Biomechanical changes accompanying unilateral and bilateral use of laterally wedged insoles with medial arch supports in patients with medial knee osteoarthritis

Changes in the Kinematics of Midfoot and Rearfoot Joints with the Use of Lateral Wedge Insoles

The lateral wedge insole (LWI) is a typical orthopedic treatment for medial knee osteoarthritis pain, chronic ankle instability, and peroneal tendon disorders. It is still unknown what the effects are in the most important joints of the foot when using LWIs as a treatment for knee and ankle pathologies. Objectives: The aim of this study was to determine the influence of LWIs on the position of the midfoot and rearfoot joints by measuring the changes using a tracking device. Methods: The study was carried out with a total of 69 subjects. Movement measurements for the midfoot were made on the navicular bone, and for the rearfoot on the calcaneus bone. The Polhemus system was used, with two motion sensors fixed to each bone. Subjects were compared by having them use LWIs versus being barefoot. Results: There were statistically significant differences in the varus movement when wearing a 4 mm LWI (1.23 ± 2.08°, p < 0.001) versus the barefoot condition (0.35 ± 0.95°), and in the plantarflexion movement when wearing a 4 mm LWI (3.02 ± 4.58°, p < 0.001) versus the barefoot condition (0.68 ± 1.34°), in the midfoot. There were also statistically significant differences in the valgus movement when wearing a 7 mm LWI (1.74 ± 2.61°, p < 0.001) versus the barefoot condition (0.40 ± 0.90°), and in the plantar flexion movement when wearing a 4 mm LWI (2.88 ± 4.31°, p < 0.001) versus the barefoot condition (0.35 ± 0.90°), in the rearfoot. Conclusions: In the navicular bone, a varus, an abduction, and plantar flexion movements were generated. In the calcaneus, a valgus, an adduction, and plantar flexion movements were generated with the use of LWIs.

Efficacy of unloader knee orthosis and lateral wedge insole on static balance in medial knee osteoarthritis

Background

Medial knee osteoarthritis can contribute to pain and stiffness, interfere with balance and limit functional activities of daily living. Unloader knee orthosis or lateral wedged insoles are current conservative approaches used to treat these conditions. The aim of this study was to identify and compare the effects of them on the balance parameters.

Methods

66 subjects with mild to moderate medial knee osteoarthritis were randomly assigned to wear unloader knee brace or full-length 6° lateral wedge insole. Primary outcome balance parameters were stability %, path length and average velocity of center of pressure and mobility score which were investigated by HUMAC® Balance and Tilt system. Secondary outcome measures were knee function score using Knee Injury and Osteoarthritis Outcome Score scale. Assessment was performed at baseline and six months post orthotic intervention period.

Findings

Both orthoses improved all parameters compared to the baseline condition (p < 0.05). Unloader knee orthosis showed a significant improvement in all balance parameters compared to lateral wedged insoles (p < 0.001) except mobility scores (p = 0.527). Except activities of daily living (p = 0.752) and sports and recreational activities (p = 0.437), unloader knee orthosis had a greater effect on the pain (p = 0.002) and symptoms (p < 0.001) sub scales than lateral wedged insoles. However, quality of life sub-scale scores for insoles were more effective than the knee orthosis.

Interpretation

Unloader knee orthosis improved balance and knee function scores more than lateral wedged insole, though both orthoses produced significantly improved results compared to baseline assessment.

An evaluation of the use of a lateral wedged insole and a valgus knee brace in combination in subjects with medial compartment knee osteoarthritis (OA)

Aim: The aim of this study was to evaluate the effect (6 weeks) of the use of a knee brace and a lateral wedge insole, both in isolation and combined, on the knee adduction moment (KAM), pain levels, kinematics (velocity, stride length, cadence), knee ROM, function, and satisfaction in patients with knee osteoarthritis (OA).Methods: Twenty-one patients with medial compartment knee OA were participated in this study. A relatively light three-point valgus knee brace (VB) and full length custom-made lateral wedge insole with arch support were prepared for each subject. Patients divided into three groups at random.Results: The use of a custom fit valgus brace with lateral edge insole concurrently can reduce a greater peak KAM than use in isolation (30%). In addition, the use of both interventions can improve walking velocity, cadence, and reduce levels of pain in patients with medial compartment OA.Conclusion: All parameters except stride length and KAM in comparison with first day of wearing interventions improved significantly in the combined, concurrent usage group. The use of a lateral wedge insole and a valgus knee brace in combination can improve the kinetic and kinematic parameters in patients with medial compartment knee OA.

Major factors influencing rearfoot external eversion moment during barefoot walking

BACKGROUND

Excessive rearfoot eversion motion during walking has been considered as a risk factor for lower limb chronic injuries. External moment due to ground reaction force (GRF) is the essential cause by which the rearfoot is passively everted during walking.

