Robotic-assisted Unicompartmental knee Arthroplasty optimizes joint line restitution better than conventional surgery

José Antonio Cordero,Nicolás O. Reyes,Maximiliano Barahona,Vicente Sepulveda,Magaly Iñiguez,Jaime Duboy,Gonzalo Ferrer,Carlos Infante,Roberto Negrín

doi:10.1186/s40634-020-00309-8

Abstract

PurposeTo compare joint line restoration after unicompartmental knee arthroplasty (UKA) between conventional and robotic-assisted surgery. Previous studies have shown that joint line distalization can lead to higher failure rates. The hypothesis was that robotic-assisted UKA is associated with less femoral component distalization and a precise tibial cut, which allows a more anatomical restitution of the knee joint line.MethodsRetrospective cohort study of patients undergoing medial or lateral UKA between May 2018 and March 2020. Preoperative and postoperative radiologic assessment of the joint line was performed by two observers, using three different methods, one for tibial slope and one for tibial resection. Robotic assisted UKA and conventional UKA groups were compared.ResultsSixty UKA were included, of which 48 (77.42%) were medial. Robotic-assisted UKA were 40 (64.52%) and 22(35.48%) were conventionalThe distalization of the femoral component was higher in the conventional group despite the method of measurement used In both Weber methods, the difference was statistically different: Conventional 2.3 (0.9 to 5.6) v/s Robotic 1.5 (− 1.1 to 4.1) (p =0.0025*). A higher proportion of patients achieved a femoral component position ≤ two millimeters from the joint line using robotic-assisted UKA compared to the conventional technique .No statistical difference between robotic-assisted and conventional UKA was found in tibial resection and slope.ConclusionRobotic-assisted UKA shows a better rate of joint line restoration due to less femoral component distalization than conventional UKA. No difference was found in the amount of tibial resection between groups in this study.Level of evidenceIII

Highlights

Unicompartmental knee arthroplasty (UKAs) is a costeffective treatment for severe femorotibial unicompartmental knee osteoarthritis
Roboticassisted UKA were 40 (64.52%), no statistical difference was found in the proportion of medial UKA, but there were significantly more left-sided in the robotic group
A higher proportion of patients achieved a femoral component position below two millimeters from the joint line using robotic-assisted UKA compared to the conventional technique. (Table 4, Fig. 5)

Summary

Introduction

Unicompartmental knee arthroplasty (UKAs) is a costeffective treatment for severe femorotibial unicompartmental knee osteoarthritis. Remarkable advantages over total knee replacement (TKA) are a better restoration of native kinematics, less morbidity, and better recovery of joint function. It has higher revision rates [1, 2]. The main reason for lower survival is aseptic loosening, which has been related to the orientation of the components and the restoration of the joint line [3,4,5]. There are reports that associate higher failure rates when the joint line is not restored, despite if it is due to the distalization of the femoral component or an excessive tibial cut [4, 6].

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