Biomechanical and Clinical Evaluation of a Gait Modifying Device for Treating Knee Pain

Gait modification may reduce pain and slow the progression of medial compartment knee OA. Several biomechanical gait modification interventions to reduce the peak KAM have been tested. The strategies include changing medial-lateral trunk sway and changing toe-in or toe-out. Medial knee thrust, medial weight transfer and wider steps may also reduce knee load based on results of individual studies. Limitations to the translation of these methods to the general OA population include the challenges of teaching people to perform a modified walking pattern and the challenges of maintaining said gait changes during activities of daily life. It remains unclear whether these gait-retraining methods can result in lasting benefits or translate to better functionality, decreased pain, and improved quality of life. The longer-term effects are not well understood. Moreover, most of these interventions are not geared toward optimizing one's own neuromuscular control about the knee joint. A possible method to achieve better neuromuscular control and reduce the peak KAM in people with medial compartment knee OA is to use gait-modifying shoes that create instability while walking. Use of these gait-modifying shoes may effectively reduce knee pain through motor learning and adaptations in one's own neuromuscular control. The investigators will study the prototype gait-modifying design to determine whether differential pain and gait responsiveness to these gait-modifying shoe design occurs. It is not currently known how the motion and joint moments of the lower extremity joints above and below the knee are impacted with these types of shoes. This is an unfortunate scientific deficit because motion at the knee is controlled in part by motion at the hips and ankles. As such, the investigators seek to determine how these gait-modifying shoes impact the kinematic chain. They also seek to understand how gait-modifying shoes change spatiotemporal gait metrics over time. Finally, the investigators want to determine how the magnitude of pain relief obtained with gait-modifying shoes relates to joint mechanics and to subjective pain interference, a patient-focused outcome that represents value of the treatment. Data are scarce with respect to the acute and training-induced changes in kinematics and muscle activation that can occur with gait-modifying shoes. This study will address this deficit by examining the acute effect of wearing gait-modifying shoes and then examine the training-induced effect by having participants wear them at home and returning at 4, 8, and 12 weeks after the initial acute study. These findings can guide the investigators on an eventual treatment protocol and ideal follow-up intervals as well as length of treatment. The goal is to provide information to practitioners and therapists so they may use gait-modifying shoe intervention programs and treatment expectations for the population with moderate knee OA.