Diagnosis of Sacroiliac Joint Pain: Predictive Value of Three Diagnostic Clinical Tests.

INTRODUCTION To date there has been no acceptable and accurate diagnostic criteria or standard of care for the management of sacroiliac joint (SIJ) pain. Several studies have yielded different contribution of clinical presentation, history and physical examination in the diagnosis of SIJ pain. Our goal in this study is to assess the sensitivity and specificity of the diagnostic clinical tests and their predictive value in accurately diagnosing SIJ pain. METHODOLOGY Upon enrolling 200 eligible patients with SIJ pain as their primary diagnosis, they were re-evaluated and their verbal rating scale (VRS) pain score and demographic data were obtained. Thereafter, three SIJ diagnostic tests were performed: "thigh thrust test", "Patrick test" and a modified version of Gaenslen test which is referred to as "Mekhail test". Subsequently, the patients were taken to the procedure room to have SIJ injection performed, for which a confirmative result was ≥50% pain relief. The physicians performing the procedure were blinded of the results of the 3 tests performed. Results from the 3 tests were incorporated with the procedure results from which we drew statistical and medical conclusions determining their predictive value and degree of aid to physicians in diagnosing SIJ Pain. RESULTS We found the cumulative effect of adding simultaneous tests increased sensitivity of the testing, but decreased specificity, which generates a powerful screening tool. The combination of Partick's and Mekhail's tests demonstrated best accuracy with 94% sensitivity, 17% specificity, 81 % PPV and 44% NPV. Patrick's test was better than other tests in discrimination SIJ from non-SIJ patients. No combination yielded both significant sensitivity and specificity. Generally, the overall predictive value of any of the tests on their own or their combination did not vary significantly from the predictive value of baseline demographics including pre-injection pain score and pain referral diagram CONCLUSION: In conclusion, our study results were similar to the publications of various authors, whom found that physical examination plays a limited role in diagnosing SIJ pain. Specifically, we found that the clinical tests and/or their combinations added no significant predictive capacity compared to patients baseline characteristics in predicting the response to diagnostic sacroiliac joint injection, albeit the combinations of Mekhail's and Patrick's test yielded high sensitivity (94%), making them viable for screening, consecutively possibly reducing unnecessary costs diagnostic SIJ injection procedures.