Bildgebung bei Hüftgelenkendoprothesen

The hip joint is the largest joint in the human body and consequently, its evaluation by diagnostic imaging is highly important. This includes imaging of hip joint arthroplasty, which is used to avoid joint immobility following a wide spectrum of diseases, such as end-stage degenerative disease, avascular necrosis of the femoral head or post-traumatic fractures. Conventional radiography is still the standard imaging modality for the evaluation of hip arthroplasty both directly following surgery and for periodical follow-up. In the majority of cases conventional radiography enables adequate assessment of early and late complications that can arise following hip arthroplasty, such as loosening, prosthetic or periprosthetic fracture, luxation, infection and soft tissue calcification. If the diagnosis cannot be established by means of radiography, advanced imaging methods such as computed tomography (CT) and magnetic resonance imaging (MRI), with or without injection of contrast media, may provide additional information. This is particularly true for the depiction of inflammatory processes. Regardless of the imaging modality used patients’ clinical symptoms must also be taken into account in order to establish the correct diagnosis.     

Imaging of hip arthroplasty

Radiography is the mainstay of the imaging evaluation of the prosthetic hip, but arthrography, aspiration, scintigraphy, sonography, computed tomography, and magnetic resonance imaging all have roles in the evaluation of the painful prosthesis. This article reviews the appearance of normal hip arthroplasty as well as the appearances of potential complications.     

CT and MRI of hip arthroplasty

Plain films are the initial imaging method of choice for evaluation of hip arthroplasty. Recent advances in technology and imaging techniques have largely overcome the problems of beam hardening in computed tomography (CT) and magnetic susceptibility artefact in magnetic resonance imaging (MRI). CT and MRI have now become useful imaging techniques in the assessment of hip arthroplasty.     

The role of ultrasound in the assessment of post-operative complications following hip arthroplasty

Hip arthroplasty is one of the most commonly performed orthopedic procedures. Clinicians can be faced with the diagnostic dilemma of the patient presenting with a painful hip following arthroplasty and satisfactory post-operative radiographs. Identifying the cause of symptoms can be challenging and ultrasound is increasingly being utilized in the evaluation of potential soft tissue complications following hip surgery. In this article, we describe the common surgical approaches used during hip arthroplasty as this can influence the nature and location of subsequent complications. A review of the literature is presented along with the imaging appearances frequently encountered when imaging this patient population.     

Diagnostic imaging in hip prostheses

Hip arthroplasty has become a common and still increasing procedure for the treatment of osteoarthritis, advanced head necrosis, post-inflammatory arthritis or rheumatoid arthritis. Radiography is the most important imaging modality for monitoring the normal, asymptomatic hip arthroplasty. Radiographs are obtained at the end of a surgical treatment, to exclude complications like fracture or component misplacement. In the follow-up radiographs are used for the diagnosis of loosening and infection of the hip arthroplasty as well as soft tissue ossification. Together with the history and clinical information, the analysis of morphological findings allows to find the grade of loosening. MRI has been advocated in the diagnosis of infection, in particular in the localisation of soft tissue involvement. Imaging, especially by radiographs, is used for the evaluation of the normal and complicated follow-up of hip arthroplasty.     

Imaging Evaluation of Complications of Hip Arthroplasty: Review of Current Concepts and Imaging Findings

Total hip arthroplasty has evolved along with improvements in component materials and design. The radiologist must accurately diagnose associated complications with imaging methods and stay informed about newer complications associated with innovations in surgical technique, prosthetic design, and novel materials. This pictorial essay presents clinical and imaging correlation of modern hip arthroplasty complications, with an emphasis on the most common complications of instability, aseptic loosening, and infection as well as those complications associated with contemporary metal-on-metal arthroplasty.     

The hip abductors at MR imaging

Imaging of the hip abductors plays an increasing role for the evaluation of greater trochanteric pain in patients with and without total hip arthroplasty. This review article addresses the anatomy of the hip abductors and their intervening bursae. It highlights different possible imaging appearances such as tendinopathy or partial and full thickness tears of the gluteal tendons. Muscle atrophy or fatty degeneration of the gluteal muscles is an important reason for limping. Inflammatory diseases such as hydroxyapatite crystal deposition disease or spondylarthritis have to be considered. Knowledge of these different entities is important to achieve optimal treatment and outcomes.     

Sonography of joint replacements

Sonography is ideally suited for the evaluation of joint effusion, synovial thickening, and the ligaments and tendons surrounding a joint replacement because it is not hampered by the dephasing artifact of magnetic resonance imaging or the beam-hardening streak artifact of computed tomographic scanning. Although it is unable to visualize deep within the joint or into the bone surrounding an arthroplasty component, its dynamic capability allows evaluation of joint kinematics and its real-time capability can guide interventional procedures. This article reviews the sonographic appearances of complications of arthroplasty of the shoulder, hip, and knee.     

