Early postoperative step count and walking time have greater impact on lower limb fracture outcomes than load-bearing metrics.

INTRODUCTION: Weight-bearing protocols for rehabilitation of lower extremity fractures are the gold standard despite not being data-driven. Additionally, current protocols are focused on the amount of weight placed on the limb, negating other patient rehabilitation behaviors that may contribute to outcomes. Wearable sensors can provide insight into multiple aspects of patient behavior through longitudinal monitoring. This study aimed to understand the relationship between patient behavior and rehabilitation outcomes using wearable sensors to identify the metrics of patient rehabilitation behavior that have a positive effect on 1-year rehabilitation outcomes. METHODS: Prospective observational study on 42 closed ankle and tibial fracture patients. Rehabilitation behavior was monitored continuously between 2 and 6 weeks post-operative using a gait monitoring insole. Metrics describing patient rehabilitation behavior, including step count, walking time, cadence, and body weight per step, were compared between patient groups of excellent and average rehabilitation outcomes, as defined by the 1-year Patient Reported Outcome Measure Physical Function t-score (PROMIS PF). A Fuzzy Inference System (FIS) was used to rank metrics based on their impact on patient outcomes. Additionally, correlation coefficients were calculated between patient characteristics and principal components of the behavior metrics. RESULTS: Twenty-two patients had complete insole data sets, and 17 of which had 1-year PROMIS PF scores (33.7 ± 14.5 years of age, 13 female, 9 in Excellent group, 8 in Average group). Step count had the highest impact ranking (0.817), while body weight per step had a low impact ranking (0.309). No significant correlation coefficients were found between patient or injury characteristics and behavior principal components. General patient rehabilitation behavior was described through cadence (mean of 71.0 steps/min) and step count (logarithmic distribution with only ten days exceeding 5,000 steps/day). CONCLUSION: Step count and walking time had a greater impact on 1-year outcomes than body weight per step or cadence. The results suggest that increased activity may improve 1-year outcomes for patients with lower extremity fractures. The use of more accessible devices, such as smart watches with step counters combined with patient reported outcome measures may provide more valuable insights into patient rehabilitation behaviors and their effect on rehabilitation outcomes.

The Relationship Between Intra-Abdominal Pressure and Body Acceleration During Exercise.

OBJECTIVES: High intra-abdominal pressure (IAP) may influence the development of pelvic floor disorders. We and others have used intravaginal pressure transducers to measure IAP in women during exercise and daily activities, but utilizing the transducer for long-term measurements creates compliance issues. Waist-worn accelerometers are prominent in research and may be a reliable alternative for approximating IAP. We hypothesized that there are pair-wise positive correlations between the mean maximal accelerometer vector magnitude and 2 IAP measurements: mean maximal IAP and area under the curve (AUC). METHODS: Twenty-five women who regularly participated in exercise performed 13 activities. Intra-abdominal pressure was measured with an intravaginal transducer and acceleration with a waist-worn accelerometer. We determined the mean maximal IAP, AUC for IAP, and mean maximal accelerometer vector magnitude for each activity and participant. The relationship between IAP and acceleration was determined by computing the Pearson correlation coefficient (R) and the 95% confidence interval for mean maximal accelerometer vector magnitude versus mean maximal IAP and mean maximal accelerometer vector magnitude versus AUC for IAP. RESULTS: The R values were 0.7353 for mean maximal accelerometer vector magnitude versus mean maximal IAP (including walking) and 0.5059 for mean maximal accelerometer vector magnitude versus AUC for IAP (excluding walking). Walking at 3 speeds, analyzed separately, presented R values of 0.72208 for mean maximal IAP and 0.21678 for AUC. CONCLUSION: Waist-worn accelerometers may provide a viable method for approximating mean maximal IAP in a population of women during most activities.

Load Monitoring System for Partial Weight Bearing Therapy for rehabilitation of lower extremity fractures.

Partial Weight Bearing Therapy (PWB) is used during in rehabilitation of lower-extremity fractures, but optimal outcomes are limited by the paucity of data supporting the current standard of care, the inability of clinicians to assess patients' compliance to the prescribed therapy, and by the patient's inability to apply clinical loading guidelines. To address these needs a Load Monitoring System (LMS) was developed using a novel long-term load measuring technology coupled with consumer electronics for storing and reporting of patient limb loading data. The project was planned as a staged effort and the results of the first stage development are presented here. During the first stage of this project, the LMS insole load sensor was developed for 6-week standalone operation. The LMS was subjected to bench-testing, demonstrating low static and dynamic drift.