The slump knee bend test is thought to have superiority over the prone knee bend test in differentiation between symptoms arising from neural vs. non-neural tissues because of the addition of the spinal flexion component. Until now not much research has been performed to examine the diagnostic value of this test.
In 2011, Trainor et al. looked at the diagnostic value of L4 nerve root compression in conjunction with other levels of nerve root compression through utilization of this test. MRI imaging was used as a gold standard for diagnosis.
How to perform:
- Subject is sidelying, slightly “cuddling” the underside leg (but not fully flexing it) with cervical and thoracic spines flexed.
- Investigator stands behind the subject supporting the upper leg to maintain a neutral hip position
- The subjects upper knee should flexed and hip extended to the point of evoked symptoms. If this point is not reached, hip extension and knee flexion should be ceased at the onset of firm resistance.
- Once symptoms are evoked, the subject is asked to extend their neck and the investigator monitors changes in symptoms and resistance to hip movement before ending the test. The results should be compared to nonsymptomatic side.
- Symptoms of stretching or discomfort on side tested
- Symptoms are felt in anterior thigh
- Normal symptoms may decrease in intensity or remain the same when cervical extension is performed
- ROM and normal symptoms response is same side-to-side
- All or part of the subjects reported symptoms are reproduced or increased during the test
- Provoked symptoms should diminish when the cervical spine is extended
- Associated symptoms (not subjects reported symptoms) are reproduced. If the associated symptoms are not in normal distribution and symptoms diminish when the cervical spine is extended, this is +. There must be evidence of asymmetry side-to-side.
- Onset of firm resistance is perceived to occur earlier in range during the testing procedure when once side is tested compared to the other. This may or may not be accompanied by symptom reproduction. There should be a decrease in resistance at the hip when extending the cervical spine.
Results: Sensitivity: 100%, Specificity: 83%, + predictive value: 67%, negative predictive value: 100%, + likelihood ratio: 6.0, – likelihood ratio: 0.
Read a case report about femoral nerve tension here by Dr. Erson Religioso.
Trainor K, Pinnington MA. Reliability and diagnostic validity of the slump knee bend neurodynamic test for upper/mid lumbar nerve root compression: a pilot study. Physiotherapy 2011: 97; 59-64.