Metabolic and endocrine disease and arthritis.

Many metabolic and endocrine disorders have effects on the musculoskeletal system, either due to primary changes in bone and collagen or resulting in secondary arthritic and bone changes. Disorders of ossification include heterotopic ossification, diffuse idiopathic skeletal hyperostosis (DISH), and the spondyloarthropathies. The early stages of heterotopic ossification have been analyzed using immunohistochemical techniques to trace the distribution of noncollagenous proteins. Several radiographic features of DISH and ankylosing spondylitis were discussed, including rib hyperostosis and syndesmophytes. Hypertrophic osteoarthropathy with associated arthritis was described in seven patients with hepatic failure and transplantation. Remarkable improvement in arthritis followed transplantation. The inverse relationship between osteoarthritis and osteoporosis continues to be studied, and it has been hypothesized that genetics play a major role in determining the rate of bone turnover, resulting in, for example, "bone formers." Both growth hormone excess and deficiency lead to changes in the incidence of osteoarthritis. Finally, one study documented the improved outcome in joint replacements in hemophiliac patients.