543 research outputs found
Knee moments of anterior cruciate ligament reconstructed and control participants during normal and inclined walking
Objectives: Prior injury to the knee, particularly
anterior cruciate ligament (ACL) injury, is known to
predispose one to premature osteoarthritis (OA). The
study sought to explore if there was a biomechanical
rationale for this process by investigating changes in
external knee moments between people with a
history of ACL injury and uninjured participants
during walking: (1) on different surface inclines and
(2) at different speeds. In addition we assessed
functional differences between the groups.
Participants: 12 participants who had undergone
ACL reconstruction (ACLR) and 12 volunteers with
no history of knee trauma or injury were recruited
into this study. Peak knee flexion and adduction
moments were assessed during flat (normal and
slow speed), uphill and downhill walking using an
inclined walkway with an embedded Kistler Force
plate, and a ten-camera Vicon motion capture
system. Knee injury and Osteoarthritis Outcome
Score (KOOS) was used to assess function.
Multivariate analysis of variance (MANOVA) was
used to examine statistical differences in gait and
KOOS outcomes.
Results: No significant difference was observed in
the peak knee adduction moment between ACLR and
control participants, however, in further analysis,
MANOVA revealed that ACLR participants with an
additional meniscal tear or collateral ligament
damage (7 participants) had a significantly higher
adduction moment (0.33Β±0.12 Nm/kg m) when
compared with those with isolated ACLR
(5 participants, 0.1Β±0.057 Nm/kg m) during gait at
their normal speed ( p<0.05). A similar (nonsignificant)
trend was seen during slow, uphill and
downhill gait.
Conclusions: Participants with an isolated ACLR
had a reduced adductor moment rather an increased
moment, thus questioning prior theories on OA
development. In contrast, those participants who
had sustained associated trauma to other key knee
structures were observed to have an increased
adduction moment. Additional injury concurrent
with an ACL rupture may lead to a higher
predisposition to osteoarthritis than isolated ACL
deficiency alone
The Complexity of Human Walking: A Knee Osteoarthritis Study
This study proposes a framework for deconstructing complex walking patterns to create a simple principal component space before checking whether the projection to this space is suitable for identifying changes from the normality. We focus on knee osteoarthritis, the most common knee joint disease and the second leading cause of disability. Knee osteoarthritis affects over 250 million people worldwide. The motivation for projecting the highly dimensional movements to a lower dimensional and simpler space is our belief that motor behaviour can be understood by identifying a simplicity via projection to a low principal component space, which may reflect upon the underlying mechanism. To study this, we recruited 180 subjects, 47 of which reported that they had knee osteoarthritis. They were asked to walk several times along a walkway equipped with two force plates that capture their ground reaction forces along 3 axes, namely vertical, anterior-posterior, and medio-lateral, at 1000 Hz. Data when the subject does not clearly strike the force plate were excluded, leaving 1β3 gait cycles per subject. To examine the complexity of human walking, we applied dimensionality reduction via Probabilistic Principal Component Analysis. The first principal component explains 34% of the variance in the data, whereas over 80% of the variance is explained by 8 principal components or more. This proves the complexity of the underlying structure of the ground reaction forces. To examine if our musculoskeletal system generates movements that are distinguishable between normal and pathological subjects in a low dimensional principal component space, we applied a Bayes classifier. For the tested cross-validated, subject-independent experimental protocol, the classification accuracy equals 82.62%. Also, a novel complexity measure is proposed, which can be used as an objective index to facilitate clinical decision making. This measure proves that knee osteoarthritis subjects exhibit more variability in the two-dimensional principal component space
Balance and gait adaptations in patients with early knee osteoarthritis
AbstractGait adaptations in people with severe knee osteoarthritis (OA) have been well documented, with increased knee adduction moments (KAM) the most commonly reported parameter. Neuromuscular adaptations have also been reported, including reduced postural control. However these adaptations may be the result of morphological changes in the joint, rather than the cause. This study aimed to determine if people with early OA have altered gait parameters and neuromuscular adaptations. Gait and postural tasks were performed by 18 people with early medial knee OA and 18 age and gender-matched control subjects. Parameters measured were kinematics and kinetics during gait and postural tasks, and centre of pressure and electromyographic activity during postural tasks. OA subjects showed no differences in the gait parameters measured, however they demonstrated postural deficits during one-leg standing on both their affected and unaffected sides and altered hip adduction moments compared with controls. Increased activity of the gluteus medius of both sides (p<0.05), and quadriceps and hamstrings of the affected side (p<0.05) during one-leg standing compared with controls were also noted. This study has demonstrated that gait adaptations commonly associated with OA do not occur in the early stages, while neuromuscular adaptations are evident. These results may be relevant for early interventions to delay or prevent osteoarthritis in its early stages
