Cobalt Chrome Heads Underperform Ceramic and Ceramicized Metal Heads in the Younger Population: An American Joint...

The impact of fourth-generation ceramic, ceramicized metal, and antioxidant polyethylene has not been well characterized in younger patients undergoing total hip arthroplasty (THA). This study aimed to compare the revision rates of modern bearing couples in this population.

American Joint Replacement Registry data was analyzed between January 2012 and June 2022 for patients aged 18 to 54 years who underwent a primary THA, had at least 1-year follow-up, and received one of six bearing types (ceramic on ceramic [CoC], ceramic on cross-linked polyethylene [CoP], ceramic on antioxidant polyethylene [CoAOP], ceramicized metal on cross-linked polyethylene [CMoP], cobalt chromium on CoP ["metal on polyethylene," MoP], and metal on antioxidant polyethylene). Outcomes were assessed through analysis of variance, chi-square, and Fisher exact tests. Cox proportional hazard models were conducted and reported as hazard ratios (HRs) and confidence intervals (CIs).

A total of 101,313 primary THA cases were identified; most patients received a CoP bearing (64.2%), and survivorship exceeded 96%. Also, CMoP had the lowest rate and a lower likelihood of all-cause revision compared to MoP (1.95%, n = 197; HR = 0.72; CIs: 0.59 to 0.87; P < 0.001). In addition to CMoP, CoP (HR = 0.73; CIs: 0.64 to 0.84; P < 0.001) and CoAOP (HR = 0.77; CIs: 0.64 to 0.94; P = 0.003) outperformed MoP. The lowest rate of revision for aseptic loosening was seen with CoC (P < 0.001), with CoAOP (HR = 0.41; CIs: 0.27 to 0.64; P < 0.001), CMoP (HR = 0.42; CIs: 0.56 to 0.70; P < 0.001), and CoP (HR = 0.55; CIs: 0.41 to 0.74; P < 0.001) also outperforming MoP.

All-cause revision rates in this younger population are low with modern bearings. Head composition remains an important driver of survivorship. Ceramic or ceramicized metal on a polyethylene bearing should be considered the gold standard in this patient population.