Elsevier

Gait & Posture

Volume 35, Issue 3, March 2012, Pages 383-388
Gait & Posture

Effects of foot orthoses: How important is the practitioner?

https://doi.org/10.1016/j.gaitpost.2011.10.356Get rights and content

Abstract

Foot orthoses (FO) are commonly used in the treatment of numerous lower limb problems, pains and injuries. Whilst many studies report their positive effects, and most practitioners would confirm those findings, the available information appears to be anecdotal. As such, the exact mechanisms in which FO work are not fully understood. Therefore, a need exists to study the influence of the inter-practitioner variability in the assessment of orthoses performance. This investigation is central to the understanding of the performance variations in custom-made foot orthoses (CFO). Eleven practitioners took part in the study. Each practitioner completed a clinical assessment of one subject, after which a pair of foot orthoses was manufactured based on casts of the subject's feet using a neutral non-weight bearing plaster cast. Ten trials per condition were recorded during which kinematic and kinetic data were collected. CFO did not have any systematic significant effects (p < 0.05) on any kinetic except for the right-leg peak active force. In addition, systematic kinematic effects could be observed mainly for the sagittal plane for forefoot-to-hindfoot and hindfoot-to-tibia peak angles. The results from this study demonstrate that inter-practitioner variability is a major factor in orthotic intervention in treating a single patient and for a specific pathology. It is therefore strongly recommended to use caution when drawing general conclusions from research studies using custommade foot orthoses. The results suggest that CFO effects can differ between limbs. More importantly, their effects are also practitioner-dependant. Great caution should be used when comparing studies on CFO with different practitioners as conclusions could vastly differ.

Introduction

Foot orthoses (FO) are generally used by clinical practitioners to treat a number of musculoskeletal pathologies. Previous researchers have attempted to study different orthotic devices to understand their effects on gait kinematics and kinetics. Understanding these differences would improve the chances of achieving the desired treatment or outcome. Nevertheless, the exact mechanisms by which FO work are yet to be fully understood. In fact, a number of studies have reported contradicting or unsystematic results [1], [2], [3], [4], [5]. Yet, certain main themes can be extracted from these studies. Recent literature surveys [6], [7] concluded that FO generally have an attenuating effect on the peak impact vertical force and loading rate. Commonly reported kinematic effects normally relate to ankle joint sagittal plane movements, rearfoot frontal plane and tibial transverse plane movements [8]. Specifically, many studies reported that FO increased plantarflexion of the foot, decreased rearfoot eversion and internal tibial rotation [5], [9], [10], [11], [12], [13], [14], [15], [16], [17]. However, kinetic or kinematic effects do not appear to be consistent through all studies [1], [2], [13], [14], [18], [19]. Hence, controversies still persist with regards to whether or not FO induce generic effects on subjects.

Furthermore, the lack of standardisation of the terminology surrounding FO only adds to the ambiguity of their effects [8]. Throughout the literature, the term “foot orthoses” is used as an umbrella term to describe a broad range of devices including custom-made foot orthoses (CFO), prefabricated foot orthoses, heel-lifts, lateral/medial wedges and even flat insoles. Whilst the inherent differences in design and purpose of each device may appear simple, all are defined as foot orthoses despite their different effects. It is therefore crucial that more precise descriptions are provided in order to allow clear and easy classification of devices. Therefore, the terminology used in the current paper will specify which type of foot orthoses is discussed in an attempt to avoid any confusion.

Heiderscheit et al. [20] suggested plausible explanations for the contradicting conclusions on the effects of orthoses. Variation in orthoses fitting methods was amongst the suggested explanations. Although it has been reported that CFO can yield good results for the treatment of lower-limb disorders and injuries [1], [15], [21], construction methods and casting techniques are seldom described in great detail. Based on previous studies [1], [2], [22], it is possible to assume that the prescription and casting method could differ between studies depending on the practitioner involved. This could, in part, explain the conflicting results. Consequently, the exact method used to produce these orthoses remains unclear and almost impossible to replicate.

However, other external factors may also influence the results. As each study focussing on custom-made foot orthoses (CFO) will use a specific practitioner to assess, prescribe and cast each subject included within a study, it is difficult to rule out the importance of the practitioner on the final outcome measure. For example, whilst Stacoff et al. [15] observed significantly different effects between three types of orthoses, three different podiatrists were involved in the process, each one in charge of making one type of orthoses. It cannot be dismissed that the observed changes could be attributed to the change in practitioner or techniques used instead of the orthoses themselves as reported.

As the process of fabricating a CFO involves many variables, the influence of each variable is currently unknown. Due to the nature of the CFO, specifically designed for each subject, assessing their effects and effectiveness is a complex task that has not been completed. Consequently, the aim of the present study was to assess the influence of one of those variables, the inter-practitioner variability of CFO and their different kinematic and kinetic effects during normal gait.

