Department of Orthopaedic Surgery, Charing Cross Hospital (Imperial College Healthcare NHS Trust and Imperial College London), Fulham Palace Road, London W6 8RF, United Kingdom.
J Bone Joint Surg Am. 2012 Feb 15;94(4):317-25. doi: 10.2106/JBJS.J.01508.
Many papers have been published recently on the subject of pseudotumors surrounding metal-on-metal hip resurfacing and replacement prostheses. These pseudotumors are sterile, inflammatory lesions within the periprosthetic tissues and have been variously termed masses, cysts, bursae, collections, or aseptic lymphocyte-dominated vasculitis-associated lesions (ALVAL). The prevalence of pseudotumors in patients with a well-functioning metal-on-metal hip prosthesis is not well known. The purpose of this study was to quantify the prevalence of pseudotumors adjacent to well-functioning and painful metal-on-metal hip prostheses, to characterize these lesions with use of magnetic resonance imaging, and to assess the relationship between their presence and acetabular cup position with use of three-dimensional computed tomography.
We performed a case-control study to compare the magnetic resonance imaging findings of patients with a well-functioning unilateral metal-on-metal hip prosthesis and patients with a painful prosthesis (defined by either revision arthroplasty performed because of unexplained pain or an Oxford hip score of <30 of 48 possible points). Thirty patients with a painful hip prosthesis and twenty-eight controls with a well-functioning prosthesis were recruited consecutively. All patients also underwent computed tomography to assess the position of the acetabular component.
Thirty-four patients were diagnosed with a pseudotumor. However, the prevalence of pseudotumors in patients with a painful hip (seventeen of thirty, 57%) was not significantly different from the prevalence in the control group (seventeen of twenty-eight, 61%). No objective differences in pseudotumor characteristics between the groups were identified. No clear association between the presence of a pseudotumor and acetabular component position was identified. The Oxford hip score in the group with a painful hip (mean, 20.2; 95% confidence interval [CI], 12.7 to 45.8) was poorer than that in the control group (mean, 41.2; 95% CI, 18.5 to 45.8; p ≤ 0.0001).
A periprosthetic cystic pseudotumor was diagnosed commonly (in thirty-four [59%] of the entire study cohort) with use of metal artifact reduction sequence (MARS) magnetic resonance imaging in this series of patients with a metal-on-metal hip prosthesis. The prevalence of pseudotumors was similar in patients with a well-functioning hip prosthesis and patients with a painful hip. Pseudotumors were also diagnosed commonly in patients with a well-positioned acetabular component. Although magnetic resonance imaging is useful for surgical planning, the presence of a cystic pseudotumor may not necessarily indicate the need for revision arthroplasty. Further correlation of clinical and imaging data is needed to determine the natural history of pseudotumors to guide clinical practice.
最近有许多关于金属对金属髋关节表面置换和置换假体周围假瘤的论文发表。这些假瘤是假体周围组织内无菌性炎症性病变，曾被不同地称为肿块、囊肿、滑囊、积液或无菌性淋巴细胞为主的血管炎相关病变（ALVAL）。功能良好的金属对金属髋关节假体患者中假瘤的患病率尚不清楚。本研究的目的是定量评估功能良好和疼痛的金属对金属髋关节假体周围假瘤的患病率，使用磁共振成像（MRI）对这些病变进行特征描述，并使用三维计算机断层扫描（CT）评估其存在与髋臼杯位置之间的关系。
我们进行了一项病例对照研究，比较了功能良好的单侧金属对金属髋关节假体患者（因不明原因疼痛而行翻修关节成形术或 Oxford 髋关节评分＜48 分中的 30 分的患者定义为疼痛）和疼痛假体患者的 MRI 结果。连续招募了 30 例疼痛性髋关节假体患者和 28 例功能良好的假体对照患者。所有患者还接受了 CT 检查以评估髋臼部件的位置。
34 例患者被诊断为假瘤。然而，疼痛髋关节患者（30 例中的 17 例，57%）中假瘤的患病率与对照组（28 例中的 17 例，61%）无显著差异。两组之间未发现假瘤特征存在客观差异。未发现假瘤的存在与髋臼部件位置之间存在明确的关联。疼痛髋关节组的 Oxford 髋关节评分（平均 20.2；95%置信区间 [CI]，12.7 至 45.8）低于对照组（平均 41.2；95%CI，18.5 至 45.8；p ≤ 0.0001）。
在本金属对金属髋关节假体系列患者中，使用金属伪影减少序列（MARS）MRI 通常可诊断出（整个研究队列中 34 例[59%]）假体周围囊性假瘤。功能良好的髋关节假体患者和疼痛髋关节患者的假瘤患病率相似。髋臼部件位置良好的患者也常被诊断出假瘤。尽管 MRI 对手术计划很有用，但囊性假瘤的存在不一定表明需要翻修关节成形术。需要进一步将临床和影像学数据进行关联，以确定假瘤的自然病史，从而为临床实践提供指导。
