A radiostereometric analysis of movements of the sacroiliac joints during the standing hip flexion test.

STUDY DESIGN: The standing hip flexion test was evaluated by using a radiostereometric analysis. OBJECTIVES: To evaluate whether the commonly used standing hip flexion test reflects movement in the sacroiliac joints, or whether the increased load of one sacroiliac joint also reduces the mobility of the other sacroiliac joint according to the theory of form and form closure in the sacroiliac joints. SUMMARY OF BACKGROUND DATA: The standing hip flexion test, used frequently to analyze sacroiliac joint mobility, is advocated as a test for study of normal or impaired motion in the sacroiliac joint. METHODS: In this study, 22 patients considered to have sacroiliac pain were analyzed with radiostereometric analysis when standing and when performing the standing hip flexion test on the right and left sides. RESULTS: Very small movements were registered in the sacroiliac joints. When provoking one side, the rotations were small on both sides. CONCLUSIONS: The small movements registered support the theory of form and force closure in the sacroiliac joints. The self-locking mechanism that goes into effect when the pelvis is loaded in a one-leg standing position probably obstructs the movements in the sacroiliac joints. Therefore, the standing hip flexion test cannot be recommended as a diagnostic tool for evaluating joint motion in the sacroiliac joints.

A radiostereometric analysis of the movements of the sacroiliac joints in the reciprocal straddle position.

STUDY DESIGN: A Radiostereometric analysis of the reciprocal straddle position. OBJECTIVES: To evaluate the magnitude of rotation in the sacroiliac joints in the reciprocal straddle position. SUMMARY OF BACKGROUND DATA: The reciprocal straddle position has been objectified in different studies, using different techniques, to show a sacroiliac motion between 5 degrees and 36 degrees. Previous studies with radiostereometric analysis during different provocations reported much smaller movements. METHODS: Six women with posterior pelvic pain of long duration after pregnancy (n = 5) and sacroiliitis (n = 1) underwent radiostereometric analysis in the sustained reciprocal straddle position. RESULTS: A reciprocal movement could be demonstrated in the sacroiliac joints in the reciprocal straddle position. However, the movements were 10 times smaller than reported in earlier studies of the reciprocal straddle position. CONCLUSIONS: It was possible to demonstrate reciprocal movements of the sacroiliac joints in the straddle position. However, the radiostereometric analysis technique showed the movements to be small, as reported in other mobility studies.

Can an external frame fixation reduce the movements in the sacroiliac joint? A radiostereometric analysis of 10 patients.

To evaluate whether a Hoffmann-Slätis frame can reduce movements in the sacroiliac joints, 10 patients (7 women) with severe posterior pelvic pain of long duration were externally stabilized. The movements were analyzed with radiostereometric analysis (RSA) in supine and standing positions, preoperatively and postoperatively with the frame applied. In 2 patients, there was no reduction in the movements with the frame, perhaps because it was not properly tightened. In the remaining 8 patients, the median reduction in rotation was 55% on the left side and 63% on the right side around the helical axes, and 74% around the x-axes on the left side and 66% on the right side. Our data suggest that external fixation using the Hoffmann-Slätis frame, substantially reduces sacroiliac joint mobility in some patients, which must be considered when using the frame as a diagnostic tool. Pre-stressing the frame by tightening the vertical bars before the compression bar is applied is recommended to reduce the risk of this shortcoming.

Pain pattern in pregnancy and "catching" of the leg in pregnant women with posterior pelvic pain.

STUDY DESIGN: A cross-sectional study of symptoms and signs in pregnant women. OBJECTIVES: To describe the clinical appearance of back pain in pregnancy and the relation between pain distribution and symptoms in women with posterior pelvic pain, in order to shed light on etiologic factors. SUMMARY OF BACKGROUND DATA: Back pain is common in the general population. During pregnancy, it is even more common, and back pain is experienced by about 50% of pregnant women. In the pregnant woman, differentiation between common low back pain and posterior pelvic pain is believed to be essential because these symptoms should be treated in different ways. METHODS: The women were interviewed with a questionnaire. Those with back symptoms completed a pain drawing and were examined by an orthopedic surgeon. Based on the symptoms and findings, the women were divided into three groups: thoracic pain, lumbar pain, and posterior pelvic pain. RESULTS: Of 335 pregnant women, 51% had back pain at the time of examination. The pain was more widespread compared with common low back pain. Seventy-one percent of the 171 patients examined by the orthopedic surgeon had a positive posterior pelvic pain test. These women more often had pain in the gluteal and posterior thigh regions. A "catching" feeling of the leg was described when walking by 44 of 122 these women, whereas only 1 of 49 women without a posterior pelvic pain test had such symptoms. CONCLUSIONS: The higher prevalence of back pain in pregnancy may be due to several factors. In women with posterior pelvic pain, there is a specific symptom-a catching of the leg when walking. The most probable explanation for the catching is that local nociception disturbs muscular function in women with posterior pelvic pain because changes in the sacroiliac joint range of motion, which is very small, cannot cause this symptom.

Movements of the sacroiliac joints. A roentgen stereophotogrammetric analysis.

Twenty-five patients (21 females and 4 males) with sacroiliac joint disorders were studied with roentgen stereophotogrammetry in physiologic positions as well as in the extreme of physiologic positions. There was a constant pattern of motion with different load, especially around the transverse axis. The rotations were small and in mean between position 2.5 degrees (0.8 degree-3.9 degrees). The translation was, mean, 0.7 mm (0.1-1.6 mm). There was no difference between symptomatic and asymptomatic joints.