Early Aseptic Tibial Loosening Is a Concern With a Modern Two-Peg Cementless Total Knee Arthroplasty Design.

BACKGROUND

While early generations of cementless total knee arthroplasty (TKA) had inferior outcomes compared to cemented TKA, modern cementless designs have offered excellent clinical results. The purpose of this study was to compare patient-reported outcome measures (PROMs) and early aseptic revision rates of a specific cementless TKA design featuring a two-pegged tibia to that of its cemented counterpart.

METHODS

A retrospective case series of all cementless and cemented TKAs utilizing a single design performed at a single, high-volume academic center was performed. Institutional review board approval was obtained. All cases were performed between November 2018 and March 2022. A minimum one-year follow-up was required. Demographics, complications, and reoperation/revision data were collected. Oxford Knee Score and Forgotten Joint Score were collected at one-year follow-up. Radiographic review was performed for cementless TKAs that were revised or had PROMs < one SD ("poor performers") or had PROMs > one SD ("high performers") below or above the mean, respectively.

RESULTS

There were 329 cementless and 349 cemented TKAs included. Mean follow-up was 1.9 and 2.6 years for cementless and cemented cohorts, respectively. There were no statistical PROM differences between the two cohorts. There was no statistical difference in aseptic revision rates between the cohorts (4.0% cementless versus 1.7% cemented, P = 0.078); however, there was a higher rate of tibial aseptic loosening in the cementless cohort (2.7% cementless versus 0% cemented, P = 0.002). The mean time to revision for aseptic tibial loosening was 17.6 months. There was no statistical difference in radiolucencies between "poor performers" and "high performers."

CONCLUSIONS

When compared to its cemented counterpart, the cementless TKA that was reintroduced in 2018 had similar one-year PROMs but a higher rate of early tibial loosening (2.7 versus 0.0%, P = 0.002).

LEVEL OF EVIDENCE

III.