Rapidly progressive destructive arthropathy of the shoulder--a viewpoint on pathogenesis.

Two cases of rapidly progressive destructive shoulder arthropathy are described. Both patients were elderly women with generalized osteoarthropathy who had used forearm crutches for walking. Their shoulder disease was characterized by large, relatively painless effusions, low numbers of infiltrating leukocytes, biopsy evidence of mild inflammation, and radiological evidence of severe joint damage. Case 1 developed persistent drainage from a joint sinus, eventually necessitating arthrodesis. This complication has not previously been described in this condition. Hydroxyapatite crystals were demonstrated in the joint fluid in both cases but their pathological role is uncertain. We suggest that bearing weight through the upper limbs may hasten the development of degenerative arthritis in the shoulder, possibly by contributing to mechanical disruption of the rotator cuff.