Bull Hosp Jt Dis (2013). 2024 Sep;82(3):199-204.
Dual mobility acetabular systems for total hip arthroplasty (THA) have been shown to have decreased dislocation rates and reduced revision rates, but there is controversy over the potential release of sufficient levels of metal ions into the blood to cause adverse local tissue reactions. However, there is a lack of long-term studies analyzing these levels of cobalt and chromium. Therefore, the purpose of this study was to investigate the levels these metal ions at a minimum 5-year follow-up after dual mobility implantation. Specifically, we analyzed: 1. overall blood and urine cobalt levels; 2. overall blood and urine chromium levels; 3. cobalt levels stratified by length of follow-up and various implant-related metrics (i.e., offset, cup size, stem, and neck angle); as well as 4. chromium levels stratified by length of follow-up and these various implant-related metrics.
A total of 41 patients who underwent THA with modular dual mobility acetabular systems between January 1, 2011, and December 31, 2016, were identified and followed for a mean time of 6 years (range: 5 to 10 years). All patients had well-functioning hips (Harris Hip Scores greater than 90 points (range: 90 to 100 points) and had no evidence of impending radiographic failure or progressive radiolucencies. Cobalt and chromium serum and plasma, blood, as well as urine levels were obtained at final followup. Additional parameters analyzed included: head material and size, stem offset, cup size, as well as stem-neck angle.
Concentrations of cobalt were low as the mean blood and urine levels for all patients were 0.6 ± 0.5 μg/L (normal < 1.8 μg/L) and 0.8 ± 0.8 μg/L (normal < 2.8 μg/L), respectively. Only one patient had a minimally elevated blood cobalt level by 0.1 μg/L. These levels were not substantially different when subgroup analyses were performed for ceramic and cobalt-chrome heads. The mean chromium levels in blood and urine were also found to be low for all patients as values were 0.8 ± 0.2 μg/L (normal: < 1.2 μg/L) and 1.2 ± 0.5 ng/milliliter (normal: < 2 ng/L), respectively. Similarly, only one patient had a very slightly elevated blood chromium level of 1.3 μg/L. Additionally, analyses of ceramic or cobalt-chrome heads separately did not demonstrate differences in blood or urine levels. Blood cobalt or chromium concentrations had minimal changes with longer lengths of follow-ups, and with different stem offsets, cup sizes, stems, or neck angles.
Dual mobility acetabular systems when combined with the two stems studied produced low levels of blood as well as urine cobalt and chromium levels at a minimum follow-up of 5 years (mean: 6 years; range: 5 to 10 years). These results remained below the threshold of normal and clinically insignificant regardless of length of follow-up, head material, or various implant measurements. To the best of our knowledge, this is the first study to demonstrate low levels of metal ions at longer than 4-year follow-up. These data may be of importance to surgeons deciding on the appropriate implants to use for their high-risk patients.
全髋关节置换术中使用双动髋臼系统已被证明可降低脱位率和降低翻修率，但关于是否会有足够水平的金属离子释放到血液中引起不良局部组织反应仍存在争议。然而，目前缺乏长期研究来分析这些钴和铬的水平。因此，本研究的目的是在双动植入物后至少 5 年的随访中，调查这些金属离子的水平。具体来说，我们分析了：1. 全血和尿液中的钴水平；2. 全血和尿液中的铬水平；3. 根据随访时间和各种植入物相关指标（即，偏心距、杯尺寸、柄和颈角度）分层的钴水平；以及 4. 根据随访时间和这些各种植入物相关指标分层的铬水平。
共确定并随访了 41 例于 2011 年 1 月 1 日至 2016 年 12 月 31 日期间接受模块化双动髋臼系统全髋关节置换术的患者，平均随访时间为 6 年（范围：5 至 10 年）。所有患者髋关节功能良好（Harris 髋关节评分大于 90 分（范围：90 至 100 分），且无影像学失败或进行性透亮线的证据。在最终随访时获得了钴和铬的血清和血浆、血液以及尿液水平。此外，还分析了其他参数，包括：头材料和尺寸、柄偏心距、杯尺寸以及柄颈角度。
钴的浓度较低，因为所有患者的全血和尿液平均水平分别为 0.6 ± 0.5 μg/L（正常值 < 1.8 μg/L）和 0.8 ± 0.8 μg/L（正常值 < 2.8 μg/L）。只有一名患者的血液钴水平略有升高，为 0.1 μg/L。当对陶瓷和钴铬头分别进行亚组分析时，这些水平没有明显差异。所有患者的血液和尿液中的铬水平也较低，分别为 0.8 ± 0.2 μg/L（正常值：< 1.2 μg/L）和 1.2 ± 0.5 ng/毫升（正常值：< 2 ng/L）。同样，只有一名患者的血液铬水平略有升高，为 1.3 μg/L。此外，对陶瓷或钴铬头分别进行分析并未显示血液或尿液水平存在差异。随着随访时间的延长以及不同的柄偏心距、杯尺寸、柄或颈角度，血液钴或铬浓度的变化很小。
双动髋臼系统与我们研究的两种柄联合使用时，在至少 5 年（平均：6 年；范围：5 至 10 年）的随访中产生了低水平的血液钴和铬水平。这些结果均低于正常值和临床无意义的阈值，无论随访时间、头材料或各种植入物测量值如何。据我们所知，这是第一项在随访时间超过 4 年后证明金属离子水平较低的研究。这些数据可能对决定为高风险患者选择合适植入物的外科医生很重要。
