Assessments
At each visit to the clinical motion analysis laboratory, our patient’s body mass index (BMI) was calculated. Because BMI is both age-specific and sex-specific for children, the BMI-for-age percentile for boys was used to interpret his BMI [25]. His leg length was measured supine from the anterior superior iliac spine to the medial malleolus. Hip, knee, and ankle passive range of motion (ROM) measures were recorded and muscle strength was measured using the six-point (0–5) Manual Muscle Test [26, 27]. At age 13 years, our patient’s selective motor control was tested using the recently introduced Selective Control Assessment of the Lower Extremity (SCALE) tool [28].
Three-dimensional kinematics were collected during barefoot walking with an eight-camera optoelectric system (Motion Analysis Corporation, Santa Rosa, CA, USA). The Gait Deviation Index (GDI) was calculated from lower extremity kinematics [29], and his medial hamstrings’ muscle-tendon length and lengthening velocity were calculated using SIMM (MusculoGraphics, Inc., Chicago, IL, USA) [30]. Surface EMG was collected for his bilateral rectus femoris, lateral quadriceps, medial hamstrings, medial gastrocnemius, and tibialis anterior using the MA-200 EMG system (Motion Lab Systems, Inc., Baton Rouge, LA, USA). EMG and foot switch data were processed using EMG Analyzer software (BL Engineering, Santa Ana, CA, USA).
Standing postural balance measures of center of pressure path length and average radial displacement were collected, as previously reported [31]. The energy efficiency index (EEI) was recorded during a 2-minute walk at a patient-selected comfortable walking speed and measured in heartbeats per meter walked, as previously reported [32].
The same experienced physical therapist and bioengineer conducted the clinical motion analysis every year. After each session, the results were presented to a multidisciplinary clinical team and recommendations for treatment were made. Treatment recommendations were then sent to our patient’s referring physician at an outside hospital. Our patient’s parents provided informed consent for the presentation of data for scientific publication. The Institutional Review Board deemed the report exempt from review and approval, as the report did not meet the definition of “Human Subjects Research.”