Lateral wedge insoles for people with medial knee osteoarthritis: one size fits all, some or none?

Muscle contributions to reduced ankle joint contact force during drop vertical jumps in patients with chronic ankle instability

Chronic ankle instability is a condition linked to progressive early ankle joint degeneration. Patients with chronic ankle instability exhibit altered biomechanics during gait and jump landings and these alterations are believed to contribute to aberrant joint loading and subsequent joint degeneration. Musculoskeletal modeling has the capacity to estimate joint loads from individual muscle forces. However, the influence of chronic ankle instability on joint contact forces remains largely unknown. The objective of this study was to compare tri-axial (i.e., compressive, anterior-posterior, and medial-lateral) ankle joint contact forces between those with and without chronic ankle instability during the ground contact phase of a drop vertical jump. Fifteen individuals with and 15 individuals without chronic ankle instability completed drop vertical jump maneuvers in a research laboratory. We used those data to drive three-dimensional musculoskeletal simulations and estimate muscle forces and tri-axial joint contact force variables (i.e., peak and impulse). Compared to those without chronic ankle instability, the ankles of patients with chronic ankle instability underwent lower compressive ankle joint contact forces as well as lower anterior-posterior and medial-lateral shearing forces during the weight acceptance phase of landing (p <.05). These findings suggest that patients with chronic ankle instability exhibit lower ankle joint loading patterns than uninjured individuals during a drop vertical jump, which may be considered in rehabilitation to potentially reduce the risk of early onset of ankle joint degeneration.

Ankle joint contact force profiles differ between those with and without chronic ankle instability during walking

BACKGROUND

Individuals with chronic ankle instability (CAI) exhibit aberrant gait biomechanics relative to uninjured controls. Altered gait biomechanics likely contribute aberrant joint loading and subsequent early onset ankle joint degeneration. Joint (i.e. cartilage) loading cannot be directly measured without invasive procedures but can be estimated via joint contact forces (JCF) generated from musculoskeletal modeling. However, no investigation has quantified JCF in those with CAI during walking despite the link between ligamentous injury and ankle post-traumatic ankle osteoarthritis.

RESEARCH QUESTION

Do patients with CAI exhibit altered ankle compressive and shear JCF profiles during the stance phase of walking compared to those without CAI?

METHODS

Ten individuals with CAI and 10 individuals without a history of ankle sprain completed a gait assessment at their self-selected speed on an instrumented treadmill. Musculoskeletal modeling was applied to estimate ankle JCF variables within a generic model. Variables included the peak, impulse, and loading rates for compressive, anteroposterior shear, and mediolateral shear JCF.

RESULTS

Those with CAI had significantly different JCF forces, relative to uninjured controls, in all directions. More specifically, lower compressive peak and impulse values were noted while higher anteroposterior shearing forces (1 st peak, impulse, loading late) were observed in those with CAI. Those with CAI also demonstrated higher mediolateral shearing forces (1 st peak and impulse).

SIGNIFICANCE

Our finding suggests that those with CAI exhibit different ankle joint loading patterns than uninjured controls. Directionality of the identified differences depends on the axis of movement.

A Study on the Effects of Lateral-Wedge Insoles on Plantar-Pressure Pattern for Medial Knee Osteoarthritis Using the Wearable Sensing Insole

Patients with knee osteoarthritis have a unique plantar-pressure pattern during walking, and lateral-wedge insoles are one of the treatment options. Participants were randomly assigned to either the lateral-wedge insole group or the ordinary insole group. The Visual Analog Scale (VAS), Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), and plantar-pressure test scores were evaluated at the baseline and at 20 weeks. Plantar pressure data were collected using a pressure insole with 89 sensing locations. In the ordinary insole group, the function and total WOMAC scores decreased significantly (function score, 24.8 (baseline) to 16.5 (week 20); total score, 34.9 (baseline) to 24.6 (week 20)). During walking, the transverse width of the center of pressure as a percentage of foot width (%Trans) significantly increased in the ordinary insole group (baseline, 6.3%; week 20, 14.8%). In addition, the values of partial foot pressure as a percentage of body weight (%PFP) on the forefoot (baseline, 30.3%; week 20, 39.2%) and heel (baseline, 28.1%; week 20, 16.9%) also increased significantly in the ordinary insole group. Significant group-by-time interaction effects were observed for partial foot pressure per body weight in the forefoot (p = 0.031) and heel (p = 0.024). In the ordinary insole group, the plantar pressure on the heel significantly decreased (p = 0.011) and that on the forefoot significantly increased (p = 0.023). In contrast, plantar pressure remained stable in all regions in the lateral-wedge insole group. Thus, lateral-wedge insoles may protect against plantar pressure deterioration in patients with knee osteoarthritis.

