Patella Strength Characteristics in Cemented vs Press-fit Implants: A Biomechanical Analysis of Initial Stability

Akshar H. Patel, MD; J. Heath Wilder, MD; John M. Weldy, MD; Bailey J. Ross, BA; Nathaniel E. Kim; Hao Wang; Fernando L. Sanchez, MD; William F. Sherman, MD, MBA

Arthroplasty Today (Apr 2022)

Patella Strength Characteristics in Cemented vs Press-fit Implants: A Biomechanical Analysis of Initial Stability

Akshar H. Patel, MD,
J. Heath Wilder, MD,
John M. Weldy, MD,
Bailey J. Ross, BA,
Nathaniel E. Kim,
Hao Wang,
Fernando L. Sanchez, MD,
William F. Sherman, MD, MBA

Affiliations

Akshar H. Patel, MD: Department of Orthopaedic Surgery, Tulane University School of Medicine, New Orleans, LA, USA
J. Heath Wilder, MD: Department of Orthopaedic Surgery, Tulane University School of Medicine, New Orleans, LA, USA
John M. Weldy, MD: Department of Orthopaedic Surgery, Tulane University School of Medicine, New Orleans, LA, USA
Bailey J. Ross, BA: Department of Orthopaedic Surgery, Tulane University School of Medicine, New Orleans, LA, USA
Nathaniel E. Kim: Department of Biomedical Engineering, Tulane University School of Science & Engineering, New Orleans, LA, USA
Hao Wang: Department of Biomedical Engineering, Tulane University School of Science & Engineering, New Orleans, LA, USA
Fernando L. Sanchez, MD: Department of Orthopaedic Surgery, Tulane University School of Medicine, New Orleans, LA, USA
William F. Sherman, MD, MBA: Department of Orthopaedic Surgery, Tulane University School of Medicine, New Orleans, LA, USA; Corresponding author. Department of Orthopaedic Surgery, Tulane University School of Medicine, 1430 Tulane Avenue, New Orleans, LA 70112, USA. Tel.: +1 504 982 0252.

Journal volume & issue: Vol. 14
pp. 140 – 147

Abstract

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Background: Patellar resurfacing is routinely performed during total knee arthroplasty to reduce pain associated with patellofemoral osteoarthritis. With 3-dimensional ingrowth materials readily available, the present study aimed to evaluate if cemented polyethylene (CP) patellar buttons conferred higher ultimate load to failure than press-fit metal-backed (PF) buttons in axial compression. Material and methods: Ten matched cadaveric and 20 composite patellae were resurfaced and implanted with either a PF or CP button. Biomechanical testing using an MTS machine was performed to measure the force required to generate a periprosthetic patella fracture. Mean load to failure and load to failure per 1-mm patellar thickness were compared with a paired and independent samples Students’ t-test for the cadaveric and composite patellae, respectively. Results: The average load to failure for the matched cadaveric patellae with PF implants was significantly lower than that for patellae with CP buttons (4082.05 N vs 5898.37 N, P = .045). The average load to failure for composite patella with PF implants was significantly higher than that for composite patellae with CP implants (6004.09 N vs 4551.40 N, P = .001). The mean load to failure per 1-mm patellar thickness was also significantly higher for composite patellae with PF implants (263.80 N/mm vs 200.37 N/mm, P = .001). Conclusion: Cadaveric patellae with cemented implants had a significantly higher ultimate load to failure in axial compression than press-fit patella. However, this result was reversed in the composite model. Exploration of biological and composite model properties could provide further insight into patellar implant selection during total knee arthroplasty.

Published in Arthroplasty Today

ISSN: 2352-3441 (Online)
Publisher: Elsevier
Country of publisher: United States
LCC subjects: Medicine: Surgery: Orthopedic surgery
Website: https://www.journals.elsevier.com/arthroplasty-today/

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