Improved radiographic outcomes with patient-specific total knee arthroplasty.

Patient-specific guides can improve limb alignment and implant positioning in total knee arthroplasty, although not all studies have supported this benefit. We compared the radiographs of 100 consecutively-performed patient-specific total knees to a similar group that was implanted with conventional instruments instead. The patient-specific group showed more accurate reproduction of the theoretically ideal mechanical axis, with fewer outliers, but implant positioning was comparable between groups. Our odds ratio comparison showed that the patient-specific group was 1.8 times more likely to be within the desired +3° from the neutral mechanical axis when compared to the standard control group. Our data suggest that reliable reproduction of the limb mechanical axis may accrue from patient-specific guides in total knee arthroplasty when compared to standard, intramedullary instrumentation.