Introduction: Ankle arthrodesis (AD) and total ankle replacement
(TAR) are typical treatments for ankle osteoarthritis (AO). Despite
clinical interest, there is a lack of their outcome evaluation using
objective criteria. Gait analysis and plantar pressure assessment are
appropriate to detect pathologies in orthopaedics but they are mostly
used in lab with few gait cycles. In this study, we propose an
ambulatory device based on inertial and plantar pressure sensors to
compare the gait during long-distance trials between healthy subjects
(H) and patients with AO or treated by AD and TAR.
Methods: Our study included four groups: 11 patients with AO,
9 treated by TAR, 7 treated by AD and 6 control subjects. An ambulatory
system (Physilog®, CH) was used for gait analysis; plantar pressure
measurements were done using a portable insole (Pedar®-X, DE). The
subjects were asked to walk 50 meters in two trials. Mean value and
coefficient of variation of spatio-temporal gait parameters were
calculated for each trial. Pressure distribution was analyzed in ten subregions
of foot. All parameters were compared among the four groups
using multi-level model-based statistical analysis.
Results: Significant difference (p <0.05) with control was noticed for
AO patients in maximum force in medial hindfoot and forefoot and in
central forefoot. These differences were no longer significant in TAR
and AD groups. Cadence and speed of all pathologic groups showed
significant difference with control. Both treatments showed a significant
improvement in double support and stance. TAR decreased variability
in speed, stride length and knee ROM.
Conclusions: In spite of a small sample size, this study showed that
ankle function after AO treatments can be evaluated objectively based
on plantar pressure and spatio-temporal gait parameters measured
during unconstrained walking outside the lab. The combination of
these two ambulatory techniques provides a promising way to evaluate
foot function in clinics.