Cementless total knee arthroplasty
The cementless total knee has gained increasing interest as an alternative fixation to cemented implants for younger, more active patient populations. Unlike cemented implants that rely on the use of cement to make small corrections in alignment and positioning, the cementless implant is dependent on optimal implant design and precise surgical technique to achieve comparable clinical outcomes. The key to its success has been a combination of appropriate patient selection, advanced implant coatings, and use of autogenous bone chips as a form of biologic cement. Careful selection of porous coating composites and pore sizes have lead to surfaces that allow optimal bone ingrowth while minimizing stress shielding or excessive bone loss during revision surgery. The use of bone grafting serves as a biologic alternative for implant fixation that avoids some of the complications encountered with methylmethacrylate. The cementless knee system may be performed using either a gap balancing or measured resection technique and can accommodate either PCL resection or preservation. Particular attention must be paid to making precise bone cuts as cement cannot be used to correct for gaps or surface incongruity. Early clinical trials have shown comparable clinical outcomes and survival to cemented implants with up to 13.6 years of follow-up. Further advancements in implant design and composite materials will hopefully lead to greater implant longevity and broaden the indications for cementless knee arthroplasty use.