Osteoarthritis of the Knee in Middle-age Athletes: Many Measures are Practiced, but Lack Sound Scientific Evidence

Osteoarthritis of the knee generally affects individuals from the fifth decade, the typical age of middle-age athletes. In the early stages, management is conservative and multidisciplinary. It is advisable to avoid sports with high risk of trauma, but it is important that patients continue to be physically active. Conservative management offers several options; however, it is unclear which ones are really useful. This narrative review briefly reports the conservative options for which there is no evidence of effectiveness, or there is only evidence of short-term effectiveness.

Effects of tailored lateral wedge insoles on medial knee osteoarthritis based on biomechanical analysis: 12-week randomized controlled trial

BACKGROUND

Lateral wedge insoles adjusted by biomechanical analysis may improve the condition of patients with medial knee osteoarthritis.

DESIGN

This is a prospective, randomized, controlled, single-blind clinical trial.

SETTING

The study was conducted in a biomechanics laboratory.

SUBJECTS

A total of 38 patients with medial knee osteoarthritis were allocated to either an experimental group (lateral wedge insoles) or a control group (neutral insoles).

INTERVENTIONS

Experimental group (n = 20) received an adjusted lateral wedge insole of 2, 4, 6, 8, or 10 degrees, after previous biomechanical analysis. Control group (n = 18) received a neutral insole (0 degrees). All patients used the insoles for 12 weeks.

MAIN MEASURES

Visual analogue scale, Knee Injury and Osteoarthritis Outcome Score questionnaire, biomechanical parameters: first and second peak of the external knee adduction moment and knee adduction angular impulse, and physical performance tests: 30-second sit-to-stand test, the 40-m fast-paced walk test, and the 12-step stair-climb test.

RESULTS

After 12 weeks, between-group differences did not differ significantly for pain intensity (-12.5 mm, (95% CI -29.4-4.4)), biomechanical parameters (p = 0.05), Knee Injury and Osteoarthritis Outcome Score, and physical performance tests, except on the Knee Injury and Osteoarthritis Outcome Score subscale other symptoms (p = 0.002; 13.8 points, (95% CI 5.6-22.0)).

CONCLUSION

Tailored wedge insoles were no more effective at improving biomechanical or clinically meaningful outcomes than neutral insoles, except on symptoms. More participants from the experimental group reported they felt some improvement. However, these effects were minimal and without clinical significance.

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.

Gait alteration strategies for knee osteoarthritis: a comparison of joint loading via generic and patient-specific musculoskeletal model scaling techniques

Gait modifications and laterally wedged insoles are non-invasive approaches used to treat medial compartment knee osteoarthritis. However, the outcome of these alterations is still a controversial topic. This study investigates how gait alteration techniques may have a unique effect on individual patients; and furthermore, the way we scale our musculoskeletal models to estimate the medial joint contact force may influence knee loading conditions. Five patients with clinical evidence of medial knee osteoarthritis were asked to walk at a normal walking speed over force plates and simultaneously 3D motion was captured during seven conditions (0°-, 5°-, 10°-insoles, shod, toe-in, toe-out, and wide stance). We developed patient-specific musculoskeletal models, using segmentations from magnetic resonance imaging to morph a generic model to patient-specific bone geometries and applied this morphing to estimate muscle insertion sites. Additionally, models were created of these patients using a simple linear scaling method. When examining the patients' medial compartment contact force (peak and impulse) during stance phase, a 'one-size-fits-all' gait alteration aimed to reduce medial knee loading did not exist. Moreover, the different scaling methods lead to differences in medial contact forces; highlighting the importance of further investigation of musculoskeletal modeling methods prior to use in the clinical setting.

Moderators and mediators of effects of unloading shoes on knee pain in people with knee osteoarthritis: an exploratory analysis of the SHARK randomised controlled trial

OBJECTIVE

To investigate moderators and biomechanical mediators of effects of unloading shoes on knee pain in people with knee osteoarthritis (OA).

