Decreased Pain and Improved Dynamic Knee Instability Mediate the Beneficial Effect of Wearing a Soft Knee Brace on Activity Limitations in Patients With Knee Osteoarthritis

OBJECTIVE: To evaluate whether improvement of proprioception, pain or dynamic knee instability mediate the effect of wearing a soft knee brace on activity limitations in persons with knee osteoarthritis (OA). METHODS: Exploratory analysis from 44 participants with knee OA and self-reported knee instability in a laboratory trial evaluating the effect of wearing a commercially available soft knee brace. Activity limitations were assessed with the 10-meter walk test and the Get up and Go test. Knee joint proprioception was assessed by an active joint position sense test; pain was assessed with the Numeric Rating Scale (NRS); pressure pain threshold (PPT) was assessed with a hand-held pressure algometer; dynamic knee instability was expressed by the Perturbation Response, i.e. a measure reflecting a deviation in mean knee varus-valgus angle after a controlled mechanical perturbation on a treadmill, with respect to level walking. Mediation analysis was conducted with the product of coefficients approach. Confidence intervals were calculated with a bootstrap procedure. RESULTS: A decrease of pain (NRS) and a decrease of dynamic knee instability mediated the effect of wearing a soft knee brace on reduction of activity limitations (p < 0.05), while changes of proprioception and PPT did not mediate this effect (p > 0.05). CONCLUSION: This study shows that decreased pain and reduced dynamic knee instability are pathways via which wearing a soft knee brace decreased activity limitations in persons with knee OA. This article is protected by copyright. All rights reserved

Skin marker-based versus bone morphology-based coordinate systems of the hindfoot and forefoot

Segment coordinate systems (CSs) of marker-based multi-segment foot models are used to measure foot kinematics, however their relationship to the underlying bony anatomy is barely studied. The aim of this study was to compare marker-based CSs (MCSs) with bone morphology-based CSs (BCSs) for the hindfoot and forefoot. Markers were placed on the right foot of fifteen healthy adults according to the Oxford, Rizzoli and Amsterdam Foot Model (OFM, RFM and AFM, respectively). A CT scan was made while the foot was loaded in a simulated weight-bearing device. BCSs were based on axes of inertia. The orientation difference between BCSs and MCSs was quantified in helical and 3D Euler angles. To determine whether the marker models were able to capture inter-subject variability in bone poses, linear regressions were performed. Compared to the hindfoot BCS, all MCSs were more toward plantar flexion and internal rotation, and RFM was also oriented toward more inversion. Compared to the forefoot BCS, OFM and RFM were oriented more toward dorsal and plantar flexion, respectively, and internal rotation, while AFM was not statistically different in the sagittal and transverse plane. In the frontal plane, OFM was more toward eversion and RFM and AFM more toward inversion compared to BCS. Inter-subject bone pose variability was captured with RFM and AFM in most planes of the hindfoot and forefoot, while this variability was not captured by OFM. When interpreting multi-segment foot model data it is important to realize that MCSs and BCSs do not always align.</p

The immediate effect of a soft knee brace on pain, activity limitations, self-reported knee instability, and self-reported knee confidence in patients with knee osteoarthritis

Background: We aimed to (i) evaluate the immediate effect of a soft knee brace on pain, activity limitations, self-reported knee instability, and self-reported knee confidence, and (ii) to assess the difference in effect between a non-tight and a tight soft brace in patients with knee osteoarthritis (OA). Methods: Forty-four patients with knee OA and self-reported knee instability participated in the single-session, laboratory, experimental study. A within-subject design was used, comparing a soft brace with no brace, and comparing a non-tight with a tight soft brace. The outcome measures were pain, self-reported knee instability and knee confidence during level and perturbed walking on the treadmill and activity limitations (10-m walk test and the get up and go (GUG) test). Linear mixed-effect model analysis for continuous outcomes and logistic generalized estimating equations for categorical outcomes were used to evaluate the effect of wearing a soft brace. Results: Wearing a soft brace significantly reduced pain during level walking (B - 0.60, P = 0.001) and perturbed walking (B - 0.80, P < 0.001), reduced the time to complete the 10-m walk (B - 0.23, P < 0.001) and the GUG tests (B - 0.23, P = 0.004), reduced self-reported knee instability during level walking (OR 0.41, P = 0.002) and perturbed walking (OR 0.36, P < 0.001), and reduced lack of confidence in the knees during level walking (OR 0.45, P < 0.001) and perturbed walking (OR 0.56, P < 0.001), compared with not wearing a soft brace. There was no difference in effects between a non-tight and tight brace, except for the 10-m walk test. Wearing a tight brace significantly reduced the time to complete the 10-m walk test in comparison with wearing a non-tight brace (B - 0.11, P = 0.03). Conclusion: The results of this study indicate that a soft brace is an efficacious intervention targeting pain, activity limitations, self-reported knee instability, and knee confidence in the immediate term in patients with knee OA. Further studies are needed evaluating the mode of action based on exerted pressure, and on the generalization to functioning in daily life. Trial registration: trialregister.nl, NTR6363. Retrospectively registered on 15 May 2017

