Department of Orthopaedic Surgery, Rush University Medical Center, 1611 West Harrison Street, Suite 300, Chicago, IL 60612, USA.
J Bone Joint Surg Am. 2013 May 15;95(10):865-72. doi: 10.2106/JBJS.L.01042.
Femoral stems with dual-taper modularity were introduced to allow additional options for hip-center restoration independent of femoral fixation in total hip arthroplasty. Despite the increasing availability and use of these femoral stems, concerns exist about potential complications arising from the modular neck-body junction.
This was a multicenter retrospective case series of twelve hips (eleven patients) with adverse local tissue reactions secondary to corrosion at the modular neck-body junction. The cohort included eight women and three men who together had an average age of 60.1 years (range, forty-three to seventy-seven years); all hips were implanted with a titanium-alloy stem and cobalt-chromium-alloy neck. Patients presented with new-onset and increasing pain at a mean of 7.9 months (range, five to thirteen months) following total hip arthroplasty. After serum metal-ion studies and metal artifact reduction sequence (MARS) magnetic resonance imaging (MRI) revealed abnormal results, the patients underwent hip revision at a mean of 15.2 months (range, ten to twenty-three months). Tissue specimens were examined by a single histopathologist, and the retrieved implants were studied with use of light and scanning electron microscopy.
Serum metal levels demonstrated greater elevation of cobalt (mean, 6.0 ng/mL) than chromium (mean, 0.6 ng/mL) or titanium (mean, 3.4 ng/mL). MRI with use of MARS demonstrated adverse tissue reactions in eight of nine patients in which it was performed. All hips showed large soft-tissue masses and surrounding tissue damage with visible corrosion at the modular femoral neck-body junction. Available histology demonstrated large areas of tissue necrosis in seven of ten cases, while remaining viable capsular tissue showed a dense lymphocytic infiltrate. Microscopic analysis was consistent with fretting and crevice corrosion at the modular neck-body interface.
Corrosion at the modular neck-body junction in dual-tapered stems with a modular cobalt-chromium-alloy femoral neck can lead to release of metal ions and debris resulting in local soft-tissue destruction. Adverse local tissue reaction should be considered as a potential cause for new-onset pain in patients with these components, and early revision should be considered given the potentially destructive nature of these reactions. A workup including serologic studies (erythrocyte sedimentation rate and C-reactive protein), serum metal levels, and MARS MRI can be helpful in establishing this diagnosis.
双锥形模块化股骨柄的引入允许在全髋关节置换术中，除股骨固定外，还可以有更多髋关节中心重建的选择。尽管这些股骨柄的可用性和使用越来越多，但仍存在对模块化颈体交界处潜在并发症的担忧。
这是一项多中心回顾性病例系列研究，共纳入 12 髋（11 例）因模块化颈体交界处腐蚀导致局部组织不良反应的病例。该队列包括 8 名女性和 3 名男性，平均年龄 60.1 岁（范围，43-77 岁）；所有髋关节均植入钛合金柄和钴铬合金颈。患者在全髋关节置换术后平均 7.9 个月（范围，5-13 个月）出现新出现的和逐渐加重的疼痛。在血清金属离子研究和金属伪影减少序列（MARS）磁共振成像（MRI）显示异常结果后，患者平均在 15.2 个月（范围，10-23 个月）进行髋关节翻修。由一名组织病理学家对组织标本进行检查，并使用光镜和扫描电子显微镜对取出的植入物进行研究。
血清金属水平显示钴的升高更为明显（平均 6.0ng/ml），而铬（平均 0.6ng/ml）或钛（平均 3.4ng/ml）升高不明显。9 例中 8 例行 MARS MRI 的患者均显示不良组织反应。所有髋关节均表现为大的软组织肿块和周围组织损伤，在模块化股骨颈体交界处可见明显腐蚀。可获得的组织学显示 7 例中有 10 例大片组织坏死，而其余存活的囊组织显示密集的淋巴细胞浸润。显微镜分析与模块化颈体界面的微动和缝隙腐蚀一致。
双锥形带模块化钴铬合金股骨颈的柄的模块化颈体交界处腐蚀会导致金属离子和碎屑的释放，从而导致局部软组织破坏。对于这些部件的患者出现新的疼痛，应考虑不良局部组织反应作为潜在原因，鉴于这些反应的潜在破坏性，应考虑早期翻修。包括红细胞沉降率和 C 反应蛋白在内的血清学研究、血清金属水平和 MARS MRI 等检查有助于确立这一诊断。