RESEARCH QUESTION

This study aims to identify the key factors influencing the rearfoot external eversion moments due to the GRF during walking.

METHODS

From 3-D foot coordinates and GRF data of 29 healthy participants during walking, the rearfoot external eversion moments due to the GRF and factors composing the moment (height of the ankle joint center, mediolateral GRF, mediolateral distance of the center of pressure relative to the ankle joint center in the transverse plane, vertical GRF) were computed.

RESULTS

The mediolateral GRF was a key factor influencing the magnitude of the rearfoot external eversion moment just after foot contact, with which pre-contact medial foot velocity was significantly correlated. During the subsequent support phase, the mediolateral distance of the center of pressure (the application point of the vertical GRF) relative to the ankle joint center was also found to be another determinant of the magnitude of the rearfoot external eversion moment.

SIGNIFICANCE

We succeeded in demonstrating the specific factors that most likely explain the magnitude of the rearfoot external eversion moment during initial contact and the subsequent support phase during walking. Based on the findings, specific measures to suppress the rearfoot external eversion moment could be proposed.

The optimal degree of lateral wedge insoles for reducing knee joint load: a systematic review and meta-analysis

Background

Lateral wedge insoles are traditionally used to reduce the adduction moment that crosses the knee during walking in people with medial knee osteoarthritis. However, the best degree to reduce knee joint load is not yet well established.

Methods

Electronic databases were searched from their inception until May 2017. Included studies reported on the immediate biomechanical effects of different degrees of lateral wedge insoles during walking in people with knee osteoarthritis. The main measures of interest relating to the biomechanics were the first and second peak of external knee adduction moment and knee adduction angular impulse. For the comparison of the biomechanical effects of different degrees of insoles, the studies were divided in three subgroups: insoles with a degree higher than 0° and equal to or lower than 5°; insoles higher than 5° and equal to or lower than 9°; and insoles higher than 9°. Eligible studies were pooled using random-effects meta-analysis.

Results

Fifteen studies with a total of 415 participants met all eligibility criteria and were included in the final review and meta-analysis. The overall effect suggests that lateral wedge insoles resulted in a statistically significant reduction in the first peak (standardized mean difference [SMD] -0.25; 95% confidence interval [CI] -0.36, - 0.13; P < 0.001), second peak (SMD -0.26 [95% CI -0.48, - 0.04]; P = 0.02) and knee adduction angular impulse (SMD -0.17 [95% CI -0.31, - 0.03]; P = 0.02). The test of subgroups found no statistically significant differences.

Conclusion

Systematic review and meta-analysis suggests that lateral wedge insoles cause an overall slight reduction in the biomechanical parameters. Higher degrees do not show higher reductions than lower degrees. Prior analysis of biomechanical parameters may be a valid option for selecting the optimal angle of wedge that best fits in knee osteoarthritis patients with the lowest possible degree.

Workflow assessing the effect of gait alterations on stresses in the medial tibial cartilage - combined musculoskeletal modelling and finite element analysis

Knee osteoarthritis (KOA) is most common in the medial tibial compartment. We present a novel method to study the effect of gait modifications and lateral wedge insoles (LWIs) on the stresses in the medial tibial cartilage by combining musculoskeletal (MS) modelling with finite element (FE) analysis. Subject's gait was recorded in a gait laboratory, walking normally, with 5° and 10° LWIs, toes inward ('Toe in'), and toes outward ('Toe out wide'). A full lower extremity MRI and a detailed knee MRI were taken. Bones and most soft tissues were segmented from images, and the generic bone architecture of the MS model was morphed into the segmented bones. The output forces from the MS model were then used as an input in the FE model of the subject's knee. During stance, LWIs failed to reduce medial peak pressures apart from Insole 10° during the second peak. Toe in reduced peak pressures by -11% during the first peak but increased them by 12% during the second. Toe out wide reduced peak pressures by -15% during the first and increased them by 7% during the second. The results show that the work flow can assess the effect of interventions on an individual level. In the future, this method can be applied to patients with KOA.