METHODS

Exploratory analysis from 164 participants in a clinical trial comparing unloading (ASICS GEL-Melbourne OA) to conventional walking shoes. The primary outcome was 6-month change in knee pain (11-point numerical rating scale (NRS)). Moderators included baseline peak knee adduction moment (KAM), radiographic severity (Kellgren & Lawrence (KL) scale), body mass, foot posture, neuropathic pain and diffuse knee pain. Mediators included change in peak KAM and KAM impulse.

RESULTS

Radiographic severity was the only moderator to interact with footwear group (P = 0.02). Participants with KL = 2 experienced greater pain reductions with conventional compared to unloading shoes (mean difference in change in pain -1.64 units, 95% CI -3.07, -0.21), while unloading shoes tended to result in greater pain reductions than conventional shoes in KL = 3 (0.98, 95% CI -0.44, 2.39) and KL = 4 (0.64, 95% CI -0.64, 1.93). No variable showed any significant mediating effect in the entire cohort. However, there was some evidence that unloading shoes may reduce pain through reductions in peak KAM (indirect effect -0.31, 95% CIs -0.65, 0.03; P = 0.07) in people with KL ≥ 3, compared to conventional shoes.

CONCLUSION

Unloading shoes conferred additional symptomatic benefits over conventional shoes in people with moderate to severe knee OA. There was some evidence effects may be mediated by a reduction in peak KAM. However, we were underpowered for subgroup analyses. These patients may represent a subgroup to which biomechanical interventions designed to reduce the KAM may be more effectively targeted.

Rear foot kinematics when wearing lateral wedge insoles and foot alignment influence the effect of knee adduction moment for medial knee osteoarthritis

Lateral wedge insoles (LWIs) are prescribed for patients with medial knee osteoarthritis to reduce the external knee adduction moment (KAM). However, the biomechanical effects of LWIs are limited in some patients. The purpose of this study was to investigate whether the biomechanical effects of LWIs depend on individual foot alignment and to examine the relationship between change in KAM and changes in foot and ankle biomechanics when wearing LWIs. Twenty-one patients participated in this study. They were categorized into normal or abnormal foot groups based on the foot posture index (FPI). All patients were requested to perform a normal gait under barefoot and LWI conditions. A three-dimensional motion analysis system was used to record 1st and 2nd KAM, knee adduction angular impulse (KAAI), center of pressure displacement, and knee-ground reaction force lever arm. Furthermore, the foot and ankle frontal plane kinematic parameters were evaluated. The 1st KAM was significantly reduced under the LWI condition compared to that under the barefoot condition in the normal foot group. In contrast, there was no significant difference in 1st KAM between both conditions in the abnormal foot group. Decreased rear foot eversion strongly correlated with reduction in the 1st KAM in the normal foot group. These findings suggested that it is helpful to assess individual foot alignment to ensure adequate insole treatment for patients with medial knee osteoarthritis and that decreased rear foot eversion during the early stance phase is significantly involved in the reduction of 1st KAM when wearing LWIs with normal feet.

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.

Plug-in-Gait calculation of the knee adduction moment in people with knee osteoarthritis during shod walking: comparison of two different foot marker models

Background

Understanding how kinematic multi-segment foot modelling influences the utility of Plug-in-Gait calculations of the knee adduction moment (KAM) during shod walking is relevant to knee osteoarthritis (OA). Multi-segment foot markers placed on the skin through windows cut in to the shoe provide a more accurate representation of foot mechanics than the traditional marker set used by Plug-in-Gait, which uses fewer markers, placed on the shoe itself. We aimed to investigate whether Plug-in-Gait calculation of the KAM differed when using a kinematic multi-segment foot model compared to the traditional Plug-in-Gait marker set.

Methods

Twenty people with medial knee OA underwent gait analysis in two test conditions: i) Plug-in-Gait model with its two standard foot markers placed on the shoes and; ii) Plug-in-Gait with the heel marker virtualised from a modified-Oxford Foot Model where 8 ft markers were placed on the skin through windows cut in shoe uppers. Outcomes were the peak KAM, KAM impulse and other knee kinetic and kinematic variables.

Results

There were no differences (P > 0.05) in any gait variables between conditions. Excellent agreement was found for all outcome variables, with high correlations (r > 0.88-0.99, P < 0.001), narrow limits of agreement and no proportional bias (R² = 0.03–0.14, P > 0.05). The mean difference and 95% confidence intervals for peak KAM were also within the minimal detectable change range demonstrating equivalence.

