3D PRINTING TECHNIQUE FOR PATIENT-SPECIFIC INSTRUMENTATION IN TOTAL KNEE ARTHROPLASTY

Abstract

The aim of the study was to evaluate clinical and radiological outcomes of knee arthroplasty using patient specific guides produced using physical prototypes and 3D printing that are applied for positioning of resection blocks. Materials and methods. The authors analyzed the treatment outcomes of 4 patients during the period from 2015 to 2016 who underwent total knee arthroplasty for posttraumatic gonarthrosis of III-IV stage with the use of patient specific guides for resection blocks positioning. The mean age of patients was 59±12 years. Initially, all patients reported marked limitation of movement in the knee joint. The average flexion prior to surgery was 53.3±35.1°. According to FLFS roentgenography all patients had a varus deformity of the lower limb with an average value of 15.0±12.3°.Results. In all cases the axis of the lower limb was normalized postoperatively. The average KOOS score for “pain” was 85.2±14.0, for “daily physical activity” — 74.5±14.8, for “symptoms and stiffness” — 69.0±11.0, for “quality of life” — 62.5±12.5 points. Average knee ROM after arthroplasty: flexion 113.3±5.787° and full extension. Such outcomes can be considered as excellent considering preoperative marked knee movement limitations in all patients.Conclusion. Preoperative planning using the technology of producing patient specific guides and prototyping on physical tibia and femur models allowed to restore normal axis of the lower limb. The authors observed a significant improvement in joint function and a pain syndrome reduction in all patients. In authors’ opinion patient specific precision guides can be used in the following cases: inflammatory process or deformation of the femur in patient’s history; when the use of intramedullary guides is difficult and does not allow positioning of the prosthesis components with sufficient accuracy or is associated with an increased risk of a purulent-inflammatory process; ipsilateral hip joint prosthesis when it is desirable to avoid opening the medullary canal; substantial bone defects or massive osteophytes of the posterior portion of femoral condyles that impede correct rotation of the femoral component; severe movement limitations in the knee joint, when it is technically impossible to perform TKA using computer navigation and the use of a standard set of instruments poses significant technical difficulties.