Matharu Gulraj S, Berryman Fiona, Brash Lesley, Pynsent Paul B, Treacy Ronan B, Dunlop David J
The Royal Orthopaedic Hospital, Birmingham, UK, B31 2AP,
Int Orthop. 2015 Sep;39(9):1803-11. doi: 10.1007/s00264-014-2644-z. Epub 2015 Feb 6.
Most factors considered to affect blood metal ions following metal-on-metal hip replacement are based on hip resurfacing patients. The study aims were to determine which factors affect blood metal ion concentrations following metal-on-metal total hip replacement (MoM THR).
All unilateral MoM THR patients at one centre with whole-blood cobalt (Co) and chromium (Cr) concentrations measured up to May 2013 were included. Blood sampling was at a mean of 4.5 years (range 1.1-11.8 years) postoperatively.
Of 496 patients (mean age 59.1 years; 52.8% male), blood metal ions >7 μg/l were observed in 9.7% (n = 48). Large femoral head sizes (≥38 mm) had significantly higher (p < 0.0001) blood metal ions than smaller sizes (28/36 mm). Corail-Pinnacle implants produced significantly lower blood metal ions compared to other implant designs (p < 0.01 Co and Cr). Univariate linear regression demonstrated the only significant predictors of both blood Co and Cr concentrations were femoral head size (R(2) = 8.6% Co and R(2) = 3.3% Cr, both p < 0.0001) and implant design (R(2) = 8.8%, p = 0.005 Co and R(2) = 5.1%, p = 0.003 Cr). When the three THR implant design groups (Corail-Pinnacle, Synergy, Other) were analysed separately, femoral head size no longer significantly affected blood metal ions in any of the three implant design groups.
Implant design was the most important factor affecting blood metal ion concentrations. We recommend the regularity of follow-up be tailored to survival rates of various MoM THR designs rather than according to femoral head size.
大多数被认为会影响金属对金属髋关节置换术后血液中金属离子的因素是基于髋关节表面置换患者得出的。本研究旨在确定哪些因素会影响金属对金属全髋关节置换术（MoM THR）后血液中的金属离子浓度。
纳入了某中心所有在2013年5月前进行过全血钴（Co）和铬（Cr）浓度测量的单侧MoM THR患者。血液样本采集时间为术后平均4.5年（范围1.1 - 11.8年）。
在496例患者（平均年龄59.1岁；52.8%为男性）中，9.7%（n = 48）的患者血液金属离子浓度>7μg/l。大尺寸股骨头（≥38mm）的血液金属离子浓度显著高于小尺寸（28/36mm）（p < 0.0001）。与其他植入物设计相比，Corail - Pinnacle植入物产生的血液金属离子浓度显著更低（Co和Cr的p < 0.01）。单变量线性回归表明，血液中Co和Cr浓度的唯一显著预测因素是股骨头尺寸（Co的R² = 8.6%，Cr的R² = 3.3%，两者p < 0.0001）和植入物设计（Co的R² = 8.8%，p = 0.005；Cr的R² = 5.1%，p = 0.003）。当对三个THR植入物设计组（Corail - Pinnacle、Synergy、其他）分别进行分析时，股骨头尺寸在任何一个植入物设计组中都不再显著影响血液金属离子浓度。
植入物设计是影响血液金属离子浓度的最重要因素。我们建议随访的规律性应根据各种MoM THR设计的生存率来调整，而不是根据股骨头尺寸。
