Evaluation of predicted knee function for component malrotation in total knee arthroplasty

• Published in: Medical engineering & physics Vol. 40; pp. 56 - 64
• Main Authors: Vanheule, Valentine, Delport, Hendrik Pieter, Andersen, Michael Skipper, Scheys, Lennart, Wirix-Speetjens, Roel, Jonkers, Ilse, Victor, Jan, Vander Sloten, Jos
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01.02.2017
• Subjects: Alignment; Arthroplasty, Replacement, Knee; Biomechanical Phenomena; Humans; In vitro; Kinematic knee rig; Knee - diagnostic imaging; Knee - physiology; Ligaments - diagnostic imaging; Ligaments - physiology; Patient-Specific Modeling; Radiology; Rotation; Soft tissue balancing; Subject-specific; Tomography, X-Ray Computed; Alignment; Subject-specific; In vitro; Soft tissue balancing; Kinematic knee rig
• ISSN: 1350-4533; 1873-4030; 1873-4030
• DOI: 10.1016/j.medengphy.2016.12.001

•Multi-body model quantitatively predicted subject-specific knee behaviour after TKA.•Experimental testing of impact of TKA malrotation on ligament lengths and motion.•Presented model could distinguish effect of TKA malrotation on knee behaviour. Soft-tissue balancing for total knee arthroplasty (TKA) remains subjective and highly dependent on surgical expertise. Pre-operative planning may support the clinician in taking decisions by integrating subject-specific computer models that predict functional outcome. However, validation of these models is essential before they can be applied in clinical practice. The aim of this study was to evaluate a knee modelling workflow by comparing experimental cadaveric measures to model-based kinematics and ligament length changes. Subject-specific models for three cadaveric knees were constructed from medical images. The implanted knees were mounted onto a mechanical rig to perform squatting, measuring kinematics and ligament length changes with optical markers and extensometers. Coronal malrotation was introduced using tibial inserts with a built-in slope. The model output agreed well with the experiment in all alignment conditions. Kinematic behaviour showed an average RMSE of less than 2.7mm and 2.3° for translations and rotations. The average RMSE was below 2.5% for all ligaments. These results show that the presented model can quantitatively predict subject-specific knee behaviour following TKA, allowing evaluation of implant alignment in terms of kinematics and ligament length changes. In future work, the model will be used to evaluate subject-specific implant position based on ligament behaviour.