Association of bilateral flat feet with knee pain and disability in patients with knee osteoarthritis: A cross-sectional study

This cross-sectional study examined the relationship of flat feet with knee pain, disability, and physical performance in patients with knee osteoarthritis (OA). Orthopedic clinic participants (n = 95; age 61-91 years; 68.4% women) with Kellgren-Lawrence (K/L) grade ≥1 in the medial compartment underwent evaluation of navicular height and foot length for flat feet. Knee pain intensity, disability, and physical performance were evaluated using the Japanese Knee Osteoarthritis Measure, 10-m walk, timed up and go, and five-repetition chair stand tests. Of the 95 enrolled patients, 24 (25.3%) had bilateral flat feet, and significantly higher knee pain compared to patients with no flat feet (11.3 ± 8.23 points vs. 6.58 ± 6.37 points; p = 0.043). A ordinal logistic regression analysis showed that bilateral flat feet were significantly associated with increased knee pain (proportional odds ratio: 5.48, 95% confidence interval: 1.96, 15.3; p = 0.001) compared with no flat feet, adjusted for age, sex, body mass index, and tibiofemoral joint K/L grade, which is consistent across various different cutoffs of the definition of flat feet. Physical performance was similar between patients with and without bilateral flat feet. The presence of unilateral flat feet was not significantly associated with any outcome measures. These findings indicate that bilateral, but not unilateral, flat feet are associated with worse knee pain. A prospective study investigating a causal relationship between bilateral flat feet posture and knee pain as well as disability would be of particular interest to verify the potential adverse effect of altered foot posture. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:2490-2498, 2017.

Effects of foot orthoses with medial arch support and lateral wedge on knee adduction moment in patients with medial knee osteoarthritis

BACKGROUND

There is contradictory evidence regarding whether the addition of medial arch supports to laterally wedged insoles reduces knee adduction moment, improves comfort, and reduces knee pain during the late stance phase of gait.

OBJECTIVES

To verify if such effects occur in participants with medial knee osteoarthritis.

STUDY DESIGN

Randomized single-blinded study.

METHODS

Gait analysis was performed on 18 patients affected by medial knee osteoarthritis. Pain and comfort scores, frontal plane kinematics and kinetics of ankle, knee, and hip were compared in four conditions: without foot orthosis, with foot orthoses, with medial arch support, and with foot orthoses with medial arch support and lateral wedge insoles with 6° and 10° inclination.

RESULTS

Lower-extremity gait kinetics were characterized by a significant decrease, greater than 6%, in second peak knee adduction moment in laterally wedged insole conditions compared to the other conditions ( p < 0.001; effect size = 0.6). No significant difference in knee adduction moment was observed between laterally wedged insole conditions. In contrast, a significant increase of 7% in knee adduction moment during the loading response was observed in the customized foot orthoses without lateral inclination condition ( p < 0.001; effect size = 0.3). No difference was found in comfort or pain ratings between conditions.

CONCLUSION

Our study suggests that customized foot orthoses with a medial arch support may only be suitable for the management of medial knee osteoarthritis when a lateral wedge is included. Clinical relevance Our data suggest that customized foot orthoses with medial arch support and a lateral wedge reduce knee loading in patients with medial knee osteoarthritis (KOA). We also found evidence that medial arch support may increase knee loading, which could potentially be detrimental in KOA patients.

The effects of shoe-worn insoles on gait biomechanics in people with knee osteoarthritis: a systematic review and meta-analysis

OBJECTIVES

The effect of shoe-worn insoles on biomechanical variables in people with medial knee osteoarthritis has been studied extensively. The majority of research has focused specifically on the effect of lateral wedge insoles at the knee. The aim of this systematic review and meta-analysis was to summarise the known effects of different shoe-worn insoles on all biomechanical variables during level walking in this patient population to date.

METHODS

Four electronic databases were searched to identify studies containing biomechanical data using shoe-worn insole devices in the knee osteoarthritis population. Methodological quality was assessed and a random effects meta-analysis was performed on biomechanical variables reported in three or more studies for each insole.

RESULTS

Twenty-seven studies of moderate-to-high methodological quality were included in this review. The primary findings were consistent reductions in the knee adduction moment with lateral wedge insoles, although increases in ankle eversion with these insoles were also found.

CONCLUSION

Lateral wedge insoles produce small reductions in knee adduction angles and external moments, and moderate increases in ankle eversion. The addition of an arch support to a lateral wedge minimises ankle eversion change, and also minimises adduction moment reductions. The paucity of available data on other insole types and other biomechanical outcomes presents an opportunity for future research.

A systematic review and meta-analysis into the effect of lateral wedge arch support insoles for reducing knee joint load in patients with medial knee osteoarthritis

OBJECTIVE

The aim of this study was to evaluate the immediate effects of lateral wedge arch support insoles (LWAS) on reducing the knee joint load in patients with medial knee osteoarthritis (OA) compared with an appropriate control.

METHODS

Databases including Medline, EMBASE, Web of Science, Wiley Online Library, Cochrane library, and Google Scholar were searched with no limits on study date or language, from the earliest available date to October 31, 2016. The included studies had to have the aim of reducing knee load and have an appropriate control. The main measured values were the first and second peak external knee adduction moments (EKAM) and the knee adduction angular impulse (KAAI). The random-effects model was used for analyzing the eligible studies.

