Medium Term Results of a Mobile Bearing Total Knee Replacement

Jung, Young Bok; Kim, Jin Soo; Tae, Suk Ki; Jung, Ho Joong; Kim, Jong Won

Abstract

PURPOSE
The LCS (low contact stress) mobile bearing knee replacement has been used extensively. The purpose of this study was to report at least five-year clinical results of a primary total knee replacement performed with LCS mobile bearing design. MATERIALS AND METHODS: From January 1992 to October 1997, author performed 80 total knee arthroplasties in 59 patients with LCS mobile bearing knee replacement. At the final follow-up, one patient had died, and ten patients had been lost to follow-up. The patients were evaluated with HSS (Hospital for Special Surgery) knee rating system and radiographic analysis. RESULTS: The fifty-six knees in the forty-two patients were examined for final clinical and radiographic analysis at five to ten years. The average active range of knee flexion was from 5 degrees to 112 degrees preoperatively and 0 degrees to 123 degrees at the final follow-up evaluation. The average HSS score was 60.7 points preoperatively and 88.9 points at the final follow-up evaluation. Of the 56 knees, none had a dislocation of the mobile bearing prosthesis, one case had a traumatic periprosthetic fracture and four cases required reoperation, one for infection, one patellar revision for patellar polyethylene breakage, one rotating platform change to thicker one for posterior instability during flexion and one meniscal bearing change for medial meniscal bearing wear. There was no significant progressive periprosthetic osteolysis on follow-up radiographs. CONCLUSION: After five to ten years of follow-up, the LCS knee replacement was found to be performing well, with durable clinical and radiographic results.