LAUSR

Background There is ongoing debate concerning the best method of femoral fixation in older patients receiving primary THA. Clinical studies have shown high survivorship for cemented and cementless femoral stems. Arthroplasty registry studies, however, have universally shown that cementless stems are associated with a higher rate of revision in this patient population. It is unclear if the difference in revision rate is a reflection of the range of implants being used for these procedures rather than the mode of fixation. Questions/purposes (1) Is the risk of revision higher in patients older than 75 years of age who receive one of the three cementless stems with the highest overall survivorship in the registry than in those of that age who received one of the three best-performing cemented stems? If so, is there a difference in risk of early revision versus late revision, defined as revision within 1 month after index surgery? (2) Are there any diagnoses (such as osteoarthritis [OA] or femoral neck hip fracture) in which the three best-performing cementless stems had better survivorship than one of the three best-performing cementless stems? (3) Do these findings change when evaluated by patient sex? Methods The Australian Orthopaedic Association National Joint Replacement Registry data were used to identify the best three cemented and the best three cementless femoral stems. The criteria for selection were the lowest 10-year revision rate and use in > 1000 procedures in this age group of patients regardless of primary diagnosis. The outcome measure was time to first revision using Kaplan-Meier estimates of survivorship. Comparisons were made for THAs done for any reason and then specifically for OA and femoral neck fracture separately. Results Overall, the cumulative percent revision in the first 3 months postoperatively was lower among those treated with one of the three best-performing cemented stems than those treated with one of the three best-performing cementless stems (hazard ratio [HR] for best three cementless versus best three cemented = 3.47 [95% confidence interval {CI}, 1.60-7.53], p = 0.001). Early revision was 9.14 times more common in the best three cementless stems than in the best three cemented stems (95% CI, 5.54-15.06, p = 0.001). Likewise, among patients with OA and femoral neck fracture, the cumulative percent revision was consistently higher at 1 month postoperatively among those treated with one of the three best-performing cementless stems than those treated with one of the three best-performing cementless stems (OA: HR for best three cementless versus best three cemented = 8.82 [95% CI, 5.08-15.31], p < 0.001; hip fracture: HR for best 3 cementless versus best three cemented = 27.78 [95% CI, 1.39-143.3], p < 0.001). Overall, the cumulative percent revision was lower in the three best cemented stem group than the three best cementless stem group for both males and females at 1 month postoperatively (male: HR = 0.42 [95% CI, 0.20-0.92], p = 0.030; female: HR = 0.06 [95% CI, 0.03-0.10], p < 0.001) and for females at 3 months postoperatively (HR = 0.15 [95% CI, 0.06-0.33], p < 0.001), after which there was no difference. Conclusions Cementless femoral stem fixation in patients 75 years or older is associated with a higher early rate of revision, even when only the best-performing prostheses used in patients in this age group were compared. Based on this review of registry data, it would seem important to ensure the proper training of contemporary cementing techniques for the next generation of arthroplasty surgeons so they are able to use this option when required. However, the absence of a difference in the two groups undergoing THA after 3 months suggests that there can be a role for cementless implants in selected cases, depending on the surgeon’s expertise and the quality and shape of the proximal femoral bone. Level of Evidence Level III, therapeutic study.