The Journal of Bone and Joint Surgery published research comparing three examination tests to determine the degree of hip flexion contractures in children with cerebral palsy. Thirty six subjects withe cerebral palsy and 37 subjects without cerebral palsy were evaluated with the Thomas Test, the Staheli test (prone hip extension test) and hamstring shift test. The results indicated the the Staheli test was the most valid method for determining hip flexion contracture in subjects with cerebral palsy.
Reference: Lee KM, Chung CY, Kwon DG, Han HS, Choi IH, Park MS. Reliability of physical examination in the measurement of hip flexion contracture and correlation with gait parameters in cerebral palsy. J Bone Joint Surg Am. 2011 Jan;93(2):150-8.