Craig Payne

Lateral wedge insoles for medial knee osteoarthritis: 12 month randomised controlled trial

Objective To assess the effect of lateral wedge insoles compared with flat control insoles on improving symptoms and slowing structural disease progression in medial knee osteoarthritis. Design Randomised controlled trial. Setting Community in Melbourne, Australia. Participants 200 people aged 50 or more with clinical and radiographic diagnosis of mild to moderately severe medial knee osteoarthritis. Interventions Full length 5 degree lateral wedged insoles or flat control insoles worn inside the shoes daily for 12 months. Main outcome measures Primary symptomatic outcome was change in overall knee pain (past week) measured on an 11 point numerical rating scale. Primary structural outcome was change in volume of medial tibial cartilage from magnetic resonance imaging scans. Secondary clinical outcomes included changes in measures of pain, function, stiffness, and health related quality of life. Secondary structural outcomes included progression of medial cartilage defects and bone marrow lesions. Results Between group differences did not differ significantly for the primary outcomes of change in overall pain (−0.3 points, 95% confidence intervals −1.0 to 0.3) and change in medial tibial cartilage volume (−0.4 mm3, 95% confidence interval −15.4 to 14.6), and confidence intervals did not include minimal clinically important differences. None of the changes in secondary outcomes showed differences between groups. Conclusion Lateral wedge insoles worn for 12 months provided no symptomatic or structural benefits compared with flat control insoles. Trial registration Australian New Zealand Clinical Trials Registry ACTR12605000503628 and ClinicalTrials.gov NCT00415259.

Lateral wedges in knee osteoarthritis: What are their immediate clinical and biomechanical effects and can these predict a three‐month clinical outcome?

OBJECTIVE To assess immediate effects of laterally wedged insoles on walking pain, external knee adduction moment, and static alignment, and whether these immediate effects together with age, body mass index, and disease severity predict clinical outcome after 3 months of wearing insoles in medial knee osteoarthritis. METHODS Forty volunteers (mean age 64.7 years, 16 men) were tested in random order with and without a pair of 5 degrees full-length lateral wedges. Immediate changes in static alignment were measured via radiographic mechanical axis and changes in adduction moment via 3-dimensional gait analysis. After 3 months of treatment with insoles, changes in pain and physical functioning were assessed via the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) and patient-perceived global change scores. RESULTS Reductions in the adduction moment occurred with insoles (first peak mean [95% confidence intervals (95% CI)] -0.22 [-0.28, -0.15] Nm/body weight x height %), accompanied by a reduction in walking pain of approximately 24% (mean [95% CI] -1.0 [-4.0, 2.0]). Insoles had no mean effect on static alignment. Mean improvement in WOMAC pain (P = 0.004) and physical functioning (mean [95% CI] -6 [-11, -1]) was observed at 3 months, with 25 (69%) and 26 (72%) of 36 individuals reporting global improvement in pain and functioning, respectively. Regression analyses demonstrated that disease severity, baseline functioning, and magnitude of immediate change in walking pain and the first peak adduction moment with insoles were predictive of clinical outcome at 3 months. CONCLUSION Lateral wedges immediately reduced knee adduction moment and walking pain but had no effect on static alignment. Although some parameters predicted clinical outcome, these explained only one-third of the variance, suggesting that other unknown factors are also important.

Effects of estrogen on the mechanical behavior of the human Achilles tendon in vivo

The purpose of this study was to elucidate the effect of normal fluctuating [non-monophasic oral contraceptive pill (MOCP) users] and low, consistent (MOCP users) endogenous plasma estrogen levels on the strain behavior of the Achilles tendon in vivo. Twenty women (age 28.0 +/- 4.2 yr, height 1.67 +/- 0.07 m, mass 61.6 +/- 6.8 kg) who had been using the MOCP for at least 12 mo together with 20 matched women who were non-MOCP users (age 31.9 +/- 7.3 yr, height 1.63 +/- 0.05 m, mass 62.5 +/- 5.9 kg) participated in this study. Non-MOCP users were tested at the time of lowest (menstruation) and highest (approximately same as ovulation) estrogen, whereas MOCP users, who exhibited constant and attenuated endogenous estrogen levels, were tested at day 1 and day 14 of their cycle. At each test session, maximal isometric plantarflexion efforts were performed on a calf-raise apparatus while synchronous real-time ultrasonography of the triceps surae aponeurosis was recorded. Achilles tendon strain (%) was calculated by dividing tendon displacement during plantarflexion by resting tendon length. Repeated-measures ANOVA revealed a significant (P < 0.05) main effect of subject group with significantly lower Achilles strain (25.5%) in the MOCP users compared with the non-MOCP users. In conclusion, acute fluctuations in plasma estrogen across the menstrual cycle in non-MOCP users did not alter the strain behavior of the Achilles tendon. Conversely, long-term exposure to attenuated estrogen in MOCP users resulted in a decrease in Achilles tendon strain, which is thought to be attributed to the effects of endogenous estrogen on collagen synthesis. These findings have a number of important functional and clinical implications.

