Analysis of Radiographic Parameters of the Forearm in Traumatic Radial Head Dislocation.

Background: Various deformities can occur in the forearm bones when the traumatically dislocated radial head is untreated for a long period. Without correction of all deformities, reduction of the dislocated radial head is difficult to maintain, and forearm and elbow motion will deteriorate after reduction. We evaluated radiographic parameters of forearms with traumatically dislocated radial heads (and of the normal sides) to understand the resulting deformities and the effectiveness of surgical treatment.

Methods: We analyzed pre- and postoperative anteroposterior and lateral radiographs of 22 forearms (22 patients) with traumatic radial head dislocation. We divided the forearm into three equal parts and measured various morphological parameters. All patients underwent surgical treatment and evaluation of radial head reduction and range of motion pre- and postoperatively.

Results: Before treatment, the middle of the ulna was significantly different from the unaffected side in both anteroposterior and lateral views. After surgery, the proximal ulna was significantly different from the unaffected side and the abnormal proximal radial neck angle persisted. The radial head was successfully reduced in 20 of 22 cases. Overall, the mean range of motion decreased after surgery, except for increased flexion-extension.

Conclusions: Complicated deformities developing during long-term remodeling after injury indicate that stable reduction is difficult to achieve with conventional one-bone osteotomy. Even after successful reduction, secondary deformity in the proximal ulna and/or remaining deformity in the proximal radius can hinder forearm rotation.