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Walker PS, Hennessy D, Perez J, Rahman F, Zapata G, Bosco J. Achieving Specified Laxity in a Noncruciate Total Knee: A Laboratory Design Study. J Arthroplasty 2024:S0883-5403(24)00231-6. [PMID: 38493966 DOI: 10.1016/j.arth.2024.03.015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/14/2023] [Revised: 03/04/2024] [Accepted: 03/07/2024] [Indexed: 03/19/2024] Open
Abstract
BACKGROUND Noncruciate total knee arthroplasty designs, including ultracongruent, medially congruent, and medial pivot, are gaining increasing attention in total knee arthroplasty surgery. However, there is no consensus for the bearing surface design, whether there should be different medial, lateral, anterior, and posterior laxities, or whether the medial side should be a medial pivot. This study proposes the criterion of reproducing the laxity of the anatomic knee, defined as the displacements and rotations of the femur on the tibia in the loaded knee when shear and torque are applied. The purpose of this study was to determine the ideal tibial radii to achieve that goal. METHODS The femoral component was based on the average knee from 100 mild arthritic knee scans. There were 8 tibial components that were designed with different sagittal radii: antero-medial, antero-lateral, postero-medial, and postero-lateral. Radii were defined as the percent height reduction from full conformity with the femoral profile. Components were 3-dimensional-printed. A test rig was constructed where the tibial component was fixed and shear and torque were applied to the femoral component. Displacements and rotations of the femoral component were measured at 0 and 45° of flexion, the latter representing any flexion angle due to the constant femoral sagittal radius. RESULTS Displacements ranged from 0 to 11 mm, and rotations ranged from 1 to 11°. Anterior femoral displacements were higher than posterior due to the shallow distal-anterior femoral profile. The final femoral and tibial components with the most closely matched anatomic laxity values were designed and tested. CONCLUSIONS A steeper distal-anterior femoral radius was an advantage. High medial-anterior tibial conformity was important. However, on the lateral side, the posterior sagittal tibial radius had to be shallower than ideal to allow femoral rollback in high flexion. This meant that the posterior laxity displacements on the lateral side were higher than anatomic, and there was no guidance for lateral femoral rollback.
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Affiliation(s)
- Peter S Walker
- New York University Langone Orthopedic Hospital, New York, New York
| | - Daniel Hennessy
- New York University Langone Orthopedic Hospital, New York, New York
| | - John Perez
- New York University Langone Orthopedic Hospital, New York, New York
| | - Fatema Rahman
- New York University Langone Orthopedic Hospital, New York, New York
| | - Gabriela Zapata
- New York University Langone Orthopedic Hospital, New York, New York
| | - Joseph Bosco
- New York University Langone Orthopedic Hospital, New York, New York
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Vakili S, Lanting B, Getgood A, Willing R. Development of Multibundle Virtual Ligaments to Simulate Knee Mechanics After Total Knee Arthroplasty. J Biomech Eng 2023; 145:1163160. [PMID: 37216311 DOI: 10.1115/1.4062421] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2022] [Indexed: 05/24/2023]
Abstract
Preclinical evaluation of total knee arthroplasty (TKA) components is essential to understanding their mechanical behavior and developing strategies for improving joint stability. While preclinical testing of TKA components has been useful in quantifying their effectiveness, such testing can be criticized for lacking clinical relevance, as the important contributions of surrounding soft tissues are either neglected or greatly simplified. The purpose of our study was to develop and determine if subject-specific virtual ligaments reproduce a similar behavior as native ligaments surrounding TKA joints. Six TKA knees were mounted to a motion simulator. Each was subjected to tests of anterior-posterior (AP), internal-external (IE), and varus-valgus (VV) laxity. The forces transmitted through major ligaments were measured using a sequential resection technique. By tuning the measured ligament forces and elongations to a generic nonlinear elastic ligament model, virtual ligaments were designed and used to simulate the soft tissue envelope around isolated TKA components. The average root-mean-square error (RMSE) between the laxity results of TKA joints with native versus virtual ligaments was 3.5 ± 1.8 mm during AP translation, 7.5 ± 4.2 deg during IE rotations, and 2.0 ± 1.2 deg during VV rotations. Interclass correlation coefficients (ICCs) indicated a good level of reliability for AP and IE laxity (0.85 and 0.84). To conclude, the advancement of virtual ligament envelopes as a more realistic representation of soft tissue constraint around TKA joints is a valuable approach for obtaining clinically relevant kinematics when testing TKA components on joint motion simulators.