Conclusions

Plug-in-Gait calculations of the KAM are not altered when using a kinematic multi-segment foot marker model with skin markers placed through windows cut in to the shoe, instead of the traditional marker set placed on top of shoes. Researchers may be confident that applying either foot model does not change the calculation of the KAM using Plug-in-Gait.

Electronic supplementary material

The online version of this article (doi:10.1186/s13047-017-0187-4) contains supplementary material, which is available to authorized users.

Foot alignments influence the effect of knee adduction moment with lateral wedge insoles during gait

Lateral wedge insoles (LWIs) reduce the peak external knee adduction moment (KAM). However, the efficacy of LWIs is limited in certain individuals for whom they fail to decrease KAM. Possible explanations for a lack of desired LWI response are variations in foot alignments. The purpose of this study was to evaluate whether the immediate biomechanical effects of LWIs depend on individual foot alignments during gait. Fifteen healthy adults participated in this study. Their feet were categorized as normal, pronated, and supinated using the foot posture index. All subjects were subsequently requested to perform a normal gait under barefoot and LWI conditions. A three-dimensional motion analysis system was used to record the kinematic and kinetic data, included peak KAM, KAM impulse (KAAI), center of pressure displacement, and knee-ground reaction force lever arm (KLA). Furthermore, lower limb frontal plane kinematic parameters at the rear foot, ankle, knee, and hip were evaluated. Among all feet, there was no significant difference in the peak KAM and KAAI between the conditions. In contrast, the peak KAM was significantly reduced under the LWI condition relative to the barefoot condition in the normal foot group. Reductions in the peak KAM were correlated with a more lateral center of pressure and reduced KLA. In addition, a reduced KLA was correlated with decreased hip adduction. LWIs significantly reduced the peak KAM in normal feet, indicating that biomechanical effects of LWIs vary between individual foot alignments. Our findings suggest that it is helpful to assess individual foot alignment to ensure adequate insole treatment for patients with knee osteoarthritis.

Wedged Insoles and Gait in Patients with Knee Osteoarthritis: A Biomechanical Review

The study of gait biomechanics in individuals with knee osteoarthritis has become widespread, especially in regards to the knee adduction moment-a variable commonly believed to be associated with knee osteoarthritis progression. Unfortunately, this variable is often studied clinically without considering how it is derived, or what it means in a mechanical context. The use of footwear for knee osteoarthritis management has received much attention as well. However, in many cases, footwear is studied without regard for the mechanical effects they actually induce on the patient. Therefore, this review aims to summarize the current state of knowledge in regards to knee osteoarthritis gait and footwear biomechanics, by taking a step back to review the foundations of these two research areas. First, an overview of the calculation of the knee adduction moment is provided, along with mechanical considerations. Then, this is used to discuss current evidence for wedged insoles and highlight knowledge gaps. The intent was to place this mechanical information in a clinically-oriented framework for approachability by scientists, engineers and clinicians alike. Based on this discussion, areas for future investigation are proposed.

Control conditions for footwear insole and orthotic research

Footwear insoles/orthotics alter variables associated with musculoskeletal injury; however, their clinical effectiveness is inconclusive. One explanation for this is the possibility that control conditions may actually produce biomechanical changes that induce clinical responses. The purpose of this study was to compare insole/orthotic control conditions to identify if variables at the ground, ankle and knee that are associated with injury are altered relative to what participants would normally experience in their own shoes. Gait analysis was performed on 15 participants during walking and running while wearing (1) their own shoes, (2) #1 with a 3mm flat insole, (3) a standardized shoe, and (4) #3 with a 3mm flat insole, where external knee adduction moments, external knee adduction angular impulses, internal ankle inversion moments, and vertical ground reaction force loading rates were determined. Conditions 2-4 were expressed as percent changes relative to condition 1, and tests of proportions assessed if there were a significant number of individuals experiencing a biomechanically relevant change for each variable. Repeated-measures ANOVAs were used to identify group differences between conditions. The majority of movement-footwear-variable combinations contained a proportion of individuals experiencing biomechanically relevant changes compared to condition 1 that was significantly greater than the expected proportion of 20%. No systematic differences were found between conditions. This suggests that conditions 2-4 may alter biomechanics relative to baseline for many participants, but not in a consistent way across participants. It is recommended that participant's own footwear be used as control conditions in future trials where biomechanics are primary variables of interest.