Patients with arthritis of the knee and an extra-articular deformity present a unique technical challenge, as it becomes more difficult to restore the mechanical axis during total knee replacement (TKR). Current treatment options include a 2-stage procedure in which an extra-articular correctional osteotomy is performed several months before the primary TKR, a 1-stage procedure in which an extra-articular correctional osteotomy is performed at the time of the index TKR, or a 1-stage procedure in which TKR is performed with correction of the extra-articular deformity. One-stage TKR with intra-articular correction of the extra-articular deformity is our treatment of choice. With proper planning, appropriate bone cuts to restore alignment, and the necessary soft tissue releases to balance the knee in flexion and extension, a satisfactory TKR can be achieved. Two patients with arthritis and a severe extra-articular deformity (varus/valgus deformity >20 degrees , recurvatum and malunion of a tibial or femoral fracture) were treated with 1-stage TKR with intra-articular correction of the extra-articular deformity. The technique followed had been successfully performed in 15 previous cases. The procedure was clinically successful in both patients without complications. At 2-year follow-up, Knee Society Scores improved from 40 to 95 and there was no evidence of instability in either case.