Ankle Orthoses, Ankle-Foot Orthoses (AFOs), and Knee-Ankle-Foot Orthoses (KAFOs)

Number: 0565

Policy

Aetna considers ankle orthoses, ankle-foot orthoses (AFOs), and knee-ankle-foot orthoses (KAFOs) medically necessary durable medical equipment (DME) according to the criteria set forth below.  (See background section of this clinical policy bulletin (CPB) for descriptions of the orthotics discussed in this policy).

1. Ankle Orthotics

   Aetna considers ankle orthoses medically necessary DME for members who meet the criteria set forth below.  (See background section of CPB for descriptions of each of these orthotics).

   • Ankle air-stirrups

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     Ankle air-stirrups (e.g., Air Cast) are considered medically necessary DME when used after an ankle injury (fractures or sprains).  Air-stirrups are considered experimental and investigational for chronically unstable ankles or to prevent ankle re-injury because of a lack of adequate evidence of the effectiveness of ankle air-stirrups for these indications.  See CPB 0009 - Orthopedic Casts, Braces, and Splints.

   • Elastic ankle sleeves

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     Aetna considers reusable elastic ankle sleeves medically necessary DME for use to treat an ankle injury (acute and rehabilitative stages).  Use of elastic ankle sleeves in a chronically unstable ankle or to prevent ankle re-injury is considered experimental and investigational because of a lack of adequate evidence of the effectiveness of elastic ankle sleeves for these indications.

   • Lace-up ankle braces

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     Lace-up ankle braces are considered medically necessary DME when used in members with ankle injuries, when used in members with chronically unstable ankles, or when used to prevent ankle re-injury.

   • Orthopedic ankle cast-braces

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     Orthopedic ankle cast-braces are considered medically necessary DME when used after an ankle injury (fractures or sprains).  See CPB 0009 - Orthopedic Casts, Braces, and Splints.

   • Orthoplast ankle stirrups

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     Orthoplast ankle stirrups are considered medically necessary DME for use after an acute injury.  Use of orthoplast ankle stirrups in chronically unstable ankles or to prevent ankle re-injury is considered experimental and investigational because of a lack of adequate evidence of the effectiveness of orthoplast ankle stirrups for these indications.

   • Post-operative rehabilitative ankle braces

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     Aetna considers post-operative rehabilitation ankle braces medically necessary when applied within 6 weeks of surgery. Such post-operative rehabilitative braces are considered an integral part of surgery.  See also CPB 0009 - Orthopedic Casts, Braces, and Splints.

   • Rigid ankle casts

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     Rigid ankle casts are considered medically necessary DME when used to treat ankle fractures.  Rigid ankle casts are considered experimental and investigational when used after ankle sprains, for chronically unstable ankles, or when used to prevent re-injury because of a lack of adequate evidence of the effectiveness of rigid ankle casts for these indications.

   • Semi-rigid ankle casts

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     Semi-rigid ankle casts are considered medically necessary DME when used to treat ankle sprains.  Semi-rigid ankle casts are considered experimental and investigational when used after ankle fractures, for use in chronically unstable ankles, or when used to prevent re-injury because of a lack of adequate evidence of effectiveness of semi-rigid ankle cases for these indications.

   • Stabilizing shoes

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     Stabilizing shoes for ankle injuries (acute or chronic) are considered experimental and investigational.  Note: In addition, most plans contractually exclude foot orthotics.  Please check benefit plan descriptions.  See CPB 0451 - Foot Orthotics.

   • Unna boots

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     Unna boots are considered medically necessary DME when used after ankle sprains and other soft tissue injuries.  Unna boots are considered experimental and investigational when used after ankle fractures, or when used in chronically unstable ankles or to prevent re-injury because of a lack of adequate evidence of the effectiveness of Unna boots for these indications.  See CPB 0009 - Orthopedic Casts, Braces, and Splints.

2. Ankle Foot Orthoses (AFOs) and Knee Ankle Foot Orthoses (KAFOs)

   1. AFOs and KAFOs used in minimally ambulatory or non-ambulatory persons

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      Static or dynamic positioning ankle foot orthoses (ankle contracture splints) and foot drop splints

      
      
      

      1. Static or dynamic positioning ankle foot orthoses

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         Aetna considers static or dynamic positioning ankle-foot orthoses medically necessary DME if all of the following criteria are met:

         
         
         
         1. The static or dynamic positioning ankle-foot orthoses is used as a component of a therapy program that includes active stretching of the involved muscles and/or tendons, and
         2. The contracture is interfering or expected to interfere significantly with the member's functional abilities, and
         3. There is a reasonable expectation of the ability to correct the contracture, and
         4. The member has a plantar flexion contracture of the ankle with dorsiflexion on passive range of motion testing of at least 10 degrees (i.e., a non-fixed contracture).

