Arthrodesis of the knee using computer navigation in failed total knee arthroplasty.

Arthrodesis is used most commonly as a salvage procedure for failed total knee arthroplasty (TKA). For successful arthrodesis, a stable fusion technique and acceptable limb mechanical alignment are needed. Although the use of TKA intramedullary alignment rods may be helpful in terms of achieving an acceptable limb mechanical axis, fat embolism and intramedullary dissemination of an infection or reactivation of latent infection may occur in failed TKA cases with an active infection or a past history of infections. In this situation, computer-assisted surgery allows precise cuts to be made in the frontal and sagittal planes without breaching medullary cavities. Navigated femoral and tibial bone resections were performed perpendicular to the coronal mechanical axis. Also, femoral resection was conducted at 0 degrees of flexion to the sagittal axis, and the tibial resection at 7 degrees of flexion to the sagittal axis. The arthrodesis was held in proper axial and rotational alignment. First, the tibia was placed against the femur, ensuring good bony apposition mediolaterally and anteroposteriorly. Second, the rotational alignment was also rechecked based on the information obtained from the navigation system, suggesting that the mechanical axis will be neutral if the rotational alignment is correct because the tibial slope was increased posteriorly. Knee arthrodesis was completed using the Ilizarov method. Postoperative radiographs revealed satisfactory alignment. We believe that computer navigation could be an alternative surgical option for arthrodesis for failed TKA secondary to intra-articular infection and could be used for failed TKA with extra-articular deformity.