Reason for Bracing
The goal of Rehabilitation is to improve upon an existing physical or functional
deficiency. There should be documented evidence to support
the achievement of this goal. In the case of ambulation,
there are complex mechanisms of the foot/ankle system that
require comprehensive evaluation. Supination and pronation
of the foot in the subtalar joint change as the foot is
non-weight bearing (open kinetic chain) or
weight bearing (closed kinetic chain) The
oblique alignment of the subtalar axis produces triplanar movement in all three cardinal
In open chain pronation, the talus and the leg do not move, while the calcaneus moves through all three planes and carries the foot with it. This triplanar motion consists of simultaneous movement of the calcaneus in eversion (frontal plane), abduction (transverse plane) and dorsiflexion (sagittal plane). Open chain supination is the reverse movement involving calcaneal inversion (frontal plane), adduction (transverse plane) and plantarflexion (sagittal plane).
During closed chain kinetic motion, the foot and heel are in contact with the ground and unable to move in the sagittal or transverse planes. To allow supination or pronation, the head of the talus must shift and the tibia must rotate around its longitudinal axis. In closed chain pronation, the calcaneus everts as in open chain pronation, but the head of the talus compensates for the distally fixed foot by adducting and plantarflexing. This movement is associated with knee flexion, internal rotation of the tibia, abduction and inversion of the forefoot on the hind foot and depression of the medial longitudinal arch. This movement pattern is the pathway for INTERNAL ROTARY PATTERN. (IRP)
During closed chain supination, the calcaneus inverts with abduction and dorsiflexion of the talus. This movement is associated with extension of the knees, external rotation of the tibia, adduction and eversion of the forefoot and elevation of the medial longitudinal arch. This movement pattern is the pathway for EXTERNAL ROTARY PATTERN. (ERP)
When the closed kinetic chain is altered by neuromuscular disorders creating IRP or ERP deformity, it must be re-established and maintained with a device that will meet each and every deficit. The bones, muscles, and ligaments of the foot and ankle mechanism in the closed kinetic chain have a relationship in triplanar motion. Each joint has force couples of agonists, antagonists, synergists, stabilizers, and neutralists to work efficiently. Even though the majority of motion occurs in the sagittal plane, stability and balance are maintained in the remaining two planes. This allows for more efficient movement patterns during the dynamic closed kinetic chain functions.
Orthotic intervention in the past did not address the demands placed upon the foot and ankle in closed kinetic chain function. This practice continues to the present day. Only a very small percentage of professionals are aware of what is required. Too many over simplify the complex issues to re-establish the altered closed kinetic chain functions. The majority of AFO's and KAFO's that are fit each day are primarily single plane devices.
Orthotic intervention of the future must address these complex issues in order to achieve the goal of Rehabilitation, which is to improve or restore lost function. Deficiencies need to be addressed at their source. The intricacies of kinetic chain motion during ambulation must be understood and related to each pathomechanical situation individually. All functional activities are triplanar and must be solved by triplanar solutions. Understanding this complex integration of body dynamics and structures allows the clinician to begin to solve them. It is this deeper understanding that realizes the importance of maintaining the structural integrity of ligaments, joints, bones, tendons, and their relationships with each other in maintaining efficiency.
There are no simple solutions to complex problems. All professionals will need to develop a better understanding of this mechanism in order to evaluate, predict and control deficiencies with orthotic intervention. Treatment without results is NOT REHABILITATION. Solutions must be offered and Outcomes must be demonstrated.