Clinical magnetic resonance imaging of arthroplasty at 1.5 T

Abstract

Magnetic resonance imaging (MRI) has historically been avoided for the routine clinical evaluation of metal implants at many clinical centers due to the presence of artifact that creates in-plane and through-plane distortions and signal intensity voids in generated images. However, when the image acquisition parameters are appropriately modified and advanced multi-spectral pulse sequences are used, high-quality diagnostic images can be generated and may be used for diagnosing patients with suspected periprosthetic pathology. MRI provides superior soft-tissue contrast and excellent sensitivity for mobile water and is, therefore, a valuable tool in the evaluation of these patients, given the increasing prevalence of arthroplasty within the general population. Knowledge of expected normal postoperative appearance in patients with total hip arthroplasty, total knee arthroplasty, and total shoulder arthroplasty facilitates the detection of abnormal findings in this population, as does familiarity with common pathologic conditions encountered in the periprosthetic region. This review article will provide background information regarding the presence of image artifacts, methods to reduce the artifacts, and application of MRI at 1.5 T for evaluating common complications in subjects with total knee arthroplasty, total hip arthroplasty, and total shoulder arthroplasty.

Keywords: adverse soft tissue reaction; arthroplasty; arthroplasty-hip; arthroplasty-knee; diagnostic imaging; implant fixation; implant wear.

Figure 1.

AP radiograph (A) in a 73 year-old man status post total hip arthroplasty demonstrates eccentric position of the femoral head within the acetabular component, consistent with polyethylene liner wear, which was reflected in the report; however, the image was read as negative for fracture. Coronal MAVRIC IR image (B) demonstrates bulk edema pattern (arrow head) and FSE PD (C) image demonstrates region of bulky osteolysis (*) preferentially affecting the greater trochanter, with superimposed subtle nondisplaced fracture line (white arrowheads).

Figure 2.

Sagittal MAVRIC IR (A) and sagittal (B), coronal (C), and axial (D) FSE PD images in a 76 year-old woman presenting with several years of pain following total knee arthroplasty demonstrates extensive fibrous membrane formation circumferentially investing the tibial component with angulation, consistent with component loosening.

Figure 3.

AP radiograph of the pelvis (A) in a 65 year-old woman status post bilateral total hip arthroplasty demonstrates asymmetric position of the femoral heads within the acetabular components bilaterally, consistent with polyethylene liner wear, with areas of bulky osteolysis (black arrowheads) along the proximal femoral components. Coronal MAVRIC PD (B) image demonstrates synovitis with isointense debris (white arrowheads) consistent with polymeric wear, with prominent osteolysis (black arrowheads) along both femoral components proximally. Isotropic MAVRIC PD (C) demonstrates ability to perform multiplanar reformats due to isotropic acquisition, allowing enhanced assessment at various obliquities.

Figure 4.

Sagittal FSE PD (A) and MAVRIC IR (B) images in a 73 year-old male presenting with subjective instability following total knee arthroplasty demonstrate fracture through polyethylene post (black arrowheads) with displacement of the fractured portion of the post posteriorly (white arrowheads).

Figure 5.

Coronal (A) and axial (B) FSE PD images in a 64 year-old woman following metal on metal total hip arthroplasty placed 1.5 years prior demonstrates synovitis with prominent synovial hyperintensity and thickening (white arrowheads), consistent with aggressive ALTR/ALVAL.

Figure 6.

Coronal MAVRIC PD (A) in a 66 year-old woman following metal on metal total hip arthroplasty placed 11 years prior demonstrates synovial expansion (white arrow head), and posteriorly located coronal IR (B) and coronal FSE PD (C) images display prominent hypointense synovial staining (B, black arrow head) and the presence of metallosis (C, black arrow heads) in the trochanteric bursa.

Figure 7.

Coronal time-resolved imaging of contrast kinetics (TRICKS) composite image (A), axial PD FSE (B), and axial reformatted single phase TRICKS image (C) in a 66 year-old man presenting with thigh swelling following total hip arthroplasty demonstrate large multilocular fluid collection (black arrowheads) with small rounded enhancing focus (white arrowheads) consistent with pseudoaneurysm along the anterior margin of the fluid collection.

Figure 8.

Sagittal MAVRIC IR (A) and FSE PD (B) images in a 66 year-old woman presenting with stiffness following total knee arthroplasty demonstrates extensive scar (white arrowheads) infiltrating the synovial recesses, consistent arthrofibrosis.

Figure 9.

Sagittal MAVRIC IR (A) and PD (B) images in a 70 year-old woman presenting with mechanical symptoms while walking status post total knee arthroplasty demonstrates focal fibrous scar nodule (white arrowheads) along the superior aspect of the patellofemoral articulation, consistent with a patellar clunk lesion.

Figure 10.

Component angle measurement in total knee arthroplasty. The angulation of the femoral component may be determined between lines defining the femoral component (A and B, dashed line to define the anterior margin of the posterior condylar backing) and the surgical transepicondylar axis, the most prominent point of the lateral epicondyle with the medial epicondylar sulcus (A, solid line), or between the femoral component and between the clinical transepicondylar axis, the line connecting the most prominent points on the lateral and medial epicondyles (B, solid line). A line perpendicular to the femoral component (dotted) is displayed in A and B. Measuring the angle between the tibial component and tibial axis is performed by first determining the anteroposterior axis of the tibial component by drawing a line from the midpoint of posterior recess of the tray through the center of the top the tibial stem to the anterior midpoint of the tray (C, dashed line). Next, this line is projected to the center of the tibial stem at the level of the tibial tubercle (D, dashed line), from which a line to the tibial plateau is drawn (D, solid line). The tibial component angulation is determined as the acute angle between these lines (D, curved arrow). The angulation between the femoral and tibial components is considered as the acute angle between the dotted line (projected from A) and dashed line displayed in Panel C.

Figure 11.

Coronal MAVRIC IR (A) and PD (B) images in a 71 year-old woman presenting with pain following reverse total shoulder arthroplasty demonstrates stress fracture of the acromion (white arrowheads), appearing as a focal area of linear hypointensity with adjacent marrow and soft tissue edema.

Figure 12.

Sagittal MAVRIC IR (A) image in a 72 year-old man presenting with pain following total knee arthroplasty demonstrates subcutaneous fluid collection (white arrowhead) which communicates with both the skin surface and joint space. Axial PD FSE image (B) demonstrates hyperintense thickened synovium with a lamellated appearance (black arrowheads), characteristic of active infection.