The mechanical response of a polyetheretherketone femoral knee implant under a deep squatting loading condition

The current study was designed to investigate the mechanical response of a polyetheretherketone-on-polyethylene total knee replacement device during a deep squat. Application of this high-demand loading condition can identify weaknesses of the polyetheretherketone relative to cobalt-chromium. This study investigated whether the implant is strong enough for this type of loading, whether cement stresses are considerably changed and whether a polyetheretherketone femoral component is likely to lead to reduced periprosthetic bone loss as compared to a cobalt-chromium component. A finite element model of a total knee arthroplasty subjected to a deep squat loading condition, which was previously published, was adapted with an alternative total knee arthroplasty design made of either polyetheretherketone or cobalt-chromium. The maximum tensile and compressive stresses within the implant and cement mantle were analysed against their yield and fatigue stress levels. The amount of stress shielding within the bone was compared between the polyetheretherketone and cobalt-chromium cases. Relative to its material strength, tensile peak stresses were higher in the cobalt-chromium implant; compressive peak stresses were higher in the polyetheretherketone implant. The stress patterns differed substantially between polyetheretherketone and cobalt-chromium. The tensile stresses in the cement mantle supporting the polyetheretherketone implant were up to 33% lower than with the cobalt-chromium component, but twice as high for compression. Stress shielding was reduced to a median of 1% for the polyetheretherketone implant versus 56% for the cobalt-chromium implant. Both the polyetheretherketone implant and the underlying cement mantle should be able to cope with the stress levels present during a deep squat. Relative to the cobalt-chromium component, stress shielding of the periprosthetic femur was substantially less with a polyetheretherketone femoral component.

Download Full-text

No difference in in vivo polyethylene wear particles between oxidized zirconium and cobalt–chromium femoral component in total knee arthroplasty

Knee Surgery Sports Traumatology Arthroscopy ◽

10.1007/s00167-013-2724-4 ◽

2013 ◽

Vol 22 (3) ◽

pp. 680-686 ◽

Cited By ~ 8

Author(s):

Yukihide Minoda ◽

Kanako Hata ◽

Hiroyoshi Iwaki ◽

Mitsuhiko Ikebuchi ◽

Yusuke Hashimoto ◽

...

Keyword(s):

Total Knee Arthroplasty ◽

Femoral Component ◽

Knee Arthroplasty ◽

Polyethylene Wear ◽

Wear Particles ◽

Cobalt Chromium ◽

Oxidized Zirconium ◽

Total Knee

Download Full-text

Various Types of Medial Tibial Bone Resorption after Total Knee Arthroplasty Using a Thick Cobalt Chromium Tibial Baseplate

The Journal of Knee Surgery ◽

10.1055/s-0040-1715085 ◽

2020 ◽

Author(s):

Sang Jun Song ◽

Hyun Woo Lee ◽

Se Gu Kang ◽

Dae Kyung Bae ◽

Cheol Hee Park

Keyword(s):

