The reliability, responsiveness and clinical utility of the proximat: A new tool for measuring hip range of movement in children with cerebral palsy

Abstract

Monitoring range of movement is a key aspect of managing hip problems in children with cerebral palsy. The aim of this study was to assess the clinical utility, reliability and responsiveness of a new measurement tool, the Proximat, for hip range of movement. Passive hip abduction, adduction, medial and lateral rotation were measured by using the Proximat on 26 children with cerebral palsy attending three special schools: 16 of whom are boys, mean age = 7 years and 6 months (standard deviation = 4.2 years), range 2-15 years. Testing was undertaken by two physiotherapists to assess interrater reliability and repeated the following day to assess test-retest reliability. Total, random and systematic errors were calculated for interrater and test-retest. The Proximat was quick and easy to use and acceptable to the children. High reliability was found for all movements (intraclass correlation coefficient = 0.83-0.93) with reasonable responsiveness; total error was 2.5-12 degrees. Most of the error was random with little evidence of systematic bias. The Proximat is a reliable, responsive and acceptable method of measuring passive hip movements in children with cerebral palsy in day-to-day clinical practice. A change of 8-12 degrees is needed to overcome measurement error and to indicate that a 'true' change in range of movement has occurred.