Pulmonary embolism after hip or knee replacement: postoperative changes on pulmonary scintigrams in asymptomatic patients

Serial pulmonary imaging has proved to be effective in the evaluation of patients undergoing total joint arthroplasty. A clinical dilemma arises in asymptomatic patients whose postoperative pulmonary images differ from the preoperative images. The authors prospectively evaluated 403 patients with serial imaging to determine the significance of changed postoperative images in asymptomatic patients undergoing total hip or knee arthroplasty. Twenty-two (5.5%) patients had significant changes on postoperative images. Seventeen were asymptomatic; all but one underwent pulmonary angiography. Documented pulmonary emboli were demonstrated in 100% of patients whose postoperative images changed to indicate a high probability of pulmonary embolism, 71% whose images changed to a moderate probability, and 0% whose images changed to indeterminate probability. Overall, pulmonary emboli occurred in 76% of all asymptomatic patients with significantly change postoperative images. Asymptomatic pulmonary embolism is a significant occurrence after total hip or knee repair, and a changed lung scan with appropriate clinical evaluation is an accurate indicator of pulmonary emboli in asymptomatic postarthroplasty patients.     

Magnetic resonance imaging of the postoperative hip

Magnetic resonance imaging (MRI) is ideally suited to imaging the patient with painful hip arthroplasty due to its superior soft tissue contrast, multiplanar capabilities, and lack of ionizing radiation. MRI is the most accurate imaging modality in the assessment of periprosthetic osteolysis and wear-induced synovitis, and can also assess regional tendons and neurovascular structures. This article discusses the technical aspects of MRI around metallic implants as well as the appearance of potential complications following hip arthroplasty, including osteolysis, wear-induced synovitis, infection, hemarthrosis, fracture, loosening, component displacement, heterotopic ossification, tendinopathy, and neurovascular impingement. The specific complication of metal hypersensitivity following metal-on-metal prostheses is reviewed.     

Bone imaging after total replacement arthroplasty of the hip joint. A follow-up with different radiopharmaceuticals.

Bone imaging was done in patients after total replacement arthroplasty of the hip joint every 3rd month using 99mTc-HEDP and 18F. Uptake ratios were estimated over cup/normal hip and femur prosthesis/normal thigh. Ratios decline rapidly and reach a stable level 6-9 months, postoperatively. Eight cases of late infection were predicted correctly 1-3 months before any radiologic evidence was present. In four cases there had been false-positive results with 99mTc-HEDP while 18F gave always correct information except in cases of soft tissue inflammation. Here both 99mTc-HEDP and 18F ratios were elevated. The early diagnosis of late complications after replacement arthroplasty seems to be possible. The clinical significance, however, is low: only one out of eight patients with manifest infection is still on conservative treatment. Bone imaging should be done to exclude late infection as a cause of pain after total replacement arthroplasty of the hip joint only.     

CT und MRT der Hüftprothese

Metal-induced artifacts impair image quality of computed tomography (CT) and magnetic resonance imaging (MRI) in patients with hip prostheses. Due to new developments in metal artifact reduction both methods can now be used for evaluation of a painful hip prosthesis. Iterative reconstruction algorithms and dual-energy scans are among the newer CT techniques for artifact reduction, while slice-encoding for metal artifact correction (SEMAC) and multi-acquisition variable-resonance image combination (MAVRIC) have introduced substantial improvements for MRI. Loosening of the hip prosthesis, osteolysis from small wear particles and pseudotumors in metal-on-metal prostheses are specific pathologies in patients with total hip arthroplasty. Other causes of painful hip prostheses are infections, fractures, tendinopathies, tendon ruptures, muscle and nerve alterations and heterotopic ossifications.     

Imaging of the postoperative hip

A basic understanding of the surgical approach, technique, and potential complications in addition to the types of hardware used is essential in interpreting postoperative imaging of the hip. This article reviews the various surgical approaches to the hip and hardware components in total hip arthroplasty and hip preservation surgery and the potential complications that may arise. The various surgical treatments in the management of acetabular dysplasia and avascular necrosis and the imaging appearances of these on different imaging modalities are also discussed.     

Imaging of total hip arthroplasty: normal and pathological imaging features, role of ultrasound, CT and MRI

Total hip arthroplasty is a frequent procedure with functional outcome that generally is excellent and lasting. Routine imaging follow-up is necessary to detect complications such as loosening and wearing out. Additional imaging with scintigraphy, CT, ultrasound or MRI may be necessary.     

Profunda femoris pseudoaneurysm following Birmingham hip resurfacing: an important differential diagnosis for a periarticular cystic mass

Vascular injury following hip resurfacing arthroplasty is rare: we present a case of profunda femoris pseudoaneurysm complicating hip resurfacing arthroplasty performed via an anterolateral approach. Over recent years, it has been recognized that an adverse reaction to metal debris from metal-on-metal arthroplasties can also result in the development of cystic masses around the hip. This case highlights a potential rare differential diagnosis that needs to be considered when imaging cystic mass lesions around the postoperative hip. Imaging can provide a definitive diagnosis if this entity is considered and its appearances recognized, resulting in appropriate management of this potentially limb- and life-threatening complication.     

