Outcomes from current treatments for knee pain reveal a persistent unmet need: even after surgical or injection-based interventions, many patients remain limited by pain that restricts movement. Addressing this gap requires new thinking—particularly around the relationship between pain, mobility, and muscle function.

KneeMo was developed by SomaTX Design Inc. (SDI) and released in 2024 to introduce a novel approach to help people with knee pain stay active. It uses smart technology to apply a motion-activated vibratory stimulus to reduce pain and improve function while the user moves. KneeMo targets sensory pathways associated with pain perception, helping to restore muscle function and reduce discomfort during activity.

The Motivation: Rethinking Pain During Movement

Patient feedback following invasive treatments such as joint injections, cartilage repair, or total knee replacement (TKR) often reflects a mismatch between technical success and functional satisfaction. Despite procedural advances, satisfaction rates for TKR average only around 80 percent, largely due to persistent pain after surgery and because many patients expect to resume a higher level of physical activity than they ultimately achieve.

The insight that guided KneeMo’s development was straightforward but transformative: reducing pain during movement may enable better function, satisfaction, and outcomes before and after invasive procedures. When patients remain active, they preserve muscle strength, cardiovascular health, and mental well-being—all factors that influence surgical outcomes and long-term quality of life.

The Opportunity: A Smart Device for a Complex Problem

Osteoarthritis (OA) is one of the leading causes of chronic knee pain, affecting millions of adults worldwide. With aging populations and rising expectations for active lifestyles, the need for noninvasive interventions that sustain mobility is increasing rapidly.

OA’s multifactorial etiology creates both a challenge and an opportunity. Pain does not arise solely from cartilage degeneration; it also stems from the subchondral bone, ligaments, menisci, tendons, and synovium. Traditional treatments aimed at specific tissues often fail to address pain arising from this complex system. KneeMo instead acts along the common neural pathway to the brain, mitigating pain irrespective of its tissue source.

Engineering the Solution: Smart, Motion-Activated Vibration

Designing a device to relieve pain as movement occurs demanded an integration of biomechanics, neuroscience, and user-centered engineering. KneeMo applies principles of Gate Control Theory, using cutaneous intermittent vibration synchronized with motion to modulate pain signaling through the somatosensory system. Each device consists of two lightweight bands placed above and below the knee, housing microprocessors, motion sensors, and Bluetooth modules. These components work together to detect motion in real time and deliver precise motion-activated intermittent cutaneous vibration that is synchronized with a user’s gait to reduce perceived pain during walking or other activity.

Bluetooth connectivity allows activity data to sync with a smartphone app, enabling users to monitor activity levels. Tracking movement was intentionally incorporated, as maintaining daily activity is closely tied to improved rehabilitation outcomes and overall satisfaction. The user-centered design offers a portable, wearable adjunct to existing treatment plans, bridging the gap between passive pain relief and active recovery.

Clinical Validation: Translating Theory into Measurable Outcomes

Clinical studies evaluated KneeMo’s effects on pain, gait, and quadriceps function. In a longitudinal, randomized, controlled crossover study, participants with chronic knee pain due to osteoarthritis or prior injury wore KneeMo and a passive device over separate four-week intervention periods. Results demonstrated significant improvements in reported pain, quadriceps function, and proprioception with KneeMo; results that were not observed with the passive control device. These findings, detailed in peer-reviewed publications (article 1; article 2; article 3), confirm that the motion-activated vibrational stimulus can improve both comfort and function during movement.

Overcoming Perceptions About Activity and Osteoarthritis

A longstanding misconception that activity worsens OA continues to discourage movement among individuals with knee pain. Contemporary research shows the opposite: regular physical activity supports joint health and improves overall well-being. By helping users stay active comfortably and improving muscle function, KneeMo addresses both physiological and psychological barriers to movement.

Implications for the Orthopedic Industry

For device manufacturers and clinicians, KneeMo represents an opportunity to complement existing surgical and nonsurgical approaches. Incorporating movement-based pain modulation early in the treatment continuum could enhance patient outcomes and satisfaction with interventions such as TKR.

Reducing pain during motion may also encourage prehabilitation and postoperative activity, two of the strongest predictors of recovery success. Integrating wearable neuromodulation into standard orthopedic protocols could redefine how clinicians manage movement-related pain.

Looking Ahead

The challenge of designing for reducing pain during movement required bridging biomechanics, neurophysiology, and smart-system engineering. The success of KneeMo demonstrates that this convergence is both achievable and impactful. As demand grows for technologies that extend mobility, innovations that prioritize pain relief in motion may play an increasingly central role in orthopedic care.

Tom Andriacchi, Ph.D., is president of SomaTX Design Inc., co-inventor of KneeMo, and professor emeritus of Mechanical Engineering and Orthopaedic Surgery at Stanford University. Dr. Andriacchi has more than 50 years of research experience on the biomechanics of the knee, focused on solving clinical problems ranging from sports injury to osteoarthritis. His research has been recognized by international awards from both engineering and medical societies.