The Computer-Aided-Surgery Improved the Accuracy of Femoral Component Rotation in Total Knee Arthroplasty for the Advanced Osteoarthritis with Valgus Deformity

Abstract

Purpose: Arthritic knees with genu valgus deformity present with soft tissue and osseous anomalies that make Total Knee Arthroplasty (TKA) difficult. We retrospectively investigate whether advanced valgus deformity would benefit from Computer-Aided Surgery-TKA (CAS-TKA). Materials and methods: From January 2003 to September 2011, twenty-six patients having osteoarthritis with valgus deformity in the mechanical axis more than 10 degrees who underwent CAS-TKA were entered into this retrospective study. The usefulness of CAS-TKA was analyzed by the accuracy of placement of the components and postoperative alignment determined using radiographic parameters and Computed Tomography (CT). The Hospital for Special Surgery (HSS) and International Knee Society (IKS) functional scores were obtained for all patients preoperatively and postoperatively. Results: The mean postoperative mechanical axis was 181° (range, 176°-181°). The CT revealed proper femoral and tibial rotational alignment. The joint line was not substantially elevated. No patient required conversion to a constrained TKA to achieve stability. At a mean follow-up of 43 months, the Hospital for Special Surgery (HSS) knee score improved from a mean preoperative score of 54 to 92 postoperatively. The International Knee Society (IKS) clinical score improved from 38 to 97. The IKS for pain improved from 15 to 48, and the IKS knee function score improved from 32 to 96. The active range of motion from 95° to 115°. Conclusions: Computer-aided surgery-TKA is a useful alternative technique for advanced valgus knee arthritis where accurate restoration of the joint line, proper alignment of the limb and prosthetic components in coronal, sagittal and axial plane may be challenging because of bony deformities and soft tissue contractures.