Total Knee Arthroplasty ◽

Bone Resorption ◽

Knee Arthroplasty ◽

Stress Shielding ◽

Varus Deformity ◽

Cobalt Chromium ◽

Tibial Bone ◽

Asian Patients ◽

Total Knee ◽

Tibial Cortex

AbstractRecent literature has implicated a thick cobalt chromium baseplate as a potential source of stress shielding and medial tibial bone resorption after total knee arthroplasty (TKA) in a Western population. The purpose was to calculate the incidence of various types and severity of medial tibial bone resorption utilizing a novel classification system after TKA with a thick cobalt chromium baseplate in Asian patients. Five hundred TKAs using Attune prostheses with mean follow-up of 3.4 years were evaluated, using the prospective radiographic data. The mean age was 71.3 years. The preoperative mechanical axis was varus, 11.2 degrees. The type and severity of medial tibial bone resorption were categorized as type U (resorption under the tibial baseplate up to 50% [U1] or beyond 50% [U2] of medial tibial tray width), C (resorption around the penetrated cement under the baseplate), and M (resorption on the medial tibial cortex without extension to the baseplate). Bone resorption of medial proximal tibia was observed in 96 knees (19.2%). Types U1 and U2 were seen in 46 and 28 knees, respectively. Type C was observed in 12 knees and type M in 10 knees. The type U resorption group had significantly more preoperative varus deformity (varus 12.9 vs. 10.9 degrees, p = 0.017). Medial tibial bone resorption after TKAs using a thick cobalt chromium baseplate is not uncommon and has various locations, types, and severities. The medial tibial bone resorption might be related to various causes, including stress shielding, thermal necrosis from cement in the bony hole, and bony devascularization. The type-U resorption has to be closely observed in patients with preoperative severe varus deformity. This is a Level IV study.

Download Full-text

What Is the Incidence of Cobalt-Chromium Damage Modes on the Bearing Surface of Contemporary Femoral Component Designs for Total Knee Arthroplasty?

The Journal of Arthroplasty ◽

10.1016/j.arth.2018.05.020 ◽

2018 ◽

Vol 33 (10) ◽

pp. 3313-3319 ◽

Cited By ~ 2

Author(s):

Christina M. Arnholt ◽

Daniel W. MacDonald ◽

Gregg R. Klein ◽

Harold E. Cates ◽

Clare M. Rimnac ◽

...

Keyword(s):

Total Knee Arthroplasty ◽

Femoral Component ◽

Knee Arthroplasty ◽

Bearing Surface ◽

Cobalt Chromium ◽

Total Knee

Download Full-text

Isolated Liner Revision for Total Knee Arthroplasty Instability: A Road That Should Remain Less Taken

The Journal of Knee Surgery ◽

10.1055/s-0040-1721091 ◽

2020 ◽

Author(s):

Jason D. Tegethoff ◽

Rafael Walker-Santiago ◽

William M. Ralston ◽

James A. Keeney

Keyword(s):

Total Knee Arthroplasty ◽

Femoral Component ◽

Knee Arthroplasty ◽

Primary Total Knee Arthroplasty ◽

P Value ◽

Surgical Morbidity ◽

Exact Test ◽

Total Knee ◽

Component Revision

AbstractIsolated polyethylene liner exchange (IPLE) is infrequently selected as a treatment approach for patients with primary total knee arthroplasty (TKA) prosthetic joint instability. Potential advantages of less immediate surgical morbidity, faster recovery, and lower procedural cost need to be measured against reoperation and re-revision risk. Few published studies have directly compared IPLE with combined tibial and femoral component revision to treat patients with primary TKA instability. After obtaining institutional review board (IRB) approval, we performed a retrospective comparison of 20 patients treated with IPLE and 126 patients treated with tibial and femoral component revisions at a single institution between 2011 and 2018. Patient demographic characteristics, medical comorbidities, time to initial revision TKA, and reoperation (90 days, <2 years, and >2 years) were assessed using paired Student's t-test or Fisher's exact test with a p-value <0.01 used to determine significance. Patients undergoing IPLE were more likely to undergo reoperation (60.0 vs. 17.5%, p = 0.001), component revision surgery (45.0 vs. 8.7%, p = 0.002), and component revision within 2 years (30.0 vs. 1.6%, p < 0.0001). Differences in 90-day reoperation (p = 0.14) and revision >2 years (p = 0.19) were not significant. Reoperation for instability (30.0 vs. 4.0%, p < 0.001) and infection (20.0 vs. 1.6%, p < 0.01) were both higher in the IPLE group. IPLE does not provide consistent benefits for patients undergoing TKA revision for instability. Considerations for lower immediate postoperative morbidity and cost need to be carefully measured against long-term consequences of reoperation, delayed component revision, and increased long-term costs of multiple surgical procedures. This is a level III, case–control study.

Download Full-text