Open-wedge osteotomy for thumb radial angulation in Apert syndrome using a bone-graft substitute

A short thumb with radial angulation causes loss of hand function in patients with Apert syndrome. Although past reports have described various procedures for the correction of the thumb, there has been no consensus on the best procedure. This study aimed to assess the clinical and radiographic results of a surgical technique for the correction of a thumb radial angulation deformity: open-wedge osteotomy using a bone-graft substitute. Ten patients (18 thumbs) who underwent open-wedge osteotomy on the proximal phalange using a bone-graft substitute were evaluated retrospectively. The open-wedge osteotomies had been performed at the center of the proximal phalanx. Thumb radial angles and thumb lengths were measured on radiographs, and the clinical results were investigated, including bone union and complications. The median patient age at the time of surgery was 5.8 years, and the average follow-up period was 6.7 years. The average thumb radial angle was 57.3° preoperatively, 6.5° immediately postoperatively, and 19.8° at the most recent follow-up. The average thumb length was 12.1 mm preoperatively, 18.1 mm immediately postoperatively, and 22.3 mm at the most recent follow-up, indicating an extension effect of more than 50% immediately postoperatively. In all cases, the artificial bone had been absorbed and developed into autologous bone, and there were no complications such as infection and skin necrosis. These findings suggest that open-wedge osteotomy with an artificial bone substitute is simple and effective for treating radial-angulation deformities in patients with Apert syndrome. Level of evidence: Level IV - retrospective case series.