The Use of Orthotic Insoles to Prevent Lower Limb Overuse Injuries: A Critically Appraised Topic

Effects of a range of 6 prefabricated orthotic insole designs on plantar pressure in a healthy population: A randomized, open-label crossover investigation

BACKGROUND

Prefabricated orthotic insoles are widely commercially available for self-selection to treat foot and lower-body musculoskeletal pain, without requiring advice from health care professionals. Although they are generally designed to mimic traditional design features of custom-made orthotics used in clinical practice, the effects of prefabricated insoles on plantar pressure distribution are poorly understood.

OBJECTIVE

This investigation aimed to evaluate and directly compare the effects of a range of 6 different commercially available prefabricated orthotic insole designs on plantar pressure in healthy individuals.

METHODS

This was a single-center, randomized, open-label, crossover investigation. In-shoe dynamic pressure (F-scan) was investigated in 24 healthy subjects with normal foot posture, wearing standard shoes alone and in combination with 6 different orthotic insoles, consecutively, measured on a single day. The biomechanical impact of each insole was determined by the statistical significance of changes from baseline measurements (standard shoe alone).

RESULTS

Insoles with heel cups and medial arch geometries consistently increased contact area at medial arch and whole-foot regions and reduced both plantar peak pressure (PP) and pressure time integral at medial arch and heel regions.

CONCLUSIONS

This investigation has aided in further understanding the mode of action of prefabricated insoles in a healthy population. The insoles in this study redistributed plantar pressure at key regions of the foot, based on design features common to prefabricated insoles. Prefabricated orthotic insoles represent an easily accessible means of reducing lower-body musculoskeletal stress for those who spend prolonged periods of time on their feet.

Foot Sole Contact Forces vs. Ground Contact Forces to Obtain Foot Joint Moments for In-Shoe Gait-A Preliminary Study

In-shoe models are required to extend the clinical application of current multisegment kinetic models of the bare foot to study the effect of foot orthoses. Work to date has only addressed marker placement for reliable kinematic analyses. The purpose of this study is to address the difficulties of recording contact forces with available sensors. Ten participants walked 5 times wearing two different types of footwear by stepping on a pressure platform (ground contact forces) while wearing in-shoe pressure sensors (foot sole contact forces). Pressure data were segmented by considering contact cells' anteroposterior location, and were used to compute 3D moments at foot joints. The mean values and 95% confidence intervals were plotted for each device per shoe condition. The peak values and times of forces and moments were computed per participant and trial under each condition, and were compared using mixed-effect tests. Test-retest reliability was analyzed by means of intraclass correlation coefficients. The curve profiles from both devices were similar, with higher joint moments for the instrumented insoles at the metatarsophalangeal joint (~26%), which were lower at the ankle (~8%) and midtarsal (~15%) joints, although the differences were nonsignificant. Not considering frictional forces resulted in ~20% lower peaks at the ankle moments compared to previous studies, which employed force plates. The device affected both shoe conditions in the same way, which suggests the interchangeability of measuring joint moments with one or the other device. This hypothesis was reinforced by the intraclass correlation coefficients, which were higher for the peak values, although only moderate-to-good. In short, both considered alternatives have drawbacks. Only the instrumented in-soles provided direct information about foot contact forces, but it was incomplete (evidenced by the difference in ankle moments between devices). However, recording ground reaction forces offers the advantage of enabling the consideration of contact friction forces (using force plates in series, or combining a pressure platform and a force plate to estimate friction forces and torque), which are less invasive than instrumented insoles (which may affect subjects' gait).

Effects of Foot Orthoses on Pain and the Prevention of Lower Limb Injuries in Runners: Systematic Review and Meta-Analysis

CONTEXT

A variety of approaches have been proposed to prevent lower limb injuries in runners. However, the evidence for the effectiveness of interventions to reduce lower limb pain and injury after intensive running is very weak.

OBJECTIVE

The authors performed a systematic review to investigate the effects of foot orthoses on pain and the prevention of lower limb injuries in runners.

EVIDENCE ACQUISITION

The authors searched the MEDLINE/PubMed, Physiotherapy Evidence Database, Scielo, and Cochrane Central (from inception to February 2022) databases for randomized controlled trials that evaluated the effects of foot orthoses in runners. The authors then calculated mean differences and 95% confidence intervals from these trials. Heterogeneity was assessed using the I2 test. Furthermore, the authors compared the criteria between runners with foot orthoses and ones with no intervention (control group).

EVIDENCE SYNTHESIS

Twelve studies (5321 runners) met our review criteria. The control and the foot orthoses group sustained 721 (37%) and 238 (24%) injuries, respectively. Compared with the control group, the use of foot orthoses resulted in a significant reduction in lower limb injury risk (risk ratio = 0.6; 95% confidence interval, 0.5-0.7; P = .00001, I2 = 54%; 7 studies, N = 2983: moderate-quality evidence). Moreover, the foot orthoses group corresponded to a 40% reduction in the risk of developing lower limb injuries.

CONCLUSIONS

The use of foot orthoses may help reduce the incidence of lower limb injuries and pain in runners.

Overuse-Related Injuries of the Musculoskeletal System: Systematic Review and Quantitative Synthesis of Injuries, Locations, Risk Factors and Assessment Techniques

Overuse-related musculoskeletal injuries mostly affect athletes, especially if involved in preseason conditioning, and military populations; they may also occur, however, when pathological or biological conditions render the musculoskeletal system inadequate to cope with a mechanical load, even if moderate. Within the MOVIDA (Motor function and Vitamin D: toolkit for risk Assessment and prediction) Project, funded by the Italian Ministry of Defence, a systematic review of the literature was conducted to support the development of a transportable toolkit (instrumentation, protocols and reference/risk thresholds) to help characterize the risk of overuse-related musculoskeletal injury. The PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) approach was used to analyze Review papers indexed in PubMed and published in the period 2010 to 2020. The search focused on stress (overuse) fracture or injuries, and muscle fatigue in the lower limbs in association with functional (biomechanical) or biological biomarkers. A total of 225 Review papers were retrieved: 115 were found eligible for full text analysis and led to another 141 research papers derived from a second-level search. A total of 183 papers were finally chosen for analysis: 74 were classified as introductory to the topics, 109 were analyzed in depth. Qualitative and, wherever possible, quantitative syntheses were carried out with respect to the literature review process and quality, injury epidemiology (type and location of injuries, and investigated populations), risk factors, assessment techniques and assessment protocols.