Board-certified Orthopaedic Surgeon, Section Chief – Joint Reconstructive Surgery

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Prevention of blood clots

Prevention of blood clots and pulmonary embolisms after hip or knee replacement surgery

Perhaps no other aspect of joint replacement surgery is as controversial as prevention of deep venous thrombosis (DVT) or pulmonary embolism (PE). It has been recognized for several decades that patients with hip and knee replacement can develop blood clots in their legs. A blood clot can break off and travel to the patient´s lungs causing a pulmonary embolism, which is potentially life-threatening. Fortunately, the incidence of fatal PE is considered to be approximately 1 in 2,000-10,000.

Because of this, many doctors recommend blood thinning (anticoagulation ) medications after joint replacement surgery. Unfortunately, the agents that are most effective at thinning the blood can also cause bleeding into surgical site. Surgeons who perform many joint replacement surgeries have recognized that bleeding into the surgical site has a complication rate far in excess of fatal PE. Importantly, infection may result from poor wound healing due to bleeding caused by blood thinners. Other risks of blood thinners include bleeding of the gastrointestinal tract and prolonged anemia (low blood count) after surgery. Because of this, many orthopaedic surgeons prefer measures other than strong blood thinners to minimize the impact of blood clots. For example, the use of calf or foot compression devices is now generally accepted for most patients. Early ambulation, efficient surgery and regional anesthesia (spinal anesthesia), as well as the use of mild blood thinners such as aspiring have become widespread. The American Academy of Orthopaedic Surgeons (AAOS) has a position paper on this topic which can be found on their website ( The Joint Commission, which is the accrediting body at many hospitals, addresses this at their website (