万古霉素骨水泥在感染人工髋关节翻修中作用的实验研究与临床观察

Effects of vancomycin-impregnated polymethylmethacrylate on the management of infection after hip arthroplasty:an experimental and clinical study

目的探讨1:20万古霉素骨水泥(VCM-PMMA)在感染人工髋关节翻修中的作用。方法观察VCM的耐热性能,VCM-PMMA体外抑制表皮葡萄球菌(SE)和生物力学特性;建立兔人工股骨头置换后SE感染模型,研究VCM-PMMA在感染兔人工股骨头一、二期翻修中的作用;在此基础上临床治疗12例感染人工髋关节。结果VCM含量室温组(25±2)℃与120℃组之间无显著性差异(P>0.05);第32天时VCM-PMMA中VCM药物浓度仍高于SE的最小抑菌浓度;VCM-PMMA与PMMA在拔出力、压缩强度上均无显著差异(P>0.05)。一期翻修组16.7%再感染,二期翻修组为8.3%,对照组为58.3%,对照组显著增高(P<0.01)。临床清创后灌洗4例,1例成功,3例失败;使用VCM-PMMA的一、二期翻修8例均获成功。结论①VCM热稳定性良好,VCM-PMMA可持续抑菌达32d,1∶20VCM-PMMA基本不影响固定兔人工股骨头的力学特性。②应用VCM-PMMA能显著提高兔感染人工股骨头一、二期翻修的成功率。

Objective To study the effects of vancomycin impregnated polymethylmethacrylate(VCM PMMA)on the management of infection after hip arthroplasty. Methods The thermal tolerance of VCM, the bacteriostatic activity to the staphylococcus epidermidis (SE) and the biomechanical characteristic of VCM PMMA were measured in vitro. The animal model of infected femoral head prosthesis was established in rabbits. Effects of VCM PMMA on the management of infection in both one stage and two stage revisions were observed in rabbit models. The 12 infected cases of hip arthroplasty were retrospectively analyzed. Results The thermal tolerance of VCM was scarcely different between the (25±2)℃and 120℃groups (P >0.05). The concentration of VCM in VCM PMMA was measured to be higher than the MIC of the SE for 32 days in vitro. As far as fixation was concerned, there was no significant difference between VCM PMMA and PMMA groups in terms of pull out strength and compression pressure (P >0.05). The re infection rate was 16.7%in the one stage reversion group, 8.3%in the two stage reversion group, and 58.3%in the control group. The differences were significant (P< 0.01). The 8 cases of one stage and two stage reversion with VCM PMMA were all successful. In the other 4 cases that were treated by simple debridement and postoperative lavage to retain the original prosthesis, only one succeeded and the other 3 failed. Conclusions The thermal tolerance of VCM is so good that VCM PMMA can keep the bacteriostatic activity for 32 days. The VCM and PMMA mixed in proportion of 1 to 20 will have little effect on the mechanical behaviors in rabbit femoral head replacement. Application of VCM PMMA can obviously increase the success rate of one stage and two stage reversions to treat the infection after the rabbit hip arthroplasty.