The Use of Inset Patella Prosthesis in Total Knee Arthroplasty / 대한정형외과학회잡지

ABSTRACT

The types of patellar component of total knee replacement prostheses are dome-shape, metalbacked, anatomically shaped, and press fit condylar type, etc. The fixation of inset patella type is achieved with bone cement supplemented by a central peg and a small extended flange around the circumference, providing resistance to torsional and shear loads. From October 1990 to June 1992, 53 cases in 40 patients had total knee arthroplasties. Ortholoc II implant was used in all patients. Cementless femoral and tibial component were used. But, cement was used in patellar component. The average follow up was 29 months(range 21-40 months). There were 37 women and 3 men and the average age was 51 years(range 22-71 years). The diagnosis of 40 patients was osteoarthritis in 25, rheumatoid arthritis in 9, infection sequelae in 6. For alignment of the patellar and congruency of the patellofemoral joint, additional retinacular release was done in 7 cases. The average preoperative Hospital for Special Surgery(H.S.S) knee rating score was 50.7 point, which improved to 89.4 point at last follow up. Postoperative patellar pain was 4 cases. In the roentgenorgraphic follow up, ratellar subluxation was 2 cases and lateral tilting of the patella was 5.9 degrees in 10 cases. The average patellar depth was 20.8mm preoperatively and 21.6mm postoperatively. In the Merchant's view, the preoperative lateral patellofemoral angle of Laurine was average 14.3 degree, which changed to average 16.4 degree at last follow up, and the preoperative Merchant's congruence angle was average 14 degrees, which decreased to average