A new dynamic testing apparatus to study glenohumeral joint motion

A dynamic shoulder testing apparatus has been developed to examine unconstrained glenohumeral joint motion in human cadaveric full upper extremities. Six computer-controlled hydraulic cylinders are used to simulate muscle action, while the corresponding tendon excursions and six-degree of freedom joint motion are measured. Trials showed that the testing apparatus creates highly reproducible glenohumeral joint motion in the scapular plane. The apparatus can be used to examine the function of the shoulder musculature and capsuloligamentous structures during normal and pathologic motion at the glenohumeral joint.