Biomechanical effects of lateral and medial wedge insoles on unilateral weight bearing

Effect of motion control versus neutral walking footwear on pain associated with lateral tibiofemoral joint osteoarthritis: a comparative effectiveness randomised clinical trial

OBJECTIVES

To determine if motion control walking shoes are superior to neutral walking shoes in reducing knee pain on walking in people with lateral knee osteoarthritis (OA).

DESIGN

Participant-blinded and assessor-blinded, comparative effectiveness, superiority randomised controlled trial.

SETTING

Melbourne, Australia.

PARTICIPANTS

People with symptomatic radiographic lateral tibiofemoral OA from the community and our volunteer database.

INTERVENTION

Participants were randomised to receive either motion control or neutral shoes and advised to wear them >6 hours/day over 6 months.

PRIMARY AND SECONDARY OUTCOME MEASURES

The primary outcome was change in average knee pain on walking over the previous week (11-point Numeric Rating Scale (NRS), 0-10) at 6 months. The secondary outcomes included other measures of knee pain, physical function, quality of life, participant-perceived change in pain and function, and physical activity.

RESULTS

We planned to recruit 110 participants (55 per arm) but ceased recruitment at 40 (n=18 motion control shoes, n=22 neutral shoes) due to COVID-19-related impacts. All 40 participants completed 6-month outcomes. There was no evidence that motion control shoes were superior to neutral shoes for the primary outcome of pain (mean between-group difference 0.4 NRS units, 95% CI -1.0 to 1.7) nor for any secondary outcome. The number of participants experiencing any adverse events was similar between groups (motion control shoes: n=5, 28%; neutral shoes: n=4, 18.2%) and were minor.

CONCLUSIONS

Motion control shoes were not superior to neutral shoes in improving knee pain on walking in symptomatic radiographic lateral tibiofemoral joint OA. Further research is needed to identify effective treatments in this important but under-researched knee OA subgroup.

TRIAL REGISTRATION NUMBER

ACTRN12618001864213.

The Effects of Short-Term Wearing of Customized 3D Printed Single-Sided Lateral Wedge Insoles on Lower Limbs in Healthy Males: A Randomized Controlled Trial

Background

Unbalanced standing and gait asymmetry are common in individuals with musculoskeletal disorders. Achieving symmetrical posture and gait is an important goal of rehabilitation. This study investigated the biomechanical differences in the lower extremities observed immediately after an insole was used and without the use of different one-sided insoles.

Material/Methods

Thirty young, healthy adult males received 3 different insole interventions: experimental group A had a customized 3-dimensional (3D)-printed single-sided lateral wedge insole (CLWI) inserted on the left side, and experimental group B had on the left side, a traditional single insert. The control had unilateral flat insoles; no insole inserted into the socks. Motion mechanics and gait parameters were collected at the 2-time points, after insertion of the insole and after 20 minutes of walking with the insole.

Results

Asymmetric posture and gait appeared immediately after using the 2 insoles (lower joint moment, P<0.05). Compared with the control group, the abnormal posture and gait of experimental group B after wearing the traditional insole for 20 minutes were not obvious (P>0.05). However, the asymmetrical posture and gait remained in experimental group A after wearing the CLWI for 20 minutes (P<0.05). The center of pressure (COP) trajectory of the left foot of experimental group A was significantly higher than that of experimental group B and the control group at the 2-time points (P<0.05).

Conclusions

The asymmetry of posture and gait can be observed in a short time using a customized 3D-printed single-sided lateral wedge insole. This experiment provides guidance for the application of customized 3D-printed single-sided lateral wedge insoles for gait rehabilitation.

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.

Effects of footwear on the knee adduction moment in medial knee osteoarthritis: classification criteria for flat flexible vs stable supportive shoes

OBJECTIVE

To validate simple criteria that distinguish flat flexible from stable supportive walking shoes by comparing their effects on the knee adduction moment (KAM) in people with medial knee osteoarthritis (OA).

DESIGN

This was a cross-sectional biomechanical study. We proposed five criteria to differentiate flat flexible from stable supportive shoes, and selected three pairs of shoes representing each class for biomechanical testing. 28 participants aged ≥50 years with symptomatic medial knee OA underwent gait analysis barefoot and wearing each of the six selected shoes, in random order. Differences in the peak KAM, KAM impulse and peak knee flexion moment (KFM) across test conditions were evaluated with a two-way repeated measures analysis of variance (ANOVA). Immediate changes in walking pain between conditions were also compared.

RESULTS

Increases in KAM from barefoot were lower with each of the three flat flexible shoe styles (peak KAM: 6.1-8.9%; KAM impulse: 2.4-5.1%) compared to their stable supportive counterparts (peak KAM: 11.6-15.1%; KAM impulse 10.5-13.2%). There was a significant main effect for footwear class on peak KAM and KAM impulse, whereby stable supportive shoes increased the KAM significantly more than flat flexible shoes (P < 0.001). There were no differences in the KFM or immediate walking pain between footwear classes.

CONCLUSIONS

Our proposed criteria can be used by researchers and clinicians to select flat flexible shoes for people with medial knee OA to minimise knee loading. Future research should evaluate whether wearing shoes based on these criteria translates to improvements in knee OA symptoms and/or slows structural disease progression.

The relationship between the load on the knee joint during walking and the biomechanical characteristics of single-leg standing

[Purpose] The purpose of the present study was to investigate the relationship between the external knee adduction moment (KAM) during walking and the biomechanical characteristics of single-leg standing in healthy subjects. [Subjects and Methods] Twenty-eight healthy subjects were recruited for this study. Data were collected while the subjects performed walking and single-leg standing using a motion analysis system with six digital video cameras and two force plates. Pearson’s correlation coefficient was used to quantify the relationship between peak KAM during walking and single-leg standing. To determine whether the kinematic behavior of the pelvis and trunk during single-leg standing are associated with peak KAM during walking, Pearson’s correlation coefficients were calculated and stepwise linear regression was performed. [Results] The peak KAM during single-leg standing was significantly correlated with that during walking. The peak KAM during walking was significantly correlated with the peak lateral lean of the trunk and the peak lateral tilt of the pelvis during single-leg standing. The results of stepwise linear regression analysis show the peak KAM during walking was partially explained by the peak lateral lean of the trunk during single-leg standing. [Conclusion] Our findings suggest that single-leg standing might be a useful method for predicting the peak KAM during walking.