INTRODUCTION: Since the fabere sign (flexion, abduction, external rotation and extension), the so‐called Patrick test, indicating osteoarthritis of the hip (OAH) and excluding sciatica was first reported in1917, the Patrick test has been used extensively to diagnose OAH. However, few papers have so far investigated the utility of the test to differentiate OAH from sciatica. The objective of this study was to assess the validity of the Patrick test.
METHODS: The subjects included 23 male and 114 female patients (43‐89years) treated by total hip arthroplasty due to OAH and 84 male and 50 female patients (16‐76years) that underwent a herniotomy due to sciatica from a herniated lumbar disk (LDH). Patients with fractures, infections and the coexistence of OAH and LDH were excluded. The diagnostic accuracy of the Patrick test was investigated in the OAH groups. The Patrick test was done to assess the presence of pain and of limitation of the fabere position.
RESULTS: Sensitivity of the Patrick test in OAH was 0.93, and specificity 0.84. Positive and negative likelihood ratios were 6.0 (95% CI: 4.57‐7.444) and 0.07(95% CI: 0.037‐0.122), which are statistically significant values for ruling OAH in or out. The pain rate was 71% in OAH, 12% in LDH (P<0.01). The pain regions of the two groups were: groin: buttock: radiated calf = 50%:12%:0% in OAH, 0.7%:13%:1.5% in LDH (including overlapping cases).
DISCUSSION: The Patrick test was demonstrated to be very sensitive for the detection of OAH and quantitatively useful to differentiate OAH from LDH (sciatica). However, based on the fact that the buttock pain rate was 12% in OAH and 13% in LDH, it must be interpreted in caution in the patients with buttock pain in the two groups.