Primary total knee arthroplasty: a comparison of computer-assisted and manual techniques.

Total knee arthroplasty has proven to be successful in improving a patient's quality of life. Traditional total knee instrumentation aligns 80% of knees within 3 degrees of neutral alignment, leaving 20% with outliers with more than 3 degrees of deformity. Computer-assisted surgery in total knee arthroplasty is a relatively new technique for decreasing these alignment outliers. Database searches from January 1990 through April 2008 were used to review studies comparing manual and computer-assisted techniques in total knee arthroplasty. A multistage assessment was used to ensure the broadest coverage. Potential articles were identified and further examined. Full data extraction was performed on 52 articles using a standardized data collection tool. Analysis of 22 randomized controlled studies showed a clear advantage in terms of alignment for computer-assisted surgery versus manual surgery; however, no studies evaluated the associations between patient characteristics and outcomes or measured functional outcome beyond the degree of malalignment within a short period after the surgery. There is a need for studies that examine functional outcomes more than 1 year postoperatively using standardized assessment tools, especially because malalignment is an intermediate outcome measure that cannot be linked causally in all cases of eventual implant failure.