We compared a novel external suction drainage (ESD) system with a conventional internal suction drainage (ISD) system in patients undergoing primary total hip or knee arthroplasties. Forty-two consecutive patients were studied: 22 who received an ISD system and 20 who received the ESD system. Drainage volume was measured, standardized questionnaires were used to assess patient comfort and response to drain removal, and number of complications were recorded. Significantly less drainage, less pain, and fewer complications occurred in patients treated with the ESD system (P<.05 for each endpoint). Results showed that ESD has advantages over ISD in primary total hip and knee arthroplasties.