BACKGROUND: Closed suction drainage after joint arthroplasty is common practice in many institutions. The purpose of this study was to determine the correlation between routine drain tip culture and the diagnosis of superficial or deep postoperative wound infection after primary knee and hip replacement.

METHODS: Over a 12-month period, drain tips were retrieved and cultured in all patients who underwent unilateral primary total knee or hip replacement with the use of closed suction drainage. A total of 393 cultures was performed in 387 patients (145 hip replacements, 242 knee replacements). Patients were followed for an average of 8.9 months after surgery to assess for postoperative wound infection.

RESULTS: Three patients had a positive drain tip culture, none of which were diagnosed with superficial or deep infection. Four patients (1%) were diagnosed with deep infection, 16 (4.1%) with superficial infection. No patient with either superficial or deep infection had a positive drain tip culture after their index procedure. The sensitivity of routine drain tip culture for the diagnosis of postoperative infection in primary joint replacement was 0% and specificity was 99.2%.

CONCLUSIONS: These data do not support the practice of routine drain tip culture after primary hip or knee replacement for the diagnosis of postoperative infection.