Effect of a rigid ankle-foot orthosis on hamstring length in children with hemiplegia

Area of Science:

• Biomechanical analysis
• Pediatric orthopedics
• Neuromuscular disorders

Background:

• Hemiplegia in children often presents with gait abnormalities.
• Hamstring muscle length is a critical factor in normal gait mechanics.
• The influence of assistive devices on hamstring length in pediatric hemiplegia requires further investigation.

Purpose of the Study:

• To assess hamstring muscle length in children with hemiplegia.
• To determine the effect of ankle-foot orthoses (AFOs) on hamstring length.
• To investigate the relationship between hamstring pathology and distal lower limb involvement.

Main Methods:

• Gait analysis and musculoskeletal modeling were performed on 18 children with hemiplegia (mean age 8 years 5 months).
• Maximum hamstring muscle lengths were measured with and without AFO use.
• Muscles were classified as short if below normal average -1SD.

Main Results:

• 8 participants exhibited short medial hamstrings in bare feet, particularly those less affected.
• All participants demonstrated increased maximum hamstring length when using an AFO.
• AFO use normalized hamstring length in all but one child.

Conclusions:

• Short hamstrings in hemiplegic gait are frequently secondary to more distal lower limb pathologies.
• Ankle-foot orthoses can effectively normalize hamstring length in this population.
• Addressing distal impairments may be key to managing hamstring length issues in pediatric hemiplegia.