Popliteal Blood Flow With Lower-Extremity Injury Mobility Devices

Abstract

Background: Ambulation devices may differ in their utility, muscle activation patterns, and how they affect regional blood flow. This study aimed to evaluate popliteal blood flow and vessel dimensions in response to ambulation with a hands-free crutch (HFC), axillary crutches (AC), a medical kneeling scooter (MKS), and regular walking in healthy adults. Methods: HFC, AC, MKS, and regular walking were completed in a random order by 40 adults aged 18-45 years. Participants ambulated at a comfortable pace for 10 minutes with each device. At baseline and immediately following each trial, a trained operator used diagnostic ultrasonography to capture popliteal vein and artery dimensional and flow characteristics. Results: Significant increases were observed from baseline (0.65 ± 0.23 cm) in venous diameter following walking (0.71 ± 0.21 cm, P = .012) and MKS (0.73 ± 0.21 cm, P = .003). Venous blood flow was also significantly different between conditions ( P = .009) but was only greater following walking (124 ± 79 mL/min) compared to MKS (90 ± 64 mL/min, P = .021). No differences were observed in arterial dimensions between ambulation conditions. Significant increases were found in arterial blood flow from baseline (107 ± 69 mL/min) following walking (184 ± 97 mL/min, P < .001) and HFC (163 ± 86 mL/min, P < .001). Arterial blood flow following walking was greater than AC (132 ± 72 mL/min, P = .016) and MKS (128 ± 74 mL/min, P = .003). Conclusion: We found an average decrease in venous time-averaged mean velocity between walking and use of the MKS, but no such decrease with either HFCs or use of ACs in this healthy experimental cohort. Level of Evidence: Level III, diagnostic comparative study.

Muscle specific declines in oxygen saturation during acute ambulation with hands-free and conventional mobility devices

“…Muscle pump activity is also a critical factor for preventing stasis ( 25 ) as knee positions at 90 degrees flexion are associated with reduced flow rates ( 26 ). However, in a previous investigation, we reported post-mobility device ambulation popliteal venous blood flow rates via diagnostic ultrasound ( 32 ). All mobility devices had some level of reduced venous flow; however, only significant changes were detected in the MKS vs. traditional walking ( 32 ).…”

“…However, in a previous investigation, we reported post-mobility device ambulation popliteal venous blood flow rates via diagnostic ultrasound ( 32 ). All mobility devices had some level of reduced venous flow; however, only significant changes were detected in the MKS vs. traditional walking ( 32 ). Given that NIRS data were collected during mobility device ambulation and blood flow indicators were taken immediately after ambulation, these data cannot be directly correlated.…”

“…The procedures were repeated until all four ambulation conditions were completed in a random order. Additional details of the research design including data quantifying oxygen consumption and hemodynamics are reported elsewhere ( 31 , 32 ). Following testing, data was exported from the NIRS units and averaged per 10 min.…”