Comparison of offset in Birmingham hip resurfacing and hybrid total hip arthroplasty

Abstract

Hip resurfacing is being performed more frequently in the United Kingdom. The possible benefits include more accurate restoration of leg length, femoral offset and femoral anteversion than occurs after total hip arthroplasty (THA). We compared anteroposterior radiographs from 26 patients who had undergone hybrid THA (uncemented cup/cemented stem), with 28 who had undergone Birmingham Hip Resurfacing arthroplasty (BHR). We measured the femoral offset, femoral length, acetabular offset and acetabular height with reference to the normal contralateral hip. The data were analysed by paired t-tests. There was a significant reduction in femoral offset (p = 0.0004) and increase in length (p = 0.001) in the BHR group. In the THA group, there was a significant reduction in acetabular offset (p = 0.0003), but femoral offset and overall hip length were restored accurately. We conclude that hip resurfacing does not restore hip mechanics as accurately as THA.

Outcome of Hip Resurfacing Arthroplasty in Patients with Developmental Hip Dysplasia

“…We found the femoral offset and hip lever arm ratio, improved in these patients. This observation contrasts those of previous reports showing that femoral offset and hip lever arm ratio decreased after surface arthroplasty, but in nondysplastic hips [12,15]. We attribute this difference to the restoration of a normal center of rotation in the resurfaced dysplastic hip.…”

Biomechanical reconstruction of the hip: comparison between modular short-stem hip arthroplasty and conventional total hip arthroplasty

“…The Proxima short-stem, which requires a lower resection level compared to the Metha stem, has also reported a postoperative limb difference of +3.1 mm [10]. The difference of +3.3 mm in our SHA group is significantly more than that of our THA group (+1.3 mm) and also greater than that of most other THA studies (−1.1 mm to +2.6 mm) [7,14,19,20]. Altogether, these results suggest that neck-preserving SHA has a tendency to prolong limb length, which should be taken into consideration when selecting an implant for a patient, as well as during implantation.…”

“…The horizontal hip centre of rotation was significantly medialized in both groups and was more medial compared to the contralateral side (2.2 mm SHA, 1.1 mm THA). A more medial cup position has also been reported after SHA (0.9 mm) [10] and THA (1.0 mm-3.1 mm) [14,19,20]. This is considered beneficial, as it affects the abductor lever arm positively and also leads to lower joint reaction forces [2,18].…”

“…For THA, a wide range in postoperative horizontal femoral offset has also been reported, with most studies describing a postoperative increase [7,14,[19][20][21]. Compared to the contralateral side, a balanced or even moderately increased horizontal femoral offset is often striven for, as this seems to offer a favourable outcome in terms of a better range of motion [3,22], an increased stability with a reduced risk of dislocation, and less wear [3,5,6,16,18].…”

Hip resurfacing: mid-term results of the last-generation metal-on-metal devices

“…The advantages of hip resurfacing over total hip replacement include wider range of motion, lower rate of dislocation, less wear, minimal bone resection, more anatomical restoration of leg length and femoral offset, easier revision and reduction of stress shielding in the proximal femur [9,10]. We present our experience with hip resurfacing using the BHR implant: the aim of this study is to evaluate the clinical and radiological outcomes of 350 consecutive hip resurfacing implants at latest available follow-up.…”