Aseptic loosening remains the leading cause of total knee arthroplasty (TKA) failure. Cementless designs aim to improve long-term fixation, but prior iterations had high failure rates. Modern cementless implants with porous coatings have renewed interest. However, concerns about fixation persist.

Cement provides immediate rigid fixation with excellent long-term survivorship. However, cement has poor fatigue resistance, and particulate debris can stimulate osteolysis. Outcomes remain superior to early cementless designs.

Cementless fixation relies on bone ingrowth into porous implant surfaces for biologic fixation, decreasing debris and adaptive remodeling over time. Highly porous tantalum and 3D-printed titanium promote osteoconduction. Prior cementless designs failed from poor metallurgy, coatings, and locking mechanisms.

Cementless fixation requires meticulous technique for initial stability. Bone defects or osteoporosis are relative contraindications. Periprosthetic fractures may occur with undersized stems or pegs.

Recent randomized trials of cemented versus cementless TKA with newer porous surfaces show minimal clinical differences up to 2 years postoperatively. Early outcomes are reassuring, but longer follow-up is needed. Aseptic loosening rates appear low thus far. Concerns remain about higher costs with cementless designs.

Modern cementless TKA achieves short-term outcomes comparable to cemented designs but long-term durability is unproven. Prospective registry data is needed. Cementless fixation is an option for young active patients at higher risk for loosening. Further study is warranted before widespread adoption.