Feasibility of Magnetic Resonance Imaging Monitoring of Postoperative Total Knee Arthroplasty without Metal Artifacts: A Preliminary Study of a Novel Implant Model

Background. Although magnetic resonance imaging (MRI) can provide superior detailed images of tissues without ionizing radiation, the imaging evaluation of total knee arthroplasty (TKA) complications and posttherapy changes can be limited because of abundant artifacts on MRI scans due to metallic implants and endoprosthesis in limb salvage and fracture fixation. This study aimed to develop a novel model of TKA using a polyetheretherketone- (PEEK-) on-highly cross-linked polyethylene (HXLPE) implant and to investigate its feasibility for MRI monitoring of peri-implant bone formation, the healing process, signs of infection, and tumor recurrence after TKA. Methods. Three skeletally mature goats underwent TKA with the PEEK-on-HXLPE implant. Radiographic and MRI examinations were performed at 4 weeks postoperatively. Images were analyzed for the existence of artifact interruption and postoperative changes in the bone and peripheral soft tissue. Results. The results showed that PEEK and HXLPE were invisible, but the metal wires were clearly visualized on X-rays. On MRI scans, PEEK and HXLPE materials showed a low signal intensity, fine metal wires generated no obvious metal artifacts on MRI scans, and the marrow and soft tissue showed a continuous signal intensity without artifact interruption. Conclusions. This preliminary study introduced a novel model using PEEK-on-HXLPE knee implant for in vivo MRI monitoring of the region around the implant without metal artifacts. This novel model may be used to apply MRI to observe bone formation and the healing process around the prosthesis and the signs of infection and tumor recurrence after TKA. This model may be used to improve the diagnostic accuracy of postoperative complications of TKA clinically.

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