Total knee arthroplasty with 4.4 mm of tibial polyethylene - 10-year followup

A consecutive series of 387, one-piece, 8-mm tibial components were implant ed in 313 patients. All tibial prostheses were manufactured with 4.4 mm of polyethylene directly molded to a 3.6 mm cobalt chrome metal baseplate. The average age of the patients at surgery was 70.6 years. From this group, a subset of 116 patients underwent bilateral total knee arthroplasties with a n 8-mm tibial component on one side and at least a 10-mm thick tibial compo nent (at least 6.4 mm of polyethylene) on the other side. The followup aver aged 10.7 years. Postoperative knee and pain scores average 81.4 points and 47.2 points, respectively. No radiographic polyethylene wear or osteolytic lesions were identified, Tibial radiolucencies were observed in four knees . There were nine failures (2.3%), Three knees were revised for infection. Five knees were revised for metallosis secondary to failure of metal-backed patellas, No loose tibial components were identified, Defining failure as revision for any reason or loosening of any component, Kaplan-Meier surviva l rates at 5, 10, and 15 years were 98.7%, 95.4%, and 94.3%, respectively. There was no significant difference in clinical scores or survival rates be tween the knee components with thicker (at least 6.4 mm) or thinner (4.4 mm ) polyethylene.