Forearm Hereditary Multiple Exostosis: A Retrospective Case Series Study

Abstract

Background Hereditary multiple exostosis (HME) is a significantly rare genetic condition with benign chondrogenic lesions affecting long bones. Forearm involvement is relatively common, with varied treatment modalities reported. Here we describe our experience with HME. The study is the first of its kind to be conducted in the Middle East and Saudi Arabia. Methods A retrospective medical record-based case review was carried out on patients with forearm HME operated from 2006 to 2022 at our institution. Patient demographics, clinical presentation, management, outcome, Masada scale, and radiological outcomes were analysed. Results Ten patients (12 affected forearms) with HME were included. The average age of those undergoing surgery was 12.7 ± 5.13 years, and the average length of follow-up was 62.25 months. Most patients (n = 5, 50%) had Masada type 1 (Type I indicates radial head not displaced, primary exostosis from the distal region of the ulna, ulna relatively short, radius bending). Five (50%) underwent radial head resection. The majority of the patients (n = 8, 80%) had no complications or recurrence. Two patients developed recurrence; the first one developed recurrent radial bone deformity and dislocation of the radial head and the second, who underwent excision with an iliac crest bone graft application, developed osteolysis of the bone graft with recurrent deformity. Conclusion HME is typically managed primarily by excision of the lesion at skeletal maturity and annual check-up and radiological follow-up. If a secondary procedure is needed in future, simple excision of the dislocated radial head would be the most feasible approach. Due to the rarity of the illness and limited literature, further studies are still required to optimize the outcome in children with HME.

Keywords: benign forearm tumors; clinical experience; diaphyseal aclasis; forearm; metachondromatosis; multiple hereditary exostosis; osteochondromas; saudi arabia.

Figure 1. A schematic illustration shows the landmarks used to measure the different radiological data included. Ulnar variance (rose color) is the distance between two horizontal lines across the linear axes of the radius and the ulna from the internal diaphyseal plate of the radius and the base of the head of the ulna. The radioarticular angle (red color) is the angle of inclination of the distal articular surface of the radius to the long axis of the forearm. Carpal slip (green color) is the percentage of the lunate on the ulnar side of the continuation of the linear axis of the forearm.

The image was illustrated by Dr. Hatan Mortada, the second author RAA: radial articular angle

Figure 2. Preoperative and postoperative clinical and radiological images of Case 2 (HME and a forearm deformity, Masada type IIA): (A) Postoperative images of the left forearm show the recurrent radial bone deformity and radial shortening with bowing after six years of the surgery; (B) Another clinical image shows the swelling; (C) Preoperative radiological image showing ulnar styloid exostosis and deformity of the distal radius; (D) Preoperative lateral image; (E) Radiological images following excision of exostosis and corrective osteotomy of the radius six years after the surgery; (F) Lateral view postoperatively

HME: hereditary multiple exostosis

Figure 3. Preoperative, intraoperative, and postoperative radiological images of Case 4 (HME and a forearm deformity - Masada type I): (A) Preoperative image of the left forearm show exostosis with radial articular angulation of 47 degrees and carpal slip of 50%; (B) Preoperative lateral view; (C) Intraoperative images after excision of the exostosis, iliac crest bone graft application, and K-wire fixation; (C) Intraoperative image, including the hand; (D) Intraoperative image lateral view; (E) Radiological image showing almost complete osteolysis of the bone graft and recurrence of the deformity after five years of the surgery; (F) Lateral view postoperative after osteolysis

K-wire: Kirschner wire; HME: hereditary multiple exostosis