Chondrocalcinosis

Chondrocalcinosis is the term employed to describe a chronic articular disease characterized by: (a) acute, intermittent attacks of joint pain and inflammation; (b) the presence of a specific crystalline material in the synovial fluid, cartilage, and periarticular soft tissue; (c) a typical roentgenographic appearance of calcium deposition in the articular cartilage of the involved joints. The etiology is unknown but a hereditary nature, as pointed out by Zitnan and Sit'aj (12), suggests a metabolic disturbance. The condition was first described by Israel-ski in 1931 (5), and subsequent reports in the literature have brought the total number of recorded cases to 70 (1, 3, 4, 6–12). The condition is not rare, and within the past year we have observed 18 patients with the disease. This report summarizes our experiences with this heretofore infrequently recognized entity. Clinical Features The sexes were equally represented with 8 men and 10 women, and no racial predilection was noted. The patients ranged in age from forty-one to eighty-three years with the majority in the sixth and seventh decades. The history of articular complaints varied from two weeks to forty years. In 16 instances the joint disease was idiopathic. In 2 additional patients similar clinical and radiographic features developed during the course of hyperparathyroidism; association of the two diseases has been previously reported (2, 6, 13). Joint symptoms were acute and episodic in 8 patients; in an additional 7 they were initially intermittent but became chronic. One case was chronic throughout the course, and another with hyperparathyroidism revealed typical roentgen findings of chondrocalcinosis in the absence of any joint symptoms. The episodic attacks were often suggestive of gouty arthritis with abrupt onset of joint pain and swelling which lasted from a few days to several weeks. The knees were involved in most cases, the shoulder, ankles, and back commonly, but the small joints of the hands and feet infrequently. Clinical evidence of joint disease usually paralleled the radiologic findings, but some instances of inflammation were noted in roentgenographically normal joints. Laboratory Findings Examination of synovial fluid from the knee joints of 9 patients disclosed the presence of multiple small rod-shaped and rhombic crystals (Fig. 1), not like the sodium monourate crystals observed in gout. They are only weakly birefringent, insoluble in alkali, and not digested by uricase. X-ray diffraction studies revealed them to be calcium pyrophosphate crystals. Other pertinent laboratory findings included negative tests for rheumatoid factor and normal serum uric acid concentration. Arthrotomy in one patient disclosed marked degenerative changes in the articular cartilage and meniscus.