Cruciate-retaining total knee arthroplasty at 5 to 7 years followup

Cruciate-retaining total knee implants may improve postoperative function in total knee arthroplasty, but whether patients experience good restoration of kinematics, undue wear, or increased revision rates is debatable. I evaluated clinical results, radiographs, and survival rates of the NexGen posterior cruciate-retaining implant at 5-7 years followup in 251 knees (198 patients) in a prospective, consecutive total knee replacement series done from 1996-1997. A consistent improvement in knee scores and range of motion was observed from preoperative evaluation through 5 years followup. Alignment remained constant and knee stability did not deteriorate. Knee Society scores were good or excellent for 90% of patients. The average range of motion was 123 degrees, and 73% of patients achieved a mean range of motion of 116 degrees -130 degrees. Mean physical quality of life measures improved from preoperative evaluation to the last followup. There were no complete or progressive radiolucencies. Four screw radiolucencies had progressive increases in diameter. Survival of the implant at 7 years was more than 98%. The NexGen posterior cruciate-retaining implant provided satisfactory kinematic and clinical results with no substantive polyethylene wear.

Therapeutic study, Level II-2 (poor-quality randomized controlled trial). See the Guidelines for Authors for a complete description of levels of evidence.