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

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 (LPBF), to fabricate monolithic cobalt-chromium-molybdenum (CoCrMo) femoral condyles with trabecular-inspired porous architectures. Compared with cast–sintered (CS) 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 ultra-high-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 MPa 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.