Resistance of a defect of the supraspinatus tendon to intraarticular hydrodynamic pressure: an experimental study on rabbits.

Abstract

The healing of a standardized defect of the supraspinatus tendon in a time-related series on rabbits was monitored with arthrography and simultaneous determination of the intra-articular hydrodynamic pressure of the glenohumeral joint. All normal glenohumeral joints produced a biphasic pressure versus volume curve. Rupture of a normal glenohumeral joint occurred at a pressure level of 140-170 mm Hg and was located in the area around the biceps tendon sheath. In joints with a defect of the supraspinatus tendon, leakage of the contrast medium was evident up to the sixth week, at an intra-articular pressure varying from 40 to 100 mm Hg. After week 6, no leakage of the cuff was seen during the determination of the intraarticular pressure. This was in accordance with the histological findings: the defect was covered with solid scar tissue from the ninth week onward. Resistance to hydrodynamic intraarticular pressure proved a reliable method of determining the strength of the healing of the supraspinal defects.