髋关节置换术后常见并发症的MRI表现

MRI findings of common complications following hip arthroplasty

目的：探讨髋关节置换术后常见并发症的MRI表现及其与手术及病理的联系，以期提高对髋关节置换术后并发症的早期诊断及病因鉴别诊断能力。方法回顾性分析46例髋关节置换术后出现并发症的患者，观察MRI图像上假体的位置、假体与骨交界处的信号改变、假体周围骨质信号改变、关节囊及关节周围软组织信号改变，以及是否出现异常软组织信号或骨质信号，并通过与手术及病理对照，评价MRI对髋关节置换术后常见并发症的诊断价值。结果术后诊断的并发症包括无菌性松动（26例）、骨溶解（12例）、感染（12例）、异位骨化（4例）、假瘤（4例）及假体周围骨折（1例）。其中24例无菌性松动患者MRI表现为假体周围光滑的线样中等信号；11例骨溶解患者MRI正常骨质信号为软组织信号取代；骨质水肿、骨质破坏、关节积液、软组织水肿、窦道等提示感染；MRI显示5例软组织内出现骨质信号沉积，提示异位骨化；5例MRI表现为与关节囊相通的类圆形囊实性肿块，提示假瘤形成；1例骨折患者MRI可见皮质断裂，伴骨膜反应及邻近软组织水肿。结论 MRI可以为髋关节置换术后并发症提供良好的诊断价值。

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.