Uncemented press-fit total knee arthroplasty.

Nineteen total knee arthroplasties in 16 patients were performed using a new prosthesis designed specifically for uncemented, press-fit fixation without any provision for tissue ingrowth. This design may be suited for use in patients with juvenile rheumatoid arthritis, postseptic knees, failed total knee arthroplasties with large bone stock deficiencies, and young, active, overweight individuals. Preservation of bone stock is possible because the fixation stems are nails rather than larger cement pegs, removal for revision is easier without cement, sequestration of microbes within cement cannot occur, and bone graft may be continually loaded with this type of prosthesis. Pain relief, discarding crutch support, operative blood loss, and corrective alignment were equivalent to results obtained with cemented arthroplasty. Seventeen of the 18 knees available for review (average follow-up period, 3 years, 7 months; range of follow-up period, 2 years, 10 months to 4 years, 11 months) were pain-free. Range of motion averaged -2 degrees of extension to 101 degrees of flexion. Ambulation was unrestricted and unsupported in the majority of patients. Radiographic evaluation showed the development of increased bone density under the tibial plateau as well as a sclerotic line at the ends of the femoral and tibial stems. This observation gives support to the theory that multiple microtrabecular fractures with healing form a new supportive "subchondral bone plate." There was one incidence of tibial subsidence. Prosthesis migration and loosening were not observed.