Thesis on blood clot and impaired healing after Achilles tendon rupture
After an Achilles tendon rupture, there is a high risk of both blood clots and slow recovery. On October 9, Annukka Saarensilta will defend her thesis, "Molecular mechanisms of venous thrombosis and healing disturbances after Achilles tendon rupture," in which she studies whether there may be shared biomarkers and potential ways to improve risk assessment and treatment.
”After Achilles tendon rupture, there is an unusually high risk of blood clots during immobilization, and many patients fail to recover fully. This doctoral thesis examines whether blood clot formation and impaired healing may share common biological mechanisms, and whether intermittent pneumatic compression can affect some of these mechanisms,” says Annukka Saarensilta, doctoral student at the Orthopaedics research group, the Department of Molecular Medicine and Surgery, Karolinska Institutet.
What are the most important results?
”We identified several common biomarker candidates for blood clot and poor recovery following Achilles tendon rupture. These biomarkers were identified from Achilles tendon biopsies. STIP1 was one of the biomarker candidates associated with both blood clot and poor recovery. STIP1 has an established role in the cellular stress response system. A likely source of cellular stress during lower limb immobilization is suboptimal tissue oxygenation and endothelial dysfunction. Intermittent pneumatic compression treatment was associated with numerically lower plasma STIP1 levels, providing exploratory support for a possible effect on stress protein biology”.
”However, plasma STIP1 was not associated with either deep vein thrombosis or poor recovery when measured after several weeks of lower limb immobilization. Furthermore, intermittent pneumatic compression treatment was associated with higher nitrite levels, which may indicate an effect on nitric oxide-related signaling and possibly endothelial function. The coagulation and fibrinolytic capacities of blood were strongly associated with deep vein thrombosis after several weeks of lower limb immobilization, with distinct patterns observed in men and women, and demonstrated diagnostic potential. We also found that a larger callus - the size of the early healing tissue within the tendon - early after surgical treatment of Achilles tendon rupture was associated with better long-term outcomes”.
How can this new knowledge contribute to the improvement of people’s health?
”We identified several potential biomarkers of thrombosis and healing which represent promising targets for development of clinical tools for risk assessment and targeted treatments. Our findings also broaden the view of intermittent pneumatic compression from a purely mechanical treatment to an intervention that may also have biological effects. Differences in fibrin formation and fibrinolytic capacity between men and women in relation to established deep vein thrombosis highlight the importance of considering sex differences in research and may prove to contribute to greater precision in clinical risk assessment during lower limb immobilization. Our results suggest that callus size - measured by ultrasound - may be a clinically useful tool for risk stratification following surgical treatment of Achilles tendon rupture”.
What are your future ambitions?
”My goal is to by combining clinical practice with research, contribute to better care for as many patients as possible,” says Annukka Saarensilta.
Dissertation
Friday October 9, 2026 at 09:00, Rehab-salen S2:01, Norrbacka. The doctoral thesis has been supervised by Paul Ackermann.
Thesis
Saarensilta, Annukka (2026). Molecular mechanisms of venous thrombosis and healing disturbances after Achilles tendon rupture. Karolinska Institutet. Thesis. https://doi.org/10.69622/32768994