Sacroiliac Joint Special Test Cluster

Background

Test Item Clusters (TIC) is a group of special tests which are developed to facilitate clinical decision making by improving diagnostic utility. Laslett et al investigated the diagnostic power of pain provocation sacroiliac joint (SIJ) tests individually and in various combinations, in relation to a diagnostic injection. The tests employed in this study were: distraction, right sided thigh thrust, right sided Gaenslen's test, compression and sacral thrust. Those tests were chosen due to its acceptable inter-rater reliability. They found that composites of provocation SIJ tests had significant diagnostic utility. Any 2 of 4 selected tests (distraction, thigh thrust, compression, and sacral thrust) have the best predictive power. When all 6 SIJ provocation tests does not reproduce symptoms, the SIJ pathology can be ruled out. 

Description of Provocation Tests

Tests	Description (Positive Findings)
Distraction	Pt supine. Examiner applies posterolateral directed pressure to bilateral ASIS. (+: reproduction of pain)
Compression	Pt sidelying. Examiner compresses pelvis with pressure applied over the iliac crest directed at the opposite iliac crest. (+: reproduction of symptoms)
Thigh Thrust	Pt supine. Examiner place hip in 90 deg flexion and adduction. Examiner then applies posteriorly directed force through the femur at varying angles of abduction/adduction. (+: reproduction of buttock pain)
Gaenslen's	Pt supine with both legs extended. The test leg is passively brought into full knee flexion, while the opposite hip remains in extension. Overpressure is then applied to the flexed extremity. (+: reproduction of pain)
Sacral Thrust	Pt prone. Examiner delivers an anteriorly directed thrust over the sacrum. (+: reproduction of pain)

Diagnostic Value of Individual SIJ Provocation Tests

	Distraction	Compression	Thigh Thrust	Gaenslen's (R)	Gaenslen's (L)	Sacral Thrust
Sensitivity	0.60	0.69	0.88	0.53	0.50	0.63
Specificity	0.81	0.69	0.69	0.71	0.77	0.75
+ LR	3.20	2.20	2.80	1.84	2.21	2.50
- LR	0.49	0.46	0.18	0.66	0.65	0.50

TIC for SIJ Provocation Test 

Laslett et al reported that the Gaenslen's test did not contribute positively when tests were combined and may be omitted from the diagnostic process without compromising diagnostic confidence.  The optimal rule was to perform the distraction, compression, thigh thrust and sacral thrust tests but stopping when there are 2 positives. The diagnostic value of 2 positive tests of the 4 selected test is as follows: 

	Values (95% CI)
Sensitivity	0.88 (0.64, 0.97)
Specificity	0.78 (0.61, 0.89)
+ LR	4.00 (2.13, 8.08)
- LR	0.16 (0.04, 0.47)