Intraoperative measurement of limb lengthening during total hip arthroplasty

Limb length discrepancy (LLD) after total hip arthroplasty (THA) is a common problem which cannot be completely resolved. Many techniques have been described in order to minimize postoperative LLD, but most of these techniques are difficult to apply. Ideal technique must be simple and accurate. The most simple technique using a suture tied on the skin has well-known limitations, but its accuracy has not been evaluated before.

Sixty THAs in sixty patients (mean age 71 years, 1:1 male to female ratio) with hip osteoarthritis (37 cases in the right, and 23 cases in the left side) were studied in this prospective study. In all surgeries, the intraoperataive measurement of limb lengthening was performed using a suture tied on the skin of the lateral pelvis. The accuracy of this technique and correlation between intraoperative and postoperative radiological measurements of lengthening were evaluated.

The mean preoperative LLD was -7.5 mm while the mean postoperative LLD was 1.58 mm. The accuracy of this technique, defined as the mean difference between the intraoperative and postoperative measurements was 1.8 mm. A strong correlation between these two measurements was noticed (r = 0.86).

The accuracy and correlation index of this simple technique were similar to those of other techniques. The studied technique is quite accurate when attention is given to certain details, such as the amount of tension applied on the suture, the position of the tied point on the skin, and the position of the leg during measurements.