Total knee replacement in Paget's disease

Due to rapid bone turnover in Paget's disease, loosening of artificial joints might be expected to be a problem, especially if they are of the tissue ingrowth type. Two patients with Paget's disease, who had had knee replacement with this type of prosthesis and have been followed for two years, have both done well to date. It appears that ingrowth-type implants can be used in the presence of Paget's disease. Paget's disease, which was first described in 1877, is characterized by a rapid turnover of bone. The cause of Paget's disease has yet to be determined. The common sites attacked, at least in a Canadian population, are the pelvis (45.4%), vertebrae (22%), femur (10%), tibiae (3.6%), and patellae (0.2%). Paget's occasionally gives rise to arthritic changes in a joint adjacent to the lesion, although the precise mechanism is uncertain. Disturbance of the subchondral bone due to hyperemia and overload due to increasing deformity have been cited as possible reasons. There was and is concern that joint replacement with cemented components would result in rapid loosening due to increased bone turnover. However, it has yet to prove a major problem. So far no reports have appeared in the literature on the effects of Paget's disease on knee replacement, specifically the effects of the porous tissue ingrowth type components that are now in common use. Two patients with Paget's disease around the knee who had had a knee replacement of this type are presented, with over two years of follow-up.