Lower Limb Orthotic Support

Ankle-Foot Orthoses

The two basic forms of ankle–foot orthoses (AFOs) are the double-upright construction attached to the shoe and the molded ankle-foot orthosis (MAFO). Depending on the pathology, they may be fixed or articulated to permit ankle motion, with various adjustments used to improve deformity control and extend their use to both flexible and rigid deformities⁽⁴⁾.

Dynamic AFO
This brace provides proprioceptive feedback from the ground through the footplate and assists ankle dorsiflexion by leveraging the material’s flexibility, which stores and releases energy during walking (see Figure 2)⁽⁴⁾. 

Hinged AFO
Clinicians prescribe the hinged AFO to patients with foot drop, with the degree of dorsiflexion assistance determined by the type of hinge used⁽⁴⁾.

The Arizona brace AFO
Clinicians use this brace to manage tibialis posterior pathology and other hindfoot conditions, aiming to achieve a neutral hindfoot by correcting hindfoot valgus and stabilizing the ankle, subtalar, and midtarsal joints to provide medial and lateral support (see Table 1 and  Figure 3)⁽⁴⁾.

Orthotics for Specific Conditions

Plantar fasciopathy
Night splints maintain ankle dorsiflexion to prevent fascia shortening during rest⁽⁷⁾. Orthotics provide medial arch support and increase midfoot contact, reducing heel pain and plantar fascia strain⁽⁴⁾. Soft hindfoot orthotics decrease heel-strike force⁽⁴⁾. Prefabricated insoles are often effective, but patients with structural malalignment may benefit from custom-molded orthoses^{(4, 8)}.

Table 1: Posterior Tibial Tendon Dysfunction (PTTD)^{(4, 6, 9)}

Achilles tendinopathy

In insertional Achilles tendinopathy, management may include a heel lift to reduce tendon strain and compression during dorsiflexion⁽¹⁰⁾. Clinicians should use heel lifts bilaterally to avoid a leg-length discrepancy⁽⁴⁾. In non-insertional Achilles tendinopathy, clinicians may treat acute symptoms with immobilization in a CAM boot to offload the tendon⁽⁴⁾. Foot orthoses should address excessive pronation and calcaneal eversion to reduce strain on the tendon⁽¹¹⁾.

Pes cavus
Cavus feet demonstrate a tripod weight bearing, resulting in increased pressure under the first and fifth metatarsal heads and the heel⁽¹²⁾. The high arch and reduced flexibility predispose patients to increased heel force, whilst a varus hindfoot places stress on the lateral ankle ligaments, contributing to chronic ankle instability⁽¹²⁾. In hindfoot-driven cavus, a custom orthosis is usually a semi-rigid, full-length device with an elevated heel to accommodate gastrocnemius/soleus tightness, a lateral hindfoot-to-midfoot wedge, and a lateral forefoot post or first-ray recess, without medial arch support⁽¹²⁾.

Pes planus
Medial arch support insoles, which redistribute pressure, reduce strain on the tibialis posterior tendon and improve overall foot mechanics, and decrease ground reaction force^{(9, 13)}.

Morton’s neuroma
Athletes should avoid high heels and footwear with a narrow toe box, as these increase the pressure on the nerve⁽¹⁴⁾. Metatarsal pads spread the metatarsals and decrease pressure on the nerve by offloading the metatarsal heads; the pad should be placed proximal to the lesion to redistribute pressure away from it (see Figure 3)⁽¹⁴⁾. 

Arthritis

• Ankle arthritis: Orthotic management should aim to limit excessive and painful dorsiflexion and plantarflexion while maintaining gait^{(4, 6)}. A molded AFO or Arizona brace can reduce ankle loading and, when combined with a rocker-bottom shoe, help compensate for restricted motion and aid propulsion during walking^{(4, 6)}.
• Subtalar arthritis: Patients usually experience pain at heel strike and during inversion and eversion. A hinged AFO controls coronal plane motion and limits subtalar movement while improving hindfoot stability^{(4, 6)}. 
• Midfoot arthritis: Pain commonly occurs during dorsiflexion while walking. Management includes stiff-soled shoes, modified lacing, and a UCLB orthosis to stabilize the midtarsal joint and limit midfoot abduction and adduction^{(4, 6)}.
• Forefoot arthritis: Management focuses on limiting the motion of the metatarsophalangeal joint. Common options include Morton extension plates, rocker-bottom shoes, and metatarsal bars^{(4, 6)}.