Lateral Trunk Motion and Knee Pain in Osteoarthritis of the Knee: a cross-sectional study

<p>Abstract</p> <p>Background</p> <p>Patients with osteoarthritis of the knee may change their gait in an attempt to reduce loading of the affected knee, thereby reducing pain. Especially changes in lateral trunk motion may be potentially effective, since these will affect the position of the centre of mass relative to the knee, enabling minimization of the load on the knee and thereby knee pain. The aim of the study was to test the hypothesis that a higher level of knee pain is associated with higher lateral trunk motion in patients with knee OA.</p> <p>Methods</p> <p>Fifty-two patients with OA of the knee were tested. Lateral trunk motion was measured during the stance phase of walking with an optoelectronic motion analysis system and a force plate. Knee pain was measured with the VAS and the WOMAC pain questionnaire. Regression analyses were performed to assess the relationship between lateral trunk motion and knee pain.</p> <p>Results</p> <p>It was shown that in bivariate analyses knee pain was not associated with lateral trunk motion. In regression analyses, pain was associated with more lateral trunk motion. In addition, more lateral trunk motion was associated with younger age, being female, higher self-reported knee stiffness and higher maximum walking speed.</p> <p>Conclusion</p> <p>Pain is associated with lateral trunk motion. This association is weak and is influenced by age, gender, self-reported stiffness and maximum walking speed.</p

Gait Retraining With Real-Time Biofeedback to Reduce Knee Adduction Moment: Systematic Review of Effects and Methods Used

Objective To review the current literature regarding methods and effects of real-time biofeedback used as a method for gait retraining to reduce knee adduction moment (KAM), with intended application for patients with knee osteoarthritis (KOA). Data Sources Searches were conducted in MEDLINE, Embase, CINAHL, SPORTDiscus, Web of Science, and Cochrane Central Register of Controlled Trials with the keywords gait, feedback, and knee osteoarthritis from inception to May 2015. Study Selection Titles and abstracts were screened by 1 individual for studies aiming to reduce KAM. Full-text articles were assessed by 2 individuals against predefined criteria. Data Extraction Data were extracted by 1 individual according to a predefined list, including participant demographics and training methods and effects. Data Synthesis Electronic searches resulted in 190 potentially eligible studies, from which 12 met all inclusion criteria. Within-group standardized mean differences (SMDs) for reduction of KAM in healthy controls ranged from .44 to 2.47 and from .29 to .37 in patients with KOA. In patients with KOA, improvements were reported in pain and function, with SMDs ranging from .55 to 1.16. Methods of implementation of biofeedback training varied between studies, but in healthy controls increased KAM reduction was noted with implicit, rather than explicit, instructions. Conclusions This review suggests that biofeedback gait training is effective primarily for reducing KAM but also for reducing pain and improving function in patients with KOA. The review was limited by the small number of studies featuring patients with KOA and the lack of controlled studies. The results suggest there is value and a need in further researching biofeedback training for reducing KAM. Future studies should include larger cohorts of patients, long-term follow-up, and controlled trials

Gait Retraining With Real-Time Biofeedback to Reduce Knee Adduction Moment:: Systematic Review of Effects and Methods Used

Objective To review the current literature regarding methods and effects of real-time biofeedback used as a method for gait retraining to reduce knee adduction moment (KAM), with intended application for patients with knee osteoarthritis (KOA). Data Sources Searches were conducted in MEDLINE, Embase, CINAHL, SPORTDiscus, Web of Science, and Cochrane Central Register of Controlled Trials with the keywords gait, feedback, and knee osteoarthritis from inception to May 2015. Study Selection Titles and abstracts were screened by 1 individual for studies aiming to reduce KAM. Full-text articles were assessed by 2 individuals against predefined criteria. Data Extraction Data were extracted by 1 individual according to a predefined list, including participant demographics and training methods and effects. Data Synthesis Electronic searches resulted in 190 potentially eligible studies, from which 12 met all inclusion criteria. Within-group standardized mean differences (SMDs) for reduction of KAM in healthy controls ranged from .44 to 2.47 and from .29 to .37 in patients with KOA. In patients with KOA, improvements were reported in pain and function, with SMDs ranging from .55 to 1.16. Methods of implementation of biofeedback training varied between studies, but in healthy controls increased KAM reduction was noted with implicit, rather than explicit, instructions. Conclusions This review suggests that biofeedback gait training is effective primarily for reducing KAM but also for reducing pain and improving function in patients with KOA. The review was limited by the small number of studies featuring patients with KOA and the lack of controlled studies. The results suggest there is value and a need in further researching biofeedback training for reducing KAM. Future studies should include larger cohorts of patients, long-term follow-up, and controlled trials

