(0.2% DVT, 0 PE)

When we perform hip or knee replacement operations we create tissue trauma that naturally cause the body to respond with a clotting response. Patients who have a defective clotting system such as hemophilia would bleed to death with these operations if we did not artificially supplement their clotting system. I use careful surgical technique, electrocautery, the Aquamantyss tissue sealer and platelet concentrates with Thrombin to minimize perioperative bleeding. But this is not enough. We depend on the patient’s normally functioning clotting system to do the rest. Clotting in the wound is natural and absolutely necessary. But sometimes the patient’s clotting system over reacts and clots are formed in the veins of the legs and pelvis.

This can lead to problems. Especially when these clots break off and travel to the lungs (pulmonary embolus). Preventative measures include rapid mobilization of the patient, pneumatic compression devices (SCD) and use of drugs that impair the clotting mechanism commonly referred to as anticoagulants or “blood thinners”. Although these drugs can reduce the chance that abnormal clots form in the veins, they also reduce the desirable clotting that occurs in the wound itself. This leads to more bleeding for up to several days postoperative.

This may then lead to more pain as well as wound drainage. The more the wound drains, the higher the chance of infection. Rarely they can cause a stroke or subdural hematoma. Therefore anticoagulants have two effects: they decrease thromboembolic events (undesirable vein clots) but they increase the rate of infection. Every persons clotting system is different. But efforts to quantitate this so far have been ineffective. We are unable to predict how strongly an individual’s clotting system will respond. The best risk-benefit ratio therefore seems to some form of limited anticoagulation for most patients.

Without any preventative measure, the incidence blood clots in the legs or pelvis (deep venous thrombosis, DVT) is approximately 50% to 60% and the incidence of blood clots traveling to the lungs (pulmonary embolus, PE) is 10%. The risk is higher in patients who are obese or who have a know hypercoaguable state. In and of themselves DVTs are not a great threat; they can be treated with blood thinners and will ultimately resolve. The patient may, however, be left with some permanent swelling of the leg due to destruction of some of the valves in the veins. But PE carries a 1% chance of death.

The protocol that we are currently using has resulted in a < 1% chance of DVT and no PE in over 1000 patients.

• Avoidance of entering marrow canal: resurfacing
• SCD for 24º, beginning in the operating room
• Spinal anesthesia
• Rapid mobilization
• Xarelto for 2 weeks/ 4weeks for high risk patients
  (once a day oral medication, no injections or blood monitoring needed)
• ASA