BACKGROUND: There is no evidence in the current literature of any significant improvement in clinical outcome when comparing computer-assisted total knee arthroplasty (CATKA) with conventional implantation. Analyses of alignment and of component orientation have shown both significant and non-significant differences between the two methods. OBJECTIVES: We compared computer-assisted and conventional surgery for TKA at 5.4 years follow-up for patients with varus osteoarthritic knees. Our goal was to assess clinical outcome and restoration of normal limb alignment. MATERIALS AND METHODS: We performed a retrospective case-control study comparing 30 patients who underwent CATKA with 30 subjects who underwent TKA by conventional methods. Patients were matched individually by preoperative clinical conditions and alignment. We analysed intraoperative data (surgical time and intraoperative complications), postoperative complications, lower limb alignment, radiographic complication on X-ray imaging, and clinical outcome through knee and function score and range of motion. RESULTS AND DISCUSSION: We found no significant clinical difference between the two groups at 5 years post-surgery. However there was a statistically significant improvement in the restoration of the mechanical axis of the lower limb in the coronal plane but not in the sagittal plane. Whether or not this leads to a higher survival rate in the longer term requires further investigation.