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A comparison of 2 techniques for measuring rectus femoris muscle thickness in cerebral palsy
Ashley P Dew1, Noelle G Moreau
1Department of Health Professions, Medical University of South Carolina, Charleston, SC 29425, USA..
Insights
Ultrasound measurements of rectus femoris (RF) muscle thickness in children with cerebral palsy (CP) show excellent agreement between two methods. The 50% thigh length (MT50) measurement is a feasible alternative to the time-consuming maximum muscle thickness (MaxMT) method.
Area of Science:
- Pediatric Rehabilitation
- Musculoskeletal Ultrasound
- Biomedical Engineering
Background:
- Accurate muscle size assessment is crucial for understanding weakness in pediatric cerebral palsy (CP).
- The rectus femoris (RF) muscle is a key muscle group often affected in CP.
- Evaluating muscle thickness provides insights into muscle atrophy or hypertrophy.
Purpose of the Study:
- To assess the agreement between two ultrasound-derived muscle thickness measurements of the rectus femoris (RF) in children with CP.
- To determine the reliability and feasibility of different measurement techniques for RF muscle thickness in this population.
Main Methods:
- Ultrasound imaging was used to measure RF muscle thickness in 13 ambulatory youth with CP (mean age 14.4 years).
- Two methods were employed: measurement at 50% thigh length (MT50) and maximum muscle thickness (MaxMT) near the proximal insertion.
- Measurements were taken bilaterally and averaged for each method.
Main Results:
- Bland-Altman analysis revealed excellent agreement between the MT50 and MaxMT methods, with most values within the 95% limits of agreement (-0.11 to 0.28 cm).
- A slight bias was observed, with the MaxMT method tending to yield higher thickness values.
- One outlier was noted, but overall consistency was high.
Conclusions:
- The MT50 measurement demonstrates excellent agreement with the MaxMT method for assessing RF muscle thickness in children with CP.
- Considering its less time-intensive nature, MT50 presents a practical and feasible alternative for clinical and research settings.
- This finding supports the use of MT50 for reliable muscle size estimation in pediatric CP studies.
Purpose:
: Precise measures of muscle size are useful when investigating weakness in children with cerebral palsy (CP). Therefore, the purpose of the study was to determine agreement between 2 muscle thickness measurements of the rectus femoris (RF) in CP.
Methods:
: Measures of RF thickness in 13 youth with CP who were ambulatory (mean age: 14.4 ± 3.6 years) were obtained bilaterally using ultrasound imaging. Three measures were obtained at 50% thigh length and averaged (MT50). Maximum muscle thickness (MaxMT) was also determined through repeated measurements toward the proximal insertion of the RF.
Results:
: The Bland-Altman plot showed that all values, except for one outlier, fell within 95% limits of agreement (-0.11 to 0.28 cm), showing excellent agreement. However, a constant bias toward higher values with MaxMT method was observed.
Conclusion:
: Given the time-consuming nature of obtaining MaxMT, the MT50 measurement may be a more feasible alternative when estimating maximum muscle thickness of the RF.
