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The effect of hip muscle weakness and femoral bony deformities on gait performance
Ines Vandekerckhove1, Mariska Wesseling2, Hans Kainz3
1Department of Rehabilitation Sciences, KU Leuven, Leuven, Belgium; Clinical Motion Analysis Laboratory, University Hospitals Leuven, Pellenberg, Belgium.
Insights
Hip muscle weakness and femoral deformities significantly impact cerebral palsy (CP) gait. Surgical correction of bony deformities appears more beneficial than strength training for improving CP gait performance.
Area of Science:
- Orthopedics
- Biomechanics
- Pediatric Rehabilitation
Background:
- Children with cerebral palsy (CP) exhibit pathological gait due to musculoskeletal impairments like muscle weakness and altered bone geometry.
- The precise impact of these impairments on gait performance remains incompletely understood.
Purpose of the Study:
- To investigate the influence of hip muscle weakness and femoral deformities on the gait performance of individuals with CP compared to typically developing (TD) subjects.
- To quantify the relationship between specific musculoskeletal impairments and gait deviations.
Main Methods:
- Creation of 6400 musculoskeletal models simulating varying degrees of hip muscle weakness (0-75%) and femoral deformities (femoral anteversion angle and neck shaft angle).
- Imposition of typical developing (TD) and five CP gait patterns onto these models to calculate muscle forces.
- Utilizing regression analysis to assess the effect of weakness and deformities on the hip's capability gap (CG).
Main Results:
- Increased hip abductor weakness, femoral anteversion angle (FAA), and neck shaft angle (NSA) were significantly correlated with a larger capability gap (CG) across various gait patterns.
- Combined hip muscle weakness and femoral deformities explained a substantial portion of the variance in CG for different gait deviations, ranging from 35% to 96%.
Conclusions:
- Surgical correction of femoral deformities may offer greater improvements in CP gait performance than hip muscle strengthening alone.
- Gait patterns such as apparent equinus and stiff knee gait appear more susceptible to limitations imposed by hip weakness and femoral deformities.
Background:
Children with cerebral palsy (CP) present with a pathological gait pattern due to musculoskeletal impairments, such as muscle weakness and altered bony geometry. However, the effect of these impairments on gait performance is still unknown. Research aim:This study aimed to explore the effect of hip muscle weakness and femoral deformities on the gait performance of CP and typical developing (TD) subjects.
Methods:
6400 musculoskeletal models were created by weakening the hip extensors, abductors, adductors and flexors from 0% to 75 % and increasing the femoral anteversion angle (FAA) and neck shaft angle (NSA) from 20° to 60° and 120° to 160°, respectively. One TD and five CP gait patterns were imposed to each model and muscle forces were calculated. The effect of weakness and bony deformities on the capability gap (CG) at the hip, i.e. the lack in hip moment generating capacity to perform the gait pattern, was investigated using regression analysis.
Results:
The CG of apparent equinus, stiff knee gait, TD gait, jump gait and true equinus increased with 0.080, 0.038, 0.015, 0.023 and 0.005 Nm/kg per 10 percent hip abductor weakness increase, with 0.211, 0.130, 0.056, 0.045 and 0.011 Nm/kg per 10 degrees FAA increase and with 0.163, 0.080, 0.036, 0.043 and 0.011 Nm/kg per 10 degrees NSA increase, respectively. Combined weakness and bony deformities explained 96 %, 85 %, 82 %, 65 %, 40 % and 35 % of the variance in the CG of apparent equinus, TD gait, stiff knee gait, jump gait, true equinus and crouch gait, respectively.
Significance:
The results suggest that surgical correction of femoral deformities is more likely to be effective than strength training of hip muscles in enhancing CP gait performance. Jump gait, true equinus and especially crouch were more robust, while apparent equinus and stiff knee gait were limited by hip weakness and femoral deformities.
