Metal-on-metal hip replacements reduce mortality in the long-term, shows a recent UK study.
Although data from several studies have supported metal-on-metal hip resurfacing, worries were expressed last year after reports that metal implants used for revision of hip resurfacing operations had an unacceptably high average failure rate of 1.29%.
The 10-year retrospective cohort study looked at prosthesis types in adults who underwent primary elective hip replacement for osteoarthritis, including cemented total hip replacement, uncemented total hip replacement, and metal-on-metal hip resurfacing. The main outcome measure was all cause mortality.
7437 patients who underwent metal-on-metal hip resurfacing were matched to 22 311 patients who underwent cemented total hip replacement; 8101 patients who underwent metal-on-metal hip resurfacing were matched to 24 303 patients who underwent uncemented total hip replacement.
10 year rates of cumulative mortality were 3.6% for metal-on-metal hip resurfacing versus 6.1% for cemented total hip replacement, and 3% for metal-on-metal hip resurfacing versus 4.1% for uncemented total hip replacement.
Patients who underwent metal-on-metal hip resurfacing had a 49% increased survival likelihood compared with patients who underwent a cemented hip replacement, and a 45% increased likelihood of survival compared with patients who underwent an uncemented hip replacement.
The researchers note that ‘although residual confounding is possible, the observed effect size is large’ and that the findings ‘require validation in external cohorts and randomised clinical trials’.