Electronic Letters to:

Hip: P. Moonot, P. J. Singh, M. D. Cronin, Y. E. Kalairajah, T. G. Kavanagh, and R. E. Field Birmingham hip resurfacing: IS ACETABULAR BONE CONSERVED? J Bone Joint Surg Br 2008; 90-B: 319-323 [Abstract] [Full text] [PDF]

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Acetabular component size in resurfacing arthroplasty

Jonathan M Loughead, Prof. Andrew W. McCaskie, and James P. Holland   (15 April 2008)

Acetabular component size in resurfacing arthroplasty 15 April 2008
Jonathan M Loughead, Orthopaedic Surgeon Freeman Hospital, Prof. Andrew W. McCaskie, and James P. Holland Send letter to journal: Re: Acetabular component size in resurfacing arthroplasty jonathan{at}loughead.fsworld.co.uk Jonathan M Loughead, et al.	Sir, We read this recent article by Moonot et al, and feel that the authors have produced a valuable paper which contributes to the debate on acetabular component size in resurfacing arthroplasty. We noted with interest the use of a smaller acetabular component in women undergoing resurfacing compared with the conventional counterpart. In conventional acetabular preparation the size of component should be optimally chosen for the patient, and it seems counter-intuitive that when performing a resurfacing a smaller acetabular component would then be implanted. With the use of a smaller head an increase in wear of the metal-on-metal articulation1 will occur. This will also increase the likelihood of impingement which may result in loss of congruent articulation and further increased wear, and therefore metal ion release. In the clinical setting it may be necessary to upsize a conventional acetabular component to ensure that an adequate thickness of polyethylene liner is used, which might explain the results seen. In addition the femoral head/neck ratios of the patients may be of importance although the authors did not specifically look at this. Age and gender matching the patients will not match for late presenting hip pathology e.g. Perthes / SUFE / sub-clinical dysplasia, which may affect the head/neck anatomy. From our previous work2 we established that the patients in whom the upsizing of the acetabular component was likely to occur were men with a large head and a low femoral head/neck ratio. These represent some of the best candidates for resurfacing who may have developed arthritis at an earlier age as a result of cam impingement. J.M. Loughead, Orthopaedic Surgeon, A.W. McCaskie, J.P. Holland, Freeman Hospital, Newcastle, UK. 1. Dowson D, Jin ZM. Metal-on-metal hip joint tribology. Proc Inst Mech Eng [H] 2006;220:107-18. 2. Loughead JM, Starks I, Chesney D, McCaskie AW, Holland JP. Removal of acetabular bone in resurfacing arthroplasty of the hip: a comparison with hybrid total hip arthroplasty. J Bone Joint Surg [Br] 2006;88-B:31-4.