Management of Extra-articular Deformity

Total knee arthroplasty (TKA) in the presence of severe extra-articular deformity remains a challenging situation. Such deformities mainly occurring secondary to femoral or tibial fracture malunion, failed osteotomy, prior physeal injury, congenital deformity, metabolic bone disease, and skeletal dysplasia. In these situations, the standard principles of TKA still apply, including restoration of the mechanical alignment and soft tissue balance. The challenge relates to the implications of the distal femoral and proximal tibial bone resection in both the coronal and sagittal planes. The extra-articular deformity must in some way be corrected by the bone resection. There are several options for correction of the deformity; one is arthroplasty with intra-articular correction, or combined with an extra-articular corrective osteotomy, either as a staged or simultaneous procedure.