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Affiliation(s)
- Samira Vakili
- School of Biomedical Engineering, Western University, 1151 Richmond Street North, London, ON N6A 3K7, Canada; Western's Bone and Joint Institute, University Hospital, London, ON N6G 2V4, Canada
| | - Brent Lanting
- Department of Orthopaedic Surgery, London Health Sciences Centre, University Hospital, 339 Windermere Road, London, ON N6A 5A5, Canada; Western's Bone and Joint Institute, University Hospital, London, ON N6G 2V4, Canada
| | - Alan Getgood
- Department of Orthopaedic Surgery, London Health Sciences Centre, University Hospital, London, ON N6A 5A5, Canada; Department of Surgery, Fowler-Kennedy Sport Medicine Clinic 3M Centre, Western University, London, ON N6A 3K7, Canada; Western's Bone and Joint Institute, University Hospital, London, ON N6G 2V4, Canada
| | - Ryan Willing
- School of Biomedical Engineering, Western University, London, ON N6A 3K7, Canada; Department of Mechanical and Materials Engineering, Western University, 1151 Richmond Street North, London, ON N6A 5B9, Canada; Western's Bone and Joint Institute, University Hospital, London, ON N6G 2V4, Canada
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3
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Walker PS, Borukhov I, LiArno S. Obtaining anatomic motion and laxity characteristics in a total knee design. Knee 2022; 35:133-141. [PMID: 35313242 DOI: 10.1016/j.knee.2022.02.013] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/20/2021] [Revised: 01/03/2022] [Accepted: 02/25/2022] [Indexed: 02/02/2023]
Abstract
BACKGROUND Since the introduction of the first total knee designs, a frequent design goal has been to reproduce normal knee motion. However, studies of many currently used total knee designs, have shown that this goal has not been achieved. We proposed that Guided Motion total knee designs, could achieve more anatomic motion than present standard designs. METHODS Several Guided Motion knees for application without cruciate ligaments were designed using a computer method where the bearing surfaces were generated by the motion required. A knee testing machine was constructed where physiological forces including compressive, shear and torque were applied during knee flexion. The neutral path of motion and the laxity about the neutral path were measured. This evaluation method was a modification of the ASTM standard Constraint Test. RESULTS The motions of the Guided Motion knees and a standard PS knee were compared with the anatomic motion of knee specimens determined in an earlier study The Guided Motion knees showed motion patterns which were closer to anatomic than the PS knee. CONCLUSIONS The results provided justification for carrying out further evaluations of functional conditions, using either knee simulators or computer modelling. If anatomic motions could be reproduced in vivo, it is possible that clinical outcomes could be improved.
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Affiliation(s)
- Peter S Walker
- NYU Langone Orthopedic Hospital, New York, NY, United States.
| | - Ilya Borukhov
- NYU Langone Orthopedic Hospital, New York, NY, United States.
| | - Sally LiArno
- NYU Langone Orthopedic Hospital, New York, NY, United States.
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4
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Liu A, Sanderson WJ, Ingham E, Fisher J, Jennings LM. Development of a specimen-specific in vitro pre-clinical simulation model of the human cadaveric knee with appropriate soft tissue constraints. PLoS One 2020; 15:e0238785. [PMID: 33052931 PMCID: PMC7556525 DOI: 10.1371/journal.pone.0238785] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2020] [Accepted: 08/21/2020] [Indexed: 11/28/2022] Open
Abstract
A human cadaveric specimen-specific knee model with appropriate soft tissue constraints was developed to appropriately simulate the biomechanical environment in the human knee, in order to pre-clinically evaluate the biomechanical and tribological performance of soft tissue interventions. Four human cadaveric knees were studied in a natural knee simulator under force control conditions in the anterior posterior (AP) and tibial rotation (TR) axes, using virtual springs to replicate the function of soft tissues. The most appropriate spring constraints for each knee were determined by comparing the kinematic outputs in terms of AP displacement and TR angle of the human knee with all the soft tissues intact, to the same knee with all the soft tissues resected and replaced with virtual spring constraints (spring rate and free length/degree). The virtual spring conditions that showed the least difference in the AP displacement and TR angle outputs compared to the intact knee were considered to be the most appropriate spring conditions for each knee. The resulting AP displacement and TR angle profiles under the appropriate virtual spring conditions all showed similar shapes to the individual intact knee for each donor. This indicated that the application of the combination of virtual AP and TR springs with appropriate free lengths/degrees was successful in simulating the natural human knee soft tissue function. Each human knee joint had different kinematics as a result of variations in anatomy and soft tissue laxity. The most appropriate AP spring rate for the four human knees varied from 20 to 55 N/mm and the TR spring rate varied from 0.3 to 1.0 Nm/°. Consequently, the most appropriate spring condition for each knee was unique and required specific combinations of spring rate and free length/degree in each of the two axes.
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Affiliation(s)
- Aiqin Liu
- Institute of Medical and Biological Engineering, School of Mechanical Engineering, Faculty of Engineering and Physical Sciences, University of Leeds, Leeds, United Kingdom
- * E-mail:
| | - William J. Sanderson
- Institute of Medical and Biological Engineering, School of Mechanical Engineering, Faculty of Engineering and Physical Sciences, University of Leeds, Leeds, United Kingdom
| | - Eileen Ingham
- Institute of Medical and Biological Engineering, School of Biomedical Sciences, Faculty of Biological Sciences, University of Leeds, Leeds, United Kingdom
| | - John Fisher
- Institute of Medical and Biological Engineering, School of Mechanical Engineering, Faculty of Engineering and Physical Sciences, University of Leeds, Leeds, United Kingdom
| | - Louise M. Jennings
- Institute of Medical and Biological Engineering, School of Mechanical Engineering, Faculty of Engineering and Physical Sciences, University of Leeds, Leeds, United Kingdom
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5
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Sintini I, Fitzpatrick CK, Clary CW, Castelli VP, Rullkoetter PJ. Computational evaluation of TKR stability using feedback-controlled compressive loading. J Orthop Res 2018; 36:1901-1909. [PMID: 29393547 DOI: 10.1002/jor.23862] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/25/2017] [Accepted: 01/08/2018] [Indexed: 02/04/2023]
Abstract
Pre-clinical assessment of stability in total knee replacement is crucial for developing preferred implant performance. Current total knee replacement patients often experience joint instability that the human body addresses with compensatory strategies. Specifically, an increased quadriceps-hamstrings co-contraction serves to increase joint stability through an increased compressive force across the tibiofemoral joint. The aim of this study is to introduce a novel method to evaluate total knee replacement by determining the compressive loading required to achieve natural knee stability. Four current total knee replacement geometries in both their cruciate-retaining and posterior-stabilized forms are modeled in a finite-element framework. The finite-element model is initially validated experimentally using traditional knee laxity testing with a constant compressive load and anterior-posterior displacement or internal-external rotation. Model predictions of constraint are in reasonable agreement with experimental results (average root mean square errors: 0.46 Nm, 62.5 N). The finite-element model is subsequently interfaced with a feedback controller to vary the compressive force that the implant requires in order to match experimental natural knee internal-external and anterior-posterior stability at different flexion angles. Results show that the lower constraint total knee replacement designs require on average 66.7% more compressive load than the higher constraint designs to achieve natural knee constraint. As expected, total knee replacement stability and compressive load requirements to replicate natural kinematics vary with inclusion of tibiofemoral ligaments. The current study represents a novel approach to evaluate stability in existing total knee replacement geometries and to design implants that better restore natural knee mechanics. © 2018 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:1901-1909, 2018.
