Deep Vein Thrombosis of the Hip
Joint replacement surgery, especially in the lower extremities, is becoming more common.
It is estimated that Orthopedic surgeons perform over 720,000 hip replacements and over 681,000 knee replacements a year. The vast majority of these surgeries are very successful, and patients go on to live fuller, more active lives without pain.
But no operation is without risks. One of the major risks facing patients who undergo surgery in the lower extremities is a complication called deep vein thrombosis, a form of venous thromboembolic disease.
Deep vein thrombosis (DVT) refers to the formation of a thrombus (blood clot) within a deep vein, commonly in the thigh or calf.
Although venous thromboembolic disease can develop after any major surgery, people who have surgery on the lower extremities are especially vulnerable.
Three factors contribute to formation of clots in veins:
1. Stasis, or stagnant blood flow through veins
This increases the contact time between blood and vein wall irregularities. It also prevents naturally occurring anticoagulants from mixing in the blood. Prolonged bed rest or immobility promotes stasis.
Coagulation is encouraged by the presence of tissue debris, collagen or fats in the veins. Orthopedic surgery often releases these materials into the blood system. During hip replacement surgery, reaming and preparing the bone to receive the prosthesis can also release chemical substances that stimulate clot formation into the blood stream.
3. Damage to the vein walls
This can occur during surgery as the physician retracts soft tissues as part of the procedure. This can also break intercellular bridges and release substances that promote blood clotting.
Other factors that may contribute to the formation of thrombi in the veins include:
- Previous history of DVT or PE (Pulmonary Embolus-a blood clot in the lung)
- Metastatic malignancy
- Vein disease (such as varicose veins)
- Estrogen usage or current pregnancy
- Genetic factors
After hip surgery, thrombi often form in the veins of the thigh. These clots are more likely to lead to PE. After knee surgery, most thrombi occur in the calf. While less likely to lead to PE, these clots are more difficult to detect.
Fewer than one third of patients with DVT present with the classic signs of calf discomfort, swelling, distended veins, or foot pain.
Diagnosing DVT is difficult. Current diagnostic techniques have both advantages and disadvantages. The most commonly used diagnostic test is a duplex or Doppler ultrasonography.
The main symptom of trochanteric bursitis is pain at the point of the hip. The pain usually extends to the outside of the thigh area. In the early stages, the pain is usually described as sharp and intense. Later, the pain may become more of an ache and spread across a larger area of the hip.
Typically, the pain is worse at night, when lying on the affected hip, and when getting up from a chair after being seated for a while. It also may get worse with prolonged walking, stair climbing, or squatting.