Aims

A recent report from France suggested an association between the use of cobalt-chrome (CoCr) femoral heads in total hip arthroplasties (THAs) and an increased risk of dilated cardiomyopathy and heart failure. CoCr is a commonly used material in orthopaedic implants. If the reported association is causal, the consequences would be significant given the millions of joint arthroplasties and other orthopaedic procedures in which CoCr is used annually. We examined whether CoCr-containing THAs were associated with an increased risk of all-cause mortality, heart outcomes, cancer, and neurodegenerative disorders in a large national database.

A recent French report suggested that cobalt metal ions released from total hip replacements (THRs) were associated with an increased risk of dilated cardiomyopathy and heart failure. If the association is causal the consequences would be significant given the millions of Orthopaedic procedures in which cobalt-chrome is used annually. We examined whether cobalt-chrome containing THRs were associated with an increased risk of all-cause mortality, heart failure, cancer, and neurodegenerative disorders.

Data from the National Joint Registry was linked to NHS English hospital inpatient episodes for 375,067 primary THRs with up to 14·5 years follow-up. Implants were grouped as either containing cobalt-chrome or not containing cobalt-chrome. The association between implant construct and the risk of all-cause mortality and incident heart failure, cancer, and neurodegenerative disorders was examined.

There were 132,119 individuals (35·2%) with an implant containing cobalt-chrome. There were 48,106 deaths, 27,406 heart outcomes, 35,823 cancers, and 22,097 neurodegenerative disorders. There was no evidence of an association that patients with cobalt-chrome implants had higher rates of any of the outcomes. For all-cause mortality there was a very small survival advantage for patients having a cobalt-chrome implant (restricted mean survival time 13·8=days, 95% CI=6·8-20·9).

Cobalt-chrome containing THRs did not have an increased risk of all-cause mortality, heart failure, cancer, and neurodegenerative disorders into the second decade post-implantation. Our findings will reassure clinicians and patients that primary THR is not associated with systemic implant effects.

The aim of this study was to compare the relative performance of total hip replacement constructs and discern if there is substantial variability in performance in currently commonly used prostheses.

All patients who underwent a primary total hip replacement (THR) registered in the NZJR between 1^st January 1999 to June 2020 were identified. Using a noninferiority analysis, the performance of hip prostheses were compared with the best performing contemporary construct. Construct failure was estimated using the 1-Kaplan Meier survival function method to estimate net failure. The difference in failure between the contemporary benchmark and other constructs was examined.

In total 135 432 THR were recorded comprising 1 035 different THR constructs. Notably 328 constructs were used just once. 48 constructs (62 251 THR) had >500 procedures at risk at 3 years post-primary of which 28 were inferior by at least 20% relative risk of which, 10 were inferior by at least 100% relative risk. 16 constructs were identified with >500 procedures at risk at 10 years with 9 inferior by at least 20%, of which one was inferior by >100% relative risk. There were fewer constructs noninferior to the best practice benchmark when we performed analysis by gender. In females at 10 years, from 5 constructs with >500 constructs at risk, 2 were inferior at the 20% margin. In males at 10 years, there were only 2 eligible constructs of which one was inferior at the 20% margin.

We discerned that there is substantial variability in construct performance and at most time points, just over half of constructs are inferior to the best performing construct by at least 20%. These results can facilitate informed decision-making when considering THR surgery.

Introduction

Total hip arthroplasty (THA) is indicated in independently mobile patients sustaining displaced intracapsular hip fractures. Studies presently suggest that the anterolateral approach is preferable to the posterior approach due to a perceived reduced risk of reoperations and dislocations. However, these observations come from small studies with short follow-up. We assessed whether surgical approach in THA performed for hip fractures effects outcomes.