Medium-term results of total knee arthroplasty using a medially pivoting implant: a multicenter study.

A multicenter study was conducted to determine the durability and performance of a medially pivoting knee prosthesis in total knee arthroplasty (TKA). Between February 1999 and June 2001, 276 patients underwent 298 primary TKAs at five centers. There were 189 patients (204 knees) available for clinical evaluation after surgery, with an average follow-up of 5.4 years (range, 5.0-7.6 years). The mean age at follow-up was 69 years (range, 39-87 years). The posterior cruciate ligament was resected in 65% of the procedures. Knee Society scores (KSS) and radiographs were assessed for patients who returned for follow-up evaluation. Patients unwilling or unable to return were asked their status via telephone. There were a total of five revisions, and 5-year survivorship using Kaplan-Meier analysis was 97.2%. All radiographs exhibited well-fixed implants with no signs of gross migration or pending failure. Preoperative mean KSS and flexion were 33 and 107°, respectively, improving at latest follow-up to 90 and 121°, respectively. The medial-pivot prosthesis resulted in excellent survivorship with good functional results at medium-term follow-up.