Muscle disbalance and proximal deformaties of the femur in children with myelomeningocele

In the clinic deformities of the proximal femur are observed in children
without innervation of the m. gluteus maximus. Spina bifida, cerebro palsy and
Down syndrome could cause this drop down. The deformities could lead to
dislocations or subluxations of the hip joint and also to flexion, adduction
and lateral rotation deformities. This research project investigates the
relation between the observed deformities and muscle imbalance in children with
myelomeningocele.

The general accepted Hueter-Volkmann law describes the inverse relation between
compressive forces on the physis and the rate of physeal growth. So compression
decreases and tension increases longitudinal growth. The observed deformities
in patients and the Hueter-Volkmann law assume the following two hypotheses:
The first is that in children with meylomeningocele, the compressive forces on
the medial part of the proximal physis are smaller than on the lateral part.
This would lead to a more vertically directed physis and the second one is that
the difference between medial and lateral compressive forces on the proximal
physis in children with a weakness or total dysfunction of the m. gluteus
maximus is larger than in normal children.

This research project needs data from static and gait trails of 10 children
with myelomeningocele and 3 healthy children. The measurements are at the gait
laboratory of Roessingh Research and Development (RRD). During the measurements
EMG signals of 8 leg muscles, VICON signals and force plate signals are
registered.

The measurements take in total 2 hours. Because only static and gait trails are
performed the risk for the children is small. To reduce the risk even further a
physician or physiologist is present during the measurements with children with
myelomeningocele.