Evaluation of AFOs using Gait Analysis and Functional Treatment Measurement Instruments
S. Hassani; M. Ferdjallah; K. Reiners; C. Johnson; M. Carter; J. Chapman; M. Urban; J. Krzak; A. Caudill; A. Flanagan; P. Johnson; P. Smith; G. Harris; Shriners Hospital for Children Chicago, IL
This study investigated two types of ankle-foot orthotics (AFOs) and changes in motor performance by assessing gait metrics, standardized gross motor function measurement (GMFM) and standardized pediatric outcomes (PODCI). Two types of AFOs, hinged (HAFOs) and dynamic (DAFOs) were applied in children with spastic diplegic cerebral palsy (DCP). Determining the correlation among these tools may impact the overall assessment methodology in this population.
Sixteen children with a diagnosis of spastic diplegic cerebral palsy (7.5+ 2.9 yrs.)were included in the study. Two types of AFOs were fitted for each subject. Subjects had one month to wear each AFO with a two-week baseline period between usage periods. Gait analysis, GMFM, and PODCI measurements were evaluated at initial baseline, after each AFO trial, and at baseline between usage periods. A multi-camera Vicon Motion Analysis System was used to acquire temporal and kinematic data (Figure 1 ).
Sections D and E of the GMFM were investigated to assess function-involving standing, walking, running, and jumping. Parents completed the Pediatric Outcomes Data Collection Instrument (PODCI), which addressed their child's walking ability, standing balance, brace fit, and endurance.
Pearson correlation and two-sample comparison methods were used to determine correlation among the evaluation tools and to examine significant differences in mean response between the two braces. GMFM scores correlated strongly (r > 0.5) with PODCI physical function parameters (Tables I -II).
|GMFM Scores||Barefoot 1 Vs. Barefoot 2||Barefoot
|Upper Extremity & Physical Function||D.956||0.077||0.297||0.334|
|Transfer & Basic Mobility||0.576||0.222||0.752||0.736|
|Sports & Physical Function||0.129||0.506||0.322||0.502|
|Global Function & SvmDtoms||0.286||0.951||0.274||0.618|
Of all normalized gait parameters, cadence, and walking speed correlated most strongly (r > 0.6) with GMFM scores. GMFM scores also correlated strongly (r > 0.5) with non-normalized stride length. Hinged AFOs and dynamic AFOs both showed significant differences from barefoot walking in gait temporal and spatial parameters (p<0.05). There were no significant differences in any parameters, between hinged AFOs and dynamic AFOs (p<0.05) (Table III).
|Barefoot 1 Vs. Barefoot 2||Barefoot
|Cadence (steps min)||0.831||0.002*||0.009*||0.919|
|Walking speed (m/s)||0.412||0.022*||0.049*||0.878|
|Stride length (m)||0.577||0.001*||0.001*||0.349|
|Step length (m)||0.849||0.00l*||0.001*||0.171|
Gait Analysis parameters improved with bracing in patients with spastic Diplegic cerebral palsy, who were independent toe walkers. There were no significant differences between braced and unbraced conditions measured with either the GMFM (sections D & E) or the PODCI. There were no differences in any of the functional measures between DAFO and AFO braces. Interestingly, PODCI and GMFM lacked sensitivity to the difference in function between braced and unbraced conditions. Conversely, gait and temporal stride measures were very sensitive to these changes. These findings point to a method for improving the functional sensitivity while maintaining a relatively simple test. Further study of correlation among GMFM, PODCI, gait, and postural measures is also suggested.