INTRODUCTION: The straight leg raise (SLR) test is a common component of a physical examination. This study compares outcomes of those with (n=343) and those without (n=1853) a positive SLR test.
METHODS: This was a prospective observational cohort study of low back pain (LBP) cases (n=2196) treated non‐operatively at 40 spine‐care clinics between January 2008 and June 2010. SLR findings were cross referenced with location of dominant pain to establish three study groups: 1) False Positives (positive SLR, back dominant pain, n=288), 2) True Positives (positive SLR, leg dominant pain, n=55), and 3) True Negatives (normal neurology, n=1853).
RESULTS: The mean age of the cohort was 39.4 years (SD= 11.8, range= 18‐65) with 61.7% males. There was only a 16% true positive rate (55/343) for SLR testing. Results by SLR status were: The True Positive group had significantly more females (p<0.02) and were significantly more chronic than the other two groups (p<0.023). The True Positive group had significantly more pain, more medication use, treatment days and less functional improvement at treatment conclusion and at 3 month follow up than the other two groups (p<0.05). For the False Positive and True Negative groups, there were no statistically significant differences in medication use and functional improvement at follow up and no difference in treatment days. The True Negative Group had the highest return to work rate (True Negatives= 85.1%, True Positives= 76.4%, False Positives= 77.4%) with a trend towards statistical significance (p<0.075).
DISCUSSION: A positive SLR was over diagnosed; a true positive SLR test was a rare clinical finding. Baseline, discharge and follow up characteristics of the True Negatives and False Positives were very similar. In spite of slower treatment response, higher medication use and less pain reduction in the True Positive group, they had comparable return to work rates.