Comparison of Radiographic Alignment of Imageless Computer-Assisted Surgery vs Conventional Instrumentation in Primary Total Knee Arthroplasty

A total of 208 patients were enrolled in a multicenter, prospective randomized, institutional review board–approved study that compared preoperative surgical plan to postoperative 2-dimensional radiographic alignment measured by a blinded reviewer for primary total knee arthroplasty (TKA) implanted using computer-assisted surgery (CAS) compared with conventional TKA instrumentation. The results demonstrated a statistically significant improvement in the coronal tibial component alignment (P < .03) and failed to demonstrate a statistically significant improvement in the mechanical axis, femoral coronal/sagittal, and tibial sagittal alignment. Knee Society Score knee and function scores and 6-minute walk test were equivalent between the 2 treatment groups at all postoperative intervals. There was a statistically significant increase in the skin-skin time (P < .0001) and the time until first bone cut (P < .0001) for the CAS knees compared with those implanted with conventional instrumentation. The use of CAS in this randomized clinical trial conducted at high-volume centers did not offer a clinically meaningful improvement in postoperative alignment, clinical, functional, or safety outcomes compared with conventional TKA.