Outcomes of anconeus interposition for proximal radioulnar synostosis

Background/HypothesisProximal radioulnar synostosis after elbow injuries can produce debilitating contractures. The estimated range of motion required to perform many activities of daily living is a 100° arc of forearm rotation. We hypothesized that excision of heterotopic bone and anconeus flap interposition could restore functional prono-supination in patients with proximal radioulnar synostosis.MethodsPatients with proximal radioulnar synostosis were subdivided into 2 groups on the basis of etiology: (1) as a complication after distal biceps tendon repair or (2) as a result of direct trauma to the proximal forearm/elbow. All patients underwent an excision of the synostosis with interposition of an anconeus flap and were observed clinically for a minimum of 6 months.ResultsTwenty-three patients (16 men, 7 women) were included, with a mean age of 47 years and mean clinical follow-up of 4.8 years. Mean arc of forearm rotation improved from 21° to 132°, pronation increased from 12° to 70°, and supination increased from 9° to 62° (P < .0001). Patients with biceps tendon repair etiology (n = 7) displayed greater gains in pronation and a trend toward greater total forearm rotation than did those with a traumatic etiology (n = 16).ConclusionAnconeus interposition flap for management of proximal radioulnar synostosis produces significant and reliable clinical improvement in elbow prono-supination. Patients with biceps tendon repair etiology had a trend toward greater motion improvement than that of patients with a traumatic etiology. The degree of improvement seen would provide nearly full restoration of functional motion, resulting in minimal limitations in activities of daily living.