Manaster B J
Department of Radiology, University of Utah Medical Center, Salt Lake City 84132, USA.
Radiographics. 1996 May;16(3):645-60. doi: 10.1148/radiographics.16.3.8897629.
Expected appearances of total hip arthroplasty vary according to type of implant, its method of fixation (cemented, porous coating for bone ingrowth, press fit), and whether it is a revision. Cemented arthroplastic components normally may show 1-2-mm-wide radiolucent zones at cement interfaces. Definite loosening is diagnosed when progressive widening of the radiolucent zone, migration of a cemented component, or change in alignment is seen. In cementless arthroplasty, normal findings include calcar resorption, radiolucent zones up to 2 mm in width, cortical thickening, periosteal reaction, endosteal sclerosis, and even subsidence of the femoral component that stabilizes at less than 1 cm. The most reliable radiographic signs of loosening in cementless arthroplasty are progressive subsidence, migration, or tilt of the component. Because subsidence or change in alignment may be very subtle, serial radiography and measurement are often required for diagnosis. Other signs that indicate loosening include bead shedding (in porous-coated prostheses), extensive cortical hypertrophy, endosteal bone bridging at the stem tip, endosteal scalloping, and a radiolucent zone wider than 2 mm. In revision arthroplasty, wide radiolucent zones and subsidence are common. The diagnosis of revision failure is based on progressive widening of the radiolucent zones and change in component position after 12 months.
全髋关节置换术的预期表现因植入物类型、固定方法（骨水泥固定、用于骨长入的多孔涂层、压配）以及是否为翻修手术而异。骨水泥关节成形术组件通常在骨水泥界面处可显示1-2毫米宽的透亮区。当透亮区逐渐增宽、骨水泥固定组件移位或对线改变时，可诊断为明确的松动。在非骨水泥关节成形术中，正常表现包括股骨距吸收、宽度达2毫米的透亮区、皮质增厚、骨膜反应、骨内膜硬化，甚至股骨组件下沉，下沉稳定在1厘米以内。非骨水泥关节成形术中最可靠的松动影像学征象是组件的逐渐下沉、移位或倾斜。由于下沉或对线改变可能非常细微，诊断通常需要进行系列X线检查和测量。其他表明松动的征象包括珠粒脱落（在多孔涂层假体中）、广泛的皮质肥大、柄尖处的骨内膜骨桥接、骨内膜扇贝样改变以及宽度超过2毫米的透亮区。在翻修关节成形术中，宽透亮区和下沉很常见。翻修失败的诊断基于透亮区逐渐增宽以及术后12个月组件位置的改变。