         If a static or dynamic positioning ankle-foot orthosis is used for the treatment of a plantar flexion contracture, the pre-treatment passive range of motion must be measured with a goniometer and documented in the medical record.  There must be documentation of an appropriate stretching program carried out by professional staff (in a nursing facility) or caregiver (at home).
         
         A static or dynamic positioning ankle-foot orthosis is considered medically necessary for plantar fasciitis.

         If a static or dynamic positioning ankle-foot orthosis is considered medically necessary, a replacement interface is also considered medically necessary DME as long as the member continues to meet medical necessity criteria for the splint. Up to 1 replacement interface per 6 months is considered medically necessary.

         A static or dynamic positioning ankle-foot orthosis and replacement interface is not considered medically necessary for the following indications:

         • Fixed contractures;
         • Members with foot drop but without an ankle flexion contracture.

         Note: In addition, under HMO plans, a static or dynamic positioning ankle-foot orthosis and replacement interface is not considered medically necessary when it is used solely for the prevention or treatment of a heel pressure ulcer because Medicare does not consider it medically necessary for these indications.

         A component of a static or dynamic positioning ankle-foot orthosis that is used to address positioning of the knee or hip is considered experimental and investigational because the effectiveness of this type of component is not established.

      2. Foot drop splint/recumbent positioning device

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         Aetna's HMO plans do not consider a foot drop splint/recumbent positioning device or replacement interface medically necessary.  A foot drop splint/recumbent positioning device and replacement interface is not considered medically necessary under HMO plans when it is used solely for the prevention or treatment of a heel pressure ulcer because Medicare does not consider it medically necessary for these indications.  A foot drop splint/recumbent positioning device and replacement interface is not considered medically necessary for members with foot drop who are non-ambulatory because there are other more appropriate treatment modalities.

      3. Additions to AFOs and KAFOs

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         Additions to AFOs or KAFOs are not considered medically necessary if either the base orthosis is not medically necessary or the specific addition is not medically necessary.

   2. AFOs and KAFOs used in ambulatory persons

      1. AFOs in ambulatory members

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         Ankle-foot orthoses (AFO) are considered medically necessary DME for ambulatory members with weakness or deformity of the foot and ankle, which require stabilization for medical reasons, and have the potential to benefit functionally.  Members prescribed custom-made “molded-to-patient-model” AFOs must also meet the criteria set forth in section II.B.3, below.  AFOs are not considered medically necessary for ambulatory members who do not meet these medical necessity criteria.

         Aetna's HMO plans do not consider AFOs and any related addition medically necessary when used solely for the treatment of edema and/or for the prevention or treatment of a heel pressure ulcer in ambulatory patients, as Medicare does not consider AFO's medically necessary for these indications.

         Additions to AFOs or KAFOs are not considered medically necessary if either the base orthosis is not medically necessary or the specific addition is not medically necessary.  (Note: Customized Noodle TA AFO and the PHAT dynamic carbon fiber AFO are considered non-covered deluxe items).

      2. KAFOs in ambulatory members

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         Knee-ankle-foot orthoses (KAFO) are considered medically necessary DME for ambulatory members for whom an ankle-foot orthosis is considered medically necessary and for whom additional knee stability is required.  Members prescribed custom-made “molded-to-patient model” KAFOs must also meet the criteria set forth in section II.B.3, below.  KAFOs are not medically necessary and are not covered for ambulatory members who do not meet these coverage criteria.

         Aetna's HMO plans do not consider KAFOs and any related addition medically necessary when used solely for the treatment of edema and/or for the prevention or treatment of a heel pressure ulcer in ambulatory members, as Medicare does not consider KAFO's medically necessary for these indications.

      3. Molded-to-patient model AFO's and KAFO's in ambulatory members

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         Custom-made AFOs and KAFOs that are “molded-to-patient-model” are considered medically necessary DME for ambulatory members when the basic medical necessity criteria listed in sections II.B.1 and II.B.2 above are met and one of the following criteria is met:
         
         

         1. The condition necessitating the orthosis is expected to be permanent or of longstanding duration (more than 6 months); or
         2. There is a need to control the knee, ankle or foot in more than 1 plane; or
         3. The member could not be fitted with a pre-fabricated (off-the-shelf) AFO; or
         4. The member has a documented neurological, circulatory, or orthopedic status that requires custom fabricating over a model to prevent tissue injury; or
         5. The member has a healing fracture that lacks normal anatomical integrity or anthropometric proportions.

      4. Additions to AFOs and KAFOs

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         Additions to AFOs and KAFOs are not considered medically necessary if either the base orthosis is not medically necessary and/or the specific addition is not medically necessary. 

