Knee Height as a Predictor of Recumbent Length for Individuals with Mobility-Impaired Cerebral Palsy

Abstract

Background: Because accurate measures of recumbent length are essential to assess growth and energy requirements of mobility-impaired individuals with cerebral palsy (CP), a reliable and simple method of estimating recumbent length is required. Prediction of recumbent length from knee height in this population has not yet been investigated.Objectives: i) To correlate direct measures of recumbent length in mobility-impaired individuals having lower leg extremity cerebral palsy (LECP) involvement with indirect measures of recumbent length calculated using knee-height prediction equations and ii) to determine if knee height is a reliable predictor of recumbent length in this population.Methods: Subjects (n=34; 15F, 19M), aged 6 to 30 years, were participants in a six-month nutrition rehabilitation program. All subjects had varying degrees of LECP involvement. Recumbent length to the nearest 0.5 cm was measured by standardised techniques. Knee height was measured to the nearest 0.5 centimetre using sliding callipers. Equations based on normal, healthy individuals with application to mobility-impaired or handicapped individuals were used to predict recumbent length from knee height.Results: Direct measures of recumbent length of subjects significantly correlated with indirect measures calculated using knee height prediction equations (R=0.88, p≤0.0001). In addition, knee height of these subjects was a reliable predictor of recumbent length (R2=0.78, p<0.0001).Conclusions: Results suggest that knee height may be a reliable predictor for recumbent length in this population.