title: Distraction test of the posterior superior iliac spine (PSIS) in the diagnosis of sacroiliac joint arthropathy.
abstract: BACKGROUND
  The sacroiliac joint (SIJ) is a frequently underestimated cause of lower back (LBP). A simple clinical test of sufficient validity would be desirable. The aim of this study was to evaluate the diagnostic value of a new PSIS distraction test for the clinical detection of SIJ arthropathy and to compare it to several commonly used clinical tests.
  
  
  METHODS
  Consecutive patients, where a SIJ pathology had been confirmed by an SIJ infiltration were enrolled (case group, 61 SIJs in 46 patients). Before infiltration, patients were tested for pain with PSIS distraction by a punctual force on the PSIS in medial-to-lateral direction (PSIS distraction test), pain with pelvic compression, pelvic distraction, Gaenslen test, Thigh Thrust, and Faber (or Patrick's) test. In addition, these clinical tests were applied to both SIJs of a population of individuals without history of LBP (control group, 64 SIJs in 32 patients).
  
  
  RESULTS
  Within the investigated cohort, the PSIS distraction test showed a sensitivity of 100% and a specificity of 89% for SIJ pathology. The accuracy of the test was 94%, the positive predictive value (PPV) was 90% and the negative predictive value (NPV) was 100%. Pelvic compression, pelvic distraction, Gaenslen test, Thigh Thrust, and Faber test were associated with a good specificity (> 90%) but a poor sensitivity (< 35%).
  
  
  CONCLUSIONS
  Within our population of patients with confirmed SIJ arthropathy the PSIS distraction test was found to be of high sensitivity, specificity and accuracy. In contrast, common clinical tests showed a poor sensitivity. The PSIS distraction test seems to be an easy-to-perform and clinically valuable test for SIJ arthropathy.
authors.forename: Clément M L
authors.initials: CM
authors.lastname: Werner
authors.forename: Armando
authors.initials: A
authors.lastname: Hoch
authors.forename: Lucienne
authors.initials: L
authors.lastname: Gautier
authors.forename: Matthias A
authors.initials: MA
authors.lastname: König
authors.forename: Hans-Peter
authors.initials: HP
authors.lastname: Simmen
authors.affiliation: Division of Trauma Surgery, University Hospital Zurich, Raemistrasse 100, Zurich 8091, Switzerland. georg.osterhoff@usz.ch.
authors.forename: Georg
authors.initials: G
authors.lastname: Osterhoff
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D016022:Case-Control Studies; D006801:Humans; D007592:Joint Diseases / Q000150:complications / Q000175:diagnosis*; D017116:Low Back Pain / Q000209:etiology*; D008875:Middle Aged; D019637:Orthopedic Procedures / Q000379:methods*; D010147:Pain Measurement; D011237:Predictive Value of Tests; D012189:Retrospective Studies; D012446:Sacroiliac Joint / Q000503:physiopathology*; D012680:Sensitivity and Specificity; D055815:Young Adult