Determinants of success of a stance-control-KAFO in former
polio patients with quadriceps weakness.

After about many years of neurological and functional stability, patients who
suffered from polio earlier in life may develop late-onset neuromuscular
symptoms, which are referred to as the post poliomyelitis syndrome (PPS). The
symptoms include new muscle weakness, fatigue and joint and muscle pain. These
new symptoms often cause difficulties with walking.
Because of quadriceps weakness, a common problem in PPS, many patients need an
ankle and/or knee orthoses to improve walking. Until recently patients were
given a knee-ankle-foot orthosis (KAFO) with locked knee hinge to assure
stability during walking with paresis of the quadriceps. This leads to a
compensational gait resulting in increased energy cost of walking. To reduce
the increased energy expenditure the *stance-control KAFO* (SC-KAFO) was
designed. This design automatically (electromagnetically/mechanical) releases
the knee to allow swing phase flexion while knee flexion is restricted during
stance (locked knee joint), approximating to the natural gait. It is well known
that the compliance to use assistive devices is not optimal, therefore it is
important to investigate the determinants of succesful use of prescribed
orthoses.
Improving physical functioning is one the main aims of rehabilitation treatment
and improving walking ability is therefore an important aim in this patient
group.

The aim of the present study is two-fold: 1) To do a survey of patients who
have been prescribed a SC-KAFO in the outpatient clinic and evaluate the
indication of prescription, compliance, experience and motives for (non) use of
the SC-KAFO. 2) To investigate the effect on walking using a SC-KAFO compared
to walking with previously used orthotics and a KAFO with locked knee hinge. As
potential determinants of succesful use of the SC-KAFO energy expenditure of
walking, walking performance, biomechanical gait parameters, muscle strength
and experience of using SC-KAFO will be measured.

A questionnaire survey and a non-randomized self-controlled trial.

Patients will attend the department of rehabilitation of the AMC twice. During
these visits a short clinical examination will take place, two questionnaires
will be completed, two different walking test (with the SC-KAVO and the old
orthotic condition) will be performed. One of the walking tes will also be
performed in a subgroup of patients with a KAFO with locked knee hinge. In
addition, muscle strenght of the knee flexors and extensors will be measured.
Walking with the old orhotic condition may cause more tiredness. The workload
of the different test is possible if enough resting breakes are taken between
the different tests.