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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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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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Walker PS, Mhadgut A, Buchalter DB, Kirby DJ, Hennessy D. The effect of total knee geometries on kinematics: An experimental study using a crouching machine. J Orthop Res 2021; 39:2537-2545. [PMID: 33713363 DOI: 10.1002/jor.25026] [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: 09/08/2020] [Revised: 01/13/2021] [Accepted: 03/10/2021] [Indexed: 02/04/2023]
Abstract
Obtaining anatomic knee kinematics after a total knee is likely to improve outcomes. We used a crouching machine to compare the kinematics of standard condylar designs with guided motion designs. The standard condylars included femoral sagittal radii with constant radius, J-curve and G-curve; the tibial surfaces were of low and high constraint. The guided motion designs were a medial pivot and a design with asymmetric condylar shapes and guiding surfaces. The machine had a flexion range from 0° to 125°, applied quadriceps and hamstring loading, and simulated the collateral soft tissues. The kinematics of all standard condylar knees were similar, showing only small anterior-posterior displacements and internal-external rotations. The two asymmetric designs showed posterior displacements during flexion, but less axial rotations than anatomic knees. The quadriceps forces throughout flexion were very similar between all designs, reflecting similar lever arms. It was concluded that standard condylar designs, even with variations in sagittal radii, are unlikely to reproduce anatomic kinematics. On the other hand, designs with asymmetric constraint between medial and lateral sides, and other guiding features, are likely to be the way forward. The mechanical testing method could be further improved by superimposing shear forces and torques during the flexion-extension motion, to include more stressful in vivo functional conditions.
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Affiliation(s)
- Peter S Walker
- Department of Orthopedic Surgery, NYU Langone Health, New York, New York, USA
| | - Aishwarya Mhadgut
- Department of Orthopedic Surgery, NYU Langone Health, New York, New York, USA
| | - Daniel B Buchalter
- Department of Orthopedic Surgery, NYU Langone Health, New York, New York, USA
| | - David J Kirby
- Department of Orthopedic Surgery, NYU Langone Health, New York, New York, USA
| | - Daniel Hennessy
- Department of Orthopedic Surgery, NYU Langone Health, New York, New York, USA
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Garner AJ, Dandridge OW, Amis AA, Cobb JP, van Arkel RJ. Partial and Combined Partial Knee Arthroplasty: Greater Anterior-Posterior Stability Than Posterior Cruciate-Retaining Total Knee Arthroplasty. J Arthroplasty 2021; 36:3765-3772.e4. [PMID: 34330602 DOI: 10.1016/j.arth.2021.06.025] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/22/2021] [Revised: 04/15/2021] [Accepted: 06/21/2021] [Indexed: 02/02/2023] Open
Abstract
BACKGROUND Little is known regarding anterior-posterior stability after anterior cruciate ligament-preserving partial (PKA) and combined partial knee arthroplasty (CPKA) compared to standard posterior cruciate-retaining total knee arthroplasty (TKA). METHODS The anterior-posterior tibial translation of twenty-four cadaveric knees was measured, with optical tracking, while under 90N drawer with the knee flexed 0-90°. Knees were tested before and after PKA, CPKA (medial and lateral bicompartmental and bi-unicondylar), and then posterior cruciate-retaining TKA. The anterior-posterior tibial translations of the arthroplasty states, at each flexion angle, were compared to the native knee and each other with repeated measures analyses of variance and post-hoc t-tests. RESULTS Unicompartmental and bicompartmental arthroplasty states had similar laxities to the native knee and to each other, with ≤1-mm differences throughout the flexion range (P ≥ .199). Bi-unicondylar arthroplasty resulted in 6- to 8-mm increase of anterior tibial translation at high flexion angles compared to the native knee (P ≤ .023 at 80-90°). Meanwhile, TKA exhibited increased laxity across all flexion angles, with increased anterior tibial translation of up to 18 ± 6 mm (P < .001) and increased posterior translation of up to 4 ± 2 mm (P < .001). CONCLUSIONS In a cadaveric study, anterior-posterior tibial translation did not differ from native laxity after PKA and CPKA. Posterior cruciate ligament-preserving TKA demonstrated increased laxity, particularly in anterior tibial translation.
