In Vivo Analysis of Polyethylene Wear Particles After Total Knee Arthroplasty: The Influence of Improved Materials and Designs

Aims Vitamin E-infused highly cross-linked polyethylene (E1) has recently been introduced in total knee arthroplasty (TKA). An in vitro wear simulator study showed that E1 reduced polyethylene wear. However there is no published information regarding in vivo wear. Previous reports suggest that newly introduced materials which reduce in vitro polyethylene wear do not necessarily reduce in vivo polyethylene wear. To assist in the evaluation of the newly introduced material before widespread use, we established an in vivo polyethylene wear particle analysis for TKA. The aim of this study was to compare in vivo polyethylene wear particle generation between E1 and conventional polyethylene (ArCom) in TKA. Methods A total of 34 knees undergoing TKA (17 each with ArCom or E1) were investigated. Except for the polyethylene insert material, the prostheses used for both groups were identical. Synovial fluid was obtained at a mean of 3.4 years (SD 1.3) postoperatively. The in vivo polyethylene wear particles were isolated from the synovial fluid using a previously validated method and examined by scanning electron microscopy. Results The total number of polyethylene wear particles obtained from the knees with E1 (mean 6.9, SD 4.0 × 107 counts/knee) was greater than that obtained from those with ArCom (mean 2.2, SD 2.6 × 107 counts/knee) (p = 0.001). The particle size (equivalent circle of diameter) from the knees with E1 was smaller (mean 0.5 μm, SD 0.1) than that of knees with ArCom (mean 1.5, SD 0.3 μm) (p = 0.001). The aspect ratio of particles from the knees with E1 (mean 1.3, SD 0.1) was smaller than that with ArCom (mean 1.4, SD 0.1) (p < 0.001 ). Conclusion This is the first report of in vivo wear particle analysis of E1. E1 polyethylene did not reduce the number of in vivo polyethylene wear particles compared with ArCom in early clinical stage. Further careful follow-up of newly introduced E1 for TKA should be carried out. Cite this article: Bone Joint J 2020;102-B(11):1527–1534.

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Asymmetrical tibial polyethylene geometry-cruciate retaining total knee arthroplasty does not fully restore in-vivo articular contact kinematics during strenuous activities

Knee Surgery Sports Traumatology Arthroscopy ◽

10.1007/s00167-020-06384-9 ◽

2021 ◽

Author(s):

Christian Klemt ◽

John Drago ◽

Venkatsaiakhil Tirumala ◽

Young-Min Kwon

Keyword(s):

Total Knee Arthroplasty ◽

Knee Arthroplasty ◽

Cruciate Retaining ◽

Contact Kinematics ◽

Total Knee

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Isolated tibial insert exchange in revision total knee arthroplasty

The Bone & Joint Journal ◽

10.1302/0301-620x.103b6.bjj-2020-1954.r2 ◽

2021 ◽

Vol 103-B (6) ◽

pp. 1103-1110

Author(s):

Matthew W. Tetreault ◽

Jeremy T. Hines ◽

Daniel J. Berry ◽

Mark W. Pagnano ◽

Robert T. Trousdale ◽

...

Keyword(s):

Total Knee Arthroplasty ◽

Knee Arthroplasty ◽

Polyethylene Wear ◽

Revision Total Knee Arthroplasty ◽

Common Reason ◽

Original Diagnosis ◽

Tibial Insert ◽

Total Knee ◽

Component Loosening ◽

Revision Tka

Aims This study aimed to determine outcomes of isolated tibial insert exchange (ITIE) during revision total knee arthroplasty (TKA). Methods From 1985 to 2016, 270 ITIEs were performed at one institution for instability (55%, n = 148), polyethylene wear (39%, n = 105), insert fracture/dissociation (5%, n = 14), or stiffness (1%, n = 3). Patients with component loosening, implant malposition, infection, and extensor mechanism problems were excluded. Results Survivorship free of any re-revision was 68% at ten years. For the indication of insert wear, survivorship free of any re-revision at ten years was 74%. Re-revisions were more frequent for index diagnoses other than wear (hazard ratio (HR) 1.9; p = 0.013), with ten-year survivorships of 69% for instability and 37% for insert fracture/dissociation. Following ITIE for wear, the most common reason for re-revision was aseptic loosening (33%, n = 7). For other indications, the most common reason for re-revision was recurrence of the original diagnosis. Mean Knee Society Scores improved from 54 (0 to 94) preoperatively to 77 (38 to 94) at ten years. Conclusion After ITIE, the risk and reasons for re-revision correlated with preoperative indications. The best results were for polyethylene wear. For other diagnoses, the re-revision rate was higher and the failure mode was most commonly recurrence of the original indication for the revision TKA. Cite this article: Bone Joint J 2021;103-B(6):1103–1110.

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Effect of Gait on Patellofemoral Mechanics

ASME 2008 Summer Bioengineering Conference, Parts A and B ◽

10.1115/sbc2008-192451 ◽

2008 ◽

Author(s):

Jeffrey E. Bischoff ◽

Justin S. Hertzler

Keyword(s):

Total Knee Arthroplasty ◽

Knee Arthroplasty ◽

Clinical Studies ◽

Patellofemoral Joint ◽

Knee Kinematics ◽

Component Design ◽

Total Knee ◽

The Impact ◽

Reconstructed Knee

Computational modeling of the reconstructed knee is an important tool in designing components for maximum functionality and life. Utilization of boundary conditions consistent with in vivo gait loading in such models enables predictions of knee kinematics and polyethylene damage [1–4], which can then be used to optimize component design. Several recent clinical studies have focused on complications associated with the patellofemoral joint [5–6], highlighting the need to better understand the mechanics of this compartment of total knee arthroplasty (TKA). This study utilizes a computational model to characterize the impact of gait loading on the mechanics of the patella in TKA.

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In Vivo Tibiofemoral Contact Kinematics and Contact Forces During Dynamic Weight-Bearing Activities Following Total Knee Arthroplasty

ASME 2008 Summer Bioengineering Conference, Parts A and B ◽

10.1115/sbc2008-192613 ◽

2008 ◽

Author(s):

Kartik M. Varadarajan ◽

Angela Moynihan ◽

Darryl D’Lima ◽

Clifford W. Colwell ◽

Harry E. Rubash ◽

...

Keyword(s):

Total Knee Arthroplasty ◽

Knee Arthroplasty ◽

Computational Models ◽

Imaging System ◽

Weight Bearing ◽

Contact Forces ◽

Inverse Dynamic ◽

Contact Kinematics ◽

Total Knee

Accurate knowledge of in vivo articular contact kinematics and contact forces is required to quantitatively understand factors limiting life of total knee arthroplasty (TKA) implants, such as polyethylene component wear and implant loosening [1]. Determination of in vivo tibiofemoral contact forces has been a challenging issue in biomechanics. Historically, instrumented tibial implants have been used to measure tibiofemoral forces in vitro [2] and computational models involving inverse dynamic optimization have been used to estimate joint forces in vivo [3]. Recently, D’Lima et al. reported the first in vivo measurement of 6DOF tibiofemoral forces via an instrumented implant in a TKA patient [4]. However this technique does not provide a direct estimation of tibiofemoral contact forces in the medial and lateral compartments. Recently, a dual fluoroscopic imaging system has been used to accurately determine tibiofemoral contact locations on the medial and lateral tibial polyethylene surfaces [5]. The objective of this study was to combine the dual fluoroscope technique and the instrumented TKAs to determine the dynamic 3D articular contact kinematics and contact forces on the medial and lateral tibial polyethylene surfaces during functional activities.

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