Andrew Sprague, assistant professor in the Department of Physical Therapy, was recently awarded $645,053 by the National Institute of Arthritis and Musculoskeletal and Skin Diseases for a five-year project titled, “Graft harvest as a model of tendon injury: Trajectory of recovery and clinical outcomes.” Below, he explains the study and its importance to future tendon injury patients.
Tendon injuries are rampant, occurring at rate that exceeds low back pain or anterior cruciate ligament (ACL) tears. More than likely, you or someone you are close to has experienced a debilitating overuse tendon injury or tendon rupture.
One of the biggest challenges in designing treatments for tendon injuries is that it can be very difficult to study how an injured tendon responds to a given intervention. When a tendon is injured, there are changes in the size and stiffness of the tendon. Researchers can evaluate whether a treatment is working by looking at these changes and determining how well the treatment restores the tendon to its pre-injury size and stiffness. Unfortunately, we rarely know what the size and stiffness was before injury since these changes begin before the patient is even aware that they are injured. Ideally, researchers would be able to recruit a large group of healthy individuals, measure their tendons, track them until they develop the injury of interest, and then apply a treatment. In reality, this is too time intensive and expensive to be practical.
Individuals undergoing anterior cruciate ligament (ACL) reconstruction may provide a solution to this dilemma. A portion of the patient's tendon (patellar, hamstring or quadricep tendons) is typically used to reconstruct the ACL. When this portion of the patient’s tendon is removed through a process called graft harvesting, it creates an "injury" to the tendon. Since we know when the "injury" will occur, we have an opportunity to collect pre-injury measures and see how well treatments return the tendon to pre-injury values.
Sprague performing a clinical examination of a patient’s patellar tendon.
When arriving at Pitt, I was looking for opportunities to bridge the gap between mechanistic studies of tendon injuries, which use animal models, and clinical research, which applies treatments to injured humans. Fortunately, the Departments of Orthopaedics and Physical Therapy, as well as our clinical collaborators at UPMC, are running one of the largest, most comprehensive ACL reconstruction clinical trials in the world.
This study, the STABILITY 2 Trial, is investigating optimal tendon graft choice (patellar or quadriceps tendon) for patients with ACL injuries that are at high risk of graft failure. As an investigator on this trial, the opportunity to look at the graft harvest site as a model of tendon injury spurred my development of this study.
During my PhD training, I developed expertise in tissue mechanics and ultrasound imaging, which gave me the tools to measure changes in the size and stiffness of the tendon before and after injury. These skills, along with Pitt's strong relationship between its Physical Therapy and Orthopaedics Departments, collaborations with the UPMC Health System, and resources for junior investigators have made this the ideal place to conduct this study.
I'm most excited about the opportunity to bridge the gap between mechanistic and clinical research. Treatments for tendon injuries are designed to restore the structure and function of the tendon, but in the clinical setting we use pain as the marker of improvement. So clinicians and researchers are using different outcomes to determine whether a treatment is effective. This study will allow us to look at all these measures at one time, or simultaneously.
Sprague performing an ultrasound on a patient’s patellar tendon.
This research has the potential for very broad impact. Once we establish the expected timeline and trajectory of changes in the tendon after an injury, we can use the ACL graft harvest site as an opportunity to test new interventions or refine existing interventions and improve clinical outcomes.
This is a career development award so it also provides the opportunity to expand and improve my research skills. As part of this grant, and partially independent of the research project, I will develop skills in designing and implementing large clinical trials, improve my understanding in tendon biology, and develop the statistical skills that are critical for designing clinical trials and interpreting the results.
Andrew Sprague joined the Department of Physical Therapy in 2020 after completing his PhD in Biomechanics and Movement Science and Doctor of Physical Therapy at the University of Delaware. His research focuses on evaluation and rehabilitation of overuse tendon injuries, with a focus on individualized exercise and recovery prescription.
Grant ID #: NIH NIAMS K23AR080741
Published September 20, 2022