Ghent University Hospital, Department of Orthopaedics and Traumatology, De Pintelaan 185, 9000 Ghent, Belgium.
Bone Joint J. 2013 Oct;95-B(10):1332-8. doi: 10.1302/0301-620X.95B10.32022.
A retrospective study was conducted to investigate the changes in metal ion levels in a consecutive series of Birmingham Hip Resurfacings (BHRs) at a minimum ten-year follow-up. We reviewed 250 BHRs implanted in 232 patients between 1998 and 2001. Implant survival, clinical outcome (Harris hip score), radiographs and serum chromium (Cr) and cobalt (Co) ion levels were assessed. Of 232 patients, 18 were dead (five bilateral BHRs), 15 lost to follow-up and ten had been revised. The remaining 202 BHRs in 190 patients (136 men and 54 women; mean age at surgery 50.5 years (17 to 76)) were evaluated at a minimum follow-up of ten years (mean 10.8 years (10 to 13.6)). The overall implant survival at 13.2 years was 92.4% (95% confidence interval 90.8 to 94.0). The mean Harris hip score was 97.7 (median 100; 65 to 100). Median and mean ion levels were low for unilateral resurfacings (Cr: median 1.3 µg/l, mean 1.95 µg/l (< 0.5 to 16.2); Co: median 1.0 µg/l, mean 1.62 µg/l (< 0.5 to 17.3)) and bilateral resurfacings (Cr: median 3.2 µg/l, mean 3.46 µg/l (< 0.5 to 10.0); Co: median 2.3 µg/l, mean 2.66 µg/l (< 0.5 to 9.5)). In 80 unilateral BHRs with sequential ion measurements, Cr and Co levels were found to decrease significantly (p < 0.001) from the initial assessment at a median of six years (4 to 8) to the last assessment at a median of 11 years (9 to 13), with a mean reduction of 1.24 µg/l for Cr and 0.88 µg/l for Co. Three female patients had a > 2.5 µg/l increase of Co ions, associated with head sizes ≤ 50 mm, clinical symptoms and osteolysis. Overall, there was no significant difference in change of ion levels between genders (Cr, p = 0.845; Co, p = 0.310) or component sizes (Cr, p = 0.505; Co, p = 0.370). Higher acetabular component inclination angles correlated with greater change in ion levels (Cr, p = 0.013; Co, p = 0.002). Patients with increased ion levels had lower Harris hip scores (p = 0.038). In conclusion, in well-functioning BHRs the metal ion levels decreased significantly at ten years. An increase > 2.5 µg/l was associated with poor function.
本研究回顾性分析了 1998 年至 2001 年期间植入的 250 例 Birmingham Hip Resurfacing（BHR）系统在至少 10 年随访时的金属离子水平变化。共纳入 232 例患者的 250 例 BHR 系统，其中 18 例患者死亡（5 例双侧 BHR），15 例失访，10 例接受了翻修手术。其余 202 例 BHR 系统（190 例患者，136 例男性，54 例女性；手术时平均年龄 50.5 岁（17-76 岁））在至少 10 年的随访中（平均 10.8 年（10-13.6 年））进行评估。术后 13.2 年的总体假体生存率为 92.4%（95%置信区间 90.8-94.0）。平均 Harris 髋关节评分为 97.7 分（中位数 100 分；65-100 分）。单侧翻修假体的离子浓度中位数和平均值较低（Cr：中位数 1.3μg/l，平均值 1.95μg/l（0.5-16.2）；Co：中位数 1.0μg/l，平均值 1.62μg/l（0.5-17.3）），双侧翻修假体的离子浓度中位数和平均值较低（Cr：中位数 3.2μg/l，平均值 3.46μg/l（0.5-10.0）；Co：中位数 2.3μg/l，平均值 2.66μg/l（0.5-9.5））。在 80 例单侧 BHR 中进行了连续离子测量，发现 Cr 和 Co 水平从最初评估时的中位数 6 年（4-8 年）到最后评估时的中位数 11 年（9-13 年）显著降低（p<0.001），Cr 和 Co 的平均降低值分别为 1.24μg/l 和 0.88μg/l。3 例女性患者 Co 离子升高>2.5μg/l，与头大小≤50mm、临床症状和骨溶解有关。总体而言，性别（Cr，p=0.845；Co，p=0.310）或部件尺寸（Cr，p=0.505；Co，p=0.370）之间离子水平变化无显著差异。髋臼组件倾斜角度增加与离子水平变化更大相关（Cr，p=0.013；Co，p=0.002）。离子水平升高的患者髋关节 Harris 评分较低（p=0.038）。总之，在功能良好的 BHR 中，10 年后金属离子水平显著下降。升高>2.5μg/l 与功能不良有关。
