Pain provocation tests for the assessment of sacroiliac joint dysfunction

A double-blind trial was carried out to determine the sensitivity and specificity of three commonly used pain provocation tests for sacroiliac joint dysfunction. The trial involved 40 patients, all of whom reported pain when they were subjected to each of the three tests. Half of the patients (20) had the symptomatic sacroiliac joint injected with 4 ml of 1% lignocaine, whereas the other 20 patients received 4 ml of normal saline to the painful joint. The level of pain produced by each of the three tests was assessed pre- and posttest injection using a visual analogue scale of 0-100. If the pain could be suppressed by 70% with injection of either normal saline or 1% lignocaine into the symptomatic sacroiliac joint under image intensification, the test was considered to be positive for pain arising from the sacroiliac joint. None of the patients receiving normal saline had their pain suppressed to any significant degree, whereas those patients receiving 1% lignocaine had their pain suppressed sufficiently for the three pain provocation tests to have a specificity of 100% for each test and a sensitivity range of 77-87%. This study indicates that the three tests, when used in combination, have a high predictive value for pain arising from the sacroiliac joint.