The effect of foot wedging on electromyographic activity in the erector spinae and gluteus medius muscles during walking

The use of foot orthoses for treatment of low back pain (LBP) has received some attention in the literature, mainly from a clinical or theoretical perspective. It has been proposed that this treatment alleviates pain by altering muscle activity in the area of the low back but there is no direct evidence of such an effect. The objective of this study was to determine the effects of different types of foot wedging on the bilateral surface electromyographic activity of erector spinae (ErSp) (L3 level) and gluteus medius (GlMed) of 13 participants without LBP. Activity in ErSp had a significantly earlier onset during the gait cycle with bilateral heel lifts and bilateral lateral forefoot wedging. GlMed activity had a significantly later onset with bilateral heel lifts, and with an unilateral heel lift on the ipsilateral side (P<0.0125). No significant amplitude changes were demonstrated in either muscle for any of the forms of wedging tested. These results show that foot wedging can produce measurable changes in timing of muscle activity within the low back and pelvis during the gait cycle. Further investigation is required to determine whether this effect contributes to the alleviation of LBP.

Effect of length on laterally-wedged insoles in knee osteoarthritis

Introduction Knee osteoarthritis (OA) is a prevalent musculoskeletal condition (1). It imposes a significant economic burden and is associated with considerable pain, disability, and loss of quality of life. Although the causative mechanisms of knee OA are not entirely clear, increased joint loads during walking have been associated with the initiation and progression of the disease and its symptoms (2). The external knee adduction moment, which reflects the dynamic load borne on the medial tibiofemoral joint compartment, has become a biomechanical marker for the risk of progression for medial compartment OA (2). Accordingly, much research is focused on devising and evaluating interventions that may reduce the peak adduction moment with a view to alleviating symptoms and reducing the risk of disease progression in knee OA. Laterally-wedged insoles are an in-shoe orthotic recommended to manage medial knee OA (3). Lateral wedges are hypothesized to reduce the moment arm of the ground reaction force vector relative to the knee center during walking (4), leading to reduced knee pain. Biomechanical studies have demonstrated that lateral wedges can reduce the peak adduction moment in patients with OA and healthy subjects (4–7). However, this finding is not consistent across all studies, with some showing no effect of the wedge on the adduction moment (8,9). Although differences in study samples and measurement methodologies may account for the conflicting findings, it is possible that the varying results may be attributable to differences in the designs of the lateral wedges tested. The most apparent difference in wedge design that is evident across studies relates to the length of the lateral wedge. Most studies that have demonstrated a beneficial effect of the wedge on the adduction moment have tested a full-length insole that wedged the foot from the heel to the forefoot (4–7). In contrast, the studies that demonstrated no effect on knee loading tested insoles that wedged only the rearfoot (8,9). The only clinical trial to evaluate the efficacy of lateral wedges for knee OA used rearfoot wedges and found no significant effect on symptoms or disease progression over time (10,11). Excluding the degree of wedging (which can mediate the effect of a wedge on the adduction moment) (5,7), the design features of laterally-wedged insoles are not considered to influence their efficacy. Evidence suggests that wedging of the entire foot is necessary for a beneficial effect, yet no study has evaluated the influence of wedge length on the adduction moment. The aim of this laboratory study was to compare the effect of a full-length, laterally-wedged insole on the adduction moment with that of a rearfoot wedge in patients with medial knee OA.

Determinants of plantar pressures in the diabetic foot

The aim of this study was to determine, by the use of regression analysis, the factors that are associated with the increased plantar pressure in the diabetic foot. In-shoe plantar pressure measurements using the Novel Pedar were carried out on 50 subjects with diabetes. Variables measured were age, body weight, duration of diabetes, a number of selected structural radiographic angles, soft tissue thickness, plantarflexion, and dorsiflexion strength at the ankle and first metatarsophalangeal joint, Neuropathy Symptom Score, and the Michigan Neuropathy Disability Score. Stepwise regression modelling indicates that 28% of the variability in hallux peak pressure could be explained by the first metatarsophalangeal joint range of motion and the Michigan Neuropathy Disability Score (P=.0004). The Michigan Neuropathy Disability Score explained 17% of the peak pressure under the first metatarsal head (P=.002). None of the measured variables could explain any of the variation in peak pressure plantar to the lateral forefoot. Thirty-two percent (32%) of the variability in peak pressure under the heel was explained by the Michigan Neuropathy Disability Score and age (P<.0001). Very little of the variation in the pressure time integrals could be explained by the measured variables except for 10.3% of the variation in the pressure time integral for the heel being explained by body weight. This study has shown that neuropathy-related variables play an important role in the plantar pressure under the diabetic foot. The range of motion of the first metatarsophalangeal joint is also important in determining pressures under the hallux.

