MRI findings of common complications following hip arthroplasty / 中华放射学杂志

ABSTRACT

Objective To discuss the MRI findings of common complications following hip arthroplasty and their association with operative and pathological findings to improve the early diagnosis and etiological differential diagnosis for common complications following hip arthroplasty. Methods Forty-six patients with hip arthroplasty complication were included in this study. We observed prosthesis location, signal changes between prosthesis and bone, and periprosthesis signal changes, signal changes of articular capsule, adjacent soft tissue and bone on MR images. Diagnostic value of MRI in detecting hip arthroplasty complication was evaluated with operative and pathological findings as reference standard. Results Complications following hip arthroplasty included aseptic loosening (n=26), osteolysis (n=12), infection (n=12), heterotopic ossification (n=4), pseudoneoplasm (n=4) and periarthroplasty fracture (n=1). The MRI finding suggestive of aseptic loosening in 24 cases was a smooth intermediate signal intensity layer along the interface. Osteolysis is seen as soft tissue signal intensity material replacing normal high signal intensity fatty marrow in 12 cases. Bone marrow edema, bone destruction, fluid collection, estracapsular collections, periprosthetic muscle edema, and sinus were predictors of infection. On MRI, mature heterotopic ossification had the appearance of cancellous bone in 5 cases. Pseudoneoplasm represents fluid signal intensity with intermediate signal intensity pseudocapsule in 5 cases. Periprosthetic fracture included hypointesense fracture lines, periosteal reaction, and periprosthetic muscle edema in one patient. Conclusion MRI is useful in detecting osseous and soft-tissue abnormalities in patients with hip implants.