Window of Trainability in Relation to Surgical Correction of Foot Deformity

The Influence of Surgical Correction of Foot Deformity on the Effect of Gait Training on Gait Capacity in Chronic Stroke Patients

Background: Stroke is the leading cause of disability in the western world. In chronic stroke patients, foot deformity such as pes equinovarus is among the most important underlying motor deficits, due to imbalance of muscle strength and activity around the ankle and tarsal joints. Both nationally and internationally, there is relative underuse of surgical treatment options, although in our clinical experience this often has the best outcome. In addition to positive clinical experiences with surgical interventions, we have experienced that before surgery, there is limited effect of gait training on gait capacity. However, we have experienced that after surgery, the restored normal ankle-foot position creates a new window for training opportunities to further improve gait capacity. Therefore, in this exploratory proof of principle study we aim to investigate the effect of surgical correction of post-stroke foot deformity on the (potential) improvement of gait capacity after gait training. Based on clinical experiences, we expect that after surgery, gait training results in a larger improvement in gait capacity compared to before the surgical intervention due to the increased possibilities to improve balance control. Objective: The primary objective of this study is to compare the effect of gait training on gait capacity (stepping performance, gait adaptability and dynamic balance) before and after surgical correction of post-stroke foot deformity. Study design: Exploratory proof of principle study with repeated-measures. Study population: Fifteen stroke patients with disabling foot deformity will be recruited from the Gait Expertise Center (LEC) of the Sint Maartenskliniek and Radboudumc. Intervention: All patients will receive two gait training interventions, each consisting of twelve one hour training sessions. The training sessions will be focussed on improving gait capacity. Main study parameters/endpoints: Primary outcomes will be gait adaptability as measured with the Emory Function Ambulation Profile (E-FAP), stepping performance as measured with the Timed-Up-And-Go test (TUG) and dynamic balance as measured with the Margin of Stability (MoS).

All patients will receive two gait training interventions, each consisting of twelve one hour training sessions. The training sessions will be focussed on improving gait capacity.

Measure for gait adaptability. The E-FAP consists of five subtasks: a 5-meter walk test on a hard-surfaced floor, a 5-meter walk test on a carpeted floor, an up and go task, an obstacle course, and ascent and descent of four stairs. The subtasks will be completed according to the sequence above and the time it takes to complete each subtask will be recorded. A standardized E-FAP protocol will be used to assess the subtasks of the E-FAP.

Measure for gait capacity. Measured by using the Gait Real Time Analysis Interactive Lab as a measurement device.

Measure for gait adaptability. For this test, a standardized ladder is placed on the floor. It consists of 17 rectangular stepping targets that gradually decrease 2 cm in length (range 64-32 cm). Participants start stepping in the largest target and walk as fast as possible to the other side, turn and hit the targets in reverse order while avoiding the ladder rungs. The instructions are to perform the test as fast as possible, without making foot placement errors. The test is timed: a faster time is indicative of a better gait adaptability. Participants perform the test four times, first twice with one foot per target and, thereafter, twice with both feet in one target. A time penalty of 0.5 s is added each time a participant makes a foot placement mistake.

Measure for gait adaptability. The modified Dynamic Gait Index consists of 8 subtasks: usual pace, change pace, horizontal head turns, vertical head turns, pivot turn, stepping over obstacles, stepping around obstacles and stairs. The subtasks will be performed according to the mDIG protocol. The time to complete each subtask will be recorded and used as outcome measure.

Measure for dynamic balance. Measured by using the Gait Real Time Analysis Interactive Lab as a measurement device.

Measure for dynamic balance. Measured by using the Gait Real Time Analysis Interactive Lab as a measurement device.

Distance between extrapolated center of mass (XCoM) and center of pressure (CoP) in anterior-posterior (AP) and medio-lateral (ML) direction (cm)

Measure for dynamic balance. Measured by using the Gait Real Time Analysis Interactive Lab as a measurement device.

Measure for dynamic balance. Measured by using the Gait Real Time Analysis Interactive Lab as a measurement device.

Measure for dynamic balance. Measured by using the Gait Real Time Analysis Interactive Lab as a measurement device.

Measure for dynamic balance. Measured by using the Gait Real Time Analysis Interactive Lab as a measurement device.

Measure for gait capacity. Measured by using the Gait Real Time Analysis Interactive Lab as a measurement device.

Measure for gait capacity. Measured by using the Gait Real Time Analysis Interactive Lab as a measurement device.

Measure for gait capacity. Measured by using the Gait Real Time Analysis Interactive Lab as a measurement device.

Measure for gait capacity. Measured by using the Gait Real Time Analysis Interactive Lab as a measurement device.

In the logbook, the therapist describes the exact tasks that are performed during the training sessions.

Measure for gait capacity. Measured by using the Gait Real Time Analysis Interactive Lab as a measurement device.

Measure for gait capacity. Measured by using the Gait Real Time Analysis Interactive Lab as a measurement device.

Inclusion Criteria: > 6 months post onset 18 years or older Functional Ambulation Classification (FAC) => 3: the patient is able to walk without physical support Will undergo a surgical correction of foot deformity Exclusion Criteria: suffers from any other disorder that seriously affects gait capacity