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Affiliation(s)
- Irene Sintini
- Center for Orthopaedics Biomechanics, University of Denver, Denver, Colorado.,Department of Industrial Engineering, University of Bologna, Bologna, Italy
| | - Clare K Fitzpatrick
- Center for Orthopaedics Biomechanics, University of Denver, Denver, Colorado
| | - Chadd W Clary
- Center for Orthopaedics Biomechanics, University of Denver, Denver, Colorado.,DePuy Synthes, Inc., Warsaw, Indiana
| | | | - Paul J Rullkoetter
- Center for Orthopaedics Biomechanics, University of Denver, Denver, Colorado
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Halewood C, Athwal KK, Amis AA. Pre-clinical assessment of total knee replacement anterior-posterior constraint. J Biomech 2018; 73:153-160. [PMID: 29622481 DOI: 10.1016/j.jbiomech.2018.03.042] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2017] [Revised: 03/22/2018] [Accepted: 03/23/2018] [Indexed: 11/19/2022]
Abstract
Pre-clinical, bench-top assessment of Total Knee Replacements (TKR) can provide information about the inherent constraint provided by a TKR, which does not depend on the condition of the patient undergoing the arthroplasty. However little guidance is given by the ASTM standard on test configurations such as medial-lateral (M:L) loading distribution, flexion angle or restriction of secondary motions. Using a purpose built rig for a materials testing machine, four TKRs currently in widespread clinical use, including medial-pivot and symmetrical condyle types, were tested for anterior-posterior translational constraint. Compressive joint loads from 710 to 2000 N, and a range of medial-lateral (M:L) load distributions, from 70:30% to 30:70% M:L, were applied at different flexion angles with secondary motions unconstrained. It was found that TKA constraint was significantly less at 60 and 90° flexion than at 0°, whilst increasing the compressive joint load increased the force required to translate the tibia to limits of AP constraint at all flexion angles tested. Additionally when M:L load distribution was shifted medially, a coupled internal rotation was observed with anterior translation and external rotation with posterior translation. This paper includes some recommendations for future development of pre-clinical testing methods.
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Affiliation(s)
- C Halewood
- Department of Mechanical Engineering, Imperial College London, South Kensington Campus, London SW7 2AZ, UK
| | - K K Athwal
- Department of Mechanical Engineering, Imperial College London, South Kensington Campus, London SW7 2AZ, UK.
| | - A A Amis
- Department of Mechanical Engineering, Imperial College London, South Kensington Campus, London SW7 2AZ, UK; Musculoskeletal Surgery Group, Department of Surgery and Cancer, Imperial College London School of Medicine, Charing Cross Hospital, London W6 8RF, UK
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How Can We Use Computational Modeling to Improve Total Knee Arthroplasty? Modeling Stability and Mobility in the Implanted Knee. J Am Acad Orthop Surg 2017; 25 Suppl 1:S33-S39. [PMID: 27997412 DOI: 10.5435/jaaos-d-16-00640] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Validated computational models promise a virtual platform to create optimal articular surfaces that best achieve desired implant characteristics. Today, designers can parametrically define the primary geometric features of an implant, and automatically modify design variables until stability/mobility performance objectives are best achieved. This preclinical, virtual design iteration minimizes the development cycle compared with testing physical prototypes and, by evaluating a broader scope of design concepts, likely improves the clinical performance of the final product. However, the scenario described is not without shortcomings and requires thorough understanding of the capabilities and the limitations of the models used. Although models typically represent the articular interface well, the interaction with the patient and the surgical process includes significant variability and increase in complexity. We present current modeling capabilities for the estimation of implant stability/mobility, with further suggestions for answering the difficult question of how an implant might perform throughout the population.
