Achilles' tendon stretch during walking in hinged controlled ankle motion boots

Area of Science:

• Biomechanics
• Orthopedics
• Rehabilitation Engineering

Background:

• Controlled ankle motion (CAM) boots are utilized in Achilles' tendon rupture rehabilitation.
• CAM boots aim to provide mechanical stress through controlled ankle movement.
• The influence of CAM boot range of motion (ROM) on Achilles' tendon strain is not well understood.

Purpose of the Study:

• To investigate the effect of varying ROM in hinged CAM boots on Achilles' tendon strain during walking.
• To determine the relationship between ankle ROM and Achilles' tendon stretch in CAM boots.
• To assess the impact of CAM boot ROM on lower limb biomechanics and walking speed.

Main Methods:

• Eight healthy participants walked in hinged CAM boots with set ROMs (0°, 15°, 30°) and normal footwear on a motorized treadmill.
• Motion capture and instrumented treadmill data were collected for kinematic and kinetic analysis.
• B-mode ultrasonography measured Achilles' tendon strain and triceps surae muscle characteristics.

Main Results:

• Achilles' tendon strain significantly increased with higher CAM boot ROM (0°, 15°, 30°).
• A strong correlation was found between ankle ROM and Achilles' tendon stretch at 15° and 30° ROM.
• Increased CAM boot ROM led to greater ankle joint work, total limb work, and self-selected walking speed.

Conclusions:

• Hinged CAM boots can deliver a controlled mechanical stimulus to the Achilles' tendon by increasing ROM.
• This controlled stimulus may have clinical applications in the early stages of Achilles' tendon rupture rehabilitation.
• Optimizing CAM boot ROM could potentially enhance tendon healing and improve functional recovery outcomes.