RESULTS

Nine studies met the inclusion criteria with a total of 356 participants of whom 337 received LWAS treatment. The risk of methodological bias scores (quality index) ranged from 21 to 27 of 32. Treatment with LWAS resulted in statistically significant reductions in the first peak EKAM (P = .005), the second peak EKAM (P = .01), and the KAAI (P = .03). However, among trials in which the control treatment was control shoes, the LWAS showed no associations on the first peak EKAM (P = .10) or the KAAI (P =  .06); among trials in which the control treatment was neutral insoles, the LWAS showed no associations on the second peak EKAM (P = .21) or the KAAI (P = .23). At the same time, the LWAS showed no statistically significant reduction on the first peak EKAM (P = .39) when compared with flat insoles.

CONCLUSION

Although meta-analysis outcomes of all studies indicated statistically significant associations between LWAS and reductions of the first peak EKAM, second peak EKAM and KAAI in people with medial knee OA while walking, different results existed in subgroups using various control conditions for comparison. These findings do not support the use of LWAS insoles for reducing knee load. An optimal LWAS treatment should provide the appropriate height of arch support and amount of lateral wedging. Further research should investigate the best combination of these 2 parameters to achieve efficacy without altered comfort.

Clinical effects of lateral wedge arch support insoles in knee osteoarthritis: A prospective double-blind randomized study

We compared the short-term efficacy of rigid versus soft lateral wedge arch support (LWAS) insoles for patients with knee osteoarthritis (OA), as assessed using the International Classification of Functioning, Disability and Health (ICF) system, through a prospective, double-blind, randomized controlled trial.Participants who fulfilled the combined radiographic and clinical criteria for knee OA, as defined by the American College of Rheumatology, were randomly prescribed 1 pair of rigid or soft LWAS insoles. Body functions and structures were evaluated according to Kellgren-Lawrence scores, the Foot Posture Index, Hospital Anxiety and Depression Scale scores, the pain-pressure threshold, postural stability, dynamic balance, and fall risk; activities and participation were assessed according to 10-m fast speed walking, stair climbing and chair rising times, and Chronic Pain Grade questionnaire responses; and knee OA-related health status was evaluated using the Knee Injury and Osteoarthritis Outcome Score (KOOS). Hospital Anxiety and Depression Scale scores, the pain-pressure threshold, physical activity, balance, Chronic Pain Grade questionnaire responses, and the KOOS were recorded before treatment and at 1-, 2-, and 3-month follow-ups.We enrolled 90 participants, 70 women and 20 men, with mean ages of 60.6 ± 10.8 and 63.1 ± 10.8 years in the rigid and soft LWAS insole groups, respectively. Repeated-measures analysis of covariance revealed significant time × group effect improvements in pain (P = 0.008 for the KOOS), stair ascent time (P = 0.003), daily living function (P = 0.003 for the KOOS), sports and recreation function (P = 0.012 for the KOOS), and quality of life (P = 0.021 for the KOOS) in the soft LWAS insole group.Patients with knee OA who used soft LWAS insoles for a short term showed more significant improvement than did those who used rigid LWAS insoles in pain, physical activity, daily living function, sports and recreation function, and quality of life, which belong to the body functions and structures and the activities and participation components in the ICF scheme.

An optimized design of in-shoe heel lifts reduces plantar pressure of healthy males

Conventional heel lift with a flat surface increases the risk of foot problems related to higher plantar pressure and decreased stability. In this study, an optimized design of in-shoe heel lifts developed to maintain the midfoot function was tested to investigate if the plantar pressure distribution was improved. The design was based on three dimensional foot plantar contour which was captured by an Infoot 3D scanning system while the heel was elevated by a heel wedge. To facilitate midfoot function, an arch support was designed to support the lateral longitudinal arch, while allowing functional movement of the medial longitudinal arch. Twenty healthy male subjects were asked to walk along an 8m walkway while wearing high-cut footwear with and without the optimized heel lift. Peak pressure, contact area and force-time integral were measured using the Pedar insole system. Range and velocity of medial-lateral center of pressure during forefoot contact phase and foot flat phase were collected using a Footscan pressure plate. Compared to the shoe only condition, peak pressure under the rearfoot decreased with the optimized heel lift, while no increase of peak pressure was observed under the forefoot and midfoot regions, indicating improved plantar pressure distribution. The findings of this study suggest that this optimized heel lift has better biomechanical performance than a conventional flat heel lift. Results from this study may have implications for insole and shoe last design, especially for people who need additional heel height without sacrificing midfoot function.

