Patellar tendon injuries, common among athletes and active individuals, can derail lives with chronic pain and restricted mobility. Recognizing the significant negative impact these injuries have on the quality of life for those suffering from them, researchers at UW hope to revolutionize treatment and help affected patients reclaim their active lives. Led by Naoaki Ito, DPT, PhD, a postdoctoral researcher and Jack Martin, PhD, a research scientist, in the UW-Madison Department of Orthopedics and Rehabilitation and Badger Athletic Performance, and Scott Crawford, PhD, an assistant professor in the UW-Madison Departments of Kinesiology at the School of Education and Orthopedics and Rehabilitation, the team is taking an innovative approach to address the challenges of both treating and tracking recovery of the tendon.

Like a bridge, the patellar tendon connects the powerful quadriceps muscle to the tibia to enable smooth knee movement. When the tendon is injured, the standard treatment is exercise therapy. However, determining the optimal exercise load to promote healing is a major, ongoing challenge. Currently, clinical practices rely on external weight measurements to guide treatment, but these don’t tell the whole story, as patients’ bodies often compensate in subtle ways, masking the true load on the tendon.

Further, traditional imaging tools like ultrasound and MRI do not fully capture the tendon’s response to treatment, making it difficult to track recovery.

Game-Changers in Tendon Load Measurement and Recovery Tracking

Research studies led by Drs. Ito, Martin, and Crawford employ a novel approach to load measurement using a shear wave tensiometer – a wearable device co-developed by Dr. Martin here at UW that directly measures tendon load during exercise. Instead of relying on external weights, the team is developing a rehabilitation protocol guided by the actual load experienced by the tendon. This approach would give clinicians a clearer picture of what is happening inside the body, leading to more precise, individualized treatment and better healing outcomes.

Leveraging a long-standing research collaboration between the Department of Orthopedics and Rehabilitation and the Departments of Radiology and Medical Physics, Dr. Ito is working with Ivan Rosado-Mendez, PhD, Diego Hernando, PhD and Samuel Hurley, PhD to explore advanced imaging techniques to improve tendon health and recovery assessment. These techniques include diffusion tensor imaging (DTI), a form of MRI that measures the tendon’s microstructure, and quantitative ultrasound imaging techniques such as shear wave elastography and back-scatter anisotropy analysis, which can provide detailed insights into tendon properties – and offer a more accurate way to track tendon healing during rehabilitation.

Fueling Innovation Through Collaboration and Funding

In May 2024, Dr. Ito launched an ongoing study funded by the Department of Orthopedics and Rehabilitation Freedom of Movement Award to test the repeatability of DTI measurements in patients with patellar tendon injuries. Additionally, through matched funding from the UW-Madison Departments of Radiology and Medical Physics Radiology Research and Development Fund, Dr. Ito and his co-PIs are collecting quantitative ultrasound images to compare different imaging methods for assessing tendon health. And beginning in 2025, Drs. Ito, Martin, and Crawford will launch a new study funded by a UW Institute for Clinical & Translational Research (ICTR) pilot grant using shear wave tensiometry to measure tendon load during 25+ rehabilitation exercises. The team will also integrate quantitative ultrasound to explore the relationship between tendon load and tendon properties, leveraging additional funding from the Wisconsin Partnership Program (WPP) 20th Anniversary Postdoctoral Grant awarded to Dr. Ito in October 2024.

Transforming Patient lives

By integrating direct tendon load measurements using cutting-edge technology with advanced imaging techniques, the team aims to provide a more accurate and individualized approach to rehabilitation while offering valuable insights into patellar tendon healing and better tracking of a treatment’s effectiveness. “This novel line of research led by Dr. Ito has substantial promise in improving how we care for tendon injuries, leading to greater function and activity levels for our patients,” says Bryan Heiderscheit, PT, PhD, Frederick Gaenslen Professor and Vice Chair of Research for the Department of Orthopedics and Rehabilitation and Director of Badger Athletic Performance.

For countless patients, this research represents the potential for pain-free movement, restored mobility, and a renewed quality of life. With each discovery, Dr. Ito and his research partners are not just advancing science; they are offering hope to those sidelined by injury – and for anyone waiting to return to the activities they love, that hope is priceless.

Last month, the Institute for Clinical and Translational Research (ICTR) at UW–Madison announced the recipients of its 2024 Translational Basic and Clinical (TBC) pilot awards. Among the 11 projects funded is a study led by Jack Martin, PhD, a research scientist in the University of Wisconsin Department of Orthopedics and Rehabilitation, and Scott Crawford, PhD, an assistant professor in the University of Wisconsin Departments of Kinesiology at the School of Education and Orthopedics and Rehabilitation at the School of Medicine and Public Health. Their project, “Measuring Patellar Tendon Load during Exercise Using Wearable Sensors,” was awarded $50,000 to advance research on rehabilitation practices for tendon injuries.

Martin and Crawford’s study seeks to improve the accuracy of patellar tendon loading during rehabilitation after tendon injuries by:

• Determining whether the external loading prescribed by physical therapists aligns with the actual load experienced by the patient’s patellar tendon;
• Investigating the potential of electrical muscle stimulation to enhance tendon loading during rehabilitation exercises;
• Exploring the use of quantitative ultrasound to monitor tendon health over time.

Co-researchers on the project include Naoaki Ito, PhD, a postdoctoral researcher in orthopedics and rehabilitation, and Ivan Rosado-Mendez, PhD, an assistant professor in medical physics and radiology. The proposal was accepted on September 27, 2024, with the awarded funds supporting this cutting-edge work to enhance patient recovery and outcomes in tendinopathy treatment.

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UW Orthopedics Trauma Team – L to R: Christopher Domes, MD, Paul Whiting, MD, Gabrielle Kuhn, MD (former Ortho Trauma research coordinator), Christopher Doro, MD, Gerald Lang, MD, and Jacquelyn Dunahoe, MD

Earlier this fall, the University of Wisconsin School of Medicine and Public Health’s orthopedic trauma research team, led by Paul Whiting, MD, received the Major Extremity Trauma Research Consortium (METRC) “Implementation and Data Quality All-Star Award”. The award was announced and presented at the Orthopedic Trauma Association’s 39th Annual Meeting held in Seattle, Washington, on October 19-21, 2023.

Established in 2009, METRC represents a large multi-center research collaborative. As part of the METRC network, dozens of major trauma centers nationwide participate in large-scale research projects aimed at improving outcomes following orthopedic trauma injuries in both the civilian and military populations.

The UW team’s METRC All-Star Award was given in recognition of the team’s “exemplary efforts to implement METRC studies with fidelity to the protocol, well-established and thoughtful local procedures, and clear attention to data completeness and data quality.”

UW has been a participating site for more than a decade and, to date, has been a part of more than ten METRC studies. Patients undergoing treatment for a variety of orthopedic trauma injuries are eligible for participation. These patients are screened and enrolled by the UW orthopedic trauma faculty members and the team’s research coordinator. Outcome data are recorded following surgical treatment and at regularly scheduled follow-up visits. Maintaining the highest level of data integrity, ensuring high rates of follow-up, and accurate data collection are critical to the success of this research consortium.

UW is proud to be an active participant in METRC and honored to be recognized for our efforts.