From the Guidelines
Deep vein thrombosis (DVT) is a significant concern in patients with knee injuries, particularly those with a high risk of venous thromboembolism (VTE), and the risk of developing DVT after knee injuries can range from 5-60% depending on the type of injury. The most recent and highest quality study, 1, published in 2021, provides guidelines for the acute care of severe limb trauma patients and recommends assessing the risk of VTE in these patients. According to this study, the prevention of VTE in patients with knee injuries requires a personalized patient risk assessment, considering factors such as the injured area, immobilization, and the opportunity for early pharmacological thromboprophylaxis.
Risk Factors for DVT
The risk of DVT after knee injuries is increased by several factors, including:
- Immobilization of the leg
- Damage to blood vessels near the injury site
- Reduced mobility during recovery
- Inflammatory response to injury, which creates a hypercoagulable state that promotes clot formation
- Proximity of the fracture to the knee, as noted in 1
Prevention of DVT
To prevent DVT after knee injuries, doctors typically recommend:
- Early mobilization when possible
- Mechanical prophylaxis like compression stockings
- In higher-risk cases, blood thinners such as low molecular weight heparin (LMWH) or direct oral anticoagulants
- The duration of prophylaxis varies based on risk factors but often continues until normal mobility resumes, as suggested in 1
Diagnosis and Treatment
Patients should be vigilant for symptoms like calf pain, swelling, warmth, and redness in the affected leg, as prompt treatment of DVT is essential to prevent complications like pulmonary embolism. The diagnosis and treatment of DVT are crucial to prevent long-term complications, such as postthrombotic syndrome (PTS), which can significantly impact quality of life, as noted in 1.
Recommendations
Based on the most recent and highest quality study, 1, it is recommended to initiate early pharmacological thromboprophylaxis with LMWH after haemorrhage control and haemostasis in patients with knee injuries who are at high risk of VTE. The timing of initiation of pharmacological thromboprophylaxis should be determined by the type of injury, and the opportunity for early pharmacological thromboprophylaxis should be assessed individually.
From the Research
Incidence of DVT in Knee Injuries
- The incidence of deep vein thrombosis (DVT) in patients with knee injuries is a significant concern, with studies indicating a varying range of occurrence 2, 3.
- A study published in 2016 found that 50% of patients with high-energy knee injuries had venographic evidence of DVT before knee arthroscopy, with 10.9% of these cases being proximal DVT 2.
- In contrast, a 2013 study reported a lower incidence of DVT, with only 3.1% of patients with below-knee immobilization due to ankle sprains or stable foot/ankle fractures developing DVT 3.
Risk Factors for DVT in Knee Injuries
- The presence of multiple risk factors can increase the likelihood of developing DVT in patients with knee injuries, with one study finding that the incidence of DVT significantly increased in patients with three or more risk factors 3.
- The D-dimer level can be a useful marker for DVT, with higher levels indicating a greater risk of developing DVT, especially in patients with symptoms persisting for more than 10 days 2.
Prevention and Treatment of DVT in Knee Injuries
- Anticoagulation therapy is a common treatment for DVT, with direct oral anticoagulants (DOACs) such as rivaroxaban and edoxaban being preferred due to their effectiveness and convenience 4.
- Chemoprophylaxis may be necessary for patients with multiple risk factors for DVT, with low molecular weight heparin (LMWH) and factor Xa inhibitors being effective options 5, 6.
- A network meta-analysis published in 2024 found that fondaparinux, rivaroxaban, and edoxaban were superior to enoxaparin in reducing the risk of DVT and venous thromboembolism (VTE) in major surgeries, including lower limb surgeries 5.