Integrated 3D printing of cementless CoCrMo femoral condyles optimizes trabecular surfaces and material performance

Abstract

Conventional cementless femoral condyles in artificial knee systems are commonly manufactured by casting followed by a surface treatment using plasma spraying or metallic sintering. However, both techniques suffer from weak coating-substrate interfaces that contribute to early loosening and higher revision rates. To overcome this limitation, we employed integrated 3D printing (I3P), an additive manufacturing strategy based on laser powder bed fusion, to fabricate monolithic cobalt-chromium-molybdenum femoral condyles with trabecular-inspired porous architectures. Compared with cast-sintered counterparts, I3P substrates exhibited refined microstructures and superior mechanical performance after hot isostatic pressing, reaching a yield strength of 637.33 MPa, ultimate tensile strength of 1140.00 MPa, and elongation of 27.33%. The I3P femoral condyles also showed enhanced fatigue resistance, withstanding 10 million cycles under a 3000 N load, and demonstrated improved wear behavior against ultrahigh-molecular-weight polyethylene liners. Furthermore, the trabecular-inspired lattice achieved stronger integration with the substrate than sintered coatings, with tensile and shear strengths of 56.09 and 49.97 MPa, respectively. Together, these findings establish I3P as a robust manufacturing strategy that integrates substrate and surface in a single step, enabling the production of durable, osteointegrative femoral condyles with significant potential to improve implant longevity and clinical outcomes in knee joint reconstruction.

Keywords

Additive manufacturing / Cementless femoral condyles / Cobalt-chromium-molybdenum alloys / Fatigue and wear resistance / Integrated 3D printing / Osteointegration / Total knee arthroplasty / Trabecular surface architecture

Funding

All materials, products, equipment, and funding for this study were provided by Suzhou Microport Orthorecon Co., Ltd.

Conflict of Interest

J.W., Z.Z., T.Y., and W.W. are employees of Suzhou Microport Orthorecon, a subsidiary of MicroPort Orthopedics which produces and markets the commercial EVOLUTION femoral condyle implant examined in this study. B.Y.C. is an employee of MicroPort at the time of publication of this work.

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