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Hip: A. J. Shimmin and D. Back Femoral neck fractures following Birmingham hip resurfacing: A NATIONAL REVIEW OF 50 CASES J Bone Joint Surg Br 2005; 87-B: 463-464 [Abstract] [Full text] [PDF]

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Reply to Mr Irvine

Andrew Shimmin, DL Back   (16 June 2005)

Femoral neck fractures following Birmingham hip resurfacing

George B Irvine   (10 May 2005)

Reply to Mr Irvine 16 June 2005
Andrew Shimmin, Consultant Orthopaedic Surgeon Melbouren Orthopaedic Group, DL Back Send letter to journal: Re: Reply to Mr Irvine ashimmin{at}optusnet.com.au Andrew Shimmin, et al.	Sir, We thank Mr Irvine for his interest in our article. We agree that age-specific data in relation to fracture would be of interest. However, there are a number of problems in producing these statistics. Firstly, there is already significant bias in the age selection of patients for this procedure. We did not study a wide distribution of ages and therefore it would be wrong to draw conclusions regarding suitability for hip resurfacing for the range of ages from this data. Secondly, we were unable to collect complete data on ages for all 3429 procedures performed in Australia. Without this data we are unable to state whether a particular age range is more prone to fracture. We performed a smaller study focusing on one state in Australia where age statistics were complete. However, the number of fractures were too few for us to reach any useful statistical conclusions. Considering the small number of fractures encountered, we must be careful not to extrapolate too many conclusions from the data. Our opinion is that there should be no specific age limit for the procedure. In our prospective study we did not impose a lower age limit; over a certain age we considered all cases on individual merit, basing our criteria on the expectations of the patient, their occupation, bone density and levels of physical activity. There is no doubt that there comes a time when resurfacing does not offer any advantages over a standard total hip replacement, (i.e. less than a 15 year life expectancy) and other disadvantages. Based on our research we do not feel that we are in a position to draw form conclusion regarding hip resurfacing based purely on age-specific data. A. SHIMMIN, MBBS D. BACK, BSc, MBBS, FRCS Ed(Orth) Melbourne Orthopaedic Group, Melbourne, Australia.
Femoral neck fractures following Birmingham hip resurfacing 10 May 2005
George B Irvine, Consultant Orthopaedic Surgeon Torbay Hospital, Devon, UK Send letter to journal: Re: Femoral neck fractures following Birmingham hip resurfacing gbirvine{at}hotmail.com George B Irvine	Sir, I read with interest the article in the April 2005 issue by Shimmin and Back entitled 'Femoral neck fractures following Birmingham hip resurfacing'.1 This pan-Australian study shows a statistically significant female preponderance but as with their earlier prospective study2 it provides no age-specific data. Hip resurfacing with a metal-on-metal bearing can provide a solution in the medium term for the younger, more active patient with osteoarthritis3 but the boundaries are far from clear. The terms 'younger' and 'more active' are both relative and subjective. Indeed, the perception of the patient may be very different from that of the surgeon. Should there be a chronological limit beyond which patients are considered unsuitable for a resurfacing procedure? The National Institute for Clinical Excellence4 has suggested 65 years, while the practice of the Melbourne Orthopaedic Group2 has been to consider men below the age of 75 years and women under 60 years. They consider patients beyond these limits on an individual basis but advise any patient with quantitative evidence of low bone density to have a conventional replacement. The evidence in fact suggests that osteopenia may not be so much of a concern as bone mineral density is preserved in Gruen5 zone 1 and increases in zone 7 after Birmingham hip resurfacing.6 Age-related loss of bone stock may well influence outcome following Birmingham hip resurfacing but the paper of Shimmin and Back1 misses the opportunity to inform of the relationship between age at operation and the likelihood of subsequent femoral neck fracture. G. B. IRVINE, FRCSEd(Orth) Torbay Hospital, Torquay, UK. 1. Shimmin AJ, Back D. Femoral neck fractures following Birmingham hip resurfacing. J Bone Joint Surg [Br] 2005;87-B:463-4. 2. Back DL, Dalziel R, Young D, Shimmin A. Early results of primary Birmingham hip resurfacings. J Bone Joint Surg [Br] 2005;87-B:324-9. 3. Treacy RBC, McBryde CW, Pynsent PB. Birmingham hip resurfacing arthroplasty. J Bone Joint Surg [Br] 2005;87-B:167-70. 4. National Institute for Clinical Excellence. Guidance on the use of metal on metal hip resurfacing arthroplasty. London: National Institute for Clinical Excellence, 2002. 5. Gruen TA, McNeice GM, Amstutz HC. 'Modes of failure' of cemented stem-type femoral components: a radiographic analysis of loosening. Clin Orthop 1979;141:17-27. 6. Kishida Y, Sugano N, Nishii T, et al. Preservation of the bone mineral density of the femur after surface replacement of the hip. J Bone Joint Surg [Br] 2004;86-B:185-9.