Ankle Foot Orthoses – Rigid vs Flexible

Ankle Foot Orthoses – Rigid vs Flexible
  • Ankle-Foot orthoses (AFOs) are used to minimize the impact of weakness in ankle dorsiflexion muscles. The study on different orthotic types defines the optimal design, which effectively improves the users’ mobility.
  • The most commonly prescribed device to restore safe mobility in patients with multiple sclerosis (PwMS).

AFO 1

Right AFO
  • AFOs have different types and are usually classified based on their structural designs. Traditional orthoses, often made with a thermoplastic material, provide resistance to plantarflexion to prevent foot drop during the swing phase.
  • Rigid (thermoplastic) AFOs are said to fail to restore healthy ankle movements.
    • They impede the active plantar flexion that individuals possess and require for propulsive gait.
    • Specifically, these AFOs disrupt the active ankle plantarflexion necessary for normal gait; thus, this process results in less foot-ground contact right after initial contact.
    • Reduces the generation of a propulsive force at a terminal stance.
    • Using a thermoplastic AFO increases the vertical ground reaction force and reduces balance during walking
Dictus Band
  • Dictus-band is another orthotic device for foot drop; it differs from traditional static or fixed AFOs.
  • It dynamically assists dorsiflexion movement to lift off the toes with an elastic rubber band.
  • This device also allows a possible range of plantar flexion if the user forcefully contracts the plantar flexor muscles during walking.
  • Active plantar flexion can be beneficial for forwarding propulsion, faster ambulation, and managing balance disturbances during walking.

AFO 2

AFO 3

The Comparison of the Effects of Flexible vs Rigid Ankle-foot orthoses on Balance and Walking Performance in Individuals With Multiple Sclerosis: A Crossover Study (Parian et al., 2021)
  • The study investigated the immediate effects of using a Dictus-band orthotic in PwMS. It fulfilled its objective and highlighted that preventing drop foot with Dictus band had no detrimental effect on the balance and mobility of users.
  • Using Dictus-band to compensate for drop foot in Person with Multiple Sclerosis (PwMS) is a feasible, safe, and potentially effective therapeutic intervention.
  • Dictus-band improves dynamic balance and walking performance, compared to a fixed thermoplastic AFO.
  • The effects of a Dictus-band orthotic on the mobility of PwMS were superior to a thermoplastic AFO. This effect could potentially be because it dynamically compensates for dorsiflexion weakness without blocking the plantarflexion required for body transfer manoeuvres and ambulation. However, it was similar in effect to a barefoot condition.
  • The concern that Dictus-band may present a challenge for balance and increased the risk of falls was not supported in this study

Parian SS, Fereshtenjad N, Hillier S, Sadeghi-Demneh E. The Comparison of the Effects of Flexible vs Rigid Ankle-foot orthoses on Balance and Walking Performance in Individuals With Multiple Sclerosis: A Crossover Study. Iranian Rehabilitation Journal. 2021; 19(2):199-206. http://dx.doi.org/10.32598/irj.19.2.1421.2

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