保留股骨颈型人工全髋关节置换术92例

目的探讨保留股骨颈型人工全髋关节置换术的疗效。方法 2000年9月—2010年9月,我科开展保留股骨颈型人工全髋关节置换术92例(104髋),其中男50例,女42例,年龄20～65岁。结果本组经过0.5～10年随访,92例人工全髋关节置换术后,髋关节功能良好。影像学检查显示人工髋关节位置良好,假体无松动和下沉。结论保留股骨颈型人工全髋关节置换符合股骨近端生理顺应性,能防止股骨近端骨质疏松引起假体松动和下沉。     

How to image metal-on-metal prostheses and their complications

OBJECTIVE: Metal-on-metal arthroplasty is a durable alternative to traditional metal-on-polyethylene total hip replacement for young active patients. Although midterm results for resurfacing arthroplasty are reasonable, there is increasing recognition of the problem of metal-induced periprosthetic reactive masses. CONCLUSION: Imaging plays an important role in the investigation of symptomatic metal-on-metal arthroplasty. Radiographs will identify fracture and loosening, but cross-sectional imaging is required to diagnose and stage periprosthetic reactive masses.     

Persistent non-specific FDG uptake on PET imaging following hip arthroplasty

Hip arthroplasty is a common surgical procedure, but the diagnosis of infection associated with hip arthroplasty remains challenging. Fluorine-18 fluoro-2-deoxy-D-glucose positron emission tomography (FDG-PET) has been shown to be a promising imaging modality in settings where infection is suspected. However, inflammatory reaction to surgery can result in increased FDG uptake at various anatomic locations, which may erroneously be interpreted as sites of infection. The purpose of this study was to assess the patterns and time course of FDG accumulation following total hip replacement over an extended period of time. Firstly, in a prospective study nine patients with total hip replacement were investigated to determine the patterns of FDG uptake over time. Three FDG-PET scans were performed in each patient at about 3, 6 and 12 months post arthroplasty. Secondly, in a retrospective analysis, the medical and surgical history and FDG-PET imaging results of 710 patients who had undergone whole-body scans for the evaluation of possible malignant disorders were reviewed. The history of arthroplasty and FDG-PET findings in the hip region were reviewed for this study. Patients with symptomatic arthroplasties or related complaints during FDG-PET scanning were excluded from the analysis. During the entire study period, all nine patients enrolled in the prospective study were demonstrated to have increased FDG uptake around the femoral head or neck portion of the prosthesis that extended to the soft tissues surrounding the femur. Among the patients reviewed in the retrospective study, 18 patients with a history of 21 hip arthroplasties who were asymptomatic at the time of FDG-PET scan met the criteria for inclusion. The time interval between the hip arthroplasty and the FDG-PET study ranged from 3 months to 288 months (mean+/-SD: 80.4+/-86.2 months). In 81% (17 of 21) of these prostheses, increased FDG uptake could be noted around the femoral head or neck portion of the prosthesis. The average time interval between arthroplasty and FDG-PET scan in these patients was 71.3 months. In only four prostheses (19%, 4 of 21) was no abnormally increased FDG uptake seen around the prostheses or adjacent sites. The average time interval in these patients was 114.8 months. It is concluded that following hip arthroplasty, non-specifically increased FDG uptake around the head or neck of the prosthesis persists for many years, even in patients without any complications. Therefore, to minimize the number of false-positive results for infection with PET studies obtained to evaluate a painful hip prosthesis, caution should be exercised when interpreting FDG uptake around the head or neck portion of the prosthesis.     

Radiology of the resurfaced hip

Hip resurfacing arthroplasty is an increasingly common procedure for osteoarthritis. Conventional radiographs are used routinely for follow-up assessment, however they only provide limited information on the radiological outcome. Various complications have been reported in the scientific literature although not all are fully understood. In an effort to investigate problematic or failing hip resurfacings, various radiological methods have been utilized. These methods can be used to help make a diagnosis and guide management. This paper aims to review and illustrate the radiographic findings in the form of radiography, computerized tomography (CT), magnetic resonance imaging (MRI), and ultrasound of both normal and abnormal findings in hip resurfacing arthroplasty. However, imaging around a metal prosthesis with CT and MRI is particularly challenging and therefore the potential techniques used to overcome this are discussed.     

Bone imaging after total replacement arthroplasty of the hip joint

Bone imaging was done in patients after total replacement arthroplasty of the hip joint every 3rd month using ^99mTc-HEDP and ¹⁸F. Uptake ratios were estimated over cup/normal hip and femur prosthesis/normal thigh.Ratios decline rapidly and reach a stable level 6–9 months, postoperatively. Eight cases of late infection were predicted correctly 1–3 months before any radiologic evidence was present. In four cases there had been false-positive results with ^99mTc-HEDP while ¹⁸F gave always correct information except in cases of soft tissue inflammation. Here both ^99mTc-HEDP and ¹⁸F ratios were elevated.The early diagnosis of late complications after replacement arthroplasty seems to be possible. The clinical significance, however, is low: only one out of eight patients with manifest infection is still on conservative treatment. Bone imaging should be done to exclude late infection as a cause of pain after total replacement arthroplasty of the hip joint only.Presented in part at the 22nd meeting of the Society of Nuclear Medicine, Philadelphia, Pa, June 17, 1975