Prescription practices for rigid ankle-foot orthoses among UK orthotists

Abstract

Objective:The purpose of this study was to investigate rigid ankle-foot orthosis (AFO) prescription practices for adult men among UK orthotists.Design:A cross-sectional study using a survey was distributed online to UK orthotists by the British Association of Prosthetists and Orthotists to its members and through social media and orthotic networks. The survey was completed between November 1, 2020, and November 29, 2020.Main outcome measures:Descriptive statistics of survey results include information related to the material used, the thickness of the material, positive cast rectification, AFO reinforcement, footplate design, padding, strapping system, and height of AFO.Results:One hundred participants completed the survey, which equates to a response rate of 30.5% of the British Association of Prosthetists and Orthotists members targeted. A clear consensus emerged on the design of a bespoke rigid AFO for the hypothetical patient in this study, which is detailed as follows: 1) 4.5 mm copolymer polypropylene, 2) no additional reinforcement, 3) full-length footplate with mediolateral trimlines terminating behind the metatarsal heads, 4) 3-point correction with parallel sides, 5) padded VELCRO straps with D-rings at the calf and heel, 6) no forefoot or other additional strapping, 7) 3-mm PORON (international Ltd) padding at the malleoli, and 8) AFO height that finishes 2 cm below the fibular head.Conclusions:This study has highlighted a consensus on AFO prescription/design among UK orthotists surveyed, based on the hypothetical patient described in this study.

A quantitative analysis of optimum design for rigid ankle foot orthoses: The effect of thickness and reinforcement design on stiffness

“…A rigid AFO 2 was produced by an orthotic technician with over 15 years’ experience (who was blinded to the study) to the specifications most commonly used by UK orthotists 7 (Figure 1(a)). The standardized procedure for AFO provision within the National Health Service in the United Kingdom was used.…”

“…The positive plaster cast was created for a healthy subject described as an adult man aged between 18 and 45 years, weighing between 64 and 88 kg, and between 173 and 188 cm in height. 7…”

“…The positive plaster cast was created for a healthy subject described as an adult man aged between 18 and 45 years, weighing between 64 and 88 kg, and between 173 and 188 cm in height. 7 On receiving the sample for testing, the actual thickness of the produced AFO was measured using a digital caliper at the areas where high stresses are expected during dorsiflexion, namely at the ankle trim lines. [17][18][19] Six equally spaced measurements were on the medial and 6 on the lateral ankle trim line [Figure 1(a)].…”

“…4 Despite the importance of adequate rigidity, to date, there is still a paucity of structured scientific studies which have explored the effects of each element of AFO design on their stiffness. 6,7 The historical view is that the shape of the ankle trim lines is the most important parameter that affects AFO stiffness. [8][9][10] However, this view is based on a research article from 1975, which provided no specific data or guidelines to inform the design of rigid AFOs.…”