scholarly journals Assessment of paradoxical anterior translation in a CR total knee prosthesis coupling dynamic RSA and FE techniques

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Agostino Igor Mirulla ◽  
Laura Bragonzoni ◽  
Stefano Zaffagnini ◽  
Tommaso Ingrassia ◽  
Raffaele Zinno ◽  
...  
Keyword(s):  
Femoral Component ◽  
Knee Prosthesis ◽  
Motor Task ◽  
Patient Specific ◽  
Fe Model ◽  
Polyethylene Insert ◽  
Anterior Translation ◽  
Contact Points ◽  
Sit To Stand ◽  
Total Knee

Abstract Purpose The study aims were to assess the kinematic data, Internal-External (IE) rotation, and Antero-Posterior (AP) translation of the contact points between the femoral condyles and polyethylene insert and to develop a combined dynamic RSA-FE (Radiostereometric – Finite Element) model that gives results congruent with the literature. Methods A cohort of 15 patients who underwent cemented cruciate-retaining highly congruent mobile-bearing total knee arthroplasty were analyzed during a sit-to-stand motor task. The kinematical data from Dynamic RSA were used as input for a patient-specific FE model to calculate condylar contact points between the femoral component and polyethylene insert. Results The femoral component showed an overall range about 4 mm of AP translation during the whole motor task, and the majority of the movement was after 40° of flexion. Concerning the IE rotation, the femoral component started from an externally rotate position (− 6.7 ± 10°) at 80° of flexion and performed an internal rotation during the entire motor task. The overall range of the IE rotation was 8.2°. Conclusions During the sit to stand, a slight anterior translation from 40° to 0° of flexion of the femoral component with respect to polyethylene insert, which could represent a paradoxical anterior translation. Despite a paradoxical anterior femoral translation was detected, the implants were found to be stable. Dynamic RSA and FE combined technique could provide information about prosthetic component’s stress and strain distribution and the influence of the different designs during the movement.

scholarly journals Over-constrained kinematic of the medial compartment leads to lower clinical outcomes after total knee arthroplasty

2021 ◽  
Author(s):  
Nicola Pizza ◽  
Stefano Di Paolo ◽  
Raffaele Zinno ◽  
Giulio Maria Marcheggiani Muccioli ◽  
Piero Agostinone ◽  
...  
Keyword(s):  
Total Knee Arthroplasty ◽  
Clinical Outcomes ◽  
Knee Arthroplasty ◽  
Motor Task ◽  
Medial Compartment ◽  
Level Of Evidence ◽  
Contact Points ◽  
Sit To Stand ◽  
Medial Pivot ◽  
Total Knee

Abstract Purpose To investigate if postoperative clinical outcomes correlate with specific kinematic patterns after total knee arthroplasty (TKA) surgery. The hypothesis was that the group of patients with higher clinical outcomes would have shown postoperative medial pivot kinematics, while the group of patients with lower clinical outcomes would have not. Methods 52 patients undergoing TKA surgery were prospectively evaluated at least a year of follow-up (13.5 ± 6.8 months) through clinical and functional Knee Society Score (KSS), and kinematically through dynamic radiostereometric analysis (RSA) during a sit-to-stand motor task. Patients received posterior-stabilized TKA design. Based on the result of the KSS, patients were divided into two groups: “KSS > 70 group”, patients with a good-to-excellent score (93.1 ± 6.8 points, n = 44); “KSS < 70 group”, patients with a fair-to-poor score (53.3 ± 18.3 points, n = 8). The anteroposterior (AP) low point (lowest femorotibial contact points) translation of medial and lateral femoral compartments was compared through Student’s t test (p < 0.05). Results Low point AP translation of the medial compartment was significantly lower (p < 0.05) than the lateral one in both the KSS > 70 (6.1 mm ± 4.4 mm vs 10.7 mm ± 4.6 mm) and the KSS < 70 groups (2.7 mm ± 3.5 mm vs 11.0 mm ± 5.6 mm). Furthermore, the AP translation of the lateral femoral compartment was not significantly different (p > 0.05) between the two groups, while the AP translation of the medial femoral compartment was significantly higher for the KSS > 70 group (p = 0.0442). Conclusion In the group of patients with a postoperative KSS < 70, the medial compartment translation was almost one-fourth of the lateral one. Surgeons should be aware that an over-constrained kinematic of the medial compartment might lead to lower clinical outcomes. Level of evidence II.

scholarly journals A Wireless Visualized Sensing System with Prosthesis Pose Reconstruction for Total Knee Arthroplasty

Sensors ◽  
2019 ◽  
Vol 19 (13) ◽  
pp. 2909 ◽  
Author(s):  
Hanjun Jiang ◽  
Shaolin Xiang ◽  
Yanshu Guo ◽  
Zhihua Wang
Keyword(s):  
Total Knee Arthroplasty ◽  
Femoral Component ◽  
Knee Arthroplasty ◽  
Knee Prosthesis ◽  
Image Data ◽  
Force Balance ◽  
Prototype System ◽  
Sensing System ◽  
Flexion Extension ◽  
Total Knee

