Rationale:
Roughly 14 million adults aged 60 or older (10% male/13% female) in the United States experience symptoms of knee osteoarthritis (OA). Knee OA pain progressively impacts aging, reducing mobility and increasing morbidity. Nonsurgical self-management of knee OA includes exercise to promote proper knee mechanics, non-steroidal anti-inflammatory drugs (NSAIDs), cortisone injections, and weight loss to reduce pain and retain function. As OA has no cure, self-management progresses to \~1 million joint replacements per year. Critically, home-based devices are lacking for specifically training the low-level proprioceptive and neuromuscular circuitry for proper knee mechanics in a safe, focused, mechanistic way. Such devices would supplement exercises for strength, mobility, and whole-body loading and movement.
Initially considered a wear-and-tear condition, knee OA is now understood as a complex disease involving inflammatory responses to mechanical loading and neuromuscular feedback loops among pain, joint damage, and dynamic loading. Home-based exercises remain a primary nonpharmacological and nonsurgical approach to managing chronic pain in OA that fundamentally disrupts proprioception and neuromuscular control of the joint, which accelerates articular degeneration.
Neuromuscular Dynamics, LLC has developed a simple, safe, quick, and effective Leg Dexterity System that is portable, wireless, and coupled to HIPAA-compliant cloud analytics. A seated participant uses their foot to compress a platform atop a slender spring, which becomes unstable as it begins to buckle at low forces. The participant must then control their leg dexterity (i.e., via short-latency sensorimotor circuits) to stabilize the unstable dynamic foot-ground interactions. A tablet computer connected to the device provides feedback during use and uploads the participant's activity data to the server for analysis and reporting, accessible to users and clinicians.
The investigators have successfully tested Leg Dexterity in control participants in multiple publications. The Leg Dexterity test is safe and poses minimal risk as the forces needed to do it are very low, does not involve full weight- bearing maneuvers, and is performed while seated without the risk of falling.
Study:
The investigators will conduct a randomized home-based clinical trial in knee OA to demonstrate the efficacy of leg dexterity training to reduce pain and improve function compared to currently prescribed dynamic exercise on a wobble board (a commonly used approach for improving proprioception and balance). Successful completion of this study will justify the adoption of the Leg Dexterity System as an effective at-home supplement to any nonsurgical management of knee OA.
The investigators propose a longitudinal double-blind dose-matched trial comparing 8 weeks of leg dexterity training (Treatment using a slender, unstable spring system that engages short-latency sensorimotor control, 42 participants) vs. at-home wobble board exercises (Control, 42 participants) at the Steadman Philippon Research Institute.
Age 40 to 85 years
Ambulatory in home and community settings
History of knee osteoarthritis in one or both knees (Kellgren-Lawrence grade II-IV)
Baseline pain of 3-10 points on the target (i.e., more-affected) knee and a pain differential of at least -2 points on the contralateral knee as exhibited by the worst pain score for the previous week (on the 11-point Numeric Rating Scale, NRS/Visual Analog Scale VAS).
Planned surgery on either the contralateral or target knee at any time during the Study period, including pre-and post-training assessments.
Within 6 months of signing informed consent has received diagnostic arthroscopy of the target knee or arthroscopic surgery (including microfracture and meniscectomy) on the target knee;
Within 12 weeks of signing informed consent has received intra-articular treatment of the target knee with steroids or hyaluronic acid derivatives;
Planned intra-articular treatment of the target knee with steroids or hyaluronic acid derivatives on either the contralateral or target knee at any time during the Study period including pre-and post-training assessments.
Parallel
Lex Dexterity Trainer
DeviceThe Leg Dexterity Trainer is a portable, wireless device. A seated participant uses their foot to compress a platform atop a slender spring, which becomes unstable as it begins to buckle at low forces. The participant must then control their leg dexterity (i.e., via short-latency sensorimotor circuits) to stabilize the unstable dynamic foot-ground interactions.
Wobble Board
DeviceA wobble board is a circular or rectangular board with a rounded base, designed to improve balance, core strength, and coordination by creating an unstable surface that challenges stability.
Pain: Numerical Rating Scale
Study participants will complete the 11-point Numerical Rating Scale (NRS), which is a simple and frequently used pain assessment tool across both clinical research and clinical practice. The resulting score is a unitless integer ranging from 0 to 10, with 0 being no pain and 10 being the most pain imaginable.
Pain and Function: WOMAC
Study participants will complete the Western Ontario McMaster Osteoarthritis Index (WOMAC) pain subscale, which consists of 5 questions about pain experienced during activities like walking, using stairs, and standing. Each item is rated on a 5-point Likert scale from 0 to 4: 0 = none, 1 = mild, 2 = moderate, 3 = severe, 4 = extreme. Scores from each subsale are summed to produce a unitless pain/function score.
Single Leg Stance Test: stance time
During the SLS, participants will be asked to maintain balance on each leg with their arms folded across their chest and eyes closed for at most 30 seconds on both stable (rigid surface) and unstable (e.g., 10 cm thick foam) surfaces on top of two Bertec® force plates with standardized software for SLS (Bertec, Inc., Columbus, OH). Participants will stand on the force plate and lift one foot off the floor (flexing the knee to approximately 60º) at their own pace and balance for up to 30 seconds. Trials will be terminated early upon ground contact with the non-test limb. Participants will complete three repetitions in each condition with each leg (12 total trials, 30 minutes for both legs). The first SLS outcome measure will be stance time.
Performance-Based Physical Function
Measures of functional performance will include the 6-minute walk test (6MW), timed-up-and-go test (TUG), and 4-meter walk (4mW) tests. The 6MW test measures the distance walked in 6 minutes to evaluate endurance. The TUG measures the time it takes a patient to rise from an armchair (seat height of 46 cm), walk 3 m, turn, and return to sitting in the same chair without physical assistance. The 4mW will be assessed at the fastest safe speed for each participant and assess the capacity for performance of certain activities (e.g., crossing a street before the light changes). These tests have been established as meaningful outcome measures in older persons with a wide range of conditions and have demonstrated validity and reliability.
Gait Analysis
Gait kinematics will be assessed using an 8-camera markerless motion capture system (Dari/Captury) during open-ground, free-speed walking. Three walking trials will be collected, with a minimum of 3 gait cycles per trial. Primary outcomes will be knee flexion angle (min/max/range and side-to-side symmetry) and stride parameters.
o 12-Item Short Form Health Survey (SF-12)
The SF-12 is a self-reported outcome measure assessing the impact of health on an individual's everyday life.
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Steadman Philippon Research Institute
Lead sponsor
Neuromuscular Dynamics
Collaborator
National Institute on Aging (NIA)
Collaborator
