Inferior short-term survivorship and patient outcomes for cementless compared to hybrid fixation with a cemented femoral implant in a novel blade-anchored medial unicompartmental knee arthroplasty design: An analysis of 132 cases.

Abstract

For younger, more active patients, a cementless unicompartmental knee arthroplasty (UKA) might be more advantageous than cemented fixation. Therefore, this study aimed to compare implant survivorship and patient-reported outcome measures (PROMs) between cementless and hybrid fixation (cemented femur and cementless tibial fixation) in a novel tibial blade-anchored, medial UKA design. Two surgeon's registries were reviewed for patients who underwent primary cementless or hybrid medial UKA for medial osteoarthritis between 2019 and 2022. Patients were included if implant survivorship and one-year postoperative PROMs (UCLA-activity score, Oxford Knee Score (OKS), Knee Injury and Osteoarthritis Outcome Score for Joint Replacement (KOOS-JR), pain (VAS) and satisfaction) were registered. Variables were compared using independent two-sample t-tests or the Chi-square test. Survival rates were determined using the Kaplan-Meier models and compared using the Log-rank test. A total of 132 knees were included (cementless 58.3%; cemented 41.7%; mean follow-up 3.1 ± 0.6 years). Three-year all-cause revision survival rate was significantly superior for the hybrid fixation (hybrid: 100%; cementless 88.5%[84.7%-92.3%], p = 0.026). However, the difference in three-year conversion rate to total knee arthroplasty (TKA) did not reach statistical significance. The one-year postoperative OKS (hybrid: 42.9 ± 4.8; cementless: 39.8 ± 6.4, p = 0.003) and KOOS-JR (hybrid:81.5 ± 13.7; cementless: 74.4 ± 12.1, p = 0.002) were significantly superior for the hybrid fixation. Three-year conversion rate to TKA and two-year postoperative PROMs did not significantly differ. The cementless medial UKA demonstrated a significantly inferior short-term all-cause survival rate and inferior postoperative one-year OKS and KOOS-JR compared to the hybrid medial UKA design with a cemented femoral component.