不同直径股骨头对高交联聚乙烯髋臼内衬磨损影响的初步研究

COMPARATIVE STUDY ON ASSOCIATION BETWEEN FEMORAL HEAD SIZE AND LINEAR WEAR RATE OF HIGHLY CROSS-LINKED POLYETHYLENE LINER

目的探讨人工全髋关节置换术（total hip arthroplasty,THA）中采用不同直径股骨头对高交联聚乙烯（highly cross-linked polyethylene,HXLPE）髋臼内衬磨损的影响。方法回顾分析2004年1月-2007年12月,41例（43髋）因髋部疾病采用不同直径股骨头及HXLPE髋臼内衬行THA治疗的患者临床资料。男22例（23髋）,女19例（20髋）;年龄35-89岁,平均60.2岁。股骨颈骨折26髋,股骨头缺血性坏死8髋,骨关节炎5髋,风湿性关节炎2髋,先天性髋臼发育不良2髋。按股骨头直径将患者分为两组：A组25例（26髋）采用普通直径（26、28 mm）球头HXLPE髋臼内衬,B组16例（17髋）采用大直径（32、36、40 mm）球头HXLPE髋臼内衬。比较两组患者股骨头累积穿透位移值、内衬线性磨损率和临床疗效。结果术后患者切口均Ⅰ期愈合,无感染、下肢深静脉血栓形成及神经损伤等并发症发生。两组患者均获随访,随访时间5-9年,平均5.7年。均未行二期翻修术。两组术后3、6个月及1、2、3、4、5年Harris评分均较术前显著提高（P〈0.05）;术后各时间点间比较,差异均无统计学意义（P〉0.05）;手术前后各时间点两组间比较,差异均无统计学意义（P〉0.05）。术后即刻A、B组髋臼外展角分别为（31.4±3.8）°和（32.3±4.1）°,比较差异无统计学意义（t=0.482,P=0.621）。末次随访时,两组均无患髋发生影像学松动及临床松动现象。A、B组各1例（1髋）于术后5年发现髋臼1、2、3区X线透亮带（均〈1 mm）,股骨假体周围未发现透亮带。A、B组术后1-5年每年股骨头累积穿透位移值比较,差异均无统计学意义（P〉0.05）。A、B组术后线性磨损率分别为（0.026±0.007）mm/年和（0.025±0.007）mm/年,比较差异无统计学意义（t=0.708,P=0.483）。结论 HXLPE髋臼内衬磨损率极低,是人工关节界面理想选择;不同直径股骨头对HXLPE髋臼内衬磨损的影响无显著差异。

Objective To investigate the effects of the femoral head size on the linear wear rate of highly crosslinked polyethylene （HXLPE） liner in total hip arthroplasty （THA）. Methods A retrospective analysis was performed on the clinical data of 41 patients （43 hips） who underwent primary THA with HXLPE liner and different sizes of femoral heads between January 2004 and December 2007 for hip diseases. There were 22 males （23 hips） and 19 females （20 hips） with a mean age of 60.2 years （range, 35-89 years）, including femoral neck fracture （26 hips）, avascular necrosis of femoral head （8 hips）, osteoarthritis （5 hips）, rheumatoid arthritis （2 hips）, and congenital hip dysplasia （2 hips）. According to the size of the femoral head, the patients were divided into 2 groups： standard head size （26 and 28 mm） was used in 25 cases （26 hips, group A） and big head size （32, 36, and 40 mm） in 16 cases （17 hips, group B）. The cumulative penetration of the femoral head, linear wear rate, and effectiveness were evaluated and compared between 2 groups. Results All the incisions healed by first intention,no complications of infection, deep vein thrombosis, or nerve injury occurred. The patients were followed up 5-9 years （mean,5.7 years）. No two-stage revision was needed. Harris score was significantly improved at 3 months, 6 months, and 1, 2, 3, 4,and 5 years after operation when compared with preoperative score in each group （P〈0.05）, but no significant difference was found between different time points after operation in 2 groups （P〈0.05）, and between 2 groups at each time point （P〈0.05）.Acetabular abduction angle was （31.4 ± 3.8）° in group A and （32.3 ± 4.1）° in group B, showing no significant difference （t=0.482,P=0.621）. At last follow-up, no radiographic or clinical loosening was observed in each group. At 5 years after operation, X-ray results of acetabular components showed radiolucent line （ 1 mm） in 1 case （1 hip） and 1 case （1 hip） of 2 groups respectively;but X-ray results of femoral components showed no radiolucent line. There was no significant difference in the cumulative penetration of the femoral head between 2 groups at 1, 2, 3, 4, and 5 years after operation （P〈0.05）. The linear wear rate was （0.026 ± 0.007） mm/year in group A and （0.025 ± 0.007） mm/year in group B, showing no significant difference between 2 groups （t=0.708, P=0.483）. Conclusion No association is found between femoral head size and the linear wear rate of HXLPE liner. It is an ideal interface of THA because of its low linear wear rate.