Rotator cuff tears are a common condition affecting approximately 25% of the population older than 60 years, and rotator cuff repair is a standard surgical procedure with nearly 500,000 procedures performed annually. In the United States alone the direct costs are over $7 billion per year. There is a relatively high rate of retears: ranging from 10% to 78%. Healing of the repair cuff is a protracted process during which the repaired tendon has to be unloaded by carefully restricting active muscle contraction. There is an inherent conflict in immobilizing the shoulder to protect the repair and mobilizing the shoulder to prevent stiffness. Teaching the patient passive exercises that do not activate contraction of the supraspinatus muscle is challenging and very difficult to monitor. To address this unmet need, we have developed a wearable sensor that provides direct real-time continuous biofeedback of muscle activity, joint angle, skin temperature, and swelling to enable passive shoulder exercises while minimizing muscle contraction. To test and validate this device we propose to the following Specific Aims.
Aim 1 : Design, manufacture, and test a wearable device with surface EMG (sEMG), inertial measurement unit (IMU), temperature, and bioimpedance sensors.
Aim 2 : Measure accuracy of Active4D sEMG and IMUs relative to standard clinical measurements. Active4D is a surgeon-driven company devoted to enhancing patient recovery from surgery by leveraging new technology. Active4D?s unique wearable sensor provides continuous long-term sensor augmented biofeedback to patients and enables remote patient monitoring for surgeons. The device measures seven physiologic metrics in real time ? muscle activation, joint range of motion, skin temperature, swelling, activity, gait, and fall risk. Real time physiologic data will increase safety, improve outcomes, and enhance patient experience while lowering the cost of rehabilitation and complications. Unique artificial intelligence driven algorithms can decrease complications through predictive analytics which enable early detection and intervention for high risk patients. The specific innovation to the application of rotator cuff repair, is the instantaneous feedback of muscle activity and motion which can accelerate recovery while reducing the risk of retears. At the successful completion of Phase I, we plan to launch a clinical trial comparing the outcomes of rotator cuff repair in patients guided by the A4D device in comparison to the current standard of postoperative rehabilitation. Active4D is a small business with the objective of developing smart wearables, which integrate multiple biological and environmental sensors, wireless communication, computer models, and data analysis for providing feedback and remote monitoring, to enhance surgical rehabilitation and improved patient outcomes in orthopaedics. Co-founders Drs. Hoenecke and D?Lima have extensive experience in shoulder surgery and rehabilitation, multi-center clinical trials, and biomechanics research; and have successfully executed challenging projects such as implantation of innovative electronic knee designs and development of new shoulder implants. Dr. Hoenecke has over 30 years of experience in the practice of sports medicine with an emphasis on shoulder repair and reconstruction. He provides care for elite athletes and is design surgeon for two shoulder implants. Active4D has partnered with expert physical therapists and orthopedists to develop and test our innovative technology.

Public Health Relevance

Rotator cuff tears are a common condition affecting approximately 25% of the population older than 60 years. Despite the popularity of surgical repair, the rate of retears is high: ranging from 10% to 78%. Healing of the repair cuff is a lengthy process during which the repaired tendon has to be unloading by carefully restricting active muscle contraction. This Phase I SBIR will develop an innovative wearable device with the potential to facilitate safe exercises, alert the patient during activities at risk for retears, and accelerate recovery while reducing the risk for retears. The device can also remotely monitor progress of the patient over the postoperative period and can modulate the feedback appropriate to the phase of recovery.

National Institute of Health (NIH)
National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS)
Small Business Innovation Research Grants (SBIR) - Phase I (R43)
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Special Emphasis Panel (ZRG1)
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Wang, Xibin
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Active4d, Inc.
Solana Beach
United States
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