Evaluation of the bent knee fall out test pre- and post- an adductor longus tenotomy.

OBJECTIVE To investigate the immediate effect of an adductor longus tenotomy on the results of the bent knee fall out test, and whether there was a correlation between pre-tenotomy measures and the magnitude of change. DESIGN Observational study. METHODS We included recreational to elite athletes with longstanding adductor-related groin pain (specifically adductor longus insertion pain) undergoing unilateral or bilateral full adductor longus tenotomy. The bent knee fall out test was performed immediately prior and immediately after the surgical procedure. We used Wilcoxon signed-rank test to compare test results pre- and post-tenotomy, and Spearman's rho (rs) to analyse correlation between pre-tenotomy values and the magnitude of change in the bent knee fall out test. RESULTS We consecutively included 60 male adult athletes. There was a statistically significant difference (p < 0.001) in the bent knee fall out result from pre-surgery (median 11.5 cm [IQR 9-15], range 5-25 cm) to post-surgery (median 8 cm [IQR 6-10], range 3-15 cm). The mean difference was 3.9 ± 2 cm, range 0-11 cm, corresponding to a large effect size, d = 1.92. There was a moderate correlation between the bent knee fall out measurement pre-tenotomy and the difference from pre-to-post, rs = 0.75, p < 0.001. CONCLUSION The bent knee fall out measurements changed considerably immediately after an adductor longus tenotomy, showing that the test is assessing adductor longus flexibility in male athletes with longstanding adductor-related groin pain. There was a moderate correlation between the bent knee fall out measure pre-tenotomy and the magnitude of change.