Background: Rationale perioperative antibiotic for prevent infection in total knee artrhplasty is well established. The recommendation are preoperative antibiotic should be administered within 1 h before skin incision and prophylactic antibiotics should be administered within 1 h before skin incision, if prolong surgery more than 4-6 hours need addition doses and duration of prophylactic antibiotic administration should not exceed the 24-hour postoperative period then not need for additional antibiotic. If there is evidences of infection, intravenous antibiotic and follow by oral antibiotic is mandatory in acute infection in conjuction with scrub and debridement. Because the burden of infection in joint replacement is disaster, it seemed to increase the antibiotic uses and impact about the cost concerned after total knee arthroplasty. No data available about the pharmaco-economical study of perioperative antibiotic in total knee arthroplasty have been established.
Objective: Primary outcomes is cost anaylsis of perioperative antibiotic uses in real clinical practice for total knee arthroplasty. Secondary outcome is infectioned total knee that need to reoperative for scrub and debridement.
Material and Method: Prospective opened lable study from joint registry in Police General Hospital from June, 2010 till March, 2011. With minimum 12 months follow-up. Total Knee Arthroplasty was enrolled in the present study about 218 cases. 3 patients lossed follow-up in each groups, so the total number in the present study are 209 patients. Perioperative antibiotic consumption initial doses and followed for 48 hour is divided in 3 group: group 1 Fosmycin 4 g (2 g initially plus 2 g intraoperatively) for 70 patients group 2: Fosmycin 2 g for 68 patients. Group 3: Cefalosporin group for 71 patients. The cost of subsequence uses of intravenous and oral antibiotic were record. And also the cases that need to scrub debridement with the indication of infected total knee arthroplasty were recorded. The minimum follow-up about 12 months (range 12-18 months).
Results: The extend of intravenous antibiotic administration postop more than 48 hours in group 1 is 38 patients (54.28%) and oral antibiotic 42 patients (60%), in group 2 is 45 patients (66.18%) and oral antibiotic 40 patients (58.2%), in group 3 58 patients (81.7%) and oral antibiotic 60 patients (84.51%). The percentage of expenses preoperative intravenous and postoperative 48 hour: intravenous antibiotic during hospitalization: post operative antibiotic in group 1 is 19.82%: 59.69%: 20.49%; group 2 is 10.41%: 68.40%: 21.19% and group 3 is 1.39% 80.85%: 17.76%. The average toal perioperative cost antibiotic (baht) in group 1: group 2: group 3 are 4,068: 4,776: 5,468. The infected case need operated for scrub and debridement in group 1 is 1 cases, group 2 is one cases and group 3 is 1 cases.
Conclusion: Overall expense increased in both intravenous and oral antibiotic prophylaxis in total knee arthtroplasty for prevention of infection. The major cost of perioperative antibiotic is intravenous antibiotic more than 48 hours during hospitalization, the least number of patients and percentages of cost is in group 1 than group 2 and 3. The percentage of patients oral antibiotics are least in group 2 than group 1, 3 but the average cost is likely to be quite substantially lower in group 1 then group 2, 3.

Keywords: Cost analysis, Perioperative antibiotic, Total knee arthroplasty