Lateral wedge shoe insoles for medial knee osteoarthritis: a 12-month randomised controlled trial

Methods A randomised participant- and assessor-blinded controlled trial was used. 200 people aged 50 or more with clinical and radiographic diagnosis of mild-to-moderately severe medial knee OA were recruited. The interventions consisted of full-length 5° lateral wedged insoles or flat control insoles worn inside the shoes daily for 12 months. The primary symptomatic outcome was change in overall knee pain (past week) measured on an 11-point numeric rating scale and primary structural outcome was change in medial tibial cartilage volume from magnetic resonance imaging. Secondary clinical outcomes included changes in measures of pain, function, stiffness, and health-related quality of life. Secondary structural outcomes included progression of medial cartilage defects and bone marrow lesions. Results There were no significant between-group differences for the primary outcomes of change in overall pain (-0.3 points 95% CI (-1.0 to 0.3)) and change in medial tibial

The Past, Present, and Future of Podiatric Biomechanics

The author places the history and development of podiatric biomechanics, as well as current thinking about its underpinnings and future, in the context of a theoretical framework drawn from the philosophy and sociology of science. This analysis sets the stage for an exploration of the possible future directions in which podiatric biomechanics could develop.

Effect of foot orthoses on lower extremity kinetics during running: a systematic literature review

BackgroundThroughout the period of one year, approximately 50% of recreational runners will sustain an injury that disrupts their training regimen. Foot orthoses have been shown to be clinically effective in the prevention and treatment of several running-related conditions, yet the physical effect of this intervention during running remains poorly understood. The aim of this literature review was therefore to evaluate the effect of foot orthoses on lower extremity forces and pressure (kinetics) during running.MethodsA systematic search of electronic databases including Medline (1966-present), CINAHL, SportDiscus, and The Cochrane Library occurred on 7 May 2008. Eligible articles were selected according to pre-determined criteria. Methodological quality was evaluated by use of the Quality Index as described by Downs & Black, followed by critical analysis according to outcome variables.ResultsThe most widely reported kinetic outcomes were loading rate and impact force, however the effect of foot orthoses on these variables remains unclear. In contrast, current evidence suggests that a reduction in the rearfoot inversion moment is the most consistent kinetic effect of foot orthoses during running.ConclusionThe findings of this review demonstrate systematic effects that may inform the direction of future research, as further evidence is required to define the mechanism of action of foot orthoses during running. Continuation of research in this field will enable targeting of design parameters towards biomechanical variables that are supported by evidence, and may lead to advancements in clinical efficacy.

Relationship between positive clinical outcomes of foot orthotic treatment and changes in rearfoot kinematics.

BACKGROUND Previous two-dimensional kinematic studies that assessed the effect of foot orthoses on rearfoot motion have yielded mixed results regarding whether control of rearfoot motion is related to symptom relief. METHODS We sought to determine the effect of foot orthoses on rearfoot motion and to correlate these changes with the degree of symptom improvement in 22 individuals with excessive rearfoot pronation (17 women and 5 men; mean +/- SD age, 44.3 +/- 16.7 years; mean +/- SD weight, 74.9 +/- 15.9 kg). Two-dimensional motion-analysis software was used to assess frontal plane rearfoot motion with and without foot orthoses. The mean +/- SD Foot Posture Index of the left foot was 8.83 +/- 3.54 and of the right foot was 9.22 +/- 3.64). The pain and function subscales of the Foot Health Status Questionnaire were then used to determine the degree of symptom relief associated with the orthoses at baseline and 4 weeks later. RESULTS Orthoses had a small but statistically significant effect on rearfoot motion, although no significant correlations were found between differences in rearfoot motion with and without foot orthoses and the improvements demonstrated in the Foot Health Status Questionnaire subscales of pain and function. CONCLUSIONS The effect of orthoses on frontal plane rearfoot motion is considered small and probably insufficient to account for the extent of symptom reduction found in this study. Other parameters of orthotic function, such as kinetic and neuromechanical variables, should be further investigated.