Dynamic analysis of intraarticular pressure in the glenohumeral joint.

Dynamic analysis of intraarticular pressure was performed in 180 glenohumeral joints. The intraarticular pressure demonstrated characteristic changes during shoulder movement. In the healthy group minimum pressure was measured at 40 degrees of elevation in the scapular plane. In patients with contractures the pressure increased in the early phase of elevation and persisted. Pressure changes of the group with incomplete tears of the rotator cuff resembled those of the healthy group, whereas those in the massive tear group showed only slight pressure changes. When patients with rotator cuff tears had no limitation of arm elevation, pressure changes close to the normal pattern were found. However, when active elevation was markedly limited, no significant pressure changes were noted in some cases. In unstable shoulders the rate of pressure increase was slower, and the range of pressure changes was more limited than that in the healthy group. It is speculated that changes in intraarticular pressure reflect the intraarticular volume. Measurement of the intraarticular pressure may be clinically useful in functional assessment.