An X-ray absorptiometry study of reflex sympathetic dystrophy syndrome.

X-ray absorptiometry (Lunar DPX) was performed before and after treatment to determine bone mineral content and density, as well as fat-free mass and body fat, in 28 males and 11 females with a mean age of 37 years who met Doury's criteria for reflex sympathetic dystrophy syndrome. Mean disease duration was eight months. Before treatment, as compared to the unaffected limb, bone mineral content was decreased by 8.8%, bone mineral density by 9.6%, and fat-free mass by 6.2%, whereas body fat was increased by 6%. These differences were largest in those patients with the longest disease durations. The severity of bone loss was not correlated with the outcome, the severity of roentgenographic lesions, or whether the patient was evaluated at the warm or cold stage of the disease process. Study parameters were unchanged after three months both in patients who were and were not improved. After nine to 12 months, increases in bone and fat-free mass were seen in those patients whose clinical manifestations had subsided.