3D MODELLING AND PRINTING IN PRIMARY AND REVISION ARTHROPLASTY

Abstract

Introduction. Acetabular arthroplasty in patients with the abnormal pelvic bone anatomy is a challenging task. In recent years the method of 3D modelling and printing of custom acetabular components is widely used at acetabular arthroplasty in patients with marked bone defects.Purpose of study: to evaluate the accuracy, convenience of the positioning and efficacy of the primary stabilization of custom acetabular components in patients with bone defects at primary and revision hip arthroplasty. Patients and methods. Eighteen surgical interventions using 3D modelling and printing, i.e. 12 for hip instability, 6 — for posttraumatic coxarthrosis were performed. The study included 9 women and 9 men with mean age 60.9±15.8 years. By Paprosky classification in 2 cases the defects corresponded to Type I, in1 case — Type IIA, in 4 cases — Type IIB (posttraumatic coxarthrosis), in 2 cases — Type IIIA, in 10 — Type IIIB out of them 2 cases with pelvic bone separation. Custom components were produced using the method of direct metal laser sintering (DMLS). The whole technologic process took from 4 to 8 weeks and was conducted jointly with the engineers. Results. Exact match of implant form and the defect was observed in 89.9% of cases. In 2 patients with pelvic bone separation additional correction of bone structures was required when placing the acetabular component. In radiograph from 2 to 8 months after surgery the constructions were stable.Conclusion. 3D technology for the custom-made acetabular components is a method of resolving the problem in patients with marked acetabular defects. It enables to plan the surgery, simplifies the choice for screws positioning avoiding their interference. The design features of the implant are three rigid flanges with screw holes that create additional contact with intact parts of the ischial, iliac and pubic bones. Screw fixation ensures initial rigid stability until the biological fixation is achieved.