(L-452) Wearable Near Infrared Spectroscopy Technology for Monitoring Internal Physiologic Data as an Objective Digital Biomarker for Ulnar Collateral Ligament Reconstruction

Introduction:: Ulnar collateral ligament (UCL) is one of the main stabilizers of the elbow joint and runs on the inner side of the elbow. UCL tears can occur due to the prolonged exposure and overworking of joint stresses and results in decreased strength in flexion and extension of the elbow. An injury to this ligament, which is common among baseball pitchers at all levels, can lead to pain and significant time off due to the duration of rehabilitation required to regain neuromuscular deficits that occur from the injury. Current rehabilitation approaches for UCL tears involve subjective assessments (pain scales) and objective measures such as monitoring joint angles and range of motion. However, there remains an unmet clinical need to measure biomarkers to provide continuous, internal data on muscle physiology during the rehabilitation process. We believe that the use of wearable near infrared spectroscopy technology enables measurement of digital biomarkers such as muscle oxygen saturation to assess oxygen utilization in the muscle groups thereby indicative of improvements in osseointegration and neovascularization of the neoligament following reconstructive surgery. This study seeks to collect baseline data on healthy collegiate baseball athletes to enable the development of musculoskeletal models for subsequent translation to injured athletes.

Materials and Methods:: This study is IRB approved (CWRU IRB #: 2019-0957). We have collected data of six healthy collegiate baseball players so far (data on one is presented herein). We plan on collecting a total of thirty healthy collegiate baseball players for this study to look at changes in muscle oxygen saturation levels over a workout. In addition (while not presented), we are also measuring heart rate as a direct measure for internal workload and also having athletes report their rating of perceived exertion, a subjective metric to collect feedback on the difficulty of the workout the athlete undergoes. All data is secured in a HIPAA compliant survey and identified by the team for analysis. Microsoft Office (2023) and Matlab (2023) were used to analyze the data.

Results, Conclusions, and Discussions::

Ulnar Collateral Ligament injuries pose a significant financial and mental hurdle for athletes of all age groups (Figure 1a). Collecting baseline data on key physiological parameters such as muscle oxygen saturation enables the development of predictive models for comparative assessment to guide return to play following such season ending injuries (Figure 1b). Muscle oxygen saturation level is calculated based on changes in oxygenated and deoxygenated hemoglobin levels (Figure 1c). For example, the muscle oxygen saturation percentage for a baseball pitcher can occur due to repetitive motion from performing each activity. Also, the muscle oxygen saturation percentage does show a higher range from 30 to 70% in muscle oxygen saturation compared to the strength exercises ranging from 25 to 60%. The data suggests that the changes in SmO2 levels for healthy baseball pitchers can happen due to intensity, and duration of the workload (Figure 1D). In other words, the pilot data presented provides evidence of the sensitivity of such technology to monitor a key biomarker critical for performance monitoring and optimization. With the increased incidence of such injuries in youth pitchers today, data from this study may help inform policy on pitch counts and player safety to reduce injury burden. Additionally, this study highlights the need for interdisciplinary collaborations between biomedical engineering, orthopedic surgery, and physical therapy is needed to address unmet clinical needs.


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