Potential of modeling and simulations of bioengineered devices: Endoprostheses, prostheses and orthoses

Modeling and simulation of prosthetic devices are the new tools investigated for the production of total customized prostheses. Computational simulations are used to evaluate the geometrical and material designs of a device while assessing its mechanical behavior. Data acquisition through magnetic resonance imaging, computed tomography or laser scanning is the first step that gives information about the human anatomical structures; a file format has to be elaborated through computer-aided design software. Computer-aided design tools can be used to develop a device that respects the design requirements as, for instance, the human anatomy. Moreover, through finite element analysis software and the knowledge of loads and conditions the prostheses are supposed to face in vivo, it is possible to simulate, analyze and predict the mechanical behavior of the prosthesis and its effects on the surrounding tissues. Moreover, the simulations are useful to eventually improve the design (as geometry, materials, features) before the actual production of the device. This article presents an extensive analysis on the use of finite element modeling for the design, testing and development of prosthesis and orthosis devices.

Effect of unilateral and bilateral use of laterally wedged insoles with arch supports on impact loading in medial knee osteoarthritis

BACKGROUND

Increased impact loading is implicated in knee osteoarthritis development and progression.

OBJECTIVES

This study examined the impact ground reaction force (GRF) peak, its loading rate, its relative timing to stance phase timing, and walking speed during unilateral and bilateral use of laterally wedged insoles with arch supports.

STUDY DESIGN

Within-subject design.

METHODS

Thirty-three female patients with medial knee osteoarthritis were examined with (unilateral 6° and 11°, and bilateral 0°, 6°, and 11°) and without insole use.

RESULTS

Repeated measures MANOVA revealed that the impact force increased significantly in bilateral 11° versus unilateral 6° and without-insole conditions. The loading rate decreased significantly in unilateral 11° versus bilateral 6° insoles. The relative timing increased significantly in each of bilateral 6°, bilateral 11°, and unilateral 11° versus bilateral 0° insoles and in each of bilateral 11° and unilateral 11° versus without-insole condition. There were significant positive correlations between the walking speed and each of the force and loading rate. The Chi-square test revealed insignificant association between the insole condition and the presence of impact forces.

CONCLUSION

Unilateral 11° insoles are capable of reducing impact loading possibly through increasing foot pronation. Walking slowly is another possible strategy to reduce loading.

CLINICAL RELEVANCE

Unilaterally applied 11° laterally wedged insoles are capable of reducing and delaying the initial impact ground reaction forces and reducing their loading rates during walking in patients with medial knee osteoarthritis, thus reducing osteoarthritis progression. Walking slowly could also be used as a strategy to reduce impact loading.

Immediate and long-term efficacy of laterally-wedged insoles on persons with bilateral medial knee osteoarthritis during walking

Background

The current study aimed to investigate the immediate and long-term effects of laterally-wedged (LW) insoles on the knee loadings, the knee abductor moment (KAM) in particular, and the compensatory changes at other lower limb joints in patients with bilateral medial knee osteoarthritis during level walking with and without LW insoles.

Methods

Older adults with bilateral medial knee OA (age 66 ± 5.3 years; height 156 ± 4.9 cm; mass 60 ± 5.1 kg; leg length 83.72 ± 3.64 cm) were studied using computerized gait analysis initially (Baseline) and 6 weeks after using LW insoles (Follow-up) during barefoot walking and walking with LW insoles (7° of lateral inclination, with medial arch support). The three-dimensional angles and internal moments at the lower limb joints, as well as the ground reaction forces, were obtained using a motion analysis system and two forceplates. Key features of all the variables were compared using paired t tests for immediate effects (barefoot vs. LW) and for long-term effects (Baseline vs. Follow-up). The symptomatic severity (WOMAC Index) was also evaluated (Baseline vs. Follow-up).

Results

The KAM with LW insoles at Baseline was significantly reduced when compared to the barefoot condition (p < 0.05), suggesting that the LW insoles were effective in reducing unfavorable loadings at the knee immediately upon wearing the insoles. After 6 weeks of wearing LW insoles (Follow-up), no significant changes were found in most of the biomechanical variables, including KAM (p > 0.05), when compared to Baseline with LW insoles. However, a specific gait adaptation with reduced knee loading was revealed when walking without LW insoles, i.e., for the barefoot condition (p < 0.05).

Conclusions

After long-term use of LW insoles, the pain and physical function were improved with decreased peak KAM. A specific gait adaptation with reduced KAM was also found when walking without LW insoles. These results indicate a positive long-term effect in persons with bilateral medial knee OA, both as an orthosis to assist walking, and as a treatment intervention to facilitate gait adaptations in favor of reduced KAM.

Do laterally wedged insoles or valgus braces unload the medial compartment of the knee in patients with osteoarthritis?

BACKGROUND

The results of conservative treatment of knee osteoarthritis (OA) are generally evaluated in epidemiological studies with clinical outcome measures as primary outcomes. Biomechanical evaluation of orthoses shows that there are potentially beneficial biomechanical changes to joint loading; however, evaluation in relation to clinical outcome measures in longitudinal studies is needed.