Hallux disorders

• Hallux rigidus: Clinicians use orthotics to reduce movement across the first MTP joint while providing protection and improving plantar pressure distribution⁽¹⁵⁾. They typically advised a Morton’s extension along with a rocker-bottom sole to decrease dorsiflexion of the first MTP joint by rocking the foot from heel-strike to toe-off⁽¹⁵⁾. Shoes should also have a high and wide toe-box⁽¹⁵⁾.
• Hallux valgus: Narrow shoes and high heels increase valgus stress at the first metatarsophalangeal joint, and athletes should avoid these where possible. Use of a foot orthosis with medial arch support decreases peak pressure in the forefoot^{(16, 17)}.

Ankle sprains
Ankle braces differ in materials, design, and degree of motion restriction, aiming to prevent excessive inversion while preserving functional mobility⁽¹⁸⁾. Semi-rigid braces are made of thermoplastic medial and lateral stirrups secured with straps, limiting inversion and eversion while allowing relatively free plantarflexion and dorsiflexion⁽¹⁸⁾. Semi-rigid ankle braces are effective in reducing the incidence of ankle sprains and offer superior preventive support compared with taping⁽¹⁹⁾. Lace-up braces are fabric-based orthotics that often incorporate figure-of-eight straps and provide moderate restriction of inversion, eversion, plantarflexion, and dorsiflexion. Braces allowing greater plantarflexion may permit higher inversion velocities, whereas designs with subtalar locking mechanisms more effectively limit inversion^{(18, 20)}. There are contrasting findings regarding the effect of ankle bracing on performance, with some studies reporting reductions in jump height and agility, while others show no change (see Table 2)⁽¹⁹⁾.

Table 2: Pros and cons of ankle braces^{(19, 21, 22)}

ACL reconstruction 
Clinicians classify knee braces as prophylactic, rehabilitative, or functional⁽²³⁾. Prophylactic braces look to prevent injury in healthy athletes; rehabilitative braces offer protection in the early post-surgical phase, and functional braces support an injured or reconstructed knee during sport⁽²³⁾. Functional braces are usually rigid and hinged, designed to limit forces associated with ACL injury, including anterior tibial translation, rotation, and valgus movement⁽²³⁾. Braces may reduce anterior tibial translation under controlled conditions. Still, their ability to control knee motion during dynamic activities is less clear, and the current literature does not support routine use after reconstruction⁽²³⁾.

Medial knee osteoarthritis
A valgus knee brace uses a three-point bending system to unload the medial compartment⁽²⁴⁾. Valgus braces reduce pain, decrease the medial-lateral knee loading ratio, and reduce the knee adduction moment⁽²⁴⁾. Comparisons of different brace designs, including a three-point valgus brace, an unloader brace inducing valgus and external rotation, and a functional ligament brace, show that all provide immediate pain relief and reduce medial knee loading during gait⁽²⁴⁾. Valgus braces appear most effective in reducing pain. In contrast, braces incorporating valgus alignment and external rotation may further decrease knee loading by promoting a toe-out gait and shifting the ground reaction force laterally. Functional braces reduce loading through improved joint stability and proprioceptive support⁽²⁴⁾.

Patellofemoral pain syndrome
The On-Track patellar tracking brace and the dynamic patellar orthosis both significantly reduce pain with minimal changes in patellar alignment⁽²⁵⁾. Bracing increases patellofemoral contact area, suggesting symptom relief may result from improved patellar seating in the trochlear and redistribution of joint forces⁽²⁵⁾.

"Orthoses can play an important role in managing lower limb pathology..."

Conclusion

Orthoses can play an important role in managing lower limb pathology by supporting structures and modifying biomechanics. An appropriate prescription requires an understanding of the design, function, and clinical indications of the device. However, orthotics should be used as an adjunct to rehabilitation, alongside targeted strengthening, mobility, and functional exercises.

References 

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