Injury management in elite sport is undergoing a transformation thanks to the integration of technologies that allow for the monitoring of recovery processes and provide objective criteria regarding tissue status. Historically, the return to competition after an ankle sprain has been based on purely chronological criteria or functional tests that often ignore the physiological state of the damaged structure. This disconnection between mechanical function and tissue health contributes to recurrence rates that reach 41%, frequently leading to chronic instability and long-term functional limitations for the professional athlete.

Given this scenario, a recent study published in the Journal of Clinical Medicine proposes the use of infrared thermography (IRT) as an objective biomarker to monitor inflammation and guide transitions during rehabilitation phases. Infrared thermography is presented as a non-invasive and rapid-acquisition tool capable of detecting thermal asymmetries linked to metabolic and inflammatory processes. Unlike other imaging techniques such as Magnetic Resonance Imaging, which can show structural anomalies long after functional recovery, thermography reflects skin temperature associated with blood flow and tissue regeneration in the region.

The research team retrospectively analyzed 26 athletes using ThermoHuman software to quantify temperature variations in the anterior ankle region from the moment of injury until the total return to competition. This approach allows for the transformation of a thermal image into precise quantitative data, eliminating the subjectivity of traditional clinical evaluations.

Key Physiological Findings

The results reveal a characteristic thermal pattern that begins with a robust hyperthermic response immediately following the ligamentous trauma. During this acute phase, a mean temperature increase of +0.594°C was observed in the injured ankle compared to the healthy one, with an effect size considered large. This initial thermal increase not only confirms the presence of a systemic inflammatory response triggered by tissue damage but also establishes a physiological reference point to assess injury severity and predict subsequent evolution.

Monitoring this initial peak is crucial, as thermal increases above this threshold could be associated with a less favorable initial prognosis and more complex reparative processes. As the rehabilitation process progresses, thermal asymmetry decreases gradually, allowing for the identification of biological milestones.

Milestones and Return to Play (RTP)

The study determined that the first significant reduction in temperature occurs between 21.5 and 28.5 days after the injury, a moment that physiologically coincides with the transition from the proliferation phase to the remodeling and maturation phase of collagen. In this fourth-week interval, the approximate thermal decrease of -0.488°C marks a window of therapeutic opportunity where the tissue becomes mechanically more competent to withstand organized loads.

A particularly relevant finding for coaching staffs is the non-linear nature of thermal recovery during the final phases of return to play. In the sixth week, researchers detected fluctuations or temporary increases in temperature that could reflect reactive structural responses to an increase in training load or reincorporation into exercises with the group. These thermal variations allow physical trainers to adjust work volume and intensity individually, detecting reactive episodes before they lead to a clinical relapse.

In conclusion, the integration of infrared thermography in the high-performance sports environment improves decision-making safety by adding a tissue status criterion to existing jump, strength, and balance tests. By establishing objective thermal asymmetry thresholds, this technology helps minimize the risk of recurrence and optimize sports absence times. The future of ankle sprain management involves this physiological monitoring model, which allows health and sports performance professionals to base their discharge criteria not only on what the athlete is capable of doing but also on the biological state of their ligaments.

Bibliography:

Escamilla-Galindo VL, Fernández-Muñoz D, Fernández-Carmona J, Ceniza-Villacastín JA, Fernández-Cuevas I. Reframing Ankle Sprain Management: The Role of Thermography in Ligament Injury Monitoring. J Clin Med. 2025 Dec 24;15(1):134. doi: 10.3390/jcm15010134. PMID: 41517383; PMCID: PMC12786798.