This study focuses on a narrow subset of patients who have sustained a displaced femoral neck fracture, the active, healthy elderly patient. The results of this analysis demonstrate several important points. First, it appears that total hip replacement is the more cost-effective arthroplasty option for displaced femoral neck fractures in the active, healthy, elderly patient population, despite the potential for increased morbidity compared with hemiarthroplasty. The incremental cost-effectiveness ratio is $1,960 per QALY, which is well below the $50,000 per QALY threshold needed to make an intervention cost-effective. 17
The cost-effectiveness of total hip replacement in this patient population is due to the increased quality of life for patients with well-functioning total hip replacements compared with hemiarthroplasty patients, reflected in the higher average utility values achieved with this procedure. 9
Second, the procedure which generates the highest average utility for patients is likely to be the most cost-effective option, and this utility value is the most important parameter in determining cost-effectiveness. This is demonstrated in several ways. For example, if the revision rate of hemiarthroplasty is greater than the rate for total hip replacement, then the average utility value associated with hemiarthroplasty must be greater than the average value achieved with THA for it to be the more cost-effective strategy (). However, this is not consistent with the utility values achieved with hemiarthroplasty in recent studies. 9
In addition, demonstrates that cost does not appear to be as important as the average utility value achieved with each procedure, as the cost differences between the two procedures must reach unlikely extremes before hemiarthroplasty becomes the more cost-effective option when using the average utility values currently reported in the literature for these two procedures in this patient population. Furthermore, many patients will not undergo a revision during their remaining lifetime, which makes the average utility value achieved with the index arthroplasty procedure, a more important variable then the revision rate. This is illustrated in , which shows the revision rate of hemiarthroplasty must increase to seven times the rate for total hip replacement before total hip becomes the more cost-effective treatment if the utility value of HEMI increases from 0.68 to 1.0. The importance of the utility value of the index procedure is also demonstrated by the fact that even if the revision rate of hemiarthroplasty is 0%, it still is only the more cost-effective option if the average utility value associated with it is 0.68 or greater, which is greater than the average value achieved in patients with displaced femoral neck fractures treated with total hip replacement in recent trials (). 9
Therefore, if total hip replacement results in a higher average utility value than hemiarthroplasty in the treatment of displaced femoral neck fractures, as recent studies have found 9
, it very likely will be the more cost-effective treatment option for this injury. This is important for future investigators to understand and highlights the need for studies precisely evaluating the utility value of these arthroplasty procedures for large numbers of patients with femoral neck fractures over time.
This analysis examined the patient population of active, healthy, elderly patients with displaced femoral neck fracture thought to be best treated with an arthroplasty procedure. The patient population that fits this description remains to be clearly defined.1
It should be noted that this is a population based analysis and not an analysis of individual patient preferences or characteristics. Therefore, surgeons will need to continue to practice the art of medicine, weighing each individual patient's medical and social situation, personal risk preferences, as well as their own surgical resources and capabilities, in deciding the best treatment option for elderly patients who sustain a displaced femoral neck fracture. The factors involved in the long-term outcome of femoral neck fractures treated with an arthroplasty procedure are difficult to weigh against each other. A limitation of the model used in this study is the estimation of the transition probabilities, such as the rate of revision surgery or peri-operative mortality, as well as the utilities and disutilities used within the model. The only definitive way to truly determine the cost-effectiveness of the two treatment strategies would be to prospectively measure the health utility and costs associated with each treatment and all its sequelae for a large patient population over an extended period of time.
Currently available data support the use of total hip arthroplasty as the more cost-effective treatment strategy in active, healthy, elderly patients with displaced femoral neck fractures. The increased upfront cost appears to be offset by the improved functional results measured by higher average post-operative utility values, when compared with hemiarthroplasty in this select patient group, resulting in an incremental cost-effectiveness ratio well below accepted thresholds for determining cost-effective treatment strategies.