Article

Femoral osseointegrated implants represent a new development in
amputee rehabilitation, eliminating socket pressure discomfort, improving hip
range of movement and facilitating prosthetic limb attachment. A clinical aspect
that has not previously been reported on is the function of muscles in the
residuum with implications concerning energy expenditure, hip-hiking and
viability of the electrogram as a myoprocessor. Typically, amputees fitted with
osseointegrated fixation have shorter residuums and weaker attachment of cleaved
muscles. Function of muscle can be assessed by surface electromyography through
changes in amplitude and median frequency of the signal. METHODS: Five male
transfemoral amputees with osseointegrated fixations participated together with a
control group comprised of ten adult males. Electrodes recorded surface
electromyographic activity of five residual limb muscles or left lower limb
muscles of control subjects. Isometric contractions were performed against
resistance. The increase in mean rectified amplitude from resting to maximally
contracting was calculated and median frequencies estimated. FINDINGS: The
amputees were unable to maintain a maximum voluntary contraction of constant
amplitude. Amplitude increase was lowest for rectus femoris and adductor magnus.
The median frequency of adductor magnus was significantly greater (P=0.02) for
the amputees than intact subjects and there was a significant difference (P<0.01)
between gluteus maximus and adductor magnus for amputee subjects. INTERPRETATION:
High electromyographic amplitude variability suggests that using residuum muscles
singly as a myoprocessor might be challenging. Adductor magnus displayed a
different sEMG profile compared to intact subjects indicating decreased function
and neuromuscular changes. Further work into optimal muscle anchorage is required
to ensure maximal mechanical performance.
CI - Copyright (c) 2011 Elsevier Ltd. All rights reserved.

Langue : ANGLAIS