The Trendelenburg test is used to assess hip stability.
The patient is asked to stand unassisted on each leg in turn, whilst the examiner's fingers are placed on the anterior superior iliac spines. The foot on the contralateral side is elevated from the floor by bending at the knee. An alternative approach is to have the patient undertake this manoeuvre facing the examiner and supported only by the index fingers of the outstretched hands; this accentuates any instability of balance shown during a positive test.
In normal function, the hip is held stable by gluteus medius acting as an abductor in the supporting leg. If the pelvis drops on the unsupported side - positive Trendelenburg sign - the hip on which the patient is standing is painful or has a weak or mechanically-disadvantaged gluteus medius.
A positive Trendelenburg test is found in:
- any condition that brings the origin and insertion of gluteus medius together:
- subluxation or dislocation of the hip
- coxa vara
- greater trochanter fractures
- slipped upper femoral epiphysis
- abductor paralysis or weakness e.g.:
- root lesion
- post-operative nerve damage
- muscle-wasting disease
- any painful hip disorder which results in gluteal inhibition
Caution must be exercised as false positives have been noted in 10% of cases.