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8
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Validation of a new computational 6-DOF knee simulator during dynamic activities. J Biomech 2016; 49:3177-3184. [DOI: 10.1016/j.jbiomech.2016.07.040] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2016] [Revised: 06/25/2016] [Accepted: 07/28/2016] [Indexed: 11/18/2022]
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Wang X, Malik A, Bartel DL, Wright TM, Padgett DE. Load Sharing Among Collateral Ligaments, Articular Surfaces, and the Tibial Post in Constrained Condylar Knee Arthroplasty. J Biomech Eng 2016; 138:2526201. [PMID: 27223672 DOI: 10.1115/1.4033678] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2014] [Indexed: 11/08/2022]
Abstract
The normal knee joint maintains stable motion during activities of daily living. After total knee arthroplasty (TKA), stability is achieved by the conformity of the bearing surfaces of the implant components, ligaments, and constraint structures incorporated in the implant design. The large, rectangular tibial post in constrained condylar knee (CCK) arthroplasty, often used in revision surgery, provides added stability, but increases susceptibility to polyethylene wear as it contacts the intercondylar box on the femoral component. We examined coronal plane stability to understand the relative contributions of the mechanisms that act to stabilize the CCK knee under varus-valgus loading, namely, load distribution between the medial and lateral condyles, contact of the tibial post with the femoral intercondylar box, and elongation of the collateral ligaments. A robot testing system was used to determine the joint stability in human cadaveric knees as described by the moment versus angular rotation behavior under varus-valgus moments at 0 deg, 30 deg, and 90 deg of flexion. The angular rotation of the CCK knee in response to the physiological moments was limited to ≤1.5 deg. The primary stabilizing mechanism was the redistribution of the contact force on the bearing surfaces. Contact between the tibial post and the femoral box provided a secondary stabilizing mechanism after lift-off of a condyle had occurred. Collateral ligaments provide limited stability because little ligament elongation occurred under such small angular rotations. Compressive loads applied across the knee joint, such as would occur with the application of muscle forces, enhanced the ability of the bearing surfaces to provide resisting internal varus-valgus moment and, thus, reduced the exposure of the tibial post to the external varus-valgus loads. Our results suggest that the CCK stability can be refined by considering both the geometry of the bearing surfaces and the contacting geometry between the tibial post and femoral box.
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10
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Athwal KK, Daou HE, Kittl C, Davies AJ, Deehan DJ, Amis AA. The superficial medial collateral ligament is the primary medial restraint to knee laxity after cruciate-retaining or posterior-stabilised total knee arthroplasty: effects of implant type and partial release. Knee Surg Sports Traumatol Arthrosc 2016; 24:2646-55. [PMID: 26519188 DOI: 10.1007/s00167-015-3796-0] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/28/2015] [Accepted: 09/15/2015] [Indexed: 10/22/2022]
Abstract
PURPOSE The aim of this study was to quantify the contributions of medial soft tissues to stability following cruciate-retaining (CR) or posterior-stabilised (PS) total knee arthroplasty (TKA). METHODS Using a robotic system, eight cadaveric knees were subjected to ±90-N anterior-posterior force, ±5-Nm internal-external and ±8-Nm varus-valgus torques at various flexion angles. The knees were tested intact and then with CR and PS implants, and successive cuts of the deep and superficial medial collateral ligaments (dMCL, sMCL) and posteromedial capsule (PMC) quantified the percentage contributions of each structure to restraining the applied loads. RESULTS In implanted knees, the sMCL restrained valgus rotation (62 % across flexion angles), anterior-posterior drawer (24 and 10 %, respectively) and internal-external rotation (22 and 37 %). Changing from CR TKA to PS TKA increased the load on the sMCL when resisting valgus loads. The dMCL restrained 11 % of external and 13 % of valgus rotations, and the PMC was significant at low flexion angles. CONCLUSIONS This work has shown that medial release in the varus knee should be minimised, as it may inadvertently result in a combined laxity pattern. There is increasing interest in preserving constitutional varus in TKA, and this work argues for preservation of the sMCL to afford the surgeon consistent restraint and maintain a balanced knee for the patient.
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Affiliation(s)
- Kiron K Athwal
- Department of Mechanical Engineering, Imperial College London, Exhibition Road, London, SW7 2AZ, UK
| | - Hadi El Daou
- Department of Mechanical Engineering, Imperial College London, Exhibition Road, London, SW7 2AZ, UK
| | - Christoph Kittl
- Department of Mechanical Engineering, Imperial College London, Exhibition Road, London, SW7 2AZ, UK
| | | | - David J Deehan
- Department of Orthopaedic Surgery, Newcastle Freeman University Hospital, Newcastle upon Tyne, UK
| | - Andrew A Amis
- Department of Mechanical Engineering, Imperial College London, Exhibition Road, London, SW7 2AZ, UK. .,Musculoskeletal Surgery Group, Department of Surgery and Cancer, Imperial College London School of Medicine, Charing Cross Hospital, London, W6 8RF, UK.
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11
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Walker PS, Arno S, Borukhoy I, Bell CP. Characterising knee motion and laxity in a testing machine for application to total knee evaluation. J Biomech 2015; 48:3551-8. [DOI: 10.1016/j.jbiomech.2015.06.013] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2014] [Revised: 06/15/2015] [Accepted: 06/17/2015] [Indexed: 11/28/2022]
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12
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Elsner JJ, Shemesh M, Shefy-Peleg A, Gabet Y, Zylberberg E, Linder-Ganz E. Quantification of in vitro wear of a synthetic meniscus implant using gravimetric and micro-CT measurements. J Mech Behav Biomed Mater 2015; 49:310-20. [PMID: 26057364 DOI: 10.1016/j.jmbbm.2015.05.017] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2015] [Revised: 05/18/2015] [Accepted: 05/20/2015] [Indexed: 10/23/2022]
Abstract
A synthetic meniscus implant was recently developed for the treatment of patients with mild to moderate osteoarthritis with knee pain associated with medial joint overload. The implant is distinctively different from most orthopedic implants in its pliable construction, and non-anchored design, which enables implantation through a mini-arthrotomy without disruption to the bone, cartilage, and ligaments. Due to these features, it is important to show that the material and design can withstand knee joint conditions. This study evaluated the long-term performance of this device by simulating loading for a total of 5 million gait cycles (Mc), corresponding to approximately five years of service in-vivo. All five implants remained in good condition and did not dislodge from the joint space during the simulation. Mild abrasion was detected by electron microscopy, but µ-CT scans of the implants confirmed that the damage was confined to the superficial surfaces. The average gravimetric wear rate was 14.5 mg/Mc, whereas volumetric changes in reconstructed µ-CT scans point to an average wear rate of 15.76 mm(3)/Mc (18.8 mg/Mc). Particles isolated from the lubricant had average diameter of 15 µm. The wear performance of this polycarbonate-urethane meniscus implant concept under ISO-14243 loading conditions is encouraging.
