Value of antibiotic prophylaxis in routine knee arthroscopy : A retrospective study.

OBJECTIVE: Prophylactic antibiotic use prior to routine knee arthroscopy remains controversial. It is important to know whether antibiotics help decrease the surgical site infection (SSI) rate. Our aims were to assess the efficacy of antibiotic prophylaxis in preventing SSI and to identify risk factors for SSI following routine knee arthroscopy without an implant.

METHODS: A retrospective study was conducted using the electronic medical records at the authors' hospital to identify patients that underwent routine knee arthroscopy without an implant between October 2010 and October 2016. Data on demographics, clinical characteristics and antibiotic administration were extracted. Arthroscopic diagnosis, debridement, partial or complete meniscectomy, arthroscopic shaving and microfracture, removal of loose bodies, synovectomy and lateral retinacular release were included. Complex knee arthroscopy with an implant was excluded. Patients were divided into evaluation (with prophylactic antibiotics) and control (no antibiotic treatment) groups. Continuous variables between groups were compared using the Student's t-test. Data were analyzed using the Chi-squared test for percentages between groups. Multivariate logistic regression was used to identify independent risk factors of SSI.

RESULTS: Of 1326 patients, 614 (46.3%) received prophylactic antibiotics, while 712 (53.7%) did not. There were seven (0.53%) SSIs. The SSI rate did not differ significantly between patients receiving antibiotics (0.49%, three) and those not (0.56%, four). Five patients (0.37%) had superficial infections, two (0.33%) were in the prophylactic antibiotic group and three (0.42%) were in the other group. Deep infections occurred in two patients (0.15%), one (0.16%) in the prophylactic antibiotic group and one (0.14%) in the other group. The difference between the two groups was not statistically significant (P = 1.0). Age over 50 years was associated with an increased risk of SSI (relative ratio [RR] = 1.469, 95% confidence interval [CI] 1.09-2.13, P = 0.009).

CONCLUSIONS: Prophylactic antibiotic use in routine knee arthroscopy without an implant may not be necessary. Age over 50 years was associated with an increased risk of SSI.