Neurodynamic responses to the femoral slump test in patients with anterior knee pain syndrome

STUDY DESIGN: Matched-control, cross-sectional study. OBJECTIVES: The purpose of this study was to compare the responses to the femoral slump test (FST), including the change in hip range of motion and level of discomfort, between subjects with and without anterior knee pain. BACKGROUND: Anterior knee pain syndrome is a common problem among adults. The FST is the neurodynamic test used to assess the mechanosensitivity of the femoral component of the nervous system. However, as of yet, there is no literature discussing the use of the FST in patients with anterior knee pain. METHODS: Thirty patients with anterior knee pain and 30 control participants, matched by gender, age, and dominant leg, were recruited. The subjects received the FST, during which the hip extension angle and the location and intensity of pain/discomfort were recorded. Reproduction of symptoms that were alleviated by neck extension was interpreted as a positive test. Differences in hip extension angle and pain intensity between groups were examined using a 2-way, repeated-measures analysis of variance and a Kruskal-Wallis analysis. The level of significance was set at α = .05. RESULTS: Subjects with anterior knee pain had a smaller hip extension angle than that of controls (-3.6° ± 5.3° versus 0.6° ± 6.1°; mean difference, 4.2°; 95% confidence interval [CI]: 1.24°, 7.15°; P = .006). Eight patients with anterior knee pain showed a positive FST, and those with a positive FST had a smaller hip extension angle (-5.7° ± 4.5°) than that of controls (mean difference, 6.3°; 95% CI: 0.8°, 11.8°; P = .007). There was no difference in the hip extension angle between the positive and negative FST groups (mean difference, 2.9°; 95% CI: -8.5°, 2.0°) or between the negative FST and control groups (mean difference, 3.4°; 95% CI: -0.4°, 7.3°). CONCLUSION: Results of this study suggest that altered mechanosensitivity of the femoral nerve occurred in the patients with anterior knee pain who presented with a positive FST. The role of increased mechanosensitivity in the development and management of anterior knee pain should be investigated in the future.