QUESTIONS/PURPOSES

We asked (1) is there an immediate effect on gait in patients using a laterally wedged insole or valgus knee brace; (2) is there a late (6 weeks) effect; and (3) is there a difference between subgroups within each group with respect to patient compliance, body mass index, and OA status?

METHODS

This was a secondary analysis of data from a previous randomized controlled trial of patients with early medial knee OA. A total of 91 patients were enrolled in that trial, and 73 (80%) completed it after 6 months. Of the enrolled patients, 80 (88%) met prespecified inclusion criteria for analysis in the present study. The patients were randomized to an insole or brace. Gait was analyzed with and without wearing the orthosis (insole or brace) at baseline and after 6 weeks. Measurements were taken of the knee adduction moment, ground reaction force, moment arm, walking speed, and toe-out angle. Data were analyzed with regression analyses based on an intention-to-treat principle.

RESULTS

A mean reduction of 4% (±10) (95% confidence interval [CI], -0.147 to -0.03, p=0.003) of the peak knee adduction moment and 4% (±13) (95% CI, -0.009 to -0.001, p=0.01) of the moment arm at baseline was observed in the insole group when walking with an insole was compared with walking without an insole. A mean reduction of 1% (±10) (95% CI, -0.002 to -0.001, p=0.001) of the peak knee adduction moment and no reduction of the moment arm were measured after 6 weeks. No reduction of knee adduction moment, moment arm, or ground reaction force was seen in the brace group at baseline and after 6 weeks. Subgroup analysis showed no differences in biomechanical effect for obesity, stage of OA, and whether patients showed a clinical response to the treatment.

CONCLUSIONS

Laterally wedged insoles unload the medial compartment only at baseline in patients with varus alignment and by an amount that might not be clinically important. No biomechanical alteration was seen after 6 weeks of wearing the insole. Valgus brace therapy did not result in any biomechanical alteration. Taken together, this study does not show a clinically relevant biomechanical effect of insole and brace therapy in patients with varus medial knee OA.

LEVEL OF EVIDENCE

Level I, therapeutic study. See Instructions for Authors for a complete description of levels of evidence.

The immediate effect of lateral wedge insoles, with and without a subtalar strap, on the lateral trunk lean motion in patients with knee osteoarthritis

BACKGROUND

Orthotic interventions for knee osteoarthritis (OA) aim to reduce mechanical loading on the medial compartment of the knee and may lessen the lateral trunk lean as the most important compensatory gait strategy. The lateral wedge insole is a known orthotic intervention for knee OA. However, the question whether the addition of a subtalar strap to the wedge improves its effect has not been addressed in the literature.

OBJECTIVE

To compare the effects of lateral wedge insoles, with and without a subtalar strap, on the lateral trunk lean in patients with knee OA.

METHODS

Twenty-three patients aged over 40 years, with grade I or II OA of the medial compartment of one knee, based on the American College of Rheumatology criteria, were included in this study. The patients were diagnosed with OA based on a clinical examination, and the diagnosis was confirmed with radiographs. A 3-dimensional motion measurement system was used to collect the gait data for 3 different conditions: (1) with no insole, (2) with a lateral wedge insole, and (3) with a lateral wedge insole and a subtalar strap. The immediate effect of the 3 test conditions on the lateral trunk lean was compared during a gait cycle a stance phase and at the point of midstance.

RESULTS

Based on the laboratory coordinate system, the 3 conditions had no significant effect on the lateral trunk lean during a gait cycle and a stance phase and at the point of midstance in patients with knee OA.

CONCLUSION

The results of this study demonstrated that the lateral wedge insoles, with and without a subtalar strap, had no immediate effect on the lateral trunk lean in patients with knee OA. However, the long-term effect of lateral wedge insoles on the lateral trunk lean in these patients requires further investigation.

Partitioning of knee joint internal forces in gait is dictated by the knee adduction angle and not by the knee adduction moment

Medial knee osteoarthritis is a debilitating disease. Surgical and conservative interventions are performed to manage its progression via reduction of load on the medial compartment or equivalently its surrogate measure, the external adduction moment. However, some studies have questioned a correlation between the medial load and adduction moment. Using a musculoskeletal model of the lower extremity driven by kinematics-kinetics of asymptomatic subjects at gait midstance, we aim here to quantify the relative effects of changes in the knee adduction angle versus changes in the adduction moment on the joint response and medial/lateral load partitioning. The reference adduction rotation of 1.6° is altered by ±1.5° to 3.1° and 0.1° or the knee reference adduction moment of 17Nm is varied by ±50% to 25.5Nm and 8.5Nm. Quadriceps, hamstrings and tibiofemoral contact forces substantially increased as adduction angle dropped and diminished as it increased. The medial/lateral ratio of contact forces slightly altered by changes in the adduction moment but a larger adduction rotation hugely increased this ratio from 8.8 to a 90 while in contrast a smaller adduction rotation yielded a more uniform distribution. If the aim in an intervention is to diminish the medial contact force and medial/lateral load ratio, a drop of 1.5° in adduction angle is much more effective (causing respectively 12% and 80% decreases) than a reduction of 50% in the adduction moment (causing respectively 4% and 13% decreases). Substantial role of changes in adduction angle is due to the associated alterations in joint nonlinear passive resistance. These findings explain the poor correlation between knee adduction moment and tibiofemoral compartment loading during gait suggesting that the internal load partitioning is dictated by the joint adduction angle.

