STRATEGIES FOR AVOIDING LEG LENGTH INEQUALITY

Abstract

Leg length inequality, both actual and functional, is the most important cause of disappointment for the surgeon and his patient.

The reported incidence of leg length inequality of 1 cm has been reported to be between 23% and 50%, and half of these patients require a lift in their shoe. In the author’s opinion, there is a relationship between leg length and stability of the hip. Increase in leg length and offset improves soft tissue tension and reduces the dislocation rate.

The goal at surgery is:

1. To restore the center of rotation for the hip

2. To restore offset, i.e. abductor moment arm

3. To restore hip center to lesser trochanter difference

The various tests for hip stability, soft tissue tension and contractures:

1. Assess component position

2. Assess for anterior impingement

3. Assess for tight anterior capsule

4. Assess for tight iliotibial band (Ober’s test)

5. Assess for tight rectus, iliopsoas and adductors

6. Correct soft tissue balance

Leg length inequality is caused by:

1. Increase in anatomic leg length or offset or both

2. Tight anterolateral structures, which include:

   1. IT band

   2. Anterior and lateral capsule and gluteus maximus

3. Adduction contractures of the opposite hip

4. Spinal deformity causing pelvic tilt

5. Excessive trochanteric advancement causing abduction contracture