Coronal Plane Stability Before and After Total Knee Arthroplasty

The success of total knee arthroplasty depends in part on proper soft tissue management to achieve a stable joint. It is unknown to what degree total knee arthroplasty changes joint stability. We used a surgical navigation system to in-traoperatively measure joint stability in 24 patients under-going primary total knee arthroplasty to address two ques-tions: (1) Is the total arc of varus-valgus motion after total knee arthroplasty different from the arc of varus-valgus mo-tion in an osteoarthritic knee? (2) Does total knee arthro-plasty produce equal amounts of varus/valgus motion (ie, is the knee “balanced”)? We observed no difference between the total arc of varus-valgus motion before and after total knee arthroplasty; the total amount of motion was un-changed. On average, osteoarthritic knees were “unbal-anced ” but were “balanced ” after prosthesis implantation