A comparison of two techniques for digital distraction lengthening in skeletally immature patients

Since 1987, 16 skeletally immature patients aged 2 to 16 years (mean, 7.9 years) underwent 27 digital lengthening procedures of terminal bones, 20 metacarpals and 7 phalanges, using the distraction callotasis technique. Seven digits were lengthened with 2 fixator half-pins on either side of the osteotomy site (dual half-pin group). Twenty digits, which were too small to accommodate 4 half-pins, were lengthened over a longitudinal intramedullary guidewire with 1 fixator half-pin on either side of the osteotomy site (single half-pin/K-wire group). No bone grafts were needed. The mean preoperative bone length in the dual half-pin group was 30 mm (range, 23-40 mm) and that of the single half-pin/K-wire group was 18 mm (10-30 mm). The mean total length gained was 14 mm (9-23 mm) in the dual half-pin group and 12 mm (6-19 mm) in the single half-pin/K-wire group. The mean percent lengthened was 49% (22% to 96%) in the dual half-pin group and 70% (27% to 136%) in the single half-pin/K-wire group. Eighteen complications occurred: 15 in the 20 cases using the central guidewire (75%) and 3 in the 7 cases without the central guidewire (43%). Only 7 complications required repeat surgery. We conclude that the use of the single half-pin/K-wire technique allows successful and substantial lengthening for bones shorter than 23 mm, making correction surgery possible for younger children. This technique, however, has a greater risk for complications.