Orthotics: Lower Limb – Ankle Foot Orthoses (1.2.2.a-e)

When studying the effect of ankle-foot orthoses (AFOs) on gait, it is important to know their sagittal plane stiffness because it helps explain the effect of AFOs on gait kinematics and kinetics [1]. However, there are no established thresholds for stiffness of non-articulated AFOs designed to be rigid [2]. Hence, if implementing published algorithms for ankle-foot orthosis-footwear combinations (AFO-FCs), it is important to confirm that the AFOs are equally stiff as those of the developer of the AFO-FC algorithms [3].

To compare the sagittal plane stiffness of AFOs designed to be rigid, made in the USA and following algorithms for AFO-FC designs, to those made and used in the UK by the developer of the AFO-FC algorithms.

Stiffness of 9 pediatric polypropylene AFOs was tested (UK: 6; USA: 3). A computer controlled motorized device was used [4] in which all AFOs were clamped with the calf shell in a fixed vertical component and the foot section in a rotating plate. Each AFO was tested for 3 trials, loading the foot plate 30 Nm towards dorsiflexion and 20 Nm towards plantarflexion. Torque-angle graphs were plotted and deflection and stiffness compared descriptively across AFOs.

AFO designs tested and torque-angle graphs are shown in Figure 1. Average deflection of AFOs was UK: 3.42±0.83° and USA: 4.81±1.05°. Average stiffness of AFOs was UK: 14.34±3.34 Nm/° and USA: 10.30±1.92 Nm/°.

All tested AFOs deflected only a few degrees in either direction (range: 2.59º to 6.02º), providing the first information reported for the stiffness of rigid pediatric non-articulated AFOs. Overall, the UK AFOs were stiffer and deflected less than the USA AFOs. AFO design features such as optimum material for height and weight, ankle rib reinforcements, and trim lines anterior to the malleoli should be carefully considered as they likely influence sagittal plane stiffness and deflection under load.

1. Totah D, et al. Gait Posture 2019;69:101-11. 2. Ielapi A, et al. Prosthet Orthot Int 2019;43:339-48. 3. Owen E. Prosthet Orthot Int 2010;34:254-69. 4. Gao F, et al. Int Conf Bioinf Biomed Eng. IEEE, 2010;1-4.

This work was supported by the National Institutes of Health Award #R21HD094823.

Stroke is a common neurological impairment resulting in reduced functional mobility due to  decreased independence in ADLs. The improvement of gait stability and physical function is a primary goal of rehabilitation following a stroke. Clinical measurements with acceptable levels of reliability and validity can be used by health care providers to evaluate the recovery of the patient’s functional ability in response to rehabilitation interventions. Ankle-foot orthoses (AFOs) are frequently prescribed to improve ambulatory function during stroke rehabilitation. 

The purpose of this systematic review and meta-analysis was to determine the effect of AFOs and comparison among them on functional outcome measurements in individuals with stroke.

This review was performed based on the PRISMA guideline. PubMed, ISI web of knowledge, Embase, Scopus, ProQuest, and Cochrane were searched from inception until June 2020. The methodological quality assessment of 30 included studies was conducted based on the Downs and Black checklist. Functional indices were pooled in accordance with their standardized mean difference (SMD) and 95% confidence intervals (CI) in a random-effect model. A narrative analysis was performed where data pooling was not feasible.  

The overall pooled results indicated a significant improvement in favor of an AFO versus without it in Berg balance scale (BBS) (SMD:0.54, CI: 0.19 to 0.88), timed-up and go test (SMD: -0.45, CI:-0.67 to -0.24), functional ambulatory categories (FAC) (SMD:1.72, CI:1.25 to 2.19), 6-minute walking test (SMD:0.91, CI:0.53 to 1.28), timed-up stair (SMD:-0.35, CI:-0.64 to 0.05), and Motricity Index (SMD: 0.65, CI: 0.38 to 0.92). Heterogeneity was not significant in the outcomes (I² <50%, p>0.05) except for BBS and FAC. 

Although the narrative analysis showed some improvement in many functional outcome measurements using an AFO such as Timed Down Stairs , Functional Reach Test , Modified Ashworth Scale , Functional Independence Measure , the modified Emory Functional Ambulation Profile (mEFAP), Barthel Index, and Rivermead Mobility Index , there were insufficient studies for reaching a valid conclusion. In addition, there was no sufficient evidence in the effectiveness of specific AFO designs over others. 

An AFO can improve ambulatory function in survivors of stroke and that an AFO is more effective on functional outcomes with long-term adaptation . Rehabilitation care during subacute phase wearing an AFO may have beneficial effects on clinical outcomes measured in individuals with stroke. Future studies should explore long-term effects of rehabilitation care wearing AFOs and comparison of differences in AFO designs. 

The authors would like to thank Dr. Corien Nikamp for providing us additional data for the meta-analysis.

Selection and adjustment of the shank to vertical angle (SVA) static alignment of ankle-foot orthoses (AFOs) is essential [1]. The normal value for SVA alignment at temporal midstance of barefoot walking is approximately 10-12° inclined [2]. A review of optimised SVA static alignment values for paediatric AFO users has been reported [2] but no review exists for adult AFO users.

To identify reported optimised SVA static alignment values for adult rigid AFO users with neurological conditions.

A non-systematic review was conducted in February 2021 using Pubmed and Google Scholar for years 1990 to 2021. Search terms included ‘ankle-foot orthosis’, ‘tuning’ and ‘shank vertical angle’. Reference lists of selected studies were reviewed in addition to articles known to the author. Papers were reviewed to ascertain diagnosis, reported static SVA alignments, SVA measurement method, and method used to select the optimum SVA for each patient.

