ORTHOSES-ARTICULATED AFO STOPS
SUMMARY
1. Plantar-flexion creates a knee extension moment and dorsiflexion creates a knee flexion moment.
PLANTARFLEXION/POSTERIOR STOP
2. The greater the plantar flexion resistance, the greater the flexion moment at the knee at heel strike, and the greater the need for active hip extensors to prevent the body from collapsing forward on a buckling knee.
3. A soft heel helps stabilize the knee by keeping the ground reaction force anterior to the knee joint. A firm heel decreases knee stability via a knee flexion moment while moving the ground reaction force posterior to the knee joint.
DORSIFLEXION/ANTERIOR STOP
4. An anterior stop (set at 5o dorsiflexion) is used to substitute for the function of the gastrocnemius-soleus complex. It is used to substitute weak calf muscles or weak quadriceps.
5. The posterior spring substitutes for dorsiflexor contraction to prevent foot drop after toe-off, for the eccentric activation of the dorsiflexors after heel strike & assists with toe-clearance during the swing-phase.
6. The posterior spring prevents rapid plantar flexion at heel strike during its compression in the posterior channel.
Reference(s)
Cifu, D.X. (2020). Braddom’s physical medicine and rehabilitation. Elsevier. Get it on Amazon.
Cuccurullo, S. (2019). Physical medicine and rehabilitation board review. New York: Demosmedical. Get it on Amazon.
O’Young, B., Young, M.A. and Stiens, S.A. (2008). Physical Medicine and Rehabilitation Secrets. Mosby. Get it on Amazon.
