New study highlights the impact of ACL surgery on tendon health and quadriceps strength
ACL injuries are common in sports that involve rapid changes in direction and can significantly impair athletic performance. Surgical reconstruction using a bone–patellar tendon–bone (BTB) graft is a widely adopted approach, though it carries potential complications such as anterior knee pain and persistent muscle weakness due to graft harvesting.
The study followed athletes for up to 12 months during rehabilitation, employing a relatively novel imaging method—Ultrasound Tissue Characterization (UTC)—to assess patellar tendon healing in detail. Early results confirmed that UTC is a highly reliable method, showing excellent intra- and inter-rater consistency, and offering a valuable tool for tracking tendon recovery over time.
Preoperative evaluations revealed reduced quadriceps strength in the injured leg, while tendon quality did not significantly differ between sides, establishing a meaningful baseline. One of the key findings from longitudinal monitoring was that harvested tendons displayed persistently reduced quality compared to both the contralateral uninjured tendon and their own preoperative state—even a year after surgery. In contrast, tendons that were not harvested maintained relatively stable quality throughout the rehabilitation period.
The researcher also investigated how changes in tendon structure related to clinical symptoms and recovery outcomes. Preoperative quadriceps weakness was associated with poorer knee stability, higher pain levels, extension deficits, and limited load tolerance. Although tendon quality was not directly linked to quadriceps strength, better quality in the donor-site gap correlated with less anterior knee pain and extension deficits, yet paradoxically with more swelling, lower load tolerance, and weaker strength, suggesting complex interactions in tendon recovery and rehabilitation outcomes.
“These insights suggest that monitoring tendon healing with UTC can help tailor rehabilitation programs, balancing the need for muscle strengthening with protection of the healing tendon,” says doctoral student Carla Soncino Pereira.
Overall, the study highlights the complex relationship between tendon health, muscle strength, and clinical outcomes following ACL reconstruction. It supports the integration of advanced imaging techniques like UTC in guiding individualized rehabilitation strategies, with the goal of reducing complications and accelerating athletes’ return to sport.
Carla Soncino Pereira will defend her doctoral dissertation “Patellar tendon quality and quadriceps strength in male athletes with a unilateral ACL injury or reconstruction” on Wednesday, the 18th of June of 2025, at 12:00 noon, in Hall L304 (Liikunta Building) at the University of Jyväskylä. The opponent will be Professor S. Peter Magnusson (University of Copenhagen) and the custos will be Professor Taija Juutinen (University of Jyväskylä).
The defense will be streamed live at https://r.jyu.fi/dissertation-pereira180625
The doctoral thesis is available in the JYX publication archive at http://urn.fi/URN:ISBN:978-952-86-0761-8
More information:
Carla Soncino Pereira
Mobile/ WhatsApp; +97450069661
carlasonsino@hotmail.com
