Current methods for restoring or preserving limb length following total hip arthroplasty are anatomically inaccurate, as they do not consider acetabular and femoral height independently. In order to address this, we present and evaluate a technique that uses the transverse acetabular ligament to control the vertical height of the acetabular component and a caliper that controls the vertical placement of the femoral component within the femoral canal. Limb lengths were measured in 200 patients who had undergone primary total hip arthroplasty using this technique. Using this method, 94% had a post-operative limb length inequality that was 6 mm or less when compared to the normal side (average +0.38 mm). The maximum measured limb length inequality was ± 8 mm.
Leg-length inequality is not uncommon following primary total hip arthroplasty and can be distressing to the patient. An excellent clinical result with respect to pain relief, function, component fixation, range of motion and radiographic appearance can be transformed into a surgical failure because of patient dissatisfaction due to leg-length inequality. Postoperative leg-length discrepancy was determined radiographically for 200 patients who had had a primary custom total hip arthroplasty. In all cases the opposite hip was considered to have a normal joint center. The femoral component was designed and manufactured individually for each patient using screened marker x-rays. A graduated calliper was used at the time of surgery to control depth of femoral component insertion. The transverse acetabular ligament was used to control placement of the acetabular component and therefore restore acetabular joint center. Using this method 94% of subjects had a postoperative leg-length discrepancy that was 6mm or less when compared to the normal side (average, +0.38mm). The maximum value measured for leg-length discrepancy was +/−8mm. We describe a simple technique for controlling leg length during primary total hip arthroplasty and propose an alternative radiographic method for measuring leg-length discrepancy.