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Affiliation(s)
- Jonathan J Elsner
- Research and Development Center, Active Implants, Netanya 42505, Israel
| | - Maoz Shemesh
- Research and Development Center, Active Implants, Netanya 42505, Israel
| | - Adaya Shefy-Peleg
- Research and Development Center, Active Implants, Netanya 42505, Israel
| | - Yankel Gabet
- Department of Anatomy and Anthropology, Sackler School of Medicine, Tel Aviv University, Tel Aviv 69978, Israel
| | - Eyal Zylberberg
- Research and Development Center, Active Implants, Netanya 42505, Israel
| | - Eran Linder-Ganz
- Research and Development Center, Active Implants, Netanya 42505, Israel.
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13
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Abdullah MR, Goharian A, Abdul Kadir MR, Wahit MU. Biomechanical and bioactivity concepts of polyetheretherketone composites for use in orthopedic implants-a review. J Biomed Mater Res A 2015; 103:3689-702. [DOI: 10.1002/jbm.a.35480] [Citation(s) in RCA: 72] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2014] [Revised: 03/22/2015] [Accepted: 04/06/2015] [Indexed: 01/13/2023]
Affiliation(s)
- Mohamed Ruslan Abdullah
- Centre for Composites; Department of Applied Mechanics and Design; Universiti Teknologi Malaysia (UTM); 81310 Skudai, Johor Malaysia
| | - Amirhossein Goharian
- Medical Devices & Technology Group; Faculty of Biosciences & Medical Engineering, Universiti Teknologi Malaysia (UTM); 81310 Skudai, Johor Malaysia
- R&D Department; Leonix Sdn. Bhd.; Penang 11960 Malaysia
| | - Mohammed Rafiq Abdul Kadir
- Medical Devices & Technology Group; Faculty of Biosciences & Medical Engineering, Universiti Teknologi Malaysia (UTM); 81310 Skudai, Johor Malaysia
| | - Mat Uzir Wahit
- Center for Composites, Institute of Vehicle System and Engineering (IVeSE), Universiti Teknologi Malaysia (UTM); 81310 Skudai, Johor Malaysia
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14
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Zietz C, Reinders J, Schwiesau J, Paulus A, Kretzer JP, Grupp T, Utzschneider S, Bader R. Experimental testing of total knee replacements with UHMW-PE inserts: impact of severe wear test conditions. JOURNAL OF MATERIALS SCIENCE. MATERIALS IN MEDICINE 2015; 26:134. [PMID: 25716024 DOI: 10.1007/s10856-015-5470-y] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/03/2014] [Accepted: 01/09/2015] [Indexed: 06/04/2023]
Abstract
Aseptic implant loosening due to inflammatory reactions to wear debris is the main reason for the revision of total knee replacements (TKR). Hence, the decrease in polyethylene wear particle generation from the articulating surfaces is aimed at improving implant design and material. For preclinical testing of new TKR systems standardized wear tests are required. However, these wear tests do not reproduce the entire in vivo situation, since the pattern and amount of wear and subsequent implant failure are underestimated. Therefore, daily activity, kinematics, implant aging and position, third-body-wear and surface properties have to be considered to estimate the wear of implant components in vivo. Hence, severe test conditions are in demand for a better reproduction of the in vivo situation of TKR. In the present article an overview of different experimental wear test scenarios considering clinically relevant polyethylene wear situations using severe test conditions is presented.
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Affiliation(s)
- Carmen Zietz
- Biomechanics and Implant Technology Research Laboratory, Department of Orthopaedics, University Medicine Rostock, Doberaner Str. 142, 18057, Rostock, Germany,
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15
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Application of a novel design method for knee replacements to achieve normal mechanics. Knee 2014; 21:353-8. [PMID: 23141366 DOI: 10.1016/j.knee.2012.08.001] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/11/2012] [Revised: 08/01/2012] [Accepted: 08/13/2012] [Indexed: 02/02/2023]
Abstract
PURPOSE The purpose of this study was to utilize a novel method for the design of total knee replacements for use in the absence of the cruciate ligaments, with the design criteria of reproducing the medial stability and lateral mobility characteristics of the normal anatomic knee. SCOPE The starting point was a femoral component with surfaces approximating anatomic. This surface was moved into multiple positions describing a neutral path of motion and laxity about the neutral path. The distal part of the femoral composite was then used to define the tibial surface. By varying the femoral design, different tibial surfaces were produced. The reference design featured a dished medial tibial surface and a shallow lateral tibial surface, but this provided limited motion guidance. To provide further guidance, two types of design were generated, one using intercondylar guide surfaces, the other providing guidance from the condylar surfaces themselves. CONCLUSIONS The design method was capable of generating a range of total knee surfaces which could potentially return the arthritic knee to more normal function.
