Implant Design and Related Outcomes Dual MobilityDual-mobility cups do not reduce the revision risk for patients with acute femoral neck fracture, as concluded by Rogmark and Nauclér in an observational cohort of 2,242 patients with dual-mobility cups compared with a matched cohort of 6,726 patients treated with a conventional total hip implant 1 . The authors reported that, with implant revision surgery as the outcome, they "could not detect any differences between a total hip arthroplasty with a dual mobility cup and one with conventional bearing." Outcomes were similar and independent of whether the implants were inserted via a direct lateral or posterior approach as well as for subgroup analyses of revision for dislocation and infection. The authors concluded that improvements in the care of patients with hip fracture are most likely to come from elsewhere in the care pathway and "not in design variations of contemporary orthopedic implants."Cnudde et al. reported similar findings when they investigated patients with neurologic disease undergoing arthroplasty for femoral neck fracture 2 . Comparing hemiarthroplasty, conventional total hip arthroplasty (THA), and dual-mobility THA performed in 9,638 patients with conditions such as Alzheimer and Parkinson diseases, the authors found that there was an increased risk of dislocation when comparing hemiarthroplasty and THA with a <32-mm head but not with conventional THA with a 32-mm head (hazard ratio [HR], 1.54 [95% confidence interval (CI), 0.94 to 2.51]; p = 0.083) and THA with a dual-mobility implant (HR, 0.68 [95% CI, 0.26 to 1.84]; p = 0.451). Overall, the authors found no difference in the rate of reoperation or revision-free survival between any of the different prostheses or sizes of the femoral head.
Cobalt-ChromiumUsing data from the National Joint Registry linked to U.K. National Health Service (NHS) English hospital inpatient episodes for 374,359 primary THAs, Deere et al. investigated 158,677 hips (42.4%) containing an implant with cobaltchromium 3 . With a maximum 14.5-year follow-up (mean [and Disclosure: The Disclosure of Potential Conflicts of Interest form is provided with the online version of the article (http://links.lww.com/JBJS/H172).