Department of Orthopedic Surgery, Rush University Medical Center, Chicago, Illinois.
J Arthroplasty. 2024 Sep;39(9):2368-2376. doi: 10.1016/j.arth.2024.04.045. Epub 2024 Apr 17.
Modular dual mobility (DM) bearings have a junction between a cobalt chrome alloy (CoCrMo) liner and titanium shell, and the risk of tribocorrosion at this interface remains a concern. The purpose of this study was to determine whether liner malseating and liner designs are associated with taper tribocorrosion.
We evaluated 28 retrieved modular DM implants with a mean in situ duration of 14.6 months (range, 1 to 83). There were 2 manufacturers included (12 and 16 liners, respectively). Liners were considered malseated if a distinct divergence between the liner and shell was present on postoperative radiographs. Tribocorrosion was analyzed qualitatively with the modified Goldberg Score and quantitatively with an optical coordinate-measuring machine. An acetabular shell per manufacturer was sectioned for metallographic analysis.
There were 6 implants (22%) that had severe grade 4 corrosion, 6 (22%) had moderate grade 3, 11 (41%) had mild grade 2, and 5 (18.5%) had grade 1 or no visible corrosion. The average volumetric material loss at the taper was 0.086 ± 0.19 mm. There were 7 liners (25%) that had radiographic evidence of malseating, and all were of a single design (P = .01). The 2 liner designs were fundamentally different from one another with respect to the cobalt chrome alloy type, taper surface finish, and shape deviations. Malseating was an independent risk factor for increased volumetric material loss (P = .017).
DM tribocorrosion with quantifiable material loss occurred more commonly in malseated liners. Specific design characteristics may make liners more prone to malseating, and the interplay between seating mechanics, liner characteristics, and patient factors likely contributes to the shell/liner tribocorrosion environment.
Level III.
模块化双动（DM）轴承在钴铬合金（CoCrMo）衬里和钛外壳之间有一个连接点，界面处的摩擦腐蚀风险仍然令人担忧。本研究的目的是确定衬里错位和衬里设计是否与锥面摩擦腐蚀有关。
我们评估了 28 个已回收的模块化 DM 植入物，平均在位时间为 14.6 个月（范围为 1 至 83 个月）。包括 2 个制造商（分别为 12 个和 16 个衬里）。如果术后 X 光片上衬里和外壳之间存在明显的差异，则认为衬里错位。使用改良的戈德堡评分进行摩擦腐蚀的定性分析，并使用光学坐标测量机进行定量分析。每个制造商的髋臼外壳均进行了金相分析。
有 6 个植入物（22%）有严重的 4 级腐蚀，6 个（22%）有中度的 3 级腐蚀，11 个（41%）有轻度的 2 级腐蚀，5 个（18.5%）有 1 级或无可见腐蚀。锥面的平均体积材料损失为 0.086 ± 0.19mm。有 7 个衬里（25%）存在放射学上的错位证据，均为单一设计（P=0.01）。这两种衬里设计在钴铬合金类型、锥面表面光洁度和形状偏差方面存在根本差异。错位是体积材料损失增加的独立危险因素（P=0.017）。
DM 摩擦腐蚀伴有可量化的材料损失，在错位衬里中更为常见。特定的设计特点可能使衬里更容易错位，而座位力学、衬里特性和患者因素之间的相互作用可能导致外壳/衬里摩擦腐蚀环境。
III 级。
