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Orthopaedic Proceedings
Vol. 99-B, Issue SUPP_4 | Pages 139 - 139
1 Feb 2017
Marra M Heesterbeek P van de Groes S Janssen D Koopman B Wymenga A Verdonschot N
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Introduction

Tibial slope was shown to majorly affect the outcomes of Total Knee Arthroplasty (TKA). More slope of the tibial component could help releasing a too tight flexion gap in cruciate-retaining (CR) TKA and is generally associated with a wider range of post-operative knee flexion. However, an excessive tibial slope could jeopardize the knee stability in flexion. The mechanism by which tibial slope affects the function of CR-TKA is not well understood. Moreover, it is not known whether the tibial bone resection should be performed by referencing the anterior cortex (AC) of the tibia or the center of the tibial plateau (CP) and whether the choice of either technique plays a role. The aim of this study was to investigate the effect of tibial slope on the position of tibiofemoral (TF) contact point, knee ligament forces, quadriceps muscle forces, and TF and patellofemoral (PF) joint contact forces during squat activity in CR-TKA.

Methods

A previously validated musculoskeletal model of CR-TKA was used to simulate a squat activity performed by a 86-year-old male subject wearing an instrumented prosthesis [1,2]. Marker data over four consecutive repetitions of a squat motion were tracked using a motion optimization algorithm. Muscle and joint forces and moments were calculated from an inverse-dynamic analysis, coupled with Force-Dependent Kinematics (FDK) to solve knee kinematics, ligament and contact forces simultaneously. The tibial slope in the postoperative case was 0 degree and constituted the reference case for our simulations. In addition, eight additional cases were simulated with −3, +3, +6, +9 degrees of tibial slope, four of them simulating an AC referencing technique and four a CP technique.


Orthopaedic Proceedings
Vol. 98-B, Issue SUPP_4 | Pages 97 - 97
1 Jan 2016
Verdonschot N Weerdesteyn V Vigneron L Damsgaard M Sitnik R Feikas T Carbone V Koopman B
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INTRODUCTION

The burden of Musculoskeletal (M-S) diseases and prosthetic revision operations is huge and increasing rapidly with the aging population. For patients that require a major surgical intervention, procedures are unsafe, uncertain in outcome and have a high complication rate. The goal of this project is to create an ICT-based patient-specific surgical navigation system that helps the surgeon safely reaching the optimal functional result for the patient and is a user friendly training facility for the surgeons. The purpose of this paper is to demonstrate the advancements in personalized musculoskeletal modeling for patients who require severe reconstructive surgery of the lower extremity.

METHODS

TLEMsafe is a European Project dedicated to generating semi-automated 3-D image-analyzing tools to simulate the musculoskeletal (M-S) system. The patient-specific parameters are fed into models with which the patient specific functional outcome can be predicted. Hence, we can analyze the functional effect e.g. due to placement of prosthetic components in a patient. Surgeons can virtually operate on the patient-specific model after which the model predicts the functional effects. Once the optimal plan is selected, this is fed into a computer navigation system (see figure 1).