Background: The spectrum of low back pain patients in general practice differs significantly from that in an orthopaedic clinic. The most frequent specific cause of low back pain is nerve-root irritation or compression caused by intervertebral protrusion, and the diagnosis is still problematic. Testing for Lasègue's sign could be a useful way of detecting high-risk patients, but so far the reproducibility of the test has been measured only in hospital-based studies.
Aim: To assess the inter-observer reproducibility of Lasègue's sign in general practice.
Method: Fifteen General practitioners from Amsterdam and the surrounding areas tested all consecutive low back pain patients who visited them during a period of two years for Lasègue's sign. The test was repeated within two weeks in two samples: sample I consisted of 50 consecutive low back pain patients; sample II consisted of all patients who had pelvic tilt, scoliosis, or positive Lasègue's sign.
Results: In sample I, the observation was repeated in 49 patients. The Kappa coefficient was 0.33, and the proportions of positive and negative agreement were 33% and 96%, respectively. In sample II, the observation was repeated in 48 patients. The Kappa coefficient was 0.56, whereas the proportion of positive agreement was 67% and the proportion of negative agreement was 91%.
Conclusions: The reproducibility of Lasègue's sign in routine general practice seems to be low, but may be similar to the reproducibility observed in hospital settings in selected patients who have a high chance of low back pain owing to a specific disease.