Thomas test


The Thomas test is a physical examination test, named after Dr. Hugh Owen Thomas, a British orthopaedic surgeon, used to rule out hip flexion contracture and psoas syndrome. Often associated with runners, dancers, and gymnasts who complain of hip "stiffness" and reported "snapping" feeling when flexing at the waist.

Description

The patient lies supine on the examination table and holds the uninvolved knee to his or her chest, while allowing the involved extremity to lie flat. Holding the knee to the chest flattens out the lumbar lordosis and stabilizes the pelvis.

Interpretation

If the iliopsoas muscle is shortened, or a contracture is present, the lower extremity on the involved side will be unable to fully extend at the hip. This constitutes a positive Thomas test. Sometimes, with a very flexible patient, the Thomas test will be normal despite a psoas dysfunction being present. However, in the patient with a normal hip joint, a positive test is a good indicator of psoas hypertonicity.
Other signs from the Thomas test:
The hip flexion contracture is physiologic in the first 3 months of life and if it is absent in this period it may be a sign of developmental dysplasia of the hip. It is used to identify unilateral fixed flexion deformity of the hip.
The test consists of 3 steps: