Does dysbaric osteonecrosis progress in the absence of further hyperbaric exposure? A 10-year radiologic follow-up of 15 patients.

Progression of dysbaric osteonecrosis of the femoral and humeral heads was evaluated in 15 caisson workers. All patients had dysbaric osteonecrosis but had had no further exposure to hyperbaric pressures for a minimum of 10 years. The original and follow-up radiographs were compared in each case. Of 24 normal articular heads (nine humeral and 15 femoral), one (4%) humeral head developed new subcortical sclerosis. Of the 36 juxta-articular lesions, seven (four humeral and three femoral) showed major changes in the 10-year interval. Of these seven, two (one humeral and one femoral) had new articular fractures and three (two humeral and one femoral) with articular fractures showed progressive osteoarthritis. We conclude that caisson workers can develop lesions in previously normal areas and experience worsening of previously known lesions in the absence of further exposure to hyperbaric pressures.