Modular Augments in Revision Total Knee Arthroplasty

Although modular metal augments do not restore host bone stock, properly applied, these augments allow immediate weight bearing and range of motion, transferring loads to intact host bone, while providing durable long-term implant stability. Additionally, the multiple sizes available with modular revision knee systems allow expedient reconstruction at cost savings compared with custom implants. In addition to modular trabecular metal augments, stems, cones, and sleeves have become widely used. These augments offer the same modular benefits as solid metal augments, which can be press fit or cemented, with the added potential for osteointegration and soft tissue interdigitation. Current clinical data support the continued application of modular augmentations in revision knee arthroplasty. Modular augments are particularly applicable in revision cases with peripheral cortical defects, allowing tremendous intraoperative flexibility in the management of tibial and femoral deficiencies. Load transfer to bone is more evenly distributed by metal augmentation than by other reported techniques of reconstruction of bone defects. Additionally, modular augments do circumvent the potential complications associated with bone graft harvest, donor site morbidity, or allograft incorporation/resorption. Though long-term data regarding various modular augments is lacking, early to midterm results are promising, and the convenience and utility of these augments appear to be the present and future of revision knee arthroplasty.