Gait and user experiences of the NEURO TRONIC stance-control knee-ankle-foot orthosis (SC-KAFO): a comparative evaluation to the E-MAG Active SC-KAFO.

People who have knee instability that is associated with weakness of the knee
extensor muscles can be provided with a custom made stance control knee-ankle
foot orthosis (SC-KAFO). These devices allow free knee flexion in swing, while
providing full stability in stance by automatically locking on initiation of
the stance phase of gait. Two commercially available locking mechanisms for
SC-KAFOs are the E-MAG Active knee-joint and the NEURO TRONIC knee-joint.
Because the E-MAG Active knee-joint requires full extension of the knee in
terminal swing to lock, versus the NEURO TRONIC knee-joint that can lock at any
flexion angle of the knee and in every part of the swing phase, it is expected
that the NEURO TRONIC knee-joint is more secure when walking under varying
circumstances. Yet, stance control securing of both joint systems and the
effects of the NEURO TRONIC SC-KAFO and E-MAG Active SC-KAFO on gait and user
experiences have never been compared.

To demonstrate superiority of the NEURO TRONIC SC-KAFO in stance control
securing while walking under challenging conditions compared to the E-MAG
Active SC-KAFO; and to demonstrate superiority of the NEURO TRONIC SC-KAFO on
walking energy cost, gait biomechanics and user experiences compared to the
E-MAG Active SC-KAFO.

The design for this study includes a prospective intervention study with three
repeated measurements, i.e. at baseline, walking with the current E-MAG Active
SC-KAFO (T0); and after 1 month (T1) and 3 months (T2) of walking with the
NEURO TRONIC SC-KAFO. The total duration of the study will be minimum 19 weeks.

The intervention includes a custom-made stance control knee-ankle-foot orthosis
(SC-KAFO) with the NEURO TRONIC system knee-joint build in. NEURO TRONIC
SC-KAFOs will be prescribed and fabricated by one orthotic company (OIM
orthopedie, location Noordwijkerhout, The Netherlands).

Patients will be asked to visit the AMC minimum 7 times for prescription of the
NEURO TRONIC SC-KAFO and to participate in the measurements (intake (10
minutes), physical examination (20 min), muscle strength assessment (30 min),
C-Mill test (25 min), 6-minute walk test (30 min) and 3D gait analysis (1.5
hours). Baseline measurement visits will be scheduled simultaneously with the
consultancies for SC-KAFO treatment (casting, fitting and delivery), to limit
the number of visits to the medical centre. In addition to the tests, patients
will be asked to fill in a questionnaire. The total duration of completing this
questionnaire is estimated at 20 minutes. Baseline as well as follow-up
measurements are non-invasive.

Possible risks related to the intervention (NEURO TRONIC SC-KAFO) are
considered minimal. The investigational product is CE certified, already used
in clinical practice for several years, and the orthotist fabricating the NEURO
TRONIC SC-KAFOs is very well experienced. Therefore the occurrence of medical
events is considered minimal.

Practical relevance of the study is that our evaluation of the efficacy of
stance control securing of the NEURO TRONIC knee-joint versus the E-MAG Active
knee-joint contributes to improving orthotic management in patients with lower
limb muscle weakness in the (near) future.