Poster 05. Wearable Muscle Oxygenation Monitoring in ACL Reconstruction: Contralateral Limb Validity and Longitudinal Surgical Limb Recovery
Year: 2026
Type: article
Study design: Observational Study
Abstract: Objective: Current clinical practice guidelines for return-to-play (RTP) following anterior cruciate ligament reconstruction (ACLR) rely on a combination of chronobiologic time, RTP functional and strength testing, and clinical judgement. Currently, there are no internal variables utilized to predict readiness for RTP. The purpose of this study is to utilize a wearable muscle oxygen sensor to collect muscle oxygen saturation (SmO2) in healthy athletes and an age-matched cohort to provide an internal variable to track physiologic readiness for RTP. Methods: A total of 50 healthy athletes aged 14-30 without history of lower extremity injury were enrolled to participate in a 1-hour training regimen consisting of a combination of aerobic, isometric, and strength testing. SmO2 sensors were placed on the vastus medialis bilaterally. An age-matched cohort of athletes who underwent ACLR were prospectively enrolled alongside the healthy cohort. For all ACLR patients, demographics, graft type, and quadriceps girth were collected at each visit. ACLR patients subsequently underwent the same testing protocol at 6-, 9-, and 12- month timepoints post-surgery. Data analysis was completed utilizing R-statistical analysis. Analysis was limited to bilateral exercises. Results: Fifty healthy athletes, consisting of 21 males and 29 females (mean age 20.1 yo; range: 18-22 yo) and 28 athletes post-ACLR, consisting of 16 males and 12 females (mean age 16.5 yo; range: 14-21 yo), successfully enrolled and completed the research trial. 25/28 surgical athletes received a patellar tendon autograft and three received a quadriceps autograft. Within the healthy cohort, the mean difference in SmO2 did not statistically differ between the right and left legs. Healthy athletes exhibited a normal variation in SmO2 of ± 5% between their right and left legs. On average, surgical athletes did not see a return of normal muscle physiology by the 6- and 9-month time points but did by the 12-month timepoint. On an individual level, 8/28 athletes at 6-months, 10/28 athletes at 9-months, and 20/28 athletes at 12-months saw recovery of physiologic SmO2. Based on current clinical practice guidelines, mean timeframe for RTP was 10.8 months. Individually, 0/28 at 6-months, 15/28 patients at 9-months, and 26/28 patients at 12-months met clinical criteria for RTP. Among the 8/28 athletes whose SmO2 did not return to normal, five met traditional criteria for clearance at 9-months, and three were cleared for RTP at 10.7 months, 12.8 months, and 17.8 months. Quadriceps girth changed by <1mm as a whole, and no relationships between quadriceps girth and internal muscle physiology were found. Conclusions: Based on a healthy population of athletes, SmO2 readings should fall within ±5% of the healthy leg. Utilizing the healthy cohort as a control, surgical athletes did not see a recovery of normal muscle physiology until the 12-month timeframe in most cases. Many athletes who do meet criteria for RTP based on current clinical practice guidelines were not seen to have normal SmO2 physiology at their time of clearance. At the same time, eight of 28 ACLR athletes were found to have normal muscle physiology at the 6-month timeframe, based on SmO2. Incorporation of an internal measure, such as SmO2, in rehabilitation can supplement the current guidelines which rely on external measurements and assessment to aid in developing a more personalized RTP timeframe. Further collection of the ACLR cohort is ongoing.
Language: English
Subfield: Surgery
Field: Medicine
Domain: Health Sciences
Open Access status: gold
Estimated APC paid: $1,500
OpenAlex ID: W7204797989
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