Department of Orthopedics, Jena University Hospital, Campus Eisenberg, Germany.
J Bone Joint Surg Am. 2021 Jun 2;103(11):992-999. doi: 10.2106/JBJS.19.00787.
For cup revision after total hip arthroplasty, sufficiently good periacetabular bone stock is a prerequisite for fixation of the revision implant. Cementless cups can lead to a relevant reduction of peri-implant bone mineral density (BMD) through stress-shielding.
Fifty patients were included in this prospective randomized controlled trial. Group 1 (RM group) received an isoelastic monoblock cup (RM Pressfit vitamys; Mathys). Group 2 (IT group) received a modular titanium cup (Allofit-S IT Alloclassic with a polyethylene liner; Zimmer). Periacetabular BMD was determined and subdivided into 4 regions of interest by dual x-ray absorptiometry at 1 week (baseline) and at 4 years postoperatively. Our primary outcome was reduction in periacetabular BMD.
Periacetabular BMD was reduced by an average of 15.1% in the RM group and 16.5% in the IT group at 4 years postoperatively. No significant difference was found between the 2 groups over the periacetabular structure as a whole. However, the decrease of BMD in the polar region was significantly different in the RM group (4.9% ± 10.0%) compared with the IT group (15.9% ± 14.9%, p = 0.005). Use of the isoelastic RM cup showed significantly less bone loss than the modular IT cup.
Relevant loss of BMD at 4 years after surgery was identified in the periacetabular region in both groups. No differences between the 2 cup systems were found when looking at the overall periacetabular region. As a secondary outcome, less postoperative periacetabular bone loss occurred in the polar region when an isoelastic cup was used. Longer follow-up is required to allow for conclusions to be drawn about the long-term course of the 2 cup systems.
Therapeutic Level I. See Instructions for Authors for a complete description of levels of evidence.
对于全髋关节置换术后的杯体翻修，足够好的髋臼周围骨量是固定翻修植入物的前提。非骨水泥杯会通过应力遮挡导致种植体周围骨矿物质密度（BMD）的显著降低。
本前瞻性随机对照试验纳入了 50 例患者。第 1 组（RM 组）接受等弹性整体式杯（RM Pressfit vitamys；Mathys）。第 2 组（IT 组）接受模块化钛杯（Allofit-S IT Alloclassic 带聚乙烯衬垫；Zimmer）。在术后 1 周（基线）和 4 年时通过双能 X 线吸收法（DXA）测定髋臼周围 BMD，并分为 4 个感兴趣区。我们的主要结局是髋臼周围 BMD 的减少。
RM 组和 IT 组在术后 4 年时髋臼周围 BMD 分别平均减少了 15.1%和 16.5%。2 组间整个髋臼结构的 BMD 无显著差异。然而，RM 组的极区 BMD 下降明显小于 IT 组（4.9%±10.0%比 15.9%±14.9%，p=0.005）。使用等弹性 RM 杯比使用模块化 IT 杯导致的骨量丢失明显更少。
在术后 4 年时，2 组患者的髋臼周围区域均发现有明显的 BMD 丢失。当观察整个髋臼区域时，2 种杯系统之间无差异。作为次要结局，使用等弹性杯时，极区的术后髋臼周围骨丢失较少。需要更长时间的随访来得出关于 2 种杯系统长期结果的结论。
治疗学 1 级。有关证据水平的完整描述，请参见作者须知。
