Gonad protection in young orthopaedic patients.

OBJECTIVE To determine whether gonad shields are correctly positioned on the pelvic radiographs of children with slipped capital femoral epiphysis. DESIGN Retrospective study of radiographs taken of children treated by in situ pinning of slipped capital femoral epiphysis between 1 January 1983 and 31 December 1988. SETTING Three teaching hospitals in north west England. PATIENTS 32 patients with complete set of radiographs. RESULTS An average of 10.8 anteroposterior pelvic radiographs plus 8.9 lateral hip radiographs had been performed per patient. Gonad shields had been completely omitted in 137 (40%) anteroposterior pelvic radiographs performed on the 32 patients at the time of completion of the study. In 100 (29%) the gonad shields were adequately protecting the gonads, but in 109 (31%) the gonad shields were not protecting the gonads due to incorrect positioning of the shield. The incorrect positioning of the gonad shields was more commonly found in girls than boys (64 vs 45; p less than 0.012), presumably because of the difficulty in determining gonadal position in relation to surface landmarks. Absence of gonad shields was also more commonly seen in girls (82 v 55; p less than 0.005), but this is not easily explained. CONCLUSIONS Gonad shields are not protecting the gonads in a large percentage of anteroposterior pelvic radiographs (71%) because they have been omitted or inadequately placed. This avoidable excess radiation exposure to the gonads, combined with the inability to shield the gonads in lateral hip radiographs and the large number of radiographs performed, results in the gonads receiving a higher dose of radiation than may otherwise be the case, and may increase the potential for disease in the future offspring of these patients.