No difference between computer-assisted and conventional total knee arthroplasty: five-year results of a prospective randomised study

The use of computer-assisted surgery (CAS) in total knee arthroplasty (TKA) results in better limb and implant alignment compared to conventional TKA; however, it is unclear whether this translates to better mid- to long-term clinical outcome. This prospective randomised study comparing CAS and conventional TKA reports the functional and patient perceived outcomes at a follow-up of 5 years. The hypothesis was that there would be a difference in functional outcome or quality of life after mid-term follow-up. Sixty-seven patients were available for physical and radiological examination at 5 years. The Knee Society Score (KSS) was used to describe functional outcome and the Euroquol questionnaire for quality of life. The mean total KSS for the CAS group improved from 91.1 (SD 22.3) points preoperatively to 157.4 (SD 21.9) and 150.2 (SD 30.4) points at 2 and 5 years, respectively. In the conventional group, the mean total KSS was 99.6 (SD 18.6) points preoperatively and 151.1 (SD 26.0) and 149.0 (SD 28.0) points at 2 and 5 years, respectively. The mean quality of life score improved from 48.2 (SD 16.5) points preoperatively to 67.4 (SD 16.3) and 66.8 (SD 22.2) points at 2 and 5 years in the CAS group, and from 52.2 (SD 17.1) points preoperatively to 65.6 (SD 14.6) and 61.7 (SD 19.3) points at 2 and 5 years, respectively, in the conventional TKA group. These differences were not statistically significant. There were radiolucent lines up to 2 mm in 11 knees (four CAS, seven conventional), but there were no changes in implant position. There were no significant differences in functional or patient perceived outcome after mid-term follow-up in this study. I.