Knee Surg Sports Traumatol Arthrosc. 2026 Jul 28. doi: 10.1002/ksa.70548. Online ahead of print.
ABSTRACT
PURPOSE: This study aimed to compare implant survivorship and patient-relevant outcomes associated with the constraint level used at first-time aseptic revision total knee arthroplasty (rTKA).
METHODS: This retrospective cohort study used data from the National Joint Registry for England, Wales, Northern Ireland, the Isle of Man, Guernsey and Jersey, linked to Hospital Episode Statistics and national patient-reported outcome measures (PROMs). Patients undergoing first-time aseptic rTKA between 1 January 2009 and 30 September 2023 were included. Constraint was categorized as unconstrained, posterior-stabilized (PS), condylar-constrained (CCK) or hinge. The primary outcome was 10-year cumulative incidence of re-revision. Prespecified subgroups included patients at high risk of re-revision and those revised for aseptic loosening or instability. Secondary outcomes included 6-month PROMs; 90-day mortality and medical complications; and length of stay. Competing risk regression was used to estimate re-revision risk, treating death as a competing event.
RESULTS: After exclusions, 12,950 cases were analysed (median follow-up 7.4 years [95% confidence interval, CI 7.3-7.5]. CCK prostheses were associated with the lowest unadjusted 10-year cumulative incidence of re-revision overall (9.2% [95% CI 8.4-10.1]) and in all subgroups. In the primary adjusted analysis, unconstrained (subdistribution hazard ratio [sHR] 1.46 [1.23-1.74], p < 0.001), PS (sHR 1.23 [1.04-1.44], p = 0.013) and hinged prostheses (sHR 1.66 [1.38-2.01], p < 0.001) were associated with higher re-revision risk than CCK constructs. There was weak evidence that the association between PS implants and re-revision was greater among low-volume than high-volume surgeons (interaction sHR 1.30 [1.00-1.70], p = 0.053). After further adjustment for implant-related factors, re-revision risk was similar for unconstrained (sHR 0.97 [0.78-1.21], p = 0.792) and PS implants (sHR 1.00 [0.83-1.19], p = 0.972) versus CCK, whilst increased risk associated with hinges persisted (sHR 1.67 [1.36-2.05], p < 0.001).
CONCLUSION: CCK constructs were consistently associated with favourable implant survivorship across a range of clinical scenarios. These findings provide reassurance that clinically indicated use of CCK constraint is not associated with compromised implant survival.
LEVEL OF EVIDENCE: Level III.
PMID:42517199 | DOI:10.1002/ksa.70548
