The purpose of this study is to evaluate in-laboratory mobility outcomes, pain perception, and user satisfaction with the Keeogo , a robotic exoskeleton for providing assistance on knees during stand and swing for a population with impaired mobility, as compare with standard knee braces. The investigators hypothesize that participants could have improved performance outcomes on walk test, timed up and go test, stair test, pick up penny from floor test, and the Short Physical Performance Battery (SPPB) when using the Keeogo as compared with their prescribed knee braces.

Knee osteoarthritis (OA) is a growing problem due to increased longevity and obesity with estimates of 14 million people living with this impairment. Knee OA results in decreased activity and lifestyle changes, further exacerbating an individual's health. Exoskeleton technology (Keeogo , B-temia, Inc.) may be a viable alternative to standard knee OA treatment by providing powered support to reduce pain during mobility. To the investigators' knowledge, the Keeogo is the only commercially available (in Canada) robotic exoskeleton for a non-paralyzed population who can stand and initiate a stepping action, but have impaired mobility for functional tasks. Keeogo provides active assistance during stance and swing phases and assists users to perform functional mobility tasks including walking, stair climbing, sit-to-stand, bending, squatting, and kneeling. Preliminary studies with the Keeogo in six persons with knee OA showed efficacy for pain reduction during different mobility tasks. Keeogo may have the potential to address functional mobility problems and pain in Veterans with knee OA but is not yet approved by the FDA. An in-laboratory evaluation of performance outcomes using the Keeogo compared with standard knee braces are lacking. Absence of published prescription and general guidelines for use in Veterans with knee OA were also identified as limitations.

The purpose of this study is to evaluate in-laboratory mobility outcomes, pain perception, and user satisfaction with the Keeogo as compare with standard knee braces. The investigators hypothesize that participants could have improved performance outcomes on mobility tests, including a 6-minute walk test, timed up and go test, 13-step stair test, pick up penny from floor test, and the Short Physical Performance Battery (SPPB) when using the Keeogo as compared with their prescribed knee braces and reduced pain with the Keeogo by the numeric pain rating scale (NPRS) as compared with their prescribed knee braces for the mobility tests.

A knee OA-specific tuning protocol will be developed and used in the in-laboratory evaluations in 26 Veterans with knee OA at the James J. Peters VA Medical Center, Bronx, NY. This in-laboratory study is expected to demonstrate improved walking velocities, stair ascent/descent times, improved sit-to-stand, stand-to-sit, and object retrieval from the floor with reduced pain while participants use the Keeogo.

Inclusion Criteria:

• medical diagnosis of Grade 3 or 4 knee OA
• have a prescribed knee brace for at least three months
• self-reported knee pain when standing, walking, climbing stairs, squatting, or other mobility activities
• self-reported limitations to mobility and walking activities due to knee pain, stiffness, loss of range of motion

Exclusion Criteria:

• neurological paralysis causing an inability to stand, weight bear or take stepping movements
• fixed contractures resulting in limited range of motion in the hip, knees, or ankles that prevent sitting, standing, walking, and/or squatting activities
• able to walk at a normal walking speed (>1.2 m/s) based on a 6-minute walk test (6MWT)
• anthropometric incompatibility with the device
• any medical complication or co-morbidity as judged by the study physician to be contraindicated for wearing the device or walking (e.g., cardiovascular disorders, pressure ulcers, open wounds, lower limb vascular disorders, or other medical conditions)
• a score of <8/10 on the MacArthur Competence Assessment Tool for Treatment (MacCAT-T) (as a proxy for cognitive competency screening); and 7) pregnancy or planning on becoming pregnant