In Vitro Verification of Simulated Daily Activities Using Implant-Specific Kinematics from In Vivo Measurements.

The mechanism and boundary conditions used to drive experimental joint simulators have historically adopted standardized profiles developed from healthy, non-total knee arthroplasty (TKA) patients. The purpose of this study was to use implant-specific in vivo knee kinematics to generate physiologically relevant boundary conditions used in the evaluation of cadaveric knees post-TKA. Implant-specific boundary conditions were generated by combining in vivo fluoroscopic kinematics, musculoskeletal modeling-generated quadriceps loading, and telemetric knee compressive loading during activities of daily living (ADL) to dynamically drive a servo-hydraulic knee joint simulator.

Instantaneous Generation of Subject-Specific Finite Element Models of the Hip Capsule.

Subject-specific hip capsule models could offer insights into impingement and dislocation risk when coupled with computer-aided surgery, but model calibration is time-consuming using traditional techniques. This study developed a framework for instantaneously generating subject-specific finite element (FE) capsule representations from regression models trained with a probabilistic approach. A validated FE model of the implanted hip capsule was evaluated probabilistically to generate a training dataset relating capsule geometry and material properties to hip laxity.

Simultaneous Evaluation of Tibiofemoral and Patellofemoral Mechanics in Total Knee Arthroplasty: A Combined Experimental and Computational Approach.

Contemporary total knee arthroplasty (TKA) has not fully restored natural patellofemoral (P-F) mechanics across the patient population. Previous experimental simulations have been limited in their ability to create dynamic, unconstrained, muscle-driven P-F articulation while simultaneously controlling tibiofemoral (T-F) contact mechanics. The purpose of this study was to develop a novel experimental simulation and validate a corresponding finite element model to evaluate T-F and P-F mechanics.

Specimen-specific finite element representations of implanted hip capsules.

The hip capsule is a ligamentous structure that contributes to hip stability. This article developed specimen-specific finite element models that replicated internal-external (I-E) laxity for ten implanted hip capsules. Capsule properties were calibrated to minimize root mean square error (RMSE) between model and experimental torques.

Effect of Modularity on the Fatigue Performance of Tibial Tray Designs in TKA Prostheses.

Fatigue performance of tibial tray in total knee arthroplasty (TKA) is of critical importance in terms of longevity of the prosthesis. Standards have been proposed by American Society for Testing and Materials (ASTM) and International Organization for Standardization (ISO) to ensure its long-term structural integrity. The aim of the current study is to evaluate the effect of modularity in the tibial tray following the testing standards, using finite element analysis.