Patient Specific Knee Design

Efforts to enhance the surgical technique of total knee arthroplasty (TKA) while avoiding the negative aspects of computer navigation have led to the development of patient-specific cutting guides. In this study, the authors examine the results of 50 TKAs. It focuses on joint replacement and hip, knee & lower extremity.

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This title focuses on such area as joint replacement and hip, knee & lower extremity. Efforts to enhance the surgical technique of total knee arthroplasty while avoiding the negative aspects of computer navigation have led to the development of patient-specific cutting guides. In this study, the authors examine the results of 50 TKAs. Detailed MR imaging of each patients knee is obtained along with several slices through the hip and ankle. From these images, proprietary software creates and orients (in space) virtual 3D models of the femur and tibia. Appropriate implant sizes are determined with the help of the software, and virtual bony resections are mapped to help the surgeon accomplish accurate position and alignment. A preoperative plan with visual images is sent to the surgeon for review. Upon approval, rapid prototyping technology is used to fabricate actual models of the patients distal femur and proximal tibia. Also developed are disposable custom guides that will fit precisely on the patients bone to determine accurate pin placement for the standard resection instrumentation of the implant manufacturer. Preliminary results in 50 TKAs show accurate femoral component sizing and restoration of alignment of 4-8 of valgus in all cases. TKA can be performed with custom jigs in truly patient specific fashion, allowing the surgeon to achieve optimal alignment without violating the intramedullary canal.