Foot Orthoses

Original Editor - Mariam Hashem

Top Contributors - Mariam Hashem, Kim Jackson, Jess Bell, Naomi O'Reilly, Admin, Tarina van der Stockt, Lucinda hampton and Matthew Chin

Definition and Mechanics

In the Atlas of Orthoses and Assistive Devices '' Foot orthoses (FO) are like the tires on an automobile. They provide a critical, biomechanical contact point for the human body, and they can be helpful to correct problems in the foot, knee, hip, and spine''.

An orthosis is a single device, a group of them are referred to as orthoses. We can use the term orthotic devices but not orthotics as they refer to braces and splints

The correct term is orthotic devices and not orthotics .

Unlike what is believe that foot orthoses work by correcting the mechanical abnormalities as seen visually such as when correcting an over-pronated foot, the therapeutic benefit might also be achieved from the internal kinetic changes.

Applying the tissue stress principals, altering the internal demands on the overloaded tissue by the use of proper orthoses can explain pain reduction and improvement in function in foot conditions .

There is also a room for applying biopsychosocial modeling to foot orthoses. Understanding the patient's condition clearly and communicating effectively with them could have positive effects on the success of use of orthoses. Asking questions on how the patient feels about orthoses, if they have positive feelings then using the orthoses could promote the therapeutic benefit. If they feel otherwise, then having an effective conversation can help determine the best route of treatment.

Clinical Uses

The uses of orthoses vary from pain relief, comfort and enhancement of performance. They are widely used clinically in the treatment of different conditions:

Plantar Heel Pain: The use of foot orthoses is recommended by the The Journal of Orthopedic Sports and Physical Therapy to support the medial longitudinal arch and cushion the heel in individuals with heel pain/plantar fasciitis to reduce pain and improve function for short- (2 weeks) to long term (1 year) periods, especially in those individuals who respond positively to antipronation taping techniques.

Wittaker and Colleagues reviewed 19 clinical trials and reported moderate-quality evidence supporting the use of foot orthoses as an effective intervention at reducing pain in the medium term of plantar heel pain.

A randomized clinical trial compared the use of orthoses to sham devices for three months in the treatment of plantar fasciitis found small short-term benefits in function and small reductions in pain but long-term beneficial effects compared with a sham device.

However, Rasenberg et al reviewed twenty studies investigating the effects of eight different types of foot orthoses on pain, function and self-reported recovery with Plantar heel pain compared with other conservative interventions. Their findings didn't support the Foot orthoses are not superior for improving pain and function compared with sham or other conservative treatment in patients with PHP. Their findings suggested there isn't enough evidence to support the use of foot orthoses for plantar heel pain.

This adds to the controversy of the use of foot orthoses. The argument is that the use of orthoses in research is different from clinical practice. The applied assessment of foot mechanics in clinic, linking those findings to the presentation and applying corrections then testing their efficacy is what most clinicians would do to treat foot conditions. For example, shifting the forefoot load laterally can help reduce the plantar fascial load is a simple adaptation of mechanics in clinical practice. A study investigated the effect of wearing custom foot orthoses on first-step pain, average 24-h pain and plantar fascia thickness in people with unilateral plantar fasciopathy over 12 weeks found improve first-step pain and reduce plantar fascia thickness over a period of 12 weeks compared to new shoes alone or a sham intervention.

Patellofemoral Pain Syndrome: The Journal of Orthopaedic & Sports Physical Therapy 2019 guidelines recommended clinicians to prescribe prefabricated foot orthoses for patients with greater than normal pronation to reduce pain, but only in the short term (up to 6 weeks). The use of foot orthoses should be combined with other interventions.

The applied use of foot orthoses on PFPS as suggested clinically and in literature is the use of single leg squat or double leg squat. If reproduced PFP then the clinician might test a foot orthosis and ask the patient to repoerform the test. If the pain reduces then it's an indication of the likelihood benefit of orthosis with this patient. Another test that was developed to identify patients with Patellofemoral Pain who are likely to benefit from foot orthoses by measuring the width of the patient's foot from a non weight bearing position, and compare it to standing mid-foot width. if there was a great increase in mid foot width, that foot orthoses would help. However, in a following study Matthews and Colleagues reported that the test is not reliable

Tibialis Posterior Tendon Dysfunction: Tibialis posterior is a powerful foot inverter. In case of dysfunction, the use of an orthosis to apply some external supinatory support and external inversion can, theoretically, decrease the load on the tibialis posterior muscle.

Peroneal Tendon dysfunction: opposite to the use in tibialis posterior tendon pain, we can use an orthosis to provide an external eversion or pronatory force to the foot and therefore hopefully get some therapeutic benefits.

