Accuracy and efficacy of osteotomy in total knee arthroplasty with patient-specific navigational template

Abstract

This study develops and validates a novel patient-specific navigational template for total knee arthroplasty (TKA). A total of 70 patients who underwent TKA were randomized and divided into conventional method group and navigational template group. In the navigational template group, the patient-specific navigational templates were designed and used intraoperatively to assist 35 patients with knee arthroplasty. Information on operation time and blood loss was recorded. After surgery, the positions of the prosthesis were evaluated using CT scan and X-rays. Analysis showed significant differences in errors between the two techniques. In addition, mean operation time and mean blood loss were statistically and significantly lower in the navigational template group than in the conventional group. Overall, the navigational template method showed a high degree of accuracy and efficacy.

Keywords: Total knee arthroplasty; custom template; navigation; rapid prototyping.

Figure 1

3D model of the knee. A. Femoral view; B. Tibial view.

Figure 2

Measuring the rotational angle preoperatively by Reverse Engineering software.

Figure 3

Analysis of limb alignment by Reverse Engineering software. A. Femoral mechanical alignment; B. Tibial mechanical alignment; C. Medial tibial plateau line.

Figure 4

Design of the navigational templates. A. Virtual femoral template. B. Virtual tibial template.

Figure 5

Surface shape after virtually cutting the distal femur and proximal tibia.

Figure 6

Total knee arthroplasty was performed on a female patient diagnosed with severe knee osteoarthritis. In this case, the right knee was in pain significantly, and the left knee experienced minimal pain. Subsequently, her right knee was replaced; A. The X-ray shows knee degenerative changes and hyperplasia, especially the right knee; B. RP model of femur and tibia navigational template, and the verification template; C. Actual cartilage degeneration; D. Navigational template fitted the femoral condyle perfectly; E. Positioned distal femur osteotomy plane and external rotation axis; F. Navigational template fitted the tibial plateau perfectly; G-I. Actual surface of the distal femur and the proximal tibia after osteotomy matching with the surface shape in the virtual setting by using the navigational template.

Figure 7

Imagic examination shows good positioning of the prosthesis. A. Distal resection of the femur and the proximal resection of the tibia is almost perpendicular to the mechanical axis of the leg in the coronal plane (FFC, FTC, HKA); B and C. Analysis of the angle in the sagittal plane (LFC, LTC); D. The posterior surface resection is parallel to the transepicondylar axis (RFA).