Neuromechanical assessment of knee joint instability during perturbed gait in patients with knee osteoarthritis

Knee joint instability is frequently reported by patients with knee osteoarthritis (KOA). Objective metrics to assess knee joint instability are lacking, making it difficult to target therapies aiming to improve stability. Therefore, the aim of this study was to compare responses in neuromechanics to perturbations during gait in patients with self-reported knee joint instability (KOA-I) versus patients reporting stable knees (KOA-S) and healthy control subjects. Forty patients (20 KOA-I and 20 KOA-S) and 20 healthy controls were measured during perturbed treadmill walking. Knee joint angles and muscle activation patterns were compared using statistical parametric mapping and discrete gait parameters. Furthermore, subgroups (moderate versus severe KOA) based on Kellgren and Lawrence classification were evaluated. Patients with KOA-I generally had greater knee flexion angles compared to controls during terminal stance and during swing of perturbed gait. In response to deceleration perturbations the patients with moderate KOA-I increased their knee flexion angles during terminal stance and pre-swing. Knee muscle activation patterns were overall similar between the groups. In response to sway medial perturbations the patients with severe KOA-I increased the co-contraction of the quadriceps versus hamstrings muscles during terminal stance. Patients with KOA-I respond to different gait perturbations by increasing knee flexion angles, co-contraction of muscles or both during terminal stance. These alterations in neuromechanics could assist in the assessment of knee joint instability in patients, to provide treatment options accordingly. Furthermore, longitudinal studies are needed to investigate the consequences of altered neuromechanics due to knee joint instability on the development of KOA

Responses in knee joint muscle activation patterns to different perturbations during gait in healthy subjects

PURPOSE: To compare the responses in knee joint muscle activation patterns to different perturbations during gait in healthy subjects. SCOPE: Nine healthy participants were subjected to perturbed walking on a split-belt treadmill. Four perturbation types were applied, each at five intensities. The activations of seven muscles surrounding the knee were measured using surface EMG. The responses in muscle activation were expressed by calculating mean, peak, co-contraction (CCI) and perturbation responses (PR) values. PR captures the responses relative to unperturbed gait. Statistical parametric mapping analysis was used to compare the muscle activation patterns between conditions. RESULTS: Perturbations evoked only small responses in muscle activation, though higher perturbation intensities yielded a higher mean activation in five muscles, as well as higher PR. Different types of perturbation led to different responses in the rectus femoris, medial gastrocnemius and lateral gastrocnemius. The participants had lower CCI just before perturbation compared to the same phase of unperturbed gait. CONCLUSIONS: Healthy participants respond to different perturbations during gait with small adaptations in their knee joint muscle activation patterns. This study provides insights in how the muscles are activated to stabilize the knee when challenged. Furthermore it could guide future studies in determining aberrant muscle activation in patients with knee disorders

How to measure responses of the knee to lateral perturbations during gait? A proof-of-principle for quantification of knee instability

Knee instability is a major problem in patients with anterior cruciate ligament injury or knee osteoarthritis. A valid and clinically meaningful measure for functional knee instability is lacking. The concept of the gait sensitivity norm, the normalized perturbation response of a walking system to external perturbations, could be a sensible way to quantify knee instability. The aim of this study is to explore the feasibility of this concept for measurement of knee responses, using controlled external perturbations during walking in healthy subjects. Nine young healthy participants walked on a treadmill, while three dimensional kinematics were measured. Sudden lateral translations of the treadmill were applied at five different intensities during stance. Right knee kinematic responses and spatio-temporal parameters were tracked for the perturbed stride and following four cycles, to calculate perturbation response and gait sensitivity norm values (i.e. response/perturbation) in various ways. The perturbation response values in terms of knee flexion and abduction increased with perturbation intensity and decreased with an increased number of steps after perturbation. For flexion and ab/adduction during midswing, the gait sensitivity norm values were shown to be constant over perturbation intensities, demonstrating the potential of the gait sensitivity norm as a robust measure of knee responses to perturbations. These results show the feasibility of using the gait sensitivity norm concept for certain gait indicators based on kinematics of the knee, as a measure of responses during perturbed gait. The current findings in healthy subjects could serve as reference-data to quantify pathological knee instability