Midfoot Osteoarthritis : A carbon fiber type shell orthosis can reduce the amount of bending stress through the midfoot.

Achilles Tendinpathy :wearing custom fit semirigid insoles for 4 weeks in combination with exercises was found to reduce pain in AT patients. Also the use of higher heels footwear and possibly orthoses was found to have less load on Achilles tendon compared to lower heel and conventional footwear in runners. Theoretically, We could also apply that to our children with paediatric population with Sever's disease to assist in reducing the tensile pull around that growing calcaneum.

MTP joint pathologies such as sesamoid problems, arthritic joints, hyper extensive injuries that can be common in rugby and American football players. Depending on the pathology, foot orthoses can off load the area in case of sesamoiditis or offer support and reduce bending in case of capsular injuries.

Plantar Plate injury, metatarsalgia and Freiberg disease: A metatarsal dome can be used to shift the load away from the area of pain. Plantar plate could be used to reduce the reverse windlass phase time therefore reducing the tensile pull on the plantar fascia .

Prescribing Foot Orthoses

Time-frame

There is often a fear of dependency when it comes to prescribing orthoses. We must know that in some conditions, foot orthoses could be recommended for long term or for the lift time of the patient such as in tibialis posterior dysfunction. However, in other conditions, it should only be used for short term. The patellofemoral pain guidelines recommended the use of foot orthoses for six weeks only.

The use of clinical reasoning and communication skills are essential to avoid dependency and to ensure that the orthoses are used to deliver the therapeutic benefit .

Prefabricated vs Customized

Prefabricated or off-the-shelf , often bought on the internet or from the pharmacy. There come in various types and shapes such as full length, forefoot cut outs and carbon polymer shell, There are various models and designs which allow the clinician and patient to choose freely depending on the desired therapeutic effect.

Prefabricated are recommended first before trying customized as you can always apply adaptations and test the results.

There was no but several randomized controlled trials have shown prefabricated orthoses to have similar efficacy to customized orthoses in the management of plantar fasciitis

A study found prefabricated orthoses better in comparison with customized orthoses in the treatment of plantar fasciitis pain, another study found no difference between the two types of orthoses for the same condition.

The PFPS 2019 guidelines There is insufficient evidence to recommend custom foot orthoses over prefabricated foot orthoses.

Regardless of the type of orthoses, there are considerations to put in mid such as patients' body weight, their beliefs, their current footwear, and their activities.

Controversy Around Foot Orhtoses

In healthcare practice, some professionals might be against the use of orthoses for treatment of foot conditions. Their preservative opinion comes from the fact that orthoses might have been overused over time and the idea that they might contribute to weakening the muscles and the individual's relying on them. However, the argument is that if they're prescribed properly, tailored for the individual's needs and their condition they can be a useful tool combined with other interventions.

The difference between the use of orthoses in research and clinical practice, is that in some mechanical stusies the use of customized devices may be made through a scanning or casting method and given an orthosis that way that is called "custom". In clinical practice, prescribing othoses depends on the assessment of patient's symptoms. Also, the design of orthoses prescribed in clinic is individualized and not standardized to all patients unlike studies which compare standard insoles or orthoses.

A clinical adaptation to individualizing orthoses is tuning the dosage up or down to meet the demands and the patient's feedback.

It is easy to fall in the sales pitch of orthoses as many of them might not deliver the benefit they claim to offer. A good clinical reasoning, detalied history taking, effective communication and assessment of the condition are needed to decide on the use of the right orthosis to avoid falling for the market industry and testing for the right orthoses .

There is a good body of evidence supporting the use of orthoses in the treatment of foot conditions which contradicts the common beliefs that they might contribute to muscle weakness and sometimes dependency provided that they used properly with considerations to individual differences.

In regards with muscle weakness, Jung et al reported an increase in cross sectional area of abductor hallucis and flexor hallucis msucles in subjects with Pes Planus with a combined foot orthosis and short-foot exercise (FOSF) group for an 8-week intervention. A 2017 study by Protopapas investigated the effect of a 12-week custom-made foot orthotic intervention on the intrinsic muscles of the foot and dynamic stability and found a significant reduction in the cross sectional area of Flexor Digitorum Brevis, Abductor Digiti Minimi and Abductor Hallucis. The changes in the muscle size didn't affect the gait parameters and the dynamic stability which might indicate adaptations of these structures when off-loaded.

Shared decision and ommunication play an integral role in the success of foot orthoses. Depending on the condition, orthoses should be combined with other interventions with considerations to the time-frame to avoid dependency and overuse.