Biomechanical Evaluation of a Modified Floor Reaction Orthosis with Pneumatic Knee Joint in Quadriplegic Cerebral Palsy: A Single-Patient Pilot Case Study

Abstract

Background: Crouch gait, characterized by excessive knee flexion during stance, is a common and debilitating gait abnormality
in children with cerebral palsy (CP). Conventional floor reaction orthoses (FROs) utilize ground reaction force (GRF)
manipulation to promote knee extension; however, rigid designs offer limited dynamic control in children with significant
hamstring tightness and proximal spasticity.
Objective: To evaluate the biomechanical and metabolic effects of a modified floor reaction orthosis incorporating a pneumatic
knee joint (mFRO-PKJ) in a single child with spastic quadriplegic cerebral palsy.
Methods: A single 7-year-old female child with spastic quadriplegic CP (GMFCS Level II) underwent gait assessment while
walking a 5-m walkway with and without the mFRO-PKJ. Spatiotemporal gait parameters and metabolic cost were assessed
using clinical gait measures and a portable metabolic system (Cosmed K4b2).
Results: In this single patient, use of the mFRO-PKJ resulted in improvements in step length, stride length, cadence, and
walking velocity, along with a reduction in oxygen consumption during ambulation. Qualitative observations indicated
improved trunk alignment and reduced compensatory movements.
Conclusion: In this single-patient pilot case study, the mFRO-PKJ demonstrated promising biomechanical and metabolic
benefits in managing crouch gait. These findings suggest that pneumatic-assisted FROs may offer a biomechanically informed
alternative to conventional rigid designs; however, further controlled studies with larger samples are necessary to establish
generalizability.