Computed tomography and radiography in the diagnosis and followup of periprosthetic osteolysis after total ankle arthroplasty

摘要

Periprosthetic osteolysis is one of the most significant long-term complications after total ankle arthroplasty (TAA). The exact pathogenesis of osteolysis is unclear. It is a biological process involving many factors, mechanical factors probably, as well. Osteolysis is a progressive phenomenon which may lead to component failure.Traditionally, patients with an ankle prosthesis are monitored only by radiography. In this study the incidence of periprosthetic osteolysis around TAAs was evaluated by radiographs and computed tomography (CT). These two methods were also compared for detection of osteolytic lesions around the prosthesis components. Acquisition parameters and positioning were studied for optimal imaging of total ankle prostheses on CT. TAAs were monitored by CT after bone grafting of osteolytic lesions and also the patients’ symptoms after bone grafting were evaluated.Early-onset TAA-associated periprosthetic osteolysis was common after arthroplasty. CT showed more and larger periprosthetic osteolytic lesions than radiographs around TAAs, especially around the talar component. CT proved to be a reliable imaging modality for studying periprosthetic lesions adjacent to ankle prostheses. Image artifacts on CT caused by the metal prosthesis components were small when acquisition parameters and, especially, orientation of the prosthesis in relation to the x-ray tube were optimal. Radiologically, progression of osteolysis continued in spite of bone grafting of periprosthetic osteolytic lesions around TAAs.We recommend adding ankle CT to the postoperative follow-up for patients with suspected or known periprosthetic osteolytic lesions on radiographs. CT is also useful when evaluating periprosthetic bone stock before a reoperation.