Knee
biomechanics during walking gait following matrix – induced autologous
chondrocyte implantation.
Ebert J, Lloyd D, Ackland T, Wood D.
Clinical Biomechanics, 2010; 25, 1011 – 1017.
Matrix – induced autologous chondrocyte
implantation (MACI) is a two – stage procedure with an initial arthroscopic
harvest of healthy cartilage, isolation and expansion of chondrocytes ex-vivo,
and subsequent re-implantation of cells into
the chondral defect. Literature proves its positive effect on reducing pain and
improving knee function, however still little is known how it influences walking
gait and normal knee biomechanics. Therefore, authors analyzed knee joint
kinematics and kinetics during walking in 61 patients following MACI, in
combination with either conservative or accelerated post-operative WB
rehabilitation. Evaluation was performed three, six and twelve months post –
surgery in both groups and two matched, healthy control groups for comparison.
In comparing the knee biomechanics during
walking gait between the two patient groups and, after controlling for BW and
knee pain, there were no differences throughout the post-operative timeline, or
at the nominated assessment time points. This would suggest that the different
post-operative rehabilitation programs did not affect the pattern of recovery
of the assessed variables throughout the post-operative timeline.
However, when comparing each patient group with their matched control group, a larger amount of
lower limb dysfunction began to emerge in the traditional patient cohort,
particularly in regard to knee loading patterns (the knee adduction and flexion
moments). Both patient groups demonstrated a reduced knee extension moment
during the stance phase of gait at all time points post-surgery, when compared
with their respective control groups. Importantly, the accelerated patient
group demonstrated no difference in both the knee adduction and the
knee flexion moments at all three time points, compared to those observed in their matched control group.
However, the traditional group demonstrated a slower recovery of these gait
parameters with a lower knee adduction moment at all three time points and a
lower knee flexion moment at 3 months. This suggests that the accelerated
rehabilitation protocol does result in a faster return to normal knee joint
kinematics patterns, than the traditional rehabilitation. Accelerated patient group
demonstrated knee moments comparable to a matched control group of subjects,
while those in the traditional group demonstrated lower knee flexion and
adduction moments compared to their matched controls. Authors believe that
their lower-than-normal knee flexion moments may have been the result of
reduced quadriceps activation and/or strength, which may act to reduce knee
joint articular loads during gait. Alternatively, if their lower knee flexion
moments were caused by high levels of co-contraction of the quadriceps and
hamstring musculature, this may increase compressive loading of the articular
surfaces.
Both patient groups demonstrated no
difference in the peak GRF at 3, 6 and 12 months, when compared to matched
controls walking at similar speeds. However, this was not reflected in knee loading, where differences between the
patients and controls were observed. While knee pain was accounted for, other
factors related to knee pathology may interact to alter movement patterns and
joint-loading profiles in gait, including knee joint capsule distention and
effusion, reduced quadriceps strength, reduced quadriceps activation and/or
increased co-contraction of the hamstrings and quadriceps muscle groups.
In conclusion, authors report that,
although no differences were observed directly between the patients who
underwent the two differing WB protocols, comparison of each patient group with
a matched control group did reveal a higher level of dysfunction in patients
who underwent traditional (conservative) rehabilitation. Nevertheless, more
research is needed to confirm that findings.
All rights reserved to the Clinical Biomechanics.
All rights reserved to the Clinical Biomechanics.
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