Pelvic ring mobility: assessed by stress radiography.
Radiologic measurement of pubic symphysis motion while the patient stands on 1 leg (Chamberlain technique) has been widely used to indicate pelvic ring instability. Static analysis, however, suggested that stresses such as simultaneous forced flexion of 1 hip and extension of the other should prove more sensitive indicators of instability. Thirty-two normal subjects were studied with this thigh lever technique and both the thigh lever and Chamberlain techniques were performed on 10 symptomatic patients. With the thigh lever technique, the normal resting superior symphysis pubic border asymmetry (mean +/- 1SD) was 0.66 +/- 0.83 mm; symphyseal motion was 0.81 +/- 0.74 mm. No relationship could be identified between the symphyseal motion values obtained by thigh lever and Chamberlain techniques, suggesting that each may measure a different dimension of sacroiliac motion. Reliability studies show interobserver and intraobserver correlations of greater than or equal to 0.95 when superior pubic border measures were used, less correlation with inferior border measures. While the simpler, more comfortable, and more reliable Chamberlain technique remains the procedure of choice, the thigh lever technique appears a useful alternative when the patient is unable to stand on 1 leg.
D000328:Adult; D000368:Aged; D001416:Back Pain / Q000209:etiology; D001696:Biomechanical Phenomena; D005260:Female; D005269:Femur / Q000503:physiopathology; D006801:Humans; D008297:Male; D008875:Middle Aged; D011631:Pubic Symphysis / Q000000981:diagnostic imaging*; D011859:Radiography; D012446:Sacroiliac Joint / Q000502:physiology / Q000503:physiopathology; D013314:Stress, Mechanical