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Athwal KK, Hunt NC, Davies AJ, Deehan DJ, Amis AA. Clinical biomechanics of instability related to total knee arthroplasty. Clin Biomech (Bristol, Avon) 2014; 29:119-28. [PMID: 24332382 DOI: 10.1016/j.clinbiomech.2013.11.004] [Citation(s) in RCA: 54] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/26/2013] [Revised: 11/01/2013] [Accepted: 11/05/2013] [Indexed: 02/07/2023]
Abstract
BACKGROUND Tibiofemoral instability is a common reason for total knee arthroplasty failure, and may be attributed to soft tissue deficiency and incorrect ligament balancing. There are many different designs of implant with varying levels of constraint to overcome this instability; however there is little advice for surgeons to assess which is suitable for a specific patient, and soft tissue balance testing during arthroplasty is very subjective. METHOD The current theories on primary and secondary soft tissue restraints to anterior/posterior, varus/valgus, and internal/external rotational motion of the knee are discussed. The paper reviews biomechanics literature to evaluate instability in the intact and implanted knee. FINDINGS The paper highlights important intra- and extra-capsular structures in the knee and describes the techniques used by clinicians to assess instability perioperatively. In vitro cadaveric studies were found to be a very useful tool in comparing different implants and contributions of different soft tissues. INTERPRETATION In vitro cadaveric studies can be utilised in helping less experienced surgeons with soft tissue releases and determining the correct implant. For this to happen, more biomechanical studies must be done to show the impact of release sequences on implanted cadavers, as well as determining if increasingly constrained implants restore the stability of the knee to pre-deficient conditions.
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Affiliation(s)
- Kiron K Athwal
- Department of Mechanical Engineering, Imperial College London, Exhibition Road, London SW7 2AZ, UK
| | - Nicola C Hunt
- Department of Orthopaedic Surgery, Newcastle Freeman University Hospital, Newcastle upon Tyne, UK; Institute of Cellular Medicine, Medical School, Framlington Place Newcastle University, Newcastle upon Tyne NE2 4HH, UK
| | | | - David J Deehan
- Department of Orthopaedic Surgery, Newcastle Freeman University Hospital, Newcastle upon Tyne, UK; Institute of Cellular Medicine, Medical School, Framlington Place Newcastle University, Newcastle upon Tyne NE2 4HH, UK
| | - Andrew A Amis
- Department of Mechanical Engineering, Imperial College London, Exhibition Road, London SW7 2AZ, UK; Orthopaedic Surgery Group, Imperial College London School of Medicine, Charing Cross Hospital, London W6 8RF, UK.
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The effect of geometric variations in posterior-stabilized knee designs on motion characteristics measured in a knee loading machine. Clin Orthop Relat Res 2014; 472:238-47. [PMID: 23917990 PMCID: PMC3889438 DOI: 10.1007/s11999-013-3088-2] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
BACKGROUND In different posterior-stabilized (PS) total knees, there are considerable variations in condylar surface radii and cam-post geometry. To what extent these variations affect kinematics is not known. Furthermore, there are no clearly defined ideal kinematics for a total knee. QUESTIONS/PURPOSES The purposes of this study were to determine (1) what the kinematic differences are caused by geometrical variations between PS total knee designs in use today; and (2) what design characteristics will produce kinematics that closely resemble that of the normal anatomic knee. METHODS Four current PS designs with different geometries and one experimental asymmetric PS design, with a relatively conforming medial side, were tested in a purpose-built machine. The machine applied combinations of compressive, shear, and torque forces at a sequence of flexion angles to represent a range of everyday activities, consistent with the ASTM standard test for measuring constraint. The femorotibial contact points, the neutral path of motion, and the AP and internal-external laxities were used as the kinematic indicators. RESULTS The PS designs showed major differences in motion characteristics among themselves and with motion data from anatomic knees determined in a previous study. Abnormalities in the current designs included symmetric mediolateral motion, susceptibility to excessive AP medial laxity, and reduced laxity in high flexion. The asymmetric-guided motion design alleviated some but not all of the abnormalities. CONCLUSIONS Current PS designs showed kinematic abnormalities to a greater or lesser extent. An asymmetric design may provide a path to achieving a closer match to anatomic kinematics. CLINICAL RELEVANCE One criterion for the evaluation of PS total knees is how closely the kinematics of the prosthesis resemble that of the anatomic knee, because this is likely to affect the quality of function.