Examination of the performance characteristics of velostat as an in-socket pressure sensor
Velostat is a low-cost, low-profile electrical bagging material with piezoresistive properties, making it an attractive option for in-socket pressure sensing. The focus of this research was to explore the suitability of a Velostat-based system for providing real-time socket pressure profiles. The prototype system performance was explored through a series of bench tests to determine properties including accuracy, repeatability and hysteresis responses, and through participant testing with a single subject. The fabricated sensors demonstrated mean accuracy errors of 110 kPa and significant cyclical and thermal drift effects of up to 0.00715 V/cycle and leading to up to a 67% difference in voltage range respectively. Despite these errors the system was able to capture data within a prosthetic socket, aligning to expected contact and loading patterns for the socket and amputation type. Distinct pressure maps were obtained for standing and walking tasks displaying loading patterns indicative of posture and gait phase. The system demonstrated utility for assessing contact and movement patterns within a prosthetic socket, potentially useful for improvement of socket fit, in a low cost, low profile and adaptable format. However, Velostat requires significant improvement in its electrical properties before proving suitable for accurate pressure measurement tools in lower limb prosthetics
Issues faced by people with amputation(s) during lower limb prosthetic rehabilitation: a thematic analysis
Background: Successful rehabilitation is essential to improve the physical and mental outcomes of people with lower limb amputation(s). Individuals have different goals and expectations of successful rehabilitation and experience issues that affect their quality of life. Objectives: To determine factors affecting lower limb prosthetic rehabilitation from people with amputation(s), important for studies focusing on prosthetic and socket design and fitting because they provide context of need and user issues. Study design: Thematic analysis of semistructured interviews. Methods: Ten people with amputation(s) were self-selected from a survey identifying factors affecting lower limb prosthetic rehabilitation. The telephone interviews were semistructured exploring the biggest impactors on and frustrations with rehabilitation and the socket. A thematic analysis was completed by following the undermentioned steps: familiarization, coding, generating themes, reviewing themes, defining and naming themes, and reporting. Results: Five distinct but interrelated themes were identified: External to Prosthesis, Body Impactors, Consequences of Ill-Fit, Prosthesis Irritants, and Work and Social Impact. Those living with amputation(s) mentioned prosthetic-related issues affecting their work and social life, including difficulties wearing their prosthesis all day, the socket's rigidity, and the ability to participate in hobbies. Conclusions: The study provides new insights into the issues experienced during prosthetic rehabilitation, highlighting impacts beyond just physical health consequences. The study provides an evidence base for areas of the rehabilitation journey which could be improved to improve the quality of life of people with amputation(s
Wearable technology for spine movement assessment: A systematic review
Continuous monitoring of spine movement function could enhance our understanding of low back pain development. Wearable technologies have gained popularity as promising alternative to laboratory systems in allowing ambulatory movement analysis. This paper aims to review the state of art of current use of wearable technology to assess spine kinematics and kinetics. Four electronic databases and reference lists of relevant articles were searched to find studies employing wearable technologies to assess the spine in adults performing dynamic movements. Two reviewers independently identified relevant papers. Customised data extraction and quality appraisal form were developed to extrapolate key details and identify risk of biases of each study. Twenty-two articles were retrieved that met the inclusion criteria: 12 were deemed of medium quality (score 33.4-66.7%), and 10 of high quality (score> 66.8%). The majority of articles (19/22) reported validation type studies. Only 6 reported data collection in real-life environments. Multiple sensors type were used: electrogoniometers (3/22), strain gauges based sensors (3/22), textile piezoresistive sensor (1/22) and accelerometers often used with gyroscopes and magnetometers (15/22). Two sensors units were mainly used and placing was commonly reported on the spine lumbar and sacral regions. The sensors were often wired to data transmitter/logger resulting in cumbersome systems. Outcomes were mostly reported relative to the lumbar segment and in the sagittal plane, including angles, range of motion, angular velocity, joint moments and forces. This review demonstrates the applicability of wearable technology to assess the spine, although this technique is still at an early stage of development
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