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

Abstract

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.

Can standard implants reproduce the native kinematics of a TKA patient?

“…A patient-specific musculoskeletal model (MSM) was previously developed and validated by Vanheule et al [3]. This model predicts kinematics and ligament length elongations when squatting, for both pre-TKA and post-TKA knees.…”

“…Musculoskeletal modeling (MSM) has the potential to explore the relationship between implant alignment and functional outcome [3]. Consequently, implant alignment can be quantitatively optimized to restore the pre-TKA joint behavior and, therefore, achieve the most favorable functional outcome for the specific patient.…”

Standard Cruciate-Retaining Total Knee Arthroplasy Implants Can Reproduce Native Kinematics

“…For two specimens, subject-specific MSM (Anybody Modeling System, Anybody Technology, Denmark) were developed and validated in previous work (Vanheule et al, 2017). The model included four segments: femur, patella, tibia and fibula.…”

“…Native kinematics were simulated and evaluated against experimentally recorded kinematics for the two specimens (Vanheule et al, 2017). Tibiofemoral kinematics were predicted for both the native and TKA joint.…”

“…Biomechanics and quality of movement similar to healthy were found to improve post-operative patient-reported outcomes (Kirschberg et al, 2018;Biggs et al, 2019). Musculoskeletal modeling (MSM) allows to investigate the interplay between patient-specific biomechanics, implant alignment and soft tissues (Vanheule et al, 2017). Moreover, the combination of MSM and artificial neural networks (ANN) (Marra et al, 2017), allow to create a fast surrogate model to optimize patient-specific implant position.…”