Abstract
Background
Method of fixation in THA is a contentious issue, with proponents of either technique citing improved implant survival and outcomes. Current comparisons rely on insufficiently powered studies with short-term follow up or larger poorly controlled registry studies. Patient factors are considered a key variable contributing to the risk of implant failure. One way to overcome this confounder is to compare the survival of cementless and cemented THAs patients who have undergone bilateral THAs with cemented hip on one side and cementless hip on the other. We compared stem survival of patients who have bilateral THA with one cemented stem in one hip and a cementless stem in the contralateral hip in the National Joint Registry.
Methods
UK National Joint Registry is the largest registry of its kind in the world. This study included 2934 patients with 5868 THAs who underwent bilateral THAs s between 2003 and 2016. These patients had undergone bilateral sequential THAs within 3 years of each other: cemented THA on one side and cementless on the other, Patients had identical pre-operative American Society of Anaesthesiologists group for both THAs and same indication for surgery. Implant survival was compared using Cox regression with an endpoint of stem revision.
Results
Ten-year all-cause survival of cementless stems was lower than for cemented stems (p<0.001), as was survival to aseptic loosening revision (p<0.001). Similar trends were seen across all age groups including young and old patients. There was a non-significant trend towards superiority of cemented stems in survival until periprosthetic fracture, dislocation and infection.
Conclusion
Comparison of cementless with cemented stems within patients is a novel method to compare the outcomes of orthopaedic implants. Survival was better for cemented stems including for younger patients and aseptic loosening.
