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Achilles Tendon Ruptures and Blood Clot Risk

Achilles tendon ruptures (ATRs) are a common injury, especially among active individuals. While recovery often focuses on regaining strength and mobility, a less-discussed but serious risk is the development of blood clots, known medically as venous thromboembolism (VTE). This article summarizes the findings of a large UK study (the UK-FATE audit) that investigated the risk of VTE after an ATR.

Reference

Solan, M., Briggs-Price, S., Houchen-Wolloff, L., Malhotra, K., Mason, L., Mangwani, J., & UK FATE. (2025). Incidence of Venous Thromboembolism Following Achilles Tendon Rupture. Data from the UK Foot and Ankle Thrombo-Embolism (UK-FATE) Audit. Articles in Press, 112212.

Key Findings

  • Significantly Higher Risk: People who experience an ATR are about 6.5 times more likely to develop a symptomatic VTE (a blood clot that causes noticeable symptoms) compared to people recovering from other foot and ankle surgeries.
  • VTE Rate: In the study, 3.69% of ATR patients developed a symptomatic VTE within 90 days of the injury. This compares to only 0.57% of patients who had other types of foot and ankle surgery.
  • Age Matters: Older individuals who suffered an ATR were more likely to develop a VTE. The average age of those who developed a clot was 54, compared to 48 for those who didn’t.
  • Treatment Type (Surgery vs. Non-Surgery): Whether the ATR was treated with surgery or non-surgically (e.g., casting or bracing) didn’t significantly change the risk of VTE. While the non-surgical group had a slightly higher rate (4.09% vs. 2.53%), this difference wasn’t statistically meaningful.
  • Immobilization and Weight-Bearing: Surprisingly, different approaches to immobilization (cast vs. boot, allowing weight-bearing early vs. later) didn’t seem to affect the VTE risk.
  • Blood Thinners (Prophylaxis): The use of blood-thinning medication (like low molecular weight heparin, or LMWH) was common (86.7% of patients received it), but the study didn’t find a statistically significant difference in VTE rates between those who received blood thinners and those who didn’t. Most patients received these medications for about 6 weeks.
  • Other Factors: Things like gender, ethnicity, the presence of other medical conditions, smoking, and long-haul flights didn’t show a statistically significant impact on VTE risk in this study. However, it’s important to note that some of these factors had very few participants, so a larger study might find different results.

Why the Higher Risk?

The exact reasons for the increased VTE risk after ATR aren’t fully understood, but several factors may contribute:

  • Inflammation: The injury itself causes inflammation near the deep veins of the calf, which could potentially trigger clot formation.
  • Immobility: While the study didn’t find a difference between immobilization types, any period of reduced movement can increase VTE risk.
  • Age: As mentioned, older individuals are generally at higher risk of VTE, and ATRs are becoming more common in an aging population.

What Does This Mean for Patients?

  • Awareness: If you experience an ATR, be aware of the increased risk of VTE. Discuss this with your doctor.
  • Symptoms: Learn the symptoms of VTE, which can include:
    • Deep Vein Thrombosis (DVT) (usually in the leg): Pain, swelling, redness, and warmth in the calf or thigh.
    • Pulmonary Embolism (PE) (in the lungs): Sudden shortness of breath, chest pain (especially with deep breaths), coughing up blood, rapid heart rate.
    • Seek immediate medical attention if you experience any of these symptoms.
  • Prophylaxis Discussion: Have a thorough discussion with your doctor about the potential benefits and risks of blood-thinning medication. This study doesn’t definitively prove or disprove their effectiveness after ATR, and more research is needed.
  • Chronic ATR: This study did not include individuals with chronic or late-presenting ATR.

Limitations of the Study

  • Symptomatic VTE Only: The study only looked at symptomatic VTE. Some people may have had clots without experiencing symptoms, so the actual VTE rate might be higher.
  • Observational: This was an observational study, meaning it can’t prove cause and effect. For example, it can’t definitively say whether blood thinners prevent VTE after ATR.
  • Missing Data: Some data, like BMI, was not collected.

In Conclusion

ATR carries a significantly higher risk of VTE compared to other foot and ankle surgeries. While the best course of action regarding blood thinners remains unclear, awareness of the risk and prompt medical attention for any symptoms are crucial for patient safety. Further research is needed to determine the optimal strategies for preventing and managing VTE after ATR.