Section snippets

Methodology

A total of 11 practitioners (six podiatrists and five orthotists) with years of clinical experience ranging from 2 to 20 years (mean 11.5 years, ±7.0) took part in the study. A broad spectrum of experience and two different professions were included in the study with a view to better represent the current services and choices available to patients suffering from musculoskeletal pathologies. The practitioners taking part in the study were considered as subjects in order to assess the

Kinematic variables

Table 1, Table 2 present a summary of the kinematic results for the knee, hindfoot-to-tibia and forefoot-to-hindfoot. For the calculated kinematic variables, there were a number of significant systematic changes recorded. On the left lower limb, peak knee flexion, peak knee internal rotation and sagittal knee angle at heel strikes were reduced by a mean of 3.28° (±1.25°), 5.88° (±3.67°) and 1.87° (±0.60°) respectively. For the left foot, a decrease in peak forefoot plantarflexion, forefoot peak

Variability and consistency

The current results suggest that high variability exists between the effects generated by the 11 different CFO used in the study. Only a third (22/64) of the calculated variables caused systematic changes. For most variables, effects appeared to be sporadic, with many CFO producing opposite effects when compared to other CFO. The standard protocol to study FO, as reported in the literature, is to use multiple subjects with a single pair of orthoses. The observed results from each condition are

Conclusion

In summary, it was found that most CFO will induce some systematic changes during gait. Furthermore, this study demonstrated that inter-practitioner variability is a major factor in orthotic intervention in treating a single patient and for a specific pathology. Based on the findings, it is strongly recommended to use caution when drawing general conclusions from research studies using CFO as it has been showed that the practitioner himself or herself will have a great influence on the

Acknowledgments

The authors would like to thank Salts TechStep for their support throughout this study and Andrew Greenhalgh for his help with the Matlab script.
Conflict of interest statement

There is no conflict of interests of any authors with the presented work in this manuscript.

References (28)

  • J. Stebbins et al.

    Repeatability of a model for measuring multi-segment foot kinematics in children

    Gait & Posture

    (2006)
  • C. MacLean et al.

    Influence of a custom foot orthotic intervention on lower extremity dynamics in healthy runners

    Clin Biomech

    (2006)
  • Genova lM et al.

    Effect of foot orthotics on calcaneal eversion during standing and treadmill walking for subjects with abnormal pronation

    J Orthop Sports Phys Ther

    (2000)
  • A. McMillan et al.

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

    J Foot Ankle Res

    (2008)
  • Cited by (28)

    • Are custom-made foot orthoses of any interest on the treatment of foot pain for prolonged standing workers?

      2019, Applied Ergonomics
      Citation Excerpt :

      This is why Tsung et al. (2004) recommend that feet be scanned in semi-weight-bearing condition as a compromise solution so that the FO give enough support to the arches while avoiding the pain and discomfort that would occur were the FO too rigid (Salles and Gyi, 2013; CHEN et al., 1994). Nevertheless, the design and manufacturing processes of general foot orthoses present many variability factors connected to the techniques used to obtain foot shape (Telfer et al., 2012) or the practitioner-specific manufacturing processes (Chevalier and Chockalingam, 2012). Prolonged standing (Freitas et al., 2005), fatigue (Garcia et al., 2015; Ochsendorf et al., 2000) and pain (Pradels et al., 2011) all affect postural activity.

    • Comparison of plantar pressure distribution in CAD–CAM and prefabricated foot orthoses in patients with flexible flatfeet

      2017, Foot
      Citation Excerpt :

      Although, Cheung and Zhang [38] concluded in their study that the importance of customization is more than material in designing foot orthoses [38], similar foam was used for both insole types to prevent any difference in material as a confounding factor [34]. The results of previous studies were conflicting due to variation in methods and the construction of the foot orthoses [25]. Moreover, the cost of foot orthoses are important factors for patients which were not paid enough attention before.

    • Influence of pressure-relief insoles developed for loaded gait (backpackers and obese people) on plantar pressure distribution and ground reaction forces

      2014, Applied Ergonomics
      Citation Excerpt :

      Possibly, these biomechanical alterations may contribute to the higher incidence of low back pain (Grimmer and Williams, 2000; Skaggs et al., 2006), higher perceived exertion and shoulder discomfort (Simpson et al., 2011), second metatarsal stress fractures (Arndt et al., 2002), muscle strain (Birrell and Haslam, 2009), joint problems (Birrell and Haslam, 2009), and foot blisters (Knapik et al., 1992) found in backpackers; and the loss of mobility (Messier et al., 1996), higher risk of hip and knee osteoarthritis (Felson, 1990; Hochberg et al., 1995; Ko et al., 2010), foot ulceration (Vela et al., 1998), and heel pain (Prichasuk and Subhadrabandhu, 1994) described in obese people. Foot orthoses is a general term to describe a broad range of devices including heel lifts, lateral/medial wedges, or insoles (custom-made or prefabricated) (Chevalier and Chockalingam, 2012). These devices have been shown to be effective for managing many foot problems (Bonanno et al., 2011; Colagiuri et al., 1995; Cronkwright et al., 2011; Lynch et al., 1998; Sasaki and Yasuda, 1987).

    • Gait phase varies over velocities

      2014, Gait and Posture
      Citation Excerpt :

      As a key parameter for gait analysis, a gait cycle (GC), defined as the time from heel strike to the ipsilateral heel strike, is widely used for the evaluation of basic and clinical disorders [1–5].

    View all citing articles on Scopus
    View full text