Hip Special Tests

Question 1

Leg Length Test

Answer 1

Assessed to differentiate between a true leg length discrepancy and an apparent discrepancy caused by other abnormalities (e.g. a leg appears shorter secondary to lateral pelvic tilt).

Apparent leg length
To assess apparent leg length, measure and compare the distance between the mediastinum and the tip of the medial malleolus of each limb.

True leg length
To assess true leg length, measure from the anterior superior iliac spine to the tip of the medial malleolus of each limb.

Question 2

Thomas Test

Answer 2

Assess for a fixed flexion deformity (i.e. an inability for the patient to fully extend their leg)
1. With the patient positioned flat on the bed, place a hand below their lumbar spine with your palm facing upwards (this helps to prevent the patient from masking a fixed flexion deformity by increasing lumbar lordosis).

2. Passively flex the hip of the unaffected leg as far as you are able to and observe the contralateral limb.
3. Repeat the assessment on the contralateral hip.

Interpretation
The test is positive (abnormal) if the affected thigh raises off the bed, indicating a loss of hip joint extension. This would suggest a fixed flexion deformity in the affected hip.

This test should not be performed on patients who have had a hip replacement as it can cause dislocation.

Question 3

Trendelenburgs Test

Answer 3

Trendelenburg’s test is used to screen for hip abductor weakness (gluteus medius and minimus).

1. With the patient upright, stand in front of them and ask them to place their hands on your forearms or shoulders for stability.
2. Position your fingers on each side of the patient’s pelvis at the iliac crest.
3. Ask the patient to stand on one leg and observe your fingers for evidence of lateral pelvic tilt.
4. Repeat the assessment with the patient standing on the other leg.

Interpretation
If the patient’s hip abductors are functioning normally the pelvis should remain stable or rise slightly on the side of the raised leg.

If the pelvis drops on the side of the raised leg it suggests contralateral hip abductor weakness (this is known as Trendelenburg’s sign).