One of the most serious complications of total knee replacement is the development of a deep vein thrombosis, or DVT -the presence of one or more blood clots that partially or completely block a vein. These DVTs can possibly result in a life-threatening pulmonary embolism.
The possibility of a DVT following a total knee replacement exists for any patient. There are some factors that have been associated with an increased risk, including:
- Age over 40 years
- Estrogen use
- Nephrotic syndrome
- Prolonged immobility
- Previous thromboembolism
- Congestive heart failure
- Indwelling femoral vein catheter
- Inflammatory bowel disease
- Varicose veins
- Diabetes mellitus
- Myocardial infarction
A DVT in a popliteal (behind the knee) vein is less common that in a calf vein, but may pose a greater risk of pulmonary embolism.
Many methods of treatment to prevent DVTs are available, including both mechanical and pharmaceutical options.
Pharmaceutical options, particularly low-molecular-weight heparin, such as enoxaparin (Lovenox), and fondaparinux (Arixtra) have been shown to be effective in preventing DVTs after total knee replacements. Some medical literature recommends treatment for at least 14 days in patients without a history of DVTs, and continued treatment for a total of 6 weeks in patients with a history of previous thromboembolism.