Does Hip Resurfacing Still Have a Role?

James N. Powell, M.D., FRCSC
Clinical Associate Professor of Surgery
University of Calgary
Calgary, AB

Modern hip resurfacing has recently come under even more scrutiny with the recognition of the very poor outcomes associated with the use of some metal-on-metal total hips. Now with ten years of clinical experience in England and Australia, the data is able to provide a more objective assessment of the role of hip resurfacing.

 

The introduction of hip resurfacing in Britain was supported by the NICE guidelines and initially the recommendations suggested an indication in women up to 55 years of age and in men up to 65 years. Outcome data from the Australian registry, and the Canadian experience have demonstrated an inferior survivorship for women by the five-year mark2. The survivorship for men was 97% and women 92% at five years in the Canadian review. The inferior experience is postulated to be as a consequence of: 1) poorer bone quality with resultant fracture of the femoral neck, 2) the high incidence of dysplasia in women with inadvertent implantation in higher combined anteversion than normal leading to edge loading, and 3) perhaps a different biologic response to the burden of metal debris in women.

The adverse reaction to metal debris is currently a subject of intensive research. The unexpected complication of so called pseudotumours has been of greatest concern. These are solid or cystic masses that occur in the periarticular soft tissues and can be aggressive and locally destructive to the soft tissues. Pseudotumours are not a new phenomenon and do occasionally occur in total hip arthroplasty. They are certainly seen more frequently in smaller women with hip dysplasia who undergo hip resurfacing. The frequency of pseudotumours among resurfacing arthroplasties in multiple Canadian centres was reported by Beaulé and co-investigators1. The overall prevalence was 0.10%. Only one male of 2339 hips developed a pseudotumour.

There are several potential advantages to resurfacing. The dislocation rate is extremely low. Reconstruction of hip biomechanics for patients without significant deformity was investigated by Girard and coauthors who compared resurfacing with total hip arthroplasty4. They assessed a number of parameters and noted that leg length and femoral offset were more accurately restored after resurfacing. They reported that leg length was restored to within 4 mm in 86% of patients and offset to within 4 mm in 59%.

There are a number of articles which have attempted to look at functional outcomes of resurfacing as compared with total hip arthroplasty. An excellent article by Shimmin and Bare concluded, after a detailed literature review, that resurfacing patients enjoyed similar outcomes to total hip arthroplasty at minimum and perhaps better outcomes according to some parameters7.

With the ten-year experience of design surgeons and registry data now available, the data clearly supports a potential role for resurfacing in male patients with osteoarthritis under the age of 65. The design surgeons of two of the more successful resurfacing systems have reported their ten-year results. Amstutz reported a 99.7% survivorship for ideal candidates (large components and small defects) and 95.3% for hips with risk factors5. Treacy and co-authors reported the ten-year results of a consecutive series of patients8. The ten-year survivorship for men was 98%. With aseptic revision as an endpoint, the ten-year survivorship for the entire cohort was 95.5%. McMinn reports a ten-year survivorship of 98%6.

A recent article by Shimmin in the British JBJS reports the first peer review data from a non design centre3. The Melbourne orthopaedic group report an overall survivorship of 94.5%. Again, as in all reported series of any size, the male survivorship was significantly better than the female survivorship, 97.5% vs. 89.1%.

The survivorship at ten years in the Oswestry registry is 95.6%. The best registry data at ten years is from Australia. The Australian registry has virtually 100% compliance. At ten years, the Australian registry reports a 92% survivorship for all implants/surgeons/bearings against 97.5% survivorship in the category of men under 65 with osteoarthritis9. It appears the durability is well established for the first decade of worldwide experience.

As we get ready to enter the second decade of experience with the current generation of hip resurfacing in Canada, can we refine our indications and anticipate greater success? The answer is yes. Obviously the indication for resurfacing in women is rare, if at all present, for various reasons. Men, however, in general, have an excellent track record of survivorship and functionality. The technical understanding of implantation technique has evolved from a rudimentary caution against varus on the femoral side to precise acetabular positioning in a relatively more closed position to avoid edge loading. By careful patient selection and precise attention to the position of implantation, better results may be attainable.

References

  1. Canadian Hip Resurfacing Study Group. A Survey of the Prevalence of Pseudotumors with Metal-on-Metal Hip Resurfacing in Canadian Academic Centers. J Bone Joint Surg [Am]. 2011; 93:118-121.
  2. Canadian Hip Resurfacing Study Group. A Survey of the Canadian Resurfacing Study Group Experience: Rates of Conversion from RSA to THR. 2011; COA Annual Meeting.
  3. Coulter G., Young D.A., Dalziel R.E., Shimmin A.J. Birmingham hip resurfacing at a mean of ten years: Results from an Independent Center. J Bone Joint Surg [Br]. 2012; 94-B: 315-321.
  4. Girard J., Lavigne M., Vendittoli P.A., Roy A.G. Biomechanical reconstruction of the Hip; A Randomized Study Comparing Total Hip Resurfacing and Total Hip Arthroplasty. J Bone Joint Surg [Br]. 2006;88-B:721-726.
  5. Hulst J.B., Ball S.T., Wu G., LeDuff M., Woon R.P., Amstutz, H. Survivorship of Conserve Plus Metal Hip Resurfacing Sockets: Radiographic Midterm Results of 580 Patients. Orthop Clin N Am 2011;42: 153-159
  6. McMinn D.J., Daniel J., Ziaee H., Pradhan C. Indications and results of hip resurfacing. International Orthopaedics. 2011; 35:231-237
  7. Shimmin A.J., Bare J., Comparison of Functional Results of hip Resurfacing and total hip Replacement: A review of the Literature. Orthop Clin N Am 2011;42:143-151.
  8. Treacy R.B., McBryde C.W., Shears E., Pynsent P.B. Birmingham Hip Resurfacing: A Minimum Follow-up of Ten Years. J Bone Joint Surg [Br]. 2011; 93-B: 27-33.
  9. No authors listed. National Joint Replacement Registry. Annual Report www.aoa.org.au. (date last accessed 2 March 2011).
 

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