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Hutter EE, Granger JF, Beal MD, Siston RA. Is there a gold standard for TKA tibial component rotational alignment? Clin Orthop Relat Res 2013; 471:1646-53. [PMID: 23392991 PMCID: PMC3613530 DOI: 10.1007/s11999-013-2822-0] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/12/2012] [Accepted: 01/24/2013] [Indexed: 01/31/2023]
Abstract
BACKGROUND Joint function and durability after TKA depends on many factors, but component alignment is particularly important. Although the transepicondylar axis is regarded as the gold standard for rotationally aligning the femoral component, various techniques exist for tibial component rotational alignment. The impact of this variability on joint kinematics and stability is unknown. QUESTIONS/PURPOSES We determined how rotationally aligning the tibial component to four different axes changes knee stability and passive tibiofemoral kinematics in a knee after TKA. METHODS Using a custom surgical navigation system and stability device to measure stability and passive tibiofemoral motion, we tested 10 cadaveric knees from five hemicorpses before TKA and then with the tibial component aligned to four axes using a modified tibial tray. RESULTS No changes in knee stability or passive kinematics occurred as a result of the four techniques of tibial rotational alignment. TKA produces a 'looser' knee over the native condition by increasing mean laxity by 5.2°, decreasing mean maximum stiffness by 4.5 N·m/°, increasing mean anterior femoral translation during passive flexion by 5.4 mm, and increasing mean internal-external tibial rotation during passive flexion by 4.8°. However, no statistically or clinically important differences occurred between the four TKA conditions. CONCLUSIONS For all tibial rotations, TKA increased laxity, decreased stiffness, and increased tibiofemoral motion during passive flexion but showed little change based on the tibial alignment. CLINICAL RELEVANCE Our observations suggest surgeons who align the tibial component to any of the axes we examined are expected to have results consistent with those who may use a different axis.
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Affiliation(s)
- Erin E. Hutter
- />Department of Mechanical and Aerospace Engineering, The Ohio State University, E305 Scott Laboratory, 201 W 19th Avenue, Columbus, OH 43210 USA
| | - Jeffrey F. Granger
- />Department of Orthopaedics, The Ohio State University, 543 Taylor Avenue, Suite 1074, Columbus, OH USA
| | - Matthew D. Beal
- />Department of Orthopaedics, The Ohio State University, 543 Taylor Avenue, Suite 1074, Columbus, OH USA
| | - Robert A. Siston
- />Department of Mechanical and Aerospace Engineering, The Ohio State University, E305 Scott Laboratory, 201 W 19th Avenue, Columbus, OH 43210 USA
- />Department of Orthopaedics, The Ohio State University, 543 Taylor Avenue, Suite 1074, Columbus, OH USA
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Fitzpatrick CK, Baldwin MA, Clary CW, Maletsky LP, Rullkoetter PJ. Evaluating knee replacement mechanics during ADL with PID-controlled dynamic finite element analysis. Comput Methods Biomech Biomed Engin 2012; 17:360-9. [PMID: 22687046 DOI: 10.1080/10255842.2012.684242] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Abstract
Validated computational knee simulations are valuable tools for design phase development of knee replacement devices. Recently, a dynamic finite element (FE) model of the Kansas knee simulator was kinematically validated during gait and deep flexion cycles. In order to operate the computational simulator in the same manner as the experiment, a proportional-integral-derivative (PID) controller was interfaced with the FE model to control the quadriceps actuator excursion and produce a target flexion profile regardless of implant geometry or alignment conditions. The controller was also expanded to operate multiple actuators simultaneously in order to produce in vivo loading conditions at the joint during dynamic activities. Subsequently, the fidelity of the computational model was improved through additional muscle representation and inclusion of relative hip-ankle anterior-posterior (A-P) motion. The PID-controlled model was able to successfully recreate in vivo loading conditions (flexion angle, compressive joint load, medial-lateral load distribution or varus-valgus torque, internal-external torque, A-P force) for deep knee bend, chair rise, stance-phase gait and step-down activities.
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Affiliation(s)
- Clare K Fitzpatrick
- a Computational Biomechanics Lab , University of Denver , 2390 S. York Street, Denver , CO 80208 , USA
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20
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Willing R, Kim IY. The development, calibration and validation of a numerical total knee replacement kinematics simulator considering laxity and unconstrained flexion motions. Comput Methods Biomech Biomed Engin 2011; 15:585-93. [PMID: 21598129 DOI: 10.1080/10255842.2010.550888] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Kinematics testing is essential during the development of total knee replacement (TKR) designs. Although computational analysis cannot replace physical testing, it offers repeatability and consistency at a much lower cost and shorter time, making it an excellent complement to experiments. Previous numerical models have been limited by several factors: the validity of the models is usually only considered for a single TKR design, friction models are typically overly simplified and the determination of simulation parameters is often inadequate, or tedious and expensive. The objective of this study is to develop, calibrate and validate a TKR kinematics simulation considering multiple TKR geometries, an accurate friction model and simulation parameters determined using a systematic optimisation method. The calibrated model was able to predict TKR kinematics for different TKR geometries, and is ideal for screening new implant designs, reducing the number of experiments required at the design stage.
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Affiliation(s)
- Ryan Willing
- Department of Mechanical and Materials Engineering, Queen's University, Kingston, ON K7L 3N6, Canada
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21
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Willing R, Kim IY. Design optimization of a total knee replacement for improved constraint and flexion kinematics. J Biomech 2011; 44:1014-20. [DOI: 10.1016/j.jbiomech.2011.02.009] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2010] [Revised: 02/10/2011] [Accepted: 02/10/2011] [Indexed: 10/18/2022]
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Walker PS, Heller Y, Cleary DJ, Yildirim G. Preclinical evaluation method for total knees designed to restore normal knee mechanics. J Arthroplasty 2011; 26:152-60. [PMID: 20381994 DOI: 10.1016/j.arth.2009.11.017] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/15/2009] [Accepted: 11/22/2009] [Indexed: 02/01/2023] Open
Abstract
The objective was to develop a simple, rapid, and low-cost method for evaluating proposed new total knee arthroplasty (TKA) models and then to evaluate 3 different TKA models with different kinematic characteristics. A "desktop" knee testing rig was used to apply forces and moments over a full flexion range, representing a spectrum of positions and activities; and the positions of the femur on the tibia were measured. The average neutral path of motion (for compressive force only) and the laxities about the neutral path (for superimposed shear and torque) were determined from 8 knee specimens to be used as a benchmark for the TKA evaluations. A typical posterior-stabilized TKA did not display the normal external femoral rotation with flexion and also showed abnormal anterior sliding on the medial side. A medial-pivot type of guided-motion design showed medial stability comparable to anatomical but still did not produce external femoral rotation and posterior lateral displacement with flexion. The addition of a central cam-post produced the rotation and displacement but only after 75° of flexion. It was concluded that the test method satisfied the objective and could be used as a design tool for evaluating new and existing designs, as well as for formulating a TKA with anatomical characteristics.
