Residual motion and function after glenohumeral or scapulothoracic arthrodesis.

The purpose of this study was to characterize humerothoracic motion and function after glenohumeral or scapulothoracic arthrodesis and to compare those results with those from normal shoulders. We evaluated 12 shoulders in 11 patients at an average of 71 months after glenohumeral arthrodesis and seven shoulders in six patients at an average of 32 months after scapulothoracic arthrodesis. The residual motion of the unfused articulation was measured with a spatial position sensor. Various activities of daily living and standard clinical range-of-motion tests were performed. Nearly all humerothoracic motions were significantly decreased in patients after either type of shoulder arthrodesis. Patients with a glenohumeral fusion maintained their scapulothoracic motion at levels comparable with that of normal subjects. Residual glenohumeral extension and external rotation after scapulothoracic fusion were significantly decreased; internal rotation remained unchanged compared with motion in subjects with normal shoulders. Glenohumeral fusion decreased the patients' ability to perform personal care activities requiring extremes of internal rotation or elevation. Although glenohumeral arthrodesis limited total humerothoracic motion considerably, the majority of patients were improved functionally and were relatively free from pain. Most personal care activities were performed successfully by all patients with scapulothoracic fusion.