Proximal congenital radial-ulnar synostosis and synchondrosis; pathogenic concept and a new therapeutic method

BACKGROUND CONTEXT Proximal congenital radial-ulnar synostosis (PCRUS) is defined by the development before birth of a bony bridge between the radius and ulna, usually at the proximal level, which blocks forearm rotation. This anomaly is rarely reported in the medical literature, because of its low prevalence, and treatment usually yields unsatisfactory results. The most commonly used surgical interventions are: forearm repositioning osteotomies with derotation of the radius and ulna, segmental resections of the middle third of the radius with muscular interposition, resection of the synostosis with the interposition of fatty tissue, tendons or fascia lata and resection of the proximal radius along with the transfer of the distal extensor carpi ulnaris tendon on the lateral edge of the radius. PURPOSE To describe a new treatment method for PCRUS, which we based on a new pathogenic concept, and to present our preliminary results. MATERIALS AND METHOD Between 2011 and 2013 our team performed two myo-osteo-arthroplastic reconstructions of the elbow and forearm for PCRUS. The intervention involves the extraperiosteal stripping of the origins of the ventral forearm musculature, release of the interosseous membrane, resection of the proximal two thirds of the radius, reshaping of the synostosis, a double osteotomy of the ulna and the transfer and fixation of a proximal fibular graft, including the head with its articular cartilage, in place of the resected segment of the radius. RESULTS Our preliminary study reveals favorable postoperative results, in comparison with other published methods. At the latest follow-up, one case had -10 degrees of pronation and 68 degrees of supination, and the other had 10 degrees of pronation and 66 degrees of supination. CONCLUSIONS Compared with other techniques, myo-osteo-arthroplastic reconstruction may seem overly invasive. However, the extent of this intervention is mandated by the pathogenic concepts of helical distortion, muscular retraction and anomalous configuration of the interosseous membrane. Benign cases do not require surgery. When there is no helical distortion, the intervention may be limited to the transfer of the proximal extremity of the fibula for the infant and small child.