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Affiliation(s)
- Peter S Walker
- Laboratory for Minimally-Invasive Surgery, Department of Orthopaedic Surgery, NYU Hospital for Joint Diseases, New York, New York, USA
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23
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Walker PS, Yildirim G, Arno S, Heller Y. Future directions in knee replacement. Proc Inst Mech Eng H 2010; 224:393-414. [PMID: 20408486 DOI: 10.1243/09544119jeim655] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
The use of artificial joints for the treatment of osteoarthritis is expected to expand considerably over the next decade. While newer technologies can offer yet further improvements in total knee systems, implementation will be strongly affected by the need to satisfy apparently competing requirements. Patients expect quicker rehabilitation, improved performance, and lifelong durability; on the other hand, economic constraints require a reduction in cost for each procedure, as well as early intervention and preventative measures, while there is increased pressure from health care systems to use evidence-based medicine as the standard of choice for implants and techniques. The success of a knee replacement depends on the design itself, the surgical technique, the rehabilitation, and, not least, the patient. The major goal of the implant design can be redefined as a restoration of normal knee mechanics, whether by maximum preservation of tissues, or by guiding surfaces that replace their function. Surgical technique needs to be less invasive but achieve optimal patient-specific alignment and soft tissue balancing. Rehabilitation procedures must achieve the expectations of realistic patients. Testing and evaluation methods need to be upgraded for enhanced predictability. This paper discusses current trends and future possibilities to address this expansive scope of design criteria.
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Affiliation(s)
- P S Walker
- Laboratory for Minimally-Invasive Surgery, Department of Orthopaedic Surgery, NYU Hospital for Joint Diseases, New York, NY 10010, USA.
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Walker PS, Sussman-Fort JM, Yildirim G, Boyer J. Design features of total knees for achieving normal knee motion characteristics. J Arthroplasty 2009; 24:475-83. [PMID: 18534451 DOI: 10.1016/j.arth.2007.11.002] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/08/2007] [Accepted: 11/02/2007] [Indexed: 02/01/2023] Open
Abstract
The goal of the study was to achieve a normal neutral anatomical path of motion with a total knee arthroplasty (TKA) using specific motion-guiding design features. Two reference TKA models were used, consisting of a partially conforming double-dished geometry and the same with a central cam-post for femoral rollback. Four experimental TKA models included features to produce femoral rollback with and without guidance for tibial rotation, and a feature to prevent paradoxical anterior femoral sliding. The femur was loaded down the tibial axis, and the femoral-tibial positions were recorded at a sequence of flexion angles. Subsequently, the positions were recorded with an anterior shear force superimposed. Software was used to reconstruct the paths of the transverse femoral axis on the tibia, during a full flexion range. The reference knees did not reproduce a normal neutral path of motion. However, this was achieved with an experimental design incorporating all of the motion-guiding features.
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Moran MF, Bhimji S, Racanelli J, Piazza SJ. Computational assessment of constraint in total knee replacement. J Biomech 2008; 41:2013-20. [DOI: 10.1016/j.jbiomech.2008.03.020] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2007] [Revised: 03/12/2008] [Accepted: 03/23/2008] [Indexed: 11/30/2022]
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Abstract
As the principles of joint arthroplasty become increasingly refined and more widely established, new designs are being developed that require careful evaluation for their propensity to generate wear debris in vivo. In the past several years, new designs intended to improve clinical performance have emerged in both total knee replacement and total spinal disk replacement. Advances in these types of implants have the potential for major clinical impact in the coming decade, due to the large number of patients seeking treatment of knee arthritis as well as back pain, neck pain, and radiculopathy.
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Abstract
The success of total knee arthroplasty depends in part on proper soft tissue management to achieve a stable joint. It is unknown to what degree total knee arthroplasty changes joint stability. We used a surgical navigation system to intraoperatively measure joint stability in 24 patients under going primary total knee arthroplasty to address two questions: (1) Is the total arc of varus-valgus motion after total knee arthroplasty different from the arc of varus-valgus motion in an osteoarthritic knee? (2) Does total knee arthroplasty produce equal amounts of varus/valgus motion (ie, is the knee "balanced")? We observed no difference between the total arc of varus-valgus motion before and after total knee arthroplasty; the total amount of motion was unchanged. On average, osteoarthritic knees were "unbalanced" but were "balanced" after prosthesis implantation. We found a negative correlation between the relative amount of varus/valgus motion in extension before and after prosthesis implantation in extension and a positive correlation between how well the knees were balanced after prosthesis implantation in extension and in flexion. Our data suggest immediately after implantation knees retain a greater than normal amount of varus-valgus motion, but this motion is more evenly distributed.
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Affiliation(s)
- Robert A Siston
- Mechanical Engineering Department, Stanford University, Stanford, CA, USA.
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