Comparison of long-bone radiographs between U.S. Navy divers and matched controls.

The long-bone radiographs of a group of nondivers consisting of 177 U.S. Navy enlisted men were compared to the long-bone radiographs of 93 U.S. Navy enlisted divers who were 35 years of age and older. The nondiver control group was matched to the diver group for age, rank, and occupational specialty. Divers were found to have significantly more films classified as positive for aseptic bone necrosis (ABN) and bone cysts than nondivers, while the nondiver group had more films classified as doubtful for ABN than the diver group. The two groups were similar in the number of members classified as having bone islands and sclerotic areas. X-ray classifications by highly experienced radiologists were found to be only moderately reliable. These data indicate that diving as practiced by the U.S. Navy contributes independently to the development of ABN and bone cysts evidenced among divers in this age group. Some caution must be exercised in interpreting these findings, however, because of the larger number of doubtful films found for the nondiver group than for the diver group, the small number of positive and doubtful cases found in either group, the age of the samples used (35 years of age and older), and the substantial degree of unreliability demonstrated in classification of the films.