Evaluation of overall gait quality in Perthes disease. Are global gait indices of value for a local musculoskeletal disorder?

Background: Until now follow-up- and outcome evaluations in Perthes disease are analysing predominantly subjective results and clinical/radiological parameters. To enlarge the assessment by quantitative, functional aspects a summary measure for overall gait quality would be helpful. Therefore, the objective of this study is to evaluate whether commonly used global gait indices are sensitive to detect gait deviations during the early stages of the Perthes disease.

Methods: 3D gait data of 70 patients scheduled for containment improving surgery with the diagnosis of Perthes were included. A group of 31 healthy children served as a control group. Based on 4 gait cycles of each subject the Gait Deviation Index, the Gillette Gait Index, the Hip Flexor Index and the Gait Deviation Index-Kinetic were calculated for the involved and non-involved side. The gait indices were compared (1) between patients and controls, (2) among patients sub-grouped by ROM/radiological classifications and (3) between the two limbs.

Findings: All applied gait indices besides the Gait Deviation Index-Kinetic of the patient-group are significantly different from the controls. The subgroup-analysis resulted only in significant differences between the radiological groups Herring B and C for the Gillette Gait Index. Comparing involved and non-involved side showed no significant differences.

Interpretation: The evaluated gait indices are sensitive to identify a pathologic gait pattern in Perthes disease, so they can be used as a functional outcome parameter evaluating treatment concepts. Nevertheless, these are not applicable to identify the pathologic side indicating that a local hip problem leads to global gait deviations.