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Arthroplasty improves function and has a lower reoperation rate than internal fixation
Displaced fracture of the intracapsular proximal femur has been termed the “unsolved fracture” because it is unclear whether it should be treated by internal fixation or by replacement of the femoral head with an artificial hip (arthroplasty).1 More than a third of fixed fractures will require revision surgery for either redisplacement (a complication of fracture healing), fracture non-union, or avascular necrosis of the femoral head. Arthroplasty, however, is a more extensive surgical procedure and may cause dislocation, loosening, and peri-prosthetic fracture, which together have an overall incidence of 5-15%. In their randomised controlled trial in this week’s BMJ, Frihagen and colleagues compare the effects of internal fixation or bipolar hemiarthroplasty after displaced fracture of the femoral neck.
Numerous reports of case series and some methodologically weak randomised controlled trials have failed to resolve the question of which treatment is best, and different surgeons tend to favour one or the other. The Scandinavian countries have generally advocated retaining the femoral head, whereas surgeons in other parts of Europe and North America have favoured arthroplasty. As the quality of randomised controlled trials in orthopaedics has improved and such trials have been evaluated in systematic reviews the mystery of the unsolved fracture is being resolved.
Frihagen and colleagues’ study was designed and carried out well.2 All potential participants were reported fully, those assessing the outcome were blinded to the type of surgery, and all relevant outcomes were clearly reported. Both treatments tested—a modern method of reduction and internal fixation and a cemented bipolar hemiarthroplasty—were appropriate. People who had hemiarthroplasty had significantly better hip function (at four and 12 months), better health related quality of life (at four months), and better scores of activities of daily living (at 12 and 24 months) than those who had internal fixation.Significantly more complications occurred in the internal fixation group, but no significant difference was seen in mortality at 24 months.
The results agree with other recent randomised controlled trials on this topic,3,4,5 which have been summarised in a Cochrane systematic review.6 The results indicate that cemented arthroplasty is better than internal fixation in most patients.
The matter is not clear cut though. Internal fixation is still appropriate for younger people, who have fewer complications of fracture healing. Also, these people have a longer life expectancy, and arthroplasty may need to be revised at a later date because of wear or loosening of the implant. At present, the age at which fixation should be replaced by arthroplasty is somewhere between 55 and 75 years. And for the very frail elderly, the lesser surgical assault of internal fixation compared with arthroplasty may enable a few more patients to survive the trauma of hip fracture.
The value of the second articulating joint within the hemiarthroplasty (bipolar joint) is questionable. The few randomised trials to date have shown no benefit for this additional joint compared with a traditional unipolar hemiarthroplasty.7 Other randomised controlled trials have suggested that total hip replacement—in which the acetabular surface is replaced—is superior to hemiarthroplasty, with less residual pain, lower revision rates, and better regain of function.3 8 Many of these studies included elderly people with hip fracture who were “fitter,” so whether these improved outcomes will apply to less fit people is unclear.
Clinicians should be wary that, along with most other clinical studies, Frihagen and colleagues’ study reports relatively short term outcomes (two years). Avascular necrosis of the femoral head after internal fixation may occasionally occur more than two years after surgery. Late complications after arthroplasty, such as loosening of the implant, can be expected in about 1% of cases each year.
In conclusion, the evidence so far suggests that a cemented arthroplasty for a displaced intracapsular fracture in elderly patients is better than reduction and fixation—it has a lower rate of reoperation and results in better function. As about one million of these fractures occur worldwide each year, we must continue to define the optimum surgical procedure for this potentially disabling condition.9
This article was published on bmj.com on 4 December 2007
Competing interests: MJP has been reimbursed for expenses when attending symposiums and product design meetings organised by manufacturers of implants for internal fixation and for arthroplasty.
Provenance and peer review: Commissioned; not externally peer reviewed.