Hip joint problems can also be responsible for radiation of pain below the knee, just like the lumbar spine. Performing a standing Kemp test (where we passively obliquely extend the patient's spine) or just putting the lumbar spine into extension may cause us to conclude that the problem originates in the lumbar spine, if pain radiates into the buttock or lower extremity. What we may not realize with this test is that the hip joint is also put into an extended stress position and may be the source of the pain.
McGann1 describes a test to help differentiate hip pain from spinal pain, especially in spinal stenosis of the foraminal type, which may cause symptoms below the knee. If a patient exhibits a positive Kemp sign, have the standing patient flex the painful hip and knee while extending and rotating the trunk. This position continues the stress on the spine while relaxing the hip, since all the hip ligaments are relaxed during hip flexion. If hip and leg symptoms persist in this position, then the spine is probably involved. If the symptoms are relieved, on the other hand, a hip disorder is probably present. Performing a Kemp test with the patient sitting might be more accurate in eliminating hip causation.
1. McGann WA. History and physical examination. In: Steinberg ME. The Hip and its Disorders. Philadelphia: W.B. Saunders Company, 1991.
Warren I. Hammer, MS, DC, DABCO
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