Department of Orthopedic Surgery, Washington University School of Medicine, Saint Louis, Missouri, USA.
Bone Joint J. 2021 Jul;103-B(7 Supple B):73-77. doi: 10.1302/0301-620X.103B7.BJJ-2021-0145.R1.
Dual mobility (DM) implants have been shown to reduce the dislocation rate after total hip arthroplasty (THA), but there remain concerns about the use of cobalt chrome liners inserted into titanium shells. The aim of this study was to assess the clinical outcomes, metal ion levels, and periprosthetic femoral bone mineral density (BMD) at mid-term follow-up in young, active patients receiving a modular DM THA.
This was a prospective study involving patients aged < 65 years, with a BMI of < 35 kg/m, and University of California, Los Angeles activity score of > 6 who underwent primary THA with a modular cobalt chrome acetabular liner, highly cross-linked polyethylene mobile bearing, and a cementless titanium femoral stem. Patient-reported outcome measures, whole blood metal ion levels (μg/l), and periprosthetic femoral BMD were measured at baseline and at one, two, and five years postoperatively. The results two years postoperatively for this cohort have been previously reported.
A total of 43 patients were enrolled. At minimum follow-up of five years, 23 (53.4%) returned for clinical and radiological review, 25 (58.1%) had metal ion analysis performed, 19 (44.2%) underwent dual energy x-ray absorptiometry scans, and 25 (58%) completed a pain-drawing questionnaire. The mean modified Harris Hip Scores improved significantly from 54.8 (SD 19) preoperatively to 93.08 (SD 10.5) five years postoperatively (p < 0.001). One patient was revised for aseptic acetabular loosening. The mean cobalt levels increased from 0.065 μg/l (SD 0.03) to 0.08 (SD 0.05) and the mean titanium levels increased from 0.35 (SD 0.13) to 0.78 (SD 0.29). The femoral BMD ratio decreased in Gruen Zone 1 (91.9%) at five years postoperatively compared with the baseline scores at six weeks potoperatively. The femoral BMD ratio was maintained in Gruen zones 2 to 7.
The use of a modular DM component and a cementless, tapered femoral stem shows excellent mid-term survivorship with minimal concerns for corrosion and metal ion release in a cohort of young, active patients undergoing primary THA. Cite this article: 2021;103-B(7 Supple B):73-77.
双动（DM）植入物已被证明可降低全髋关节置换术后（THA）的脱位率，但对于将钴铬衬垫插入钛壳中仍存在担忧。本研究的目的是评估在年轻、活跃的患者中接受模块化 DM-THA 后的中期临床结果、金属离子水平和假体周围股骨骨密度（BMD）。
这是一项前瞻性研究，纳入了年龄<65 岁、BMI<35kg/m2和加利福尼亚大学洛杉矶分校（UCLA）活动评分>6 的患者，这些患者接受了模块化钴铬髋臼衬垫、高交联聚乙烯活动轴承和非骨水泥钛股骨柄的初次 THA。在术前、术后 1、2 和 5 年时测量患者报告的结果测量、全血金属离子水平（μg/l）和假体周围股骨 BMD。该队列术后 2 年的结果已在前一篇报道中报告。
共纳入 43 例患者。在至少 5 年的随访中，23 例（53.4%）返回进行临床和影像学检查，25 例（58.1%）进行了金属离子分析，19 例（44.2%）进行了双能 X 射线吸收法（DXA）扫描，25 例（58%）完成了疼痛图问卷调查。改良 Harris 髋关节评分从术前的 54.8（SD 19）显著改善至术后 5 年的 93.08（SD 10.5）（p<0.001）。1 例患者因无菌性髋臼松动而翻修。钴水平从 0.065μg/l（SD 0.03）增加到 0.08（SD 0.05），钛水平从 0.35μg/l（SD 0.13）增加到 0.78μg/l（SD 0.29）。术后 5 年时，假体周围股骨 BMD 比值在 Gruen 区 1（91.9%）较术后 6 周时明显下降。Gruen 区 2 至 7 区的股骨 BMD 比值保持不变。
在接受初次 THA 的年轻、活跃患者中，使用模块化 DM 组件和非骨水泥、锥形股骨柄显示出优异的中期存活率，对腐蚀和金属离子释放的担忧最小。