Risk factors associated with medial tibial stress syndrome in runners: a systematic review and meta-analysis

Background

Medial tibial stress syndrome (MTSS) affects 5%–35% of runners. Research over the last 40 years investigating a range of interventions has not established any clearly effective management for MTSS that is better than prolonged rest. At the present time, understanding of the risk factors and potential causative factors for MTSS is inconclusive. The purpose of this review is to evaluate studies that have investigated various risk factors and their association with the development of MTSS in runners.

Methods

Medical research databases were searched for relevant literature, using the terms “MTSS AND prevention OR risk OR prediction OR incidence”.

Results

A systematic review of the literature identified ten papers suitable for inclusion in a meta-analysis. Measures with sufficient data for meta-analysis included dichotomous and continuous variables of body mass index (BMI), ankle dorsiflexion range of motion, navicular drop, orthotic use, foot type, previous history of MTSS, female gender, hip range of motion, and years of running experience. The following factors were found to have a statistically significant association with MTSS: increased hip external rotation in males (standard mean difference [SMD] 0.67, 95% confidence interval [CI] 0.29–1.04, P<0.001); prior use of orthotics (risk ratio [RR] 2.31, 95% CI 1.56–3.43, P<0.001); fewer years of running experience (SMD −0.74, 95% CI −1.26 to −0.23, P=0.005); female gender (RR 1.71, 95% CI 1.15–2.54, P=0.008); previous history of MTSS (RR 3.74, 95% CI 1.17–11.91, P=0.03); increased body mass index (SMD 0.24, 95% CI 0.08–0.41, P=0.003); navicular drop (SMD 0.26, 95% CI 0.02–0.50, P=0.03); and navicular drop >10 mm (RR 1.99, 95% CI 1.00–3.96, P=0.05).

Conclusion

Female gender, previous history of MTSS, fewer years of running experience, orthotic use, increased body mass index, increased navicular drop, and increased external rotation hip range of motion in males are all significantly associated with an increased risk of developing MTSS. Future studies should analyze males and females separately because risk factors vary by gender. A continuum model of the development of MTSS that links the identified risk factors and known processes is proposed. These data can inform both screening and countermeasures for the prevention of MTSS in runners.

A biomechanical perspective on physical therapy management of knee osteoarthritis

SYNOPSIS

Altered knee joint biomechanics and excessive joint loading have long been considered as important contributors to the development and progression of knee osteoarthritis. Therefore, a better understanding of how various treatment options influence the loading environment of the knee joint could have practical implications for devising more effective physical therapy management strategies. The aim of this clinical commentary was to review the pertinent biomechanical evidence supporting the use of treatment options intended to provide protection against excessive joint loading while offering symptomatic relief and functional improvements for better long-term management of patients with knee osteoarthritis. The biomechanical and clinical evidence regarding the effectiveness of knee joint offloading strategies, including contralateral cane use, laterally wedged shoe insoles, variable-stiffness shoes, valgus knee bracing, and gait-modification strategies, within the context of effective disease management is discussed. In addition, the potential role of therapeutic exercise and neuromuscular training to improve the mechanical environment of the knee joint is considered. Management strategies for treatment of joint instability and patellofemoral compartment disease are also mentioned. Based on the evidence presented as part of this clinical commentary, it is argued that special considerations for the role of knee joint biomechanics and excessive joint loading are necessary in designing effective short- and long-term management strategies for treatment of patients with knee osteoarthritis.

LEVEL OF EVIDENCE

Therapy, level 5.

Gait deviations in individuals with inflammatory joint diseases and osteoarthritis and the usage of three-dimensional gait analysis

This chapter describes three-dimensional gait analysis and common gait deviations in adults with rheumatoid arthritis (RA) and osteoarthritis (OA). Furthermore, we describe changes in gait deviations following surgical and non-surgical interventions. Gait analysis is used to define gait deviations and to evaluate varying surgical approaches, types of surgeries and non-pharmacologic interventions. Most studies examine gait in adults with knee OA. Limitations of existing studies include small samples, poor selection of controls, sample heterogenecity, lack of baseline gait assessments and inconsistency in measurement. Across studies, time and distance parameters are generally used to provide a global measure of gait deviations. Individuals with RA and OA in the lower extremities exhibit reduced walking speed/cadence and decreased motion and moments in relation to healthy subjects. Future research should include larger sample sizes, the use of proper controls, pre- and post-assessments and identify gait abnormalities early in the disease process to minimise long-term consequences.