         
         
         

      5. Concentric adjustable torsion-style mechanisms

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         Concentric adjustable torsion style mechanisms used to assist knee joint extension are considered medically necessary for members who require knee extension assist in the absence of any co-existing joint contracture. 

         Concentric adjustable torsion style mechanisms used to assist ankle joint plantarflexion or dorsiflexion are considered medically necessary for members who require ankle plantar or dorsiflexion assist in the absence of any co-existing joint contracture. 

         A dynamic adjustable ankle extension/flexion device is considered medically necessary for treatment of contractures.

      6. Microprocessor-controlled KAFOs

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         Electronic KAFOs (e.g., the Sensor Walk Electronic KAFO, C-Brace Orthotronic Mobility System) are considered experimental and investigational because of insufficient evidence that they improve ambulation compared to standard KAFOs.

3. General Notes:

   • Prophylactic orthotics

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     Aetna does not consider ankle orthotics, AFOs, and KAFOs medically necessary treatment of disease when used to prevent injury in a previously uninjured ankle or knee.  Such use is solely preventive, and therefore is considered not considered medically necessary treatment of disease or injury.  In addition, many Aetna plans exclude coverage of safety items.  See CPB 0623 - Safety Items.

   • Repairs and replacements

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     Repairs to a medically necessary ankle orthosis, AFO, or KAFO due to wear and tear are considered medically necessary DME when they are needed to make the orthosis functional.  Replacement of a complete ankle orthosis, AFO, or KAFO or component of these orthoses due to a significant change in the member's condition or irreparable wear is considered medically necessary DME if the device is still medically necessary.

   • Shoes

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     Please see CPB 0451 - Foot Orthotics for medical necessity criteria for shoes and related items that are an integral part of a leg brace.

   • Socks

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     Socks used in conjunction with ankle orthoses, AFOs, or KAFOs are not covered because socks do not meet the contractual definition of durability for covered DME.

   • Spare orthotics

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     Identical spare orthotics purchased for the member's convenience is not considered medically necessary.  More than 1 set of different orthotics, however, may be medically necessary.

   • Sports orthotics

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     Aetna does not consider ankle orthotics, AFOs, and KAFOs medically necessary if they are to be used only during participation in sports.  Such use is considered not medically necessary, as participation in sports is considered an elective activity.

See also  CPB 0696 - Suit Therapy.

Background

An orthosis (brace) is a rigid or semi-rigid device that is used for the purpose of supporting a weak or deformed body member or restricting or eliminating motion in a diseased or injured part of the body.  An orthosis can be either pre-fabricated or custom-fabricated.

Custom-Made versus Pre-Fabricated (Off-the-Shelf) Orthoses

A pre-fabricated (off-the-shelf) orthosis is one that is manufactured in quantity without a specific patient in mind.  A pre-fabricated orthosis may be trimmed, bent, molded (with or without heat), or otherwise modified for use by a specific patient (i.e., custom-fitted).  An orthosis that is assembled from pre-fabricated components is considered pre-fabricated.  Any orthosis that does not meet the definition of a custom-fabricated (custom-made) orthosis is considered pre-fabricated.

A custom-fabricated (custom-made) orthosis is one that is individually made for a specific patient starting with basic materials including, but not limited to, plastic, metal, leather, or cloth in the form of sheets, bars, etc.  It involves substantial work such as cutting, bending, molding, sewing, etc.  It may involve the incorporation of some pre-fabricated components.  It involves more than trimming, bending, or making other modifications to a substantially pre-fabricated item.  A molded-to-patient-model orthosis is a particular type of custom-fabricated orthosis in which an impression of the specific body part is made (by means of a plaster cast, CAD-CAM technology, etc.) and this impression is then used to make a positive model (of plaster or other material) of the body part.  The orthosis is then molded on this positive model.

Ankle Orthotics

Ankle orthotics may potentially be useful after an acute ankle injury (acute ankle sprain (ligament injury) or fracture), for rehabilitation, to prevent ankle re-injury, and for chronically unstable ankles.  Whether a specific ankle orthotic is effective depends on the particular indication for its use.

Treatment after acute injury: The ankle begins to swell after injury, and swelling continues to increase for about 3 days following injury.  Significant swelling persists for about 2 weeks following injury.

Rehabilitation: Ankle supports have been used for the first few weeks following injury to prevent re-injury during early return to activity.  After the pain has subsided and the patient can walk without a limp, use of the ankle support is only appropriate during high-risk activities (i.e., especially racquetball, football, and basketball).  Leaving the ankle support on all the time only serves to restrict functional range of motion and encourage psychological dependence.

Prophylaxis: Ankle supports have been used to prevent injury in uninjured individuals and persons with a history of ankle sprain.  There is generally no reason for prophylactic bracing in low-risk activities, such as standing, walking, or climbing stairs.  And it is not clear that prophylactic bracing should be advocated for use during high-risk sports as well, because of prophylactic bracing's cost, inconvenience, and possible detraction from athletic performance.

