Better Implant Positioning and Clinical Outcomes With a Morphometric Unicompartmental Knee Arthroplasty. Results of a Retrospective, Matched-Controlled Study

Abstract

Keywords:unicompartmental knee arthroplasty morphometric tibial tray implant positioning medial overhang tibial bone coverage a b s t r a c t Background: During medial unicompartmental knee arthroplasty (UKA), tibial tray implantation requires compromise between bone coverage and rotational position. It was hypothesized that morphometric tibial tray (MTT) would improve implant positioning and subsequently clinical outcomes as compared to symmetric tibial tray (STT). Methods: A total of 106 patients who underwent medial UKA in our department between January 2017 and March 2018 were included matched on gender and age (53 in each group). Inclusion criteria were symptomatic medial femorotibial osteoarthritis, functional anterior cruciate ligament, primary arthritis, or osteonecrosis. Rotation of the tibial implant, tibial bone coverage, medial and posterior overhang were assessed with a postoperative computed tomography scan. The Knee Society Score (KSS), the Knee injury and Osteoarthritis Outcome Score Short Form (KOOS SF), and the quality of life score EuroQoL 5-Dimensions 3-Levels (EQ5D3L) were assessed at a minimum of 1-year follow-up. Results: Implants of the STT group exhibited more external rotation (6.3 ± 4.02 vs 4.6 ± 3.59 ; P ¼ .04), and medial and posterior overhang >3 mm (35% vs 0% and 22% vs 0%; P < .0001) but no difference for tibial bone coverage (97.3% ± 11.35% vs 94.7% ± 10.89%; P ¼ .23). Global KSS (188.6 ± 6.6 vs 175.2 ± 31.7; P < .01), KOOS SF (16.9 ± 6.1 vs 22.5 ± 11.8; P < .003), and EQ5D3L (1 ± 0.1 vs 0.9 ± 0.2; P < .001) were higher in MTT group. According to the multivariate analysis, MTT had a positive independent effect on the KSS, KOOS SF, and EQ5D3L. Conclusion: The use of an MTT in medial UKA allowed better implant positioning when decreasing the rate of overhang; superior short-term clinical outcomes were found as compared to STT.

Contemporary knee arthroplasty: one fits all or time for diversity?

“…The anatomical differences between the medial and lateral tibial plateau are not taken into account. The use of a custom UKA or a morphometric implant [ 45 ] can be the solution. Patient-specific instruments can easily help with accurate cuts, avoiding too deep posterior cuts or undercutting of the spine [ 46 ].…”

A Morphometric Fixed-Bearing Unicompartmental Knee Arthroplasty Can Reproduce Normal Knee Kinematics. An In Vitro Robotic Evaluation

“…Our study did not find a significant difference in the femoral rollback motion between preoperative and postoperative knees. The advantages of the morphometric implants in the UKA positioning have been described in a previous comparative study [ 30 ]. They allow to optimize the rotational-coverage ratio and the femoral fit, avoiding the compromises between size and positioning.…”

Comparison of Functional Outcome of Total and Unicompartmental Knee Arthroplasty Using Computer-Assisted Patient-Specific Templating

“…It is also worth mentioning that using different tibial trays in UKA has an impact on implant positioning. This was investigated by Escudier et al, and they found that using a morphometric tibial tray is better than using a symmetric tibial tray in terms of decreasing the rate of overhand and improving the short-term clinical outcomes at one-year follow-up [ 14 ].…”

“…Functional assessment of KSS, FKS, and ROF. morphometric tibial tray is better than using a symmetric tibial tray in terms of decreasing the rate of overhand and improving the short-term clinical outcomes at one-year follow-up [14].…”