Comparison of survival between cemented vs cementless unicompartimental knee arthroplasty: a case control study with propensity score matching.

Introduction: The first results of cementless prosthesis were rather disappointing. However recent progress in methods of cementless fixation of prosthesis should lead to better results in terms of survival of these prostheses. The main objective is to compare the survival rate at last follow-up of UKA with cemented tibial or cementless.

Hypothesis: We hypothesize that UKAs with uncemented tibial implants have better survival compared to UKAs with cemented tibial implants.

Material and methods: This single center case-control study included 94 medial UKA with a cemented tibial component that were paired by propensity score matching to 94 medial UKA with a uncemented tibial component. The main evaluation criterion was the comparison of the survivorship of the UKA between a cemented tibial implant and those with a cementless tibial implant in terms of all-cause revision surgery at last follow-up. The secondary endpoints were the analysis of the causes of failure.

Results: The mean final follow-up was 6.1years (2.3). The overall survival rate in our serie of medial UKA was 92.4% [88.7%-96.3%] at five years. The overall survival rate in cemented group was and 91.5% [86.0%-97.3%] at five years and at 93.2% [88.1%-98.7%] at five years, in the uncemented group. No differences significant were observed in the two groups (p.value = 0.6). Only the tibial preoperative deformity was a risk factor of failure (HR: 1.11 [1.02, 1.20], value = 0.02).

Discussion: The use of a cemented or a cementless tibial component in a medial UKA did not influence the survival rate.

Level of evidence: III; case control study.