Chronic instability: Ankle supports are used to stabilize the ankle in patients with chronic instability.  In most instances, they are to be used only during high-risk sports and activities.  It is unusual for ankle supports to be prescribed for use during normal daily activities.

Many types of ankle supports exist as an alternative to ankle taping.  In addition, shoes for some sports (particularly basketball) are available with high tops and built in straps for additional ankle protection.

Recent studies have shown that use of ankle supports during early rehabilitation of acute grade I or grade II ankle sprains (partial ligament rupture) produced results as good as cast immobilization, with more rapid return to activity.

The following is a description of various types of ankle supports, and a summary of the evidence of their effectiveness.  Numerous difficulties arise in interpreting the studies of the various treatments for ankle sprains.  First, most ankle sprains heal well regardless of the form of treatment; thus, almost all treatments produce good results.  It is difficult to measure marginal differences among them.

Second, difficulties arise in comparing different treatment protocols and brands of products.  Research is needed to standardize forms of treatment and to compare the many products on the market.

Third, research has focused on which provide the best mechanical support of the ankle in laboratory stress testing, but it has not been demonstrated that this is the most important factor in predicting clinical outcomes.  It may be that the quality of the proprioceptive (position-sense) feedback from the device is the most important predictor of clinical outcomes.

Taping

A number of studies have supported the use of tape in helping stabilize the ankle and reducing sprains in persons with previous sprains.

The goal of taping is to prevent the ankle ligaments from being stressed to the point of injury.  Taping should limit ankle inversion and eversion but allow functional dorsiflexion and plantarflexion.  There is evidence that ankle taping also helps prevent injury by stimulating proprioceptive (position-sense) nerve fibers, causing the peroneus brevis muscle to be activated just before heel strike.

For treatment of acute injury (beginning within about 3 days following injury), taping may be used to provide support and to help reduce edema (swelling).  Felt or foam pads may be applied under the tape to help reduce edema.

Taping may be used for rehabilitation (i.e., to prevent re-injury during early return to activity).  About 3 days after the injury, swelling subsides, and tape is re-applied to decrease the risk of re-injury.  Using tape to prevent injury, however, is a time-consuming procedure, so it is recommended for early stages of rehabilitation only.  Tape may be applied for the first few weeks after return to activity for rehabilitation of ankle injuries.

Taping may be used prophylactically in persons with or without a prior ankle sprain, although it is not recommended for routine use for this indication.  Although taping probably reduces the rate of ankle injuries, it loses support rapidly with movement and sweating.  This is not as much as a factor in acute sprains, because in which tape is not stressed so much.  For use prophylactically, however, it is not a time- and cost-effective option compared to the alternatives described below.

Taping has also been recommended as a possible treatment for chronic instability, although it is not recommended for routine use in this situation.  With movement and sweating, tape rapidly loses support.  Also, if used permanently, tape becomes expensive.  This approach is probably not as cost- and time-effective as other options described below.

One-inch wide standard tape is used for the foot, and 1½-inch tape for the ankle.  Areas sensitive to blistering must be protected with lubricated gauze sponges.  Special adherent spray may be applied under the tape.  If tape is to be re-applied often, an underwrap is used to prevent chronic skin irritation.

Tape should only be wrapped by a person well-trained in its application, such as a trainer, physician, nurse, or physician assistant.  Improperly applied tape may cause further injury.

Elastic tape has also been studied, and although it provides more compression than non-elastic tape, it loses its restriction of range of motion even more than standard tape.

Tape and wrapping does not meet the durability requirement for covered durable medical equipment, in that it is not reusable and is not “made to withstand prolonged use.”  Although Aetna will cover taping or wrapping provided by a healthcare provider in their office, take-home tape and wrapping are not covered.

Elastic Wrapping and Sleeves

Wrapping with elastic bandages is useful in the early stages (about the first 3 days) of ankle sprain to provide compression that reduces swelling.  It is used as an adjunct to ice and elevation.  It needs to be changed often to monitor the skin.  Wrapping has not been proven to be useful for other indications: prevention of re-injury, prophylactic use, and use for chronic ankle instability.  This is because wrapping provides little or no support during activity.

Elastic ankle sleeves that are pulled over the foot like open-ended socks offer no value as supports.  They may, however, enhance proprioception.  They may also provide even compression to reduce ankle edema.  Thus, they have been shown to be useful only in treating an acute ankle sprain (i.e., within about 3 days after injury).  Like elastic wrapping, elastic ankle sleeves have not been proven to be useful for rehabilitation, prophylaxis, or use in chronically unstable ankles.

Certain manufacