Removal of acetabular bone in resurfacing arthroplasty of the hip

Abstract

Resurfacing arthroplasty of the hip is being performed more frequently in the United Kingdom. The majority of these patients are younger than 55 years of age, and in this group the key benefits include conservation of femoral bone stock and the potential reduction in the rate of dislocation afforded by the larger resurfacing head. Early aseptic loosening is well recognised in patients younger than 55 years of age, and proponents of resurfacing believe that the improved wear characteristics of the metal-on-metal bearing may improve the long-term survival of this implant. There has been some concern, however, that resurfacing may not be conservative of acetabular bone. We compared a series of 33 consecutive patients who had a hybrid total hip arthroplasty with an uncemented acetabular component and a cemented femoral implant, with 35 patients undergoing a Birmingham hip resurfacing arthroplasty. We compared the diameter of the implanted acetabulum in both groups and, because they were not directly comparable, we corrected for patient size by measuring the diameter of the contralateral femoral head. The data were analysed using unpaired t-tests and analysis of covariance. There was a significantly larger acetabulum in the Birmingham arthroplasty group (mean diameter 56.6 mm vs 52.0 mm; p < 0.001). However, this group had a significantly larger femoral head diameter on the contralateral side (p = 0.03). Analysis of covariance revealed a significant difference between the mean size of the acetabular component implanted in the two operations. The greatest difference in the size of acetabulum was in those patients with a larger diameter of the femoral head. This study shows that more bone is removed from the acetabulum in hip resurfacing than during hybrid total hip arthroplasty, a difference which is most marked in larger patients.

Does Hip Resurfacing Require Larger Acetabular Cups Than Conventional THA?

“…Two previous studies suggest removal of acetabular bone during HRA is comparable to that of conventional THA [15,23], whereas another report suggests increased acetabular bone resection is required for resurfacing surgery [13]. However, these reports are difficult to compare because they had methodologic limitations, used different implants and techniques, and had different patient demographics [13,15,23]. We therefore addressed the following questions: (1) Does HRA require larger acetabular components than conventional THA using a press-fit cup?…”

“…However, controversy exists regarding the amount of bone removed from the acetabular side. Two studies suggest removal of acetabular bone during HRA is comparable to that of conventional THA [15,23], whereas another study reported increased acetabular bone resection for HRA [13]. These studies are difficult to compare because they have some Each author certifies that he or she has no commercial associations (eg, consultancies, stock ownership, equity interest, patent/licensing arrangements, etc) that might pose a conflict of interest in connection with the submitted article.…”

“…methodologic limitations (ie, small series of unmatched patients [13], no data for patient height or weight [15], heavier patients in the THA cohort [23] [23]) and implantation techniques used [13,15,23].…”

The John Charnley Award: Metal-on-Metal Hip Resurfacing versus Large-diameter Head Metal-on-Metal Total Hip Arthroplasty

“…It appears, in a proportion of cases, to require a greater resection of acetabular bone than conventional arthroplasty, and there is concern over the long-term survivorship of the femoral component [24,32]. At 3.5 years followup, Amstutz et al [1] reported an overall failure rate of 6%.…”

Removal of acetabular bone in resurfacing arthroplasty of the hip

“…including this one by Pandit et al, 1 used it along the conventional scale. It was interesting to see two papers from Oxford, again including this paper, using the OKS in its 'Oswestry' form.…”