Persistent hemarthrosis of the shoulder joint with a rotator-cuff tear in the elderly.

Three elderly patients developed persistent hemarthrosis of the shoulder joint without having suffered injury. Complete tears of the rotator cuff, attrition of the undersurface of the acromion, and instability were noted in the affected shoulders. Synovial fluids examined from two patients contained many alizarin red S-positive microspheroids. The synovium obtained at surgery from two patients showed hypervascularity, vasodilatation, and severe degenerative changes of collagenous tissues. The tendon of the m. supraspinatus showed infiltrations of multinucleated giant cells around calcified deposits consisting of hydroxyapatite crystals. Anatomical and mechanical derangements, and possible biological reactions following phagocytosis of hydroxyapatite crystals, may have contributed to the persistent hemorrhage in the shoulder joints.