Response: Tuning of rigid ankle-foot orthoses is essential

Dear Dr Curran,

We write with reference to the recently published letter by Meadows ‘tuning ankle foot orthosis is essential’. ¹ We are indeed strong advocates of tuning ankle-foot orthosis–footwear combinations (AFO-FCs), and the purpose of the published article ² is to increase the awareness and the need for structured approached to tuning. Therefore, we feel that we must respond to Dr Meadows’ comment ‘I am very concerned that the conclusions listed in the article might dissuade clinicians from undertaking tuning of rigid AFOs’.

First, our intention is to highlight the need for AFO-FC tuning, not to dissuade its use. Dr Meadows’ comment ‘most rigid AFOs can be successfully tuned using small heel wedges and visual gait analysis’ is somewhat misleading. Dr Meadows himself outlines some of the key processes required to optimally tune an AFO-FC: (a) correct AFO design and fabrication, (b) accommodation of gastrocnemius, (c) adequate stiffness of the AFO, (d) choice of initial shank to vertical angle (SVA) and (e) alteration of the SVA. In addition to these, we would like to add, adaptions to the footwear to effect entry and exit to stance phase if required. It is this full process of AFO-FC tuning which is often misunderstood yet is crucial to successful tuning.

Following this structured review, we had completed a survey of UK registered orthotists, which is due to be published in Prosthetics and Orthotics International, ³ that supports the opinion that AFO-FC tuning is not fully understood among UK orthotists. A significant outcome of the study was that only one orthotist was able to correctly identify the aforementioned process described by Dr Meadows on AFO-FC tuning.

The use of visual observation of gait to optimally tune AFO-FCs is very difficult as the phases of the gait cycle change too quickly to be processed accurately by the eye alone. Therefore, some sort of augmented gait analysis is recommended; this is also advocated in Dr Meadows article: ⁴

Accurate visual assessment of gait is difficult due to its complexity and the speed at which the phases of the gait cycle change. This is especially true of the gait of patients with neurological disorders. Decision making may be informed by augmented clinical gait assessment … To be successful it is necessary to utilise some form of augmentative clinical gait assessment.

Our article due to be published also highlights the fact that there is confusion among UK orthotists as to what equipment can be used to carry out AFO-FC tuning with 37% of participants reporting they don’t carry out AFO-FC tuning because they don’t have access to three-dimensional (3D) gait analysis equipment, although such equipment is not necessary.

We believe that AFO-FC tuning is not a complex procedure, but it seems to appear confusing and complex within the available literature, and this maybe one of the reasons it is not yet standard clinical practice among UK orthosists.

In conclusion, we fully agree with Dr Meadows’ assertion ‘no orthotist should deliver rigid AFOs without confirming they have been optimally aligned, AFO tuning is essential’. We need to work on training orthotists to have a greater understanding of the full process of AFO-FC tuning and also on the changes in technology which has transformed structured/instrumented movement analysis in the recent years.