The anatomic total knee resurfacing arthroplasty.

The long-term results of total knee arthroplasty are largely dependent on the degree to which the implants and the technique for their insertion duplicate the normal joint anatomy, mechanics, and kinematics. Aberrations in these modalities, occasioned by technical malalignment of the joint or by nonanatomic designing, sizing, or positioning of the implants, are the predominant causes of postoperative limitation of motion and loosening of the implants. Although inadequacies in the bonding effect of cement and in the structural strength of polyethylene have been cited as contributing factors in the incidence of loosening of the tibial component, this complication occurred in less than 2% of 532 cemented Anatomic Total Knee (ATK) replacements that were available for review at a follow-up period of two to 11 years. The long-term follow-up results, based on pain relief, motion, and level of activity, were judged excellent or good in 89% of the knees. Problems related to the patella and loosening of the tibial component were the predominant mechanical complications that required revision. The incidence of loosening was routinely related to technical malalignment of the knee joint or the prosthesis. However, experimental and recent clinical studies indicate that porous-surfaced implants may provide a more durable and long-lasting mode of stabilization. Except for the adaptation of the implants to the porous-coated, noncemented technique, the ATK arthroplasty ensemble has remained essentially unchanged from the original 1972 design.