Thomas Test

Background: Originally described by High Owens Thomas in 1876, the original test was developed to differentiate "morbus coxae," or inflammatory disease of the hip , from abscesses, sciatica, or hysterical simulation of hip joint pain (Thomas 1876). He described the test as follows:

  • "Having undressed the patient and laid him on his back upon a table or other hard plane surface, the surgeon takes the sound limb and flexes it, so that the sound knee joint is in contact with the chest. Thus he makes certain that the spine and back of the pelvis are lying flat on the table; an assistant maintains the sound limb in this fixed position; the patient is then urged to extend, as far as he is able, the diseased limb, and this he will be able to do in a degree varying with the previous duration of the infection…By noticing the amount of flexion, the surgeon will, with practice, soon be able to guess the pregious duration of the disease."

Over time the Thomas test became the common method of measurement for fixed flexion deformities of the hip. There are also several variations or modifications that have been proposed since the test was introduced. The most common techniques used today in clinics are described below.

Procedure 1: The patient lies supine while the examiner checks for excessive lordosis. The examiner flexes one of the patient's hips, brings the knee to the chest to flatten out the lumbar spine, and the patient holds the flexed hip against the hip. If there is no flexion contracture, the hip being tested (the straight leg) remains on the examining table. If a contracture is present, the patient's leg rises off the table. The angle of contracture can be measured. (Magee 2002)

  • Reliability
    • Thurston 1982: 5-20 degree variability in measuring the hip flexion deformity
    • Bartlett 1985: Rater comparison error of 3 degrees (CI: 1.1-2.6 degrees). Two experienced therapists performed test in 15 healthy children

Procedure 2 (Modified Thomas Test): The subject sits at the end of the plinth, then rolls back onto the plinth, and holds both knees to the chest to ensure the lumbar spine was flat on the plinth and the pelvis was in posterior rotation. The subject held the contralateral hip in maximal flexion with the arms, while the tested limb was lowered towards the floor. (Harvey 1998)

  • Reliability
    • ICC=.91 (Harvey 1998)
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