Treatment of septic flexor tenosynovitis at the hand requires significant hospital resources in terms of operative time and subsequent management of tendon irrigation. Delayed recovery or treatment failure may require re-irrigation and drainage. This may be due to failure to adequately irrigate the entire flexor sheath. We describe a method of closed tendon sheath irrigation which is simple to use and ensures that the complete tendon sheath is adequately irrigated. Unwieldy continuous irrigation is avoided and patient inconvenience is kept to a minimum.