The Exeter technique can lead to a lower incidence of leg-length discrepancy after total hip arthroplasty

Abstract

We evaluated an operative technique, described by the Exeter Hip Unit, to assist accurate introduction of the femoral component. We assessed whether it led to a reduction in the rate of leg-length discrepancy after total hip arthroplasty (THA). A total of 100 patients undergoing THA were studied retrospectively; 50 were undertaken using the test method and 50 using conventional methods as a control group. The groups were matched with respect to patient demographics and the grade of surgeon. Three observers measured the depth of placement of the femoral component on post-operative radiographs and measured the length of the legs. There was a strong correlation between the depth of insertion of the femoral component and the templated depth in the test group (R = 0.92), suggesting accuracy of the technique. The mean leg-length discrepancy was 5.1 mm (0.6 to 21.4) pre-operatively and 1.3 mm (0.2 to 9.3) post-operatively. There was no difference between Consultants and Registrars as primary surgeons. Agreement between the templated and post-operative depth of insertion was associated with reduced post-operative leg-length discrepancy. The intra-class coefficient was R ≥ 0.88 for all measurements, indicating high observer agreement. The post-operative leg-length discrepancy was significantly lower in the test group (1.3 mm) compared with the control group (6.3 mm, p < 0.001). The Exeter technique is reproducible and leads to a lower incidence of leg-length discrepancy after THA.

Double-Stitch Technique: A Simple and Effective Method to Minimize Limb Length Discrepancy after Total Hip Arthroplasty

“…Template techniques used to ensure equal limb length require accurate restoration of acetabular center of rotation which may not be entirely possible during final seating of components 7121819. Similarly, recreation of depth of insertion of the femoral stem may not be as accurate.…”

Intraoperative measurement of limb lengthening during total hip arthroplasty

“… 4 Many studies have been published, describing techniques about the management of LLD. These methods can be divided into four main categories: (1) Based on the preoperative templating to define the correct neck cut, the correct neck length of the femoral component (in case of a modular head) or the correct depth of insertion of the femoral component (by measuring the distance of the tip of the greater trochanter to the shoulder of the femoral component), 5 6 7 8 (2) based on the usage of a standard pelvic reference point and of a femoral reference point, and measurement of the distance of these two points as the limb length changes intraoperatively [the marking of the pelvic reference point and the measurement can be performed with the aid of calipers, 9 10 11 12 13 14 15 16 17 bented K-wire, 18 suture (tied in the skin, in a K-wire, or in a pin), 19 Steinman pin in the infracotyloid groove or screw above the superior acetabular rim, 20 21 (3) based on clinical tests intraoperatively such as the shuck test, the drop kick test, and the leg-to-leg comparison, 15 22 23 and (4) based on navigation system's measurements. 16 24 25 26 In addition, some other techniques have been described, such as measuring the gap between the tenotomy limb edges of the abductor musculotendinous insertion on the greater trochanter 15 or evaluating the level of the center of the head in relation to the tip of the greater trochanter with the aid of a plate in a femoral head slot.…”

“…However, the osseous tip of the greater trochanter during the operation is not easily assessed and accurately defined, so mistakes can be made intraoperatively. 5 …”

Limb length discrepancy after total hip arthroplasty: a systematic review

“…25,36 Halai et al were able to reduce mean postoperative to 1.3mm (range 0.2-9.3mm) by Exeter technique and templating and concluded that Exeter technique was reproducible and was helpful in reducing incidence of leg-length discrepancy after THA. 38 Woolson et al were able to achieve desired level of neck osteotomy within 6mm in 86% of patients and within 10 mm in 97% of patients. 18 Template technique depends on intraoperative reproduction of centre of rotation of hip and femoral stem length which may not be as accurate.…”