Six studies were identified: one reported target values rather than actual optimised values; one reported range of optimised values only and four studies reported optimised static SVA values (table 1) [3–6]. These 4 studies included patients with diagnoses of: stroke (CVA) (n=6); spinal cord injury (SCI) (n=2); traumatic brain injury (TBI) (n=1); peripheral neuropathy (PN) (n=1). Mean optimised static SVA alignment was 11.7° incline (range 10-14°) for all subjects and 12.3° (range 10-14°) for stroke. Methods used for determining optimal SVA and measuring SVA static alignments were not always clearly described.

Table 1

This review reports the limited data available for optimised static SVA alignment values selected for adults with neurological conditions. The optimised SVA values are similar to those reported for children, which were 7-15° (mean 11.4°) [2]. Optimal SVA values may vary, depending on the underlying pathology and gait pattern. Further research on selecting optimal SVA static alignments in adults with neurological conditions is needed. Future work should specify the methods used to select and measure SVA.

1. Owen E; 2019 J Prosthet Orthot.

2. Owen E; 2010 Prosthet Orthot Int.

3. Young J; 2019 Disabil Rehabil Assist Technol.

4. Young J; 2020 J Prosthet Orthot.

5. Jagadamma K; 2010 Prosthet Orthot Int. 

6. Choi H; 2016 Disabil Rehabil Assist Technol.

Cerebral palsy is one of the most common childhood motor disabilities, and ankle-foot orthoses (AFOs) are commonly used as part of the treatment plan. People who are prescribed AFOs, and their families and carers will often search online to find information about AFOs  However, little is known about the accuracy of online information about use of AFOs for cerebral palsy.

The aim of this study was to assess the accuracy and quality of internet information aimed at patients and their families or carers, about AFO use in the management of cerebral palsy, by comparing identified websites to evidence-based practice.

An accuracy checklist was created, based on ISPO's Consensus Conference on Cerebral Palsy (Morris and Condie, 2009). This was supported with an up-to-date literature search of relevant literature between 2009-2020. A quality checklist was created which was informed by the Health On the Net (HON) (2020) guidelines. If websites meet these guidelines they can apply for HON certification, to demonstrate they meet quality guidelines. The next stage of the process involved a web search of terms relevant to AFOs and cerebral palsy using three search engines, to identify relevant web pages to review. These web pages were then assessed for accuracy and quality using the created checklists.

Twenty-nine websites were identified as meeting criteria for further analysis. Three (10.34%) websites were categorised as academic; eighteen (62.07%) commercial; one (3.45%) government and seven (24.14%) non-governmental organisations. Important aspects of  AFO interventions which were indequately addressed by the web sites included: the role and responsibilities of the orthotist; AFO design; aims and benefits of AFO use; and risks of AFO use. The quality of the websites varied across different website type and also within these types. Only one website displayed Health on the Net certification, demonstrating an acceptable quality of information provided. 

Websites have an important role to play in patient education. This project has identified areas of concern regarding accuracy and quality of frequently found websites when searching AFO use in cerebral palsy. Clinicians may need to address these information gaps during consultations.

Morris, C. and Condie, D. (eds.) Recent Developments in Healthcare for Cerebral Palsy: Implications and Opportunities for Orthotics.  Copenhagen: International Society for Prosthetics and Orthotics 

Health on the Net (HON) (2020) HONcode Guidelines.  Available at: https://www.hon.ch/en/guidelines-honcode.html#guidelinespdf (Accessed: 15 September 2020).

A novel algorithm for orthotic prescription proposes a patient-specific method for adjusting AFO alignment and integrating footwear modifications (Ankle Foot Orthoses-Footwear Combinations, AFO-FC).^1,2 The goal of AFO-FCs is to improve stability by facilitating more normal segment kinematics in single limb stance and decreasing excessive hip/knee flexion. This approach includes modifications internally to the rigid AFO and/or externally to the shoes, and multiple fitting visits with the orthotist, thus potentially influencing the acceptability/tolerance of by child/family.

The purpose of this project was to describe the lived experience of families and clinicians implementing the AFO-FC intervention in ambulatory children with cerebral palsy (CP).

A qualitative informant interview study was conducted with informed consent. Subjects included mothers of children with spastic diplegic CP (Gross Motor Function Classification System levels II (n=7), III (n=3)), wearing AFO-FC and clinicians (7 orthotists, 3 physical therapists) who implemented AFO-FC. Children received joint orthotist/therapist visits at assessment, fitting and follow-up. Guided interviews were conducted by phone (n=20). Participants were asked what they liked/did not like about the AFO-FC, how it compared to other approaches, and suggestions to improve management. Responses were manually scribed during interviews. Three investigators individually reviewed and coded the transcripts for common themes. Final themes were determined when all 3 investigators reached consensus. 

Table 1 summarizes parent and clinician themes illustrated with an exemplar quote. 

Positive and negative themes about implementation of the AFO-FC approach were documented by parents and clinicians. Results may be unique given the singular site, from which subjects were recruited and their experience of joint therapist/orthotist visits, which are not common practice. The results highlight tension between positive functional results and the bother of the intervention. While further study is needed, results suggest framing expectations at treatment outset is important along with consideration of combined provider visits. 

1.  Owen, E. Association of Chartered Paediatric Physiotherapist (ACPP), 2014a. 5(1): p. 7-18. 

2.  Owen, E. ACPP, 2014b. 5(2): p. 4-16

Funding support: NIH K23 HD060764