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Affiliation(s)
- Amy J Garner
- MSk Lab, Sir Michael Uren Biomedical Engineering Research Hub, Imperial College London, White City Campus, London, UK; Mechanical Engineering Department, Biomechanics Group, Imperial College London, London, UK; Royal College of Surgeons of England and Dunhill Medical Trust Clinical Research Fellowship, Royal College of Surgeons of England, London, UK; Health Education Kent, Surrey and Sussex, London, UK
| | - Oliver W Dandridge
- Mechanical Engineering Department, Biomechanics Group, Imperial College London, London, UK
| | - Andrew A Amis
- Mechanical Engineering Department, Biomechanics Group, Imperial College London, London, UK
| | - Justin P Cobb
- MSk Lab, Sir Michael Uren Biomedical Engineering Research Hub, Imperial College London, White City Campus, London, UK
| | - Richard J van Arkel
- Mechanical Engineering Department, Biomechanics Group, Imperial College London, London, UK
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Willinger L, Athwal KK, Williams A, Amis AA. An Anterior Cruciate Ligament In Vitro Rupture Model Based on Clinical Imaging. Am J Sports Med 2021; 49:2387-2395. [PMID: 34115540 PMCID: PMC8283191 DOI: 10.1177/03635465211017145] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
BACKGROUND Biomechanical studies on anterior cruciate ligament (ACL) injuries and reconstructions are based on ACL transection instead of realistic injury trauma. PURPOSE To replicate an ACL injury in vitro and compare the laxity that occurs with that after an isolated ACL transection injury before and after ACL reconstruction. STUDY DESIGN Controlled laboratory study. METHODS Nine paired knees were ACL injured or ACL transected. For ACL injury, knees were mounted in a rig that imposed tibial anterior translation at 1000 mm/min to rupture the ACL at 22.5° of flexion, 5° of internal rotation, and 710 N of joint compressive force, replicating data published on clinical bone bruise locations. In contralateral knees, the ACL was transected arthroscopically at midsubstance. Both groups had ACL reconstruction with bone-patellar tendon-bone graft. Native, ACL-deficient, and reconstructed knee laxities were measured in a kinematics rig from 0° to 100° of flexion with optical tracking: anterior tibial translation (ATT), internal rotation (IR), anterolateral (ATT + IR), and pivot shift (IR + valgus). RESULTS The ACL ruptured at 26 ± 5 mm of ATT and 1550 ± 620 N of force (mean ± SD) with an audible spring-back tibiofemoral impact with 5o of valgus. ACL injury and transection increased ATT (P < .001). ACL injury caused greater ATT than ACL transection by 1.4 mm (range, 0.4-2.2 mm; P = .033). IR increased significantly in ACL-injured knees between 0° and 30° of flexion and in ACL transection knees from 0° to 20° of flexion. ATT during the ATT + IR maneuver was increased by ACL injury between 0° and 80° and after ACL transection between 0° and 60°. Residual laxity persisted after ACL reconstruction from 0° to 40° after ACL injury and from 0° to 20° in the ACL transection knees. ACL deficiency increased ATT and IR in the pivot-shift test (P < .001). The ATT in the pivot-shift increased significantly at 0° to 20° after ACL transection and 0° to 50° after ACL injury, and this persisted across 0° to 20° and 0° to 40° after ACL reconstruction. CONCLUSION This study developed an ACL injury model in vitro that replicated clinical ACL injury as evidenced by bone bruise patterns. ACL injury caused larger increases of laxity than ACL transection, likely because of damage to adjacent tissues; these differences often persisted after ACL reconstruction. CLINICAL RELEVANCE This in vitro model created more realistic ACL injuries than surgical transection, facilitating future evaluation of ACL reconstruction techniques.
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Affiliation(s)
- Lukas Willinger
- Biomechanics Group, Mechanical Engineering Department, Imperial College London, London, UK,Orthopaedic Surgery Department, Technical University of Munich, Munich, Germany
| | - Kiron K. Athwal
- Biomechanics Group, Mechanical Engineering Department, Imperial College London, London, UK
| | - Andy Williams
- Biomechanics Group, Mechanical Engineering Department, Imperial College London, London, UK,Fortius Clinic, London, UK
| | - Andrew A. Amis
- Biomechanics Group, Mechanical Engineering Department, Imperial College London, London, UK,Andrew A. Amis, FREng, DSc(Eng), Mechanical Engineering Department, Imperial College London, London, SW7 2AZ, UK ()
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Athwal KK, Milner PE, Bellier G, Amis AA. Posterior capsular release is a biomechanically safe procedure to perform in total knee arthroplasty. Knee Surg Sports Traumatol Arthrosc 2019; 27:1587-1594. [PMID: 30094498 PMCID: PMC6527529 DOI: 10.1007/s00167-018-5094-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/21/2018] [Accepted: 08/03/2018] [Indexed: 01/25/2023]
Abstract
PURPOSE Surgeons may attempt to strip the posterior capsule from its femoral attachment to overcome flexion contracture in total knee arthroplasty (TKA); however, it is unclear if this impacts anterior-posterior (AP) laxity of the implanted knee. The aim of the study was to investigate the effect of posterior capsular release on AP laxity in TKA, and compare this to the restraint from the posterior cruciate ligament (PCL). METHODS Eight cadaveric knees were mounted in a six degree of freedom testing rig and tested at 0°, 30°, 60° and 90° flexion with ± 150 N AP force, with and without a 710 N axial compressive load. After the native knee was tested, a deep dished cruciate-retaining TKA was implanted and the tests were repeated. The PCL was then cut, followed by releasing the posterior capsule using a curved osteotome. RESULTS With 0 N axial load applied, cutting the PCL as well as releasing the posterior capsule significantly increased posterior laxity compared to the native knee at all flexion angles, and CR TKA states at 30°, 60° and 90° (p < 0.05). However, no significant increase in laxity was found between cutting the PCL and subsequent PostCap release (n.s.). In anterior drawer, there was a significant increase of 1.4 mm between cutting the PCL and PostCap release at 0°, but not at any other flexion angles (p = 0.021). When a 710 N axial load was applied, there was no significant difference in anterior or posterior translation across the different knee states (n.s.). CONCLUSIONS Posterior capsular release only caused a small change in AP laxity compared to cutting the PCL and, therefore, may not be considered detrimental to overall AP stability if performed during TKA surgery. LEVEL OF EVIDENCE Controlled laboratory study.
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Affiliation(s)
- K K Athwal
- Department of Mechanical Engineering, Imperial College London, Exhibition Road, London, SW7 2AZ, UK
| | - P E Milner
- Department of Mechanical Engineering, Imperial College London, Exhibition Road, London, SW7 2AZ, UK
| | - G Bellier
- Cabinet Goethe, 23 Avenue Niel, Paris, 75017, France
| | - 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, W6 8RF, London, UK.
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