One-Bone Forearm Procedure for Severe Recalcitrant Forearm Deformities in Masada IIb Hereditary Multiple Exostoses

Hereditary multiple exostoses (HME) Masada IIB has traditionally been treated by gradual ulnar lengthening with questionable efficacy in reducing the dislocated head. One-bone forearm (OBF) has been used as a reconstructive procedure in forearm deformities with very scarce literature for HME. The study aims to report short-term results of OBF as a definitive procedure for severe forearm deformities in Masada IIB patients with respect to clinical and radiological parameters.

Four patients with HME Masada IIb were included in this retrospective study. All patients complained of forearm and wrist deformity with an abnormal bony protrusion restricting elbow motion. Indications for OBF were ulnar shortening > 3 cm, dysplastic proximal radius with convex radial head and restricted prono-supination. All patients were examined pre-operatively and post-operatively clinically and radiographically using the Peterson's outcome score.

The average age was 13 years (12-14 years). Pre-operative ulnar shortening, carpal slip percentage, and radial articular angle was 3.4 cm, 79.5%, and 47.5°, respectively. All radial heads were dislocated with convex articular surface restricting elbow extension and forearm prono-supination. At the latest follow-up, the mean elbow flexion was 110° with forearm in 10° supination. The mean carpal slip percentage, radial articular angle, and Peterson functional grade was 15%, 22.5°, and 8 points, respectively. The mean follow-up period was 30.25 months with no recurrence.

We recommend one bone forearm as a definitive procedure in HME Masada IIB patients with severe forearm deformities with ulnar shortening > 3 cm and dysplastic proximal radius with a dislocated radial head, for faster return to function.