The biomechanical effects of a new design of lateral wedge insole on the knee and ankle during walking.

Lateral wedged insoles are a common treatment in individuals with medial tibiofemoral osteoarthritis of the knee joint. One concern has been the potential for increased foot and ankle pain due to increased eversion. The purpose of this study was to assess the biomechanical effectiveness of a typical lateral wedged insole and a combined insole with a lateral wedge and off-the-shelf anti-pronatory device in shoes while walking. A cross-over randomized design was used where each insole was worn by fifteen healthy subjects while three-dimensional motion data were collected in three different conditions: (1) control condition (with standard shoes), (2) with an insole with a lateral wedge and additional off-the-shelf anti-pronatory support (supporting), and (3) with an insole with a lateral wedge with no additional support (unsupported) in the standard shoes. The unsupported insole significantly increased the amount of ankle/subtalar joint complex eversion than the other experimental conditions, with the supporting insole reducing the ankle/subtalar joint complex eversion, and was found to be more comfortable. Both the supporting and unsupported lateral wedged insoles significantly reduced knee loading (external knee adduction moment reduction 8.5% and 9.1%, respectively), the knee adduction angular impulse. This new design of lateral wedge may offer increased adherence in future osteoarthritis population studies while offering reductions in joint loading.

A comparison of the biomechanical effects of valgus knee braces and lateral wedged insoles in patients with knee osteoarthritis.

Increases in the external knee adduction moment (EKAM) have been associated with increased mechanical load at the knee and progression of knee osteoarthritis. Valgus knee braces and lateral wedged insoles are common approaches to reducing this loading; however no study has directly compared the biomechanical and clinical effects of these two treatments in patients with medial tibiofemoral osteoarthritis. A cross-over randomised design was used where each intervention was worn by 28 patients for a two week period. Pre- and post-intervention gait kinematic/kinetic data and clinical outcomes were collected to evaluate the biomechanical and clinical effects on the knee joint. The valgus knee brace and the lateral wedged insole significantly increased walking speed, reduced the early stance EKAM by 7% and 12%, and the knee adduction angular impulse by 8.6 and 16.1% respectively. The lateral wedged insole significantly reduced the early stance EKAM compared to the valgus knee brace (p=0.001). The valgus knee brace significantly reduced the knee varus angle compared to the baseline and lateral wedged insole. Improvements in pain and function subscales were comparable for the valgus knee brace and lateral wedged insole. There were no significant differences between the two treatments in any of the clinical outcomes; however the lateral wedged insoles demonstrated greater levels of acceptance by patients. This is the first study to biomechanically compare these two treatments, and demonstrates that given the potential role of knee loading in osteoarthritis progression, that both treatments reduce this but lateral wedge insoles appear to have a greater effect.

Development and evaluation of prefabricated antipronation foot orthosis.

Our aim was to develop and evaluate a new antipronation foot orthosis that addressed problems perceived by clinicians and users with existing foot orthoses. Clinicians and users were engaged to develop a user specification for the orthosis, and orthotic geometry and materials were developed using clinical reasoning. The orthotic material properties were tested and the ability of the orthosis to reduce foot pronation evaluated on 27 individuals. Clinicians expressed concern that current prefabricated orthoses often did not offer sufficient support to the foot because of a combination of the shape and materials used, and users concurred but also highlighted issues of durability and hygiene. The geometry of the new orthosis was, therefore, adjusted to enable individual foot size orthoses to be produced. A material was selected that was harder and more durable than materials used in many prefabricated orthoses. When the new orthosis was being worn, maximum rear foot eversion was reduced in both walking (mean reduction -3.8 degrees, p < 0.001) and running (mean reduction -2.5 degrees, p < 0.001). Through a structured process, orthotic design decisions were made that addressed the specific concerns of clinicians and users and the new orthosis was proven to reduce rearfoot pronation.

Orthotic control of rear foot and lower limb motion during running in participants with chronic Achilles tendon injury.

This study examined the kinematic effects of orthoses in participants with a history of chronic Achilles tendon injury. Twelve participants ran at self-selected speeds on a treadmill with and without customized orthoses. Joint and segment angles including leg abduction, calcaneal, eversion, ankle dorsiflexion, and knee flexion angles were calculated from three-dimensional data throughout stance. Five footfalls were obtained for each participant and condition. Statistical tests revealed an increase in maximum eversion with orthoses (P < 0.001, eta(p)2 = 0.642). In the individual participant analysis, this was evident in 9 of 12 participants. Trends towards increased eversion range of motion and decreased ankle dorsiflexion maximum and range of motion angles were also observed. Increased eversion was unexpected as all devices were designed to provide pronation control as deemed necessary by the podiatrist. Despite this, participants reported between 50 and 100% (average 92%) relief from symptoms with the use of orthoses. Further analysis of the angle-time curves and coordination between angular measures is recommended.

Lower limb kinematics of subjects with chronic achilles tendon injury during running.

This study examined the kinematic differences between subjects who had a history of chronic Achilles tendon (AT) injury and matched controls during running. Eleven subjects from each group ran barefoot (BF) and shod at self-selected speeds on a treadmill. Three-dimensional angles describing rearfoot and lower limb motion were calculated throughout stance. Five footfalls were obtained for each subject and condition. Pairwise comparisons revealed greater eversion, ankle dorsiflexion and less leg abduction during stance in the AT group compared with controls. Running kinematics were exaggerated in shod compared with BF conditions, as expected from previous research. The differences between conditions were more exaggerated in AT subjects compared with control subjects. Further analysis using a curve-based approach is recommended.