small external fixators have been developed allowing the principles of distraction osteogenesis to be applied to the small bones of the hand and thus permitting digital lengthening and realignment in patients that have suffered a traumatic or congenital amputation of a digit. Aim: Presentation of our series and analysis of the results. Patients and methods: From 1998 to 2005, 32 patients (41 rays) were treated with metacarpal or phalangeal lengthening through distraction osteogenesis using a monolateral frame with two half pins on each site of the osteotomy. The mean age of the patients was 21 years (4-48) and the indications were traumatic amputation in 25 and congenital amputation (transverse deficiency, brachydactyly, constriction band syndrome) in 7. The technique included dorsal approach, pin placement, drilling of the osteotomy site and if necessary realignment of the clinodactyly. The lengthening was started 5 days postop and proceeded with a rate of 1 mm per day in four 0.25 mm increments. The mean distraction period was 3 weeks and the mean consolidation period was 7 weeks. No protective splinting or additional bone grafting was necessary. Results: The distraction callus consolidated in all patients. The mean total length gained was 17.5 mm (68% of the original length). In one patient the holding screw of a miniclamp failed, leading to angulation at the distraction site and the fixator had to be revised. In 2 patients with pseudarthrosis late internal fixation and bone graft was done. No infection fracture or half pin loosening were observed. Conclusions: Callotasis using contemporary monolateral external fixators is a reliable technique for digital ray lengthening. Meticulous surgical technique and close observation of the patient during the distraction period are necessary in order to avoid complications. Over 2 cm of lengthening can be achieved.