The surgery quality of the total knee arthroplasty (TKA) depends on how accurate the knee prosthesis is implanted. The knee prosthesis is composed of the femoral component, the plastic spacer and the tibia component. The instant and kinetic relative pose of the knee prosthesis is one key aspect for the surgery quality evaluation. In this work, a wireless visualized sensing system with the instant and kinetic prosthesis pose reconstruction has been proposed and implemented. The system consists of a multimodal sensing device, a wireless data receiver and a data processing workstation. The sensing device has the identical shape and size as the spacer. During the surgery, the sensing device temporarily replaces the spacer and captures the images and the contact force distribution inside the knee joint prosthesis. It is connected to the external data receiver wirelessly through a 432 MHz data link, and the data is then sent to the workstation for processing. The signal processing method to analyze the instant and kinetic prosthesis pose from the image data has been investigated. Experiments on the prototype system show that the absolute reconstruction errors of the flexion-extension rotation angle (the pitch rotation of the femoral component around the horizontal long axis of the spacer), the internal–external rotation (the yaw rotation of the femoral component around the spacer vertical axis) and the mediolateral translation displacement between the centers of the femoral component and the spacer based on the image data are less than 1.73°, 1.08° and 1.55 mm, respectively. It provides a force balance measurement with error less than ±5 N. The experiments also show that kinetic pose reconstruction can be used to detect the surgery defection that cannot be detected by the force measurement or instant pose reconstruction.

scholarly journals Modelling and Analysis on Biomechanical Dynamic Characteristics of Knee Flexion Movement under Squatting

2014 ◽  
Vol 2014 ◽  
pp. 1-14 ◽  
Author(s):  
Jianping Wang ◽  
Kun Tao ◽  
Huanyi Li ◽  
Chengtao Wang
Keyword(s):  
Knee Flexion ◽  
Soft Tissues ◽  
Knee Prosthesis ◽  
Three Dimensional ◽  
Experimental System ◽  
Dynamic Contact ◽  
Internal Stresses ◽  
Fe Model ◽  
Total Knee

The model of three-dimensional (3D) geometric knee was built, which included femoral-tibial, patellofemoral articulations and the bone and soft tissues. Dynamic finite element (FE) model of knee was developed to simulate both the kinematics and the internal stresses during knee flexion. The biomechanical experimental system of knee was built to simulate knee squatting using cadaver knees. The flexion motion and dynamic contact characteristics of knee were analyzed, and verified by comparing with the data from in vitro experiment. The results showed that the established dynamic FE models of knee are capable of predicting kinematics and the contact stresses during flexion, and could be an efficient tool for the analysis of total knee replacement (TKR) and knee prosthesis design.

scholarly journals Sit-to-Stand Movement as a Performance-Based Measure for Patients With Total Knee Arthroplasty

2010 ◽  
Vol 90 (2) ◽  
pp. 149-156 ◽  
Author(s):  
Miranda C. Boonstra ◽  
Paul J.A. Schwering ◽  
Maarten C. De Waal Malefijt ◽  
Nico Verdonschot
Keyword(s):  
Total Knee Arthroplasty ◽  
Knee Arthroplasty ◽  
Knee Prosthesis ◽  
Visual Analog Scale Score ◽  
Knee Extension ◽  
Self Report ◽  
Control Group ◽  
Sit To Stand ◽  
Total Knee ◽  
Improved Performance

BackgroundFunctional recovery of patients after a total knee arthroplasty (TKA) usually is measured with questionnaires. However, these self-report measures assess the patient's perspective on his or her ability to perform a task. Performance-based tests are needed to assess the patient's actual ability to perform a task.ObjectiveThe main purpose of this study was to quantify improvement in performance of the sit-to-stand movement of patients with a TKA.Design and MethodsIn this prospective study of 16 patients with end-stage knee osteoarthritis followed by a TKA, the maximal knee angular extension velocity and amount of unloading (shifting weight) of the affected leg during the sit-to-stand movement and the visual analog scale score for pain were assessed preoperatively and 6 months and 1 year postoperatively. These data were compared with data for a control group of individuals who were healthy (n=27).ResultsBefore surgery, the participants in the TKA group unloaded their affected leg, but within 6 months after implantation, the affected leg was almost fully loaded again and comparable to the loading symmetry ratio of the control group. Furthermore, knee extension velocity also had increased, but remained lower than that of the control group. The changes in knee extension velocity took place during the first 6 months, after which a plateau was visible.LimitationsA potential limitation of the study design was that the patients were not perfectly matched with the control subjects.ConclusionsImplantation of a total knee prosthesis partly improved performance of the sit-to-stand movement. Participants in the TKA group could fully load their operated leg, but they could not generate enough knee angular velocity during rising compared with the control group.

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