title: Heterotopic ossification presenting as arthritis.
abstract: We report 4 patients with arthritis as a presenting manifestation of heterotopic ossification. This cause of arthritis has only recently been noted. The synovial fluids from all 4 patients showed low leukocyte counts (90, 670, 167 and 500/mm3) while the protein concentrations were discordantly high in 3 cases (3.1, 5.3, 4.3 and 2.6 g/dl, respectively). The mechanism for the relatively elevated synovial protein concentration is unknown. These findings may be useful for the early diagnosis of heterotopic ossification.
mesh_terms: D000328:Adult; D000368:Aged; D001168:Arthritis / Q000000981:diagnostic imaging* / Q000473:pathology; D003937:Diagnosis, Differential; D006801:Humans; D007958:Leukocyte Count; D008297:Male; D008875:Middle Aged; D009221:Myositis Ossificans / Q000000981:diagnostic imaging* / Q000378:metabolism; D011506:Proteins / Q000378:metabolism; D011859:Radiography; D013582:Synovial Fluid / Q000378:metabolism / Q000473:pathology
chemical_list: D011506:Proteins