Comparison of mid-term survival of uncemented total knee arthroplasties with modular tibial components made of porous tantalum vs. cemented total knee arthroplasties.

Background & objectives: Cementless total knee arthroplasties (TKAs) with porous tantalum tibial components were developed to improve fixation and reduce implant failure rates in younger, active patients. However, mid-term outcomes remain uncertain. This retrospective study compared survival rates of cementless TKAs with porous tantalum posterior-stabilized (PS) modular tibial components to cemented PS components from the same implant system, using revision for aseptic loosening as the endpoint.

Materials and methods: From January 2017 to November 2021, 899 TKAs were performed at a single tertiary center for osteoarthritis. Of these, 645 (71.7%) were cemented and 254 (28.3%) cementless. Median BMI was similar in both groups (30.0 kg/m² vs 31.0 kg/m²; p = 0.814). Cementless recipients were younger (median 66.0 vs. 72.0 years; p < 0.001). Follow-up continued through 31 December 2023.

Results: Seven-year survival was lower in the cementless group (97.1%, 95% CI 94.9-99.3) vs. cemented group (97.8%, 95% CI 96.6-99.0). Tibial component loosening led to 5 revisions in the cementless group vs. 2 revisions in the cemented group (p < 0.05). Two cementless cases involved tibial tray fractures. Overall, 86 patients (9.6%) died of unrelated causes.

Conclusions: Cementless porous tantalum TKAs had inferior mid-term performance for aseptic loosening, prompting their discontinuation at our institution.