Total hip replacement and NICE

Around 150-200 different hip prostheses are available for use. Some require cement fixation, some are cementless, and each consists of an acetabular and a femoral component. The evolution of hip replacement led to alterations in design and materials, some of which proved disastrous (the 3M Capital implant is the best known failure).¹ Guidelines for the selection of implants for hip replacement were introduced in the United Kingdom by the National Institute for Clinical Excellence (NICE) in 2000.² Knowledge of the NICE guidelines is limited among both patients and clinicians, and a noteworthy number of surgeons in the United Kingdom are perhaps using prostheses that are not specified as suitable.³ Although guidelines do not suspend individual clinical autonomy, many surgeons are left in a quandary as to whether they are open to litigation.

The NICE guidelines set a rate of revision for failure of 10% or less for a given prosthesis at 10 years, or performance compatible with that benchmark at three years. Prostheses unable to satisfy these requirements should be the subject of formal research or observational study if the implant is already in use.² Concerns have been raised that NICE guidelines may replace the Bolam test in a court of law,⁴ supplanting the custom that a doctor is innocent of negligence if he or she has acted in accordance with a practice accepted as proper by a reasonable body of men skilled in that particular art.⁵

In the United States, the Food and Drug Administration authorises which hip prostheses may be used, allowing a wide range. The American Academy of Orthopaedic Surgeons says that most orthopaedic surgeons select the prosthesis based on the patient's needs, the surgeon's own preference and experience, and perhaps those of their colleagues or mentors (personal communication, Murphy TB, 2004). The academy provides a comprehensive booklet on osteoarthritis of the hip, which incorporates design of hip prosthesis, materials, fixation, and the outcomes and survivorship of the various bearing surfaces.⁶ Kaiser Permanente, the largest non-profit healthcare plan in the United States, does not produce specific recommendations on the selection of prosthesis but has set up a total joint registry in 2001.

Registries act as a valuable source of information on individual prostheses, allowing informed decisions. The Swedish hip arthroplasty registry was established in 1979. Finland followed in 1980. The Danish hip registry is about to publish its 10 year results, and the Danish national association has informed us that, these results will influence surgeons' choice in the future and act as guidelines” (personal communication, Thomsen PB, 2004).

In Norway, the view is that the Charnley prosthesis is the only device with good long term follow up results in excess of 15 years, and until long term results are available, uncemented prostheses cannot be recommended for routine use.⁷ In Holland and Germany, there are no specific guidelines, and selection of prosthesis is left to the surgeon. Representatives of both these countries have emphasised that the cost of prostheses will play an increasingly important part in future (personal communication, van Osterhout F, Puhl W, 2004). A joint registry was introduced in the United Kingdom in 2003.

In our department, three implants were identified that did not meet the NICE criteria. One was included in a multicentre international trial. For the others, we raised funds from charitable events and manufacturers to appoint a research assistant and set up an observational study. We obtained ethical approval and identified patients from the operating theatre database and invited them for review three years after their surgery. We obtained hip scores and did radiological evaluations to confirm that the components meet the three year minimum benchmark recommended by NICE.

A spirit of cooperation with NICE is probably the best way forward for doctors and law makers alike. NICE guidelines, however, have areas of uncertainty. These include a lack of specific information on the acetabular component in published guidelines; lack of clarity on hybrid variants—either in the form of cementless and cemented technology combined, or in relation to cup and stem from different manufacturers; and the place of generic copies of original designs. Moreover, NICE guidelines do not cover implants in use from the late 1990s—for which no satisfactory three or 10 year data exist. Patients with such implants should not receive an abrupt and unexpected communication from their surgeon that they now form part of research into an untested implant.

A review of the current guidelines this year may tackle some of these problems. In the current period of evolution and uncertainty, the measures we describe here may help departments to meet the demands and requirements of central agencies and the law.