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HipFurther Opinion

The case for removing the subchondral bone plate in preparation of the acetabulum

Gilbody J

J Bone Joint Surg [Br] 2011;93-B:435-8.

Since the pioneering work of Sir John Charnley, total hip replacement has become a widely performed operation with largely good results. In the intervening years the orthopaedic literature has included a large number of studies proposing alternatives to the cemented hip replacement. The performance of some of the hybrid combinations and uncemented systems has been extremely good. There have, however, been a number of well documented cases where “developments” in both implant design and bearing choices have led to higher failure rates and new complications.

The outcomes of cemented hip arthroplasty on national joint registries continue to support the view that the cemented hip remains one of the best options available to patients and surgeons. It is therefore imperative to continue to look at ways in which we can improve/optimise the outcome of these operations. Preparation of the acetabular bone for cemented and uncemented components, has been a popular topic in the recent literature, not least regarding preservation or loss of bone. The author of this paper proposed a fresh look at a long standing issue: are we optimising the cementation of acetabular component. Gilbody highlighted the ongoing concerns relating to aseptic loosening of the acetabular component. The current generation of hip surgeons have the same concerns as the early pioneers, including: appropriate preparation of the bone bed, optimal cementation techniques and correct orientation of the component.

The article referenced in this paper by Crites et al1 noted five factors that the authors felt were “essential for the long term success of cemented acetabular components”:

  • Good cancellous acetabular bed with particular attention given to removing sclerotic areas from Zone 1
  • Complete cover of the component within the bony acetabulum
  • Pulsed lavage irrigation of the canellous bone
  • Drying the acetabulum
  • Pressurisation of the entire acetabulum

The current economic climate and the escalating costs of healthcare have resulted in an increase in financial pressures on providers.  Often cemented hip systems are the cheaper option. Many surgeons have moved away from cemented acetabular components, in some cases due to concerns about the radiological features of demarcation at the cement bone interface, as described by a number of authors in this paper.

The article presented by Gilbody lacks a clear definition of what the author means by preservation or removal of the subchondral plate. In at least one of the articles referenced,2 subchondral plate preservation was described as: “Cartilage was scraped away and multiple fixation holes drilled into the ilium, ischium and pubis”. Gilbody described Sir John Charnely “reaming the acetabulum until a bed of cancellous bone was achieved” during subchondral plate removal. In the article by Eftekhar et al,3 Charnely’s original concept was described as: “maximum deepening of the acetabulum, which usually included a perforation by a 12.5mm drill and complete removal of the subchondral plate of the roof of the acetabulum”. A review of a number of articles and textbooks refer to “partial preservation of the subchondral plate”. Therefore, it is likely that there is a great variance in what individual surgeons mean by subchondral plate removal.

Gilbody highlighted that cemented acetabular component failure through aseptic loosening remains considerably higher than the best performing cemented stems. He proposed that it is perhaps time to revive decortication as a standard technique of acetabular preparation. As is often the case, the exact definition of terms used in one paper is not identical to that used in another article. If future investigators are to pursue this issue, it would add great clarification to clearly define both the depth and extent of “decortication” or “subchondral plate removal” proposed.

The development of new designs and refinement of old ideas continue to offer alternatives to the cemented total hip replacement.  While long term outcome data on alternatives such as hip resurfacing are still awaited, the indications and pitfalls of such surgery continue to be clarified. The proponents of uncemented acetabular components continue to cite their potential advantages regarding choice of bearings and a perceived greater ease of implantation.

It is perhaps time to revisit the topic of acetabular preparation with the potential consequence of increasing confidence in the use of cemented acetabular components which are often cheaper to implant and offer some of the best registry outcomes.

 

References

1. Crites BM, Berend ME, Ritter MA. Technical considerations of cemented acetabular components: a 30-year evaluation. Clin Orthop 2000; 381:114-19.
2. Carter DR, Vasu R, Harris WH. Periacetabular stress distribution after joint replacement with subchondral bone retention. Acta Orthop Scan 1983;54:29-35.
3. Eftekhar NS, Tzitzikalakis GI. Failures and reoperations following low-friction arthroplasty of the hip: a five to fifteen-year follow up study. Clin Orthop 1986;211:65-78.

 

Mr G J C Myers FRCS (Tr & Orth)

 

Consultant Orthopaedic Surgeon

Ipswich Hospital NHS Trust

Heath Road

Ipswich

IP4 5PD

Email: Graham.Myers@ipswichhospital.nhs.uk