addition:添加？

The use of preoperative/perioperative antibiotics has become a standard of care for orthopedic surgeries. They have been proven to reduce the incidence of surgical site and prosthesis site infection. Prosthetic site infections incur staggering costs with the potential need for multiple reoperations. Therefore, it is recommended that all total joint replacement patients receive antibiotics prior to any arthroplasty. The primary agent used in the United States is typically a 1st generation cephalosporin. The addition of vancomycin as a second agent is also very common. Appropriate antibiotic prophylaxsis includes adequate dosing based on ideal body weight, timing of administration with respect to surgical incision and appropriate re-dosing.

在术前/围术期预防性使用抗生素已成为骨科手术的常规。研究证实，这样做有助于降低手术部位及假体周围感染的风险。假体周围感染会引发巨额医疗费用，往往需多次手术处理感染。因此，对于所有的全关节置换术，建议在关节置换操作前输入抗生素。在美国，首选药物为一代头孢。一代头孢加万古霉素可作为二线用药也很常见。合适的抗生素预防治疗包括：根据理想体重给予患者充足剂量的药物，给药时机与手术切皮时间吻合，同时还需在合理时机再次用药。

addition:添加万古霉素可作为二线用药。也就是说头孢+万古是二线用药?而不是万古霉素单独作为二线用药，对吗？