Abstract：
BACKGROUND: Vitamin E-doped cross-linked polyethylene (VEPE) has encouraged the use of larger heads in thinner liners in total hip arthroplasty (THA). However, there are concerns about wear and mechanical failure of the thin liner, especially when metal heads are used. The aim of this randomized controlled trial was to investigate if the use of a large metal head in thin VEPE liner would increase polyethylene wear compared with a standard 32-mm metal head and to compare periacetabular radiolucencies and patient-reported outcomes in THA.
METHODS: There were 96 candidates for uncemented THA who were randomly allocated to either the largest possible metal head (36 to 44 mm) that could be fitted in the thinnest available VEPE liner (intervention group) or a standard 32-mm metal head (control group). The primary outcome was proximal head penetration, measured with a model-based radiostereometric analysis. Secondary outcomes were periacetabular radiolucencies and patient-reported outcomes. The midterm results of the trial at 5 years are presented.
RESULTS: The median total proximal head penetration (interquartile range) was -0.04 mm (-0.12 to 0.02) in the intervention group and -0.03 mm (-0.14 to 0.05) in the control group (P = .691). The rates of periacetabular radiolucencies were 1 of 44 and 4 of 42 (P = .197), respectively. Patient-reported hip function and health-related quality of life did not differ between the groups, but participants in the intervention group reported a higher level of activity (median University of California Level of Activity score 7 versus 6, P = .020). There were 5 revisions caused by dislocations (2), periprosthetic fracture (1), stem subsidence (1), or iliopsoas impingement (1).
CONCLUSIONS: Large metal heads in thin VEPE liners did not increase liner wear and were not associated with liner failure 5 years after THA.
METHODS: There were 96 candidates for uncemented THA who were randomly allocated to either the largest possible metal head (36 to 44 mm) that could be fitted in the thinnest available VEPE liner (intervention group) or a standard 32-mm metal head (control group). The primary outcome was proximal head penetration, measured with a model-based radiostereometric analysis. Secondary outcomes were periacetabular radiolucencies and patient-reported outcomes. The midterm results of the trial at 5 years are presented.
RESULTS: The median total proximal head penetration (interquartile range) was -0.04 mm (-0.12 to 0.02) in the intervention group and -0.03 mm (-0.14 to 0.05) in the control group (P = .691). The rates of periacetabular radiolucencies were 1 of 44 and 4 of 42 (P = .197), respectively. Patient-reported hip function and health-related quality of life did not differ between the groups, but participants in the intervention group reported a higher level of activity (median University of California Level of Activity score 7 versus 6, P = .020). There were 5 revisions caused by dislocations (2), periprosthetic fracture (1), stem subsidence (1), or iliopsoas impingement (1).
CONCLUSIONS: Large metal heads in thin VEPE liners did not increase liner wear and were not associated with liner failure 5 years after THA.
摘要：
背景：维生素E掺杂的交联聚乙烯（VEPE）鼓励在全髋关节置换术（THA）中在较薄的衬里中使用较大的头部。然而,担心薄衬板的磨损和机械故障，特别是当使用金属头。这项随机对照试验的目的是研究与标准的32毫米金属头相比，在薄的VEPE衬里中使用大金属头是否会增加聚乙烯的磨损，并比较THA中髋臼周围的放射性透明度和患者报告的结果。
方法：有96名患者被随机分配到最大可能的金属头（36至44毫米），该金属头可以安装在最薄的VEPE衬垫（干预组）或标准的32毫米金属头（对照组）。主要结果是近端头部穿透，使用基于模型的放射立体测量分析进行测量。次要结果是髋臼周围放射性和患者报告的结果。提供了5年试验的中期结果。
结果：干预组的中位近端头部穿透（四分位距）为-0.04mm（-0.12至0.02），对照组为-0.03mm（-0.14至0.05）（P=.691）。髋臼周围放射性的发生率是44个中的1个和42个中的4个（P=.197），分别。两组患者报告的髋关节功能和健康相关生活质量没有差异，但干预组的参与者报告的活动水平较高(加州大学活动水平得分为7分和6分,P=0.020).有5次由位错引起的修正(2次)，假体周围骨折(1),茎沉陷(1)，或髂腰肌撞击(1)。
结论：薄VEPE衬板中的大金属头不会增加衬板磨损，并且在THA后5年与衬板失效无关。
方法：有96名患者被随机分配到最大可能的金属头（36至44毫米），该金属头可以安装在最薄的VEPE衬垫（干预组）或标准的32毫米金属头（对照组）。主要结果是近端头部穿透，使用基于模型的放射立体测量分析进行测量。次要结果是髋臼周围放射性和患者报告的结果。提供了5年试验的中期结果。
结果：干预组的中位近端头部穿透（四分位距）为-0.04mm（-0.12至0.02），对照组为-0.03mm（-0.14至0.05）（P=.691）。髋臼周围放射性的发生率是44个中的1个和42个中的4个（P=.197），分别。两组患者报告的髋关节功能和健康相关生活质量没有差异，但干预组的参与者报告的活动水平较高(加州大学活动水平得分为7分和6分,P=0.020).有5次由位错引起的修正(2次)，假体周围骨折(1),茎沉陷(1)，或髂腰肌撞击(1)。
结论：薄VEPE衬板中的大金属头不会增加衬板磨损，并且在THA后5年与衬板失效无关。
