Five-year implant survival does not differ between hybrid and cementless total knee arthroplasty in a cohort of 5361 patients using a deep-dish mobile bearing design.

Abstract

Purpose: This study compared total knee arthroplasty (TKA) outcomes between cementless and hybrid fixation, with separate analysis of tibial and femoral cementation. The primary hypothesis was that equivalence would exist in implant survivorship between cementless and hybrid fixation techniques. The secondary hypothesis was that cementless and hybrid TKAs would demonstrate comparable mid-term surgery-free survival rates, rates of aseptic reoperation and functional outcomes.

Methods: A multicentre retrospective study was conducted using prospectively collected data from a large cohort, all implanted with the same deep-dish mobile bearing. Patients were divided according to the fixation method: fully cementless, femoral cemented/tibial uncemented and tibial cemented/femoral uncemented. The survival rates of cementless and hybrid TKA were compared with a median follow-up of 27 months. Evolution of functional outcomes (International Knee Society [IKS] score, range of motion [ROM]) from preoperative to 5-year follow-up were also compared. Propensity score matching (PSM) was performed to balance covariates (age, sex, body mass index and patellar procedure) between groups.

Results: Among the 5361 primary TKA included (4549 cementless, 435 tibial hybrid and 377 femoral hybrid), 1505 reached the 5-year follow-up. Five-year revision-free survival rate was 98.7% (95% confidence interval: 98.2; 99.1) for cementless, 97.8% (94.6; 99.1) for tibial hybrid (p = 0.537) and 98.4% (94.9; 99.5) for femoral hybrid (p = 0.669). Cumulative surgery-free survival rates and functional outcomes at 5 years showed no significant differences between groups with clinically comparable results.

Conclusion: No difference in survivorship was observed between cementless and hybrid TKA at 5 years in this cohort of 5361 patients, whether the tibia or femur was cemented. Rates of reoperation and aseptic reoperation were also comparable, as were clinical outcomes. These results suggest that the choice between hybrid and cementless fixation does not impact mid-term TKA survival.

Level of evidence: Level III.