Rational Prescription of Foot and Ankle Orthotics

Orthotic prescription mirrors expertise of a specialist!

Orthotic prescription should have logic and rationale. Consideration of a few simple points will make a prescription perfect.

Criteria for Prescribing Orthotic or Shoe Modification

Criteria for orthotic prescription are listed in Box 3.1.

Box 3.1 Criteria for orthotic prescription

♦ Age of the patient

♦ Activity level of the patient

♦ Type and location of deformity

♦ Status of sensations in foot

♦ Bony prominences and ulcers

♦ Study and analysis of existing orthotics

♦ Age of the patient: A young and active patient would need stronger and durable material. These orthotics need to be slim in order to be easily accommodated in the shoe. Orthotics for female patients must take care of cosmetic aspects. In the older age group, associated comorbid conditions, poor vision, presence of arthritis, and issues of balance are of prime consideration.

♦ Activity level of the patient: Activity level has a direct bearing on the wear and tear of orthotics, which needs repetitive check-ups, changes, and replacements.

♦ Type and location of deformity? Is the deformity rigid or flexible? Complete description of deformity is needed. Flexible deformity needs corrective orthotics, while a rigid deformity needs accommodative orthotics.

♦ Status of sensations in foot: An impaired sensation in the foot requires special care to make sure that there is no pressure from orthotics. Repetitive examination by patient, consultant, and orthotist is required to ensure proper fit of orthotics and lack of any pressure on an insensate foot by orthotics.

♦ Bony prominences and ulcers with its location and details: Drawing of bony prominences or ulcers on a paper is advisable. Locations with depth or prominence are noted. Amount of discharge from ulcer is specified to judge the need for space for dressing material.

♦ Study and analysis of existing orthotics or shoe modifications: Wear and tear of existing orthotic/shoe would give an idea about usage, habits, and hygiene of the patient. It is advisable to send all previous orthotics/shoes to an orthotist for study before preparing a new one.

Formulation of an Orthotic/Shoe Modification

The key is to get answers to the following questions:

♦ Why do I want orthotic or footwear modification in this patient? What objectives should it fulfil? Objectives could be any one of the following:

• Reduce the impact and improve shock absorption

• Relieve the pressure over sensitive structures

• Correct the flexible deformity

• Accommodate the fixed deformity and compensate for reduced movements

• Provide support and maintain the neutral position

• Limit abnormal or excessive movements

♦ Does this patient need custom-molded orthotics or would a prefabricated orthotics work?

♦ Presence of deformity and abnormal shape and size of foot would mandate the use of custom-molded orthotics.

♦ Any other specific factors to be considered? Age, activity level, cosmesis, and sensations are the factors to be considered.

Table 3.1 gives details of various foot and ankle conditions and commonly prescribed orthotics or shoe modifications for them.

Table 3.1 Conditions and common orthotic prescriptions

Foot and ankle problems	Goal	Prescribed orthotics/shoe modifications
Hallux valgus	Align first ray Offload first metatarsophalangeal (MTP) joint	Night splint Toe spreader Gel pad inside shoe/insole Rocker bottom shoe/insole Carbon fiber insole
Hallux rigidus	Total plantar surface contact to reduce load over first MTP	Silicone gel sleeve Low heel, high toe crest footwear Rocker bottom shoe Carbon fiber insole
Hammer, claw, and mallet toes	Total surface bearing Stress-free toe tip Stretching of shortened extensors	Flexible: Metatarsal bar Night splints Rigid custom-molded total contact orthosis Toe crest pad
Morton neuroma	Offload painful neuroma site	Silicone gel pad Metatarsal pad Carbon fiber foot plate
Metatarsalgia	Maintain parabolic arch of foot	Metatarsal arch pad Carbon fiber foot plate insert Total contact orthosis
Plantar corn/callosity	Take pressure off the painful area	Offloading pads Scalloping inside insole Silicone gel pad
Flat foot—stages 1 and 2	Arch correction Deformity prevention	Valgus pads with C and E heel UCBL Supramalleolar orthosis
Flat foot stage 3	Accommodation of deformity	Total contact foot orthosis/insole Foot mold orthosis
Heel varus	Maintaining subtalar joint to neutral	Lateral/outer heel wedge Reverse C and E heel High wall UCBL
Pes cavus	Minimizing foot fatigue with total surface contact	Custom-molded total contact foot orthotic
Midfoot arthritis	Arrest progression of deformity Take load off painful site	Supramalleolar orthosis Short ankle–foot orthosis (AFO) Longitudinal firm arch support
Plantar fasciitis	Relieve load over inflamed fascia	Silicone heel cushion Scooped heel Arch support
Retrocalcaneal bursitis, insertional tendinitis	Release tension on tendo Achilles	Heel raise/lift (minimum 3 cm) Silicone heel (donut shape)
Foot drop	Prevent gravitational dropping of foot Assist in gait	Toe-raising splints Dynamic AFO Static AFO
Charcot neuroarthropathy	Stabilization of foot	Charcot restraint orthotic walker (CROW)