Osteoarthritis (OA) is a joint disease that causes chronic pain and disability, reducing patient quality of life. Currently, there is no cure for OA. In fact, many patients are not diagnosed with the disease until they report pain or disability. Radiographic assessments for osteoarthritis diagnosis are not part of routine medical screening, thus, pain is a required symptom for an OA diagnosis. Without pain, even a highly damaged joint is medically regarded as pre-osteoarthritic [1].

Preclinical osteoarthritis research has been historically concerned with developing disease modifying drugs and has taken a heavily chondrocentric view of OA. This approach might seem to be the logical path forward, as cartilage damage is a hallmark of the disease. However, studies show a marked disparity between patient reports of pain and the severity of observed joint damage. Fortunately, the links between OA pain and pathogenesis are becoming a focus of preclinical research, and pain is becoming a more commonly included metric in preclinical studies.

However, pain assessment in animal models is not trivial. In this work, rodent gait analysis is presented as a quantitative measure of osteoarthritic pain and disability. Importantly, while rodents and humans clearly differ in many respects, the concept of gait assessment as a tool to assess OA’s consequences has a direct clinical analogue. Herein rodent gait parameter calculation and assessment is presented, as well as a novel method of simultaneous dynamic and spatiotemporal gait data collection for rodent models (EDGAR).

These methods and technologies were applied to two common models of osteoarthritis in the rat:​ a chemical and surgical model. While these models are ostensibly both OA models, they present different pathology and symptoms. EDGAR was used to investigate gait abnormality development in both models. Additionally, EDGAR was used to investigate the effects of light exercise on a rat model of OA. Exercise is one of the most common non-pharmacological OA therapies and has been reported to significantly alleviate OA pain in many patients.

Using gait analysis, it was found that different OA models induce unique pathologic gaits, with profiles similar to those observed in human pathologic gaits. It was also found that exercise reduced the severity of maladaptive gait changes in the medial meniscus transection model of OA. Advancing gait technology and applying it to preclinical OA research provides a translational measure of OA pain that may improve the likelihood of successful OA therapeutic development in the future.