Medial arch supports do not significantly alter the knee adduction moment in people with knee osteoarthritis

OBJECTIVE

This study aimed to evaluate the immediate effects of medial arch supports on indices of medial knee joint load (the peak external knee adduction moment (KAM) and knee adduction angular (KAA) impulse) and knee pain during walking in people with medial knee osteoarthritis (OA).

DESIGN

Twenty-one people with medial compartment OA underwent gait analysis in standardised athletic shoes wearing (1) no medial arch supports and (2) prefabricated medial arch supports, in random order. Outcomes were the first and second peaks in the external KAM, the KAA impulse and severity of knee pain during testing. Outcomes were compared across conditions using paired t tests (gait data) and Wilcoxon Signed Ranks test (pain data).

RESULTS

There were no significant changes in either first or second peak KAM, or in the KAA impulse, with the addition of medial arch supports (all P > 0.05). Considerable individual variation in response to the arch supports was observed across participants. There was no immediate change in knee pain during walking when medial arch supports were worn (P = 0.56).

CONCLUSIONS

This study showed no mean change in any of the measured indices of medial knee load with medial arch supports. No immediate changes in knee pain were evident.

Redistribution of knee stress using laterally wedged insole intervention: Finite element analysis of knee-ankle-foot complex

BACKGROUND

Laterally wedged insoles are widely applied in the conservative treatment for medial knee osteoarthritis. Experimental studies have been conducted to understand the effectiveness of such an orthotic intervention. However, the information was limited to the joint external loading such as knee adduction moment. The internal stress distribution is difficult to be obtained from in vivo experiment alone. Thus, a three-dimensional finite element model of the human knee-ankle-foot complex, together with orthosis, was developed in this study and used to investigate the redistribution of knee stress using laterally wedged insole intervention.

METHODS

Laterally wedged insoles with wedge angles of 0, 5, and 10° were fabricated for intervention. The subject-specific geometry of the lower extremity with details was characterized in the reconstruction of MR images. Motion analysis data and muscle forces were input to drive the model. The established finite element model was employed to investigate the loading responses of tibiofemoral articulation in three wedge angle conditions during simulated walking stance phase.

FINDINGS

With either of the 5° or 10° laterally wedged insole, significant decreases in von Mises stress and contact force at the medial femur cartilage region and the medial meniscus were predicted comparing with the 0° insole.

INTERPRETATION

The diminished stress and contact force at the medial compartment of the knee joint demonstrate the immediate effect of the laterally wedged insoles. The intervention may contribute to medial knee osteoarthritis rehabilitation.

Combined effects of a valgus knee brace and lateral wedge foot orthotic on the external knee adduction moment in patients with varus gonarthrosis

OBJECTIVE

To test the hypothesis that a custom-fit valgus knee brace and custom-made lateral wedge foot orthotic will have greatest effects on decreasing the external knee adduction moment during gait when used concurrently.

DESIGN

Proof-of-concept, single test session, crossover trial.

SETTING

Biomechanics laboratory within a tertiary care center.

PARTICIPANTS

Patients (n=16) with varus alignment and knee osteoarthritis (OA) primarily affecting the medial compartment of the tibiofemoral joint (varus gonarthrosis).

INTERVENTIONS

Custom-fit valgus knee brace and custom-made full-length lateral wedge foot orthotic. Amounts of valgus angulation and wedge height were tailored to each patient to ensure comfort.

MAIN OUTCOME MEASURES

The external knee adduction moment (% body weight [BW]*height [Ht]), frontal plane lever arm (cm), and ground reaction force (N/kg), determined from 3-dimensional gait analysis completed under 4 randomized conditions: (1) control (no knee brace, no foot orthotic), (2) knee brace, (3) foot orthotic, and (4) knee brace and foot orthotic.

RESULTS

The reduction in knee adduction moment was greatest when concurrently using the knee brace and foot orthotic (effect sizes ranged from 0.3 to 0.4). The mean decrease in first peak knee adduction moment compared with control was .36% BW*Ht (95% confidence interval [CI], -.66 to -.07). This was accompanied by a mean decrease in frontal plane lever arm of .59cm (95% CI, -.94 to -.25).

CONCLUSIONS

These findings suggest that using a custom-fit knee brace and custom-made foot orthotic concurrently can produce a greater overall reduction in the knee adduction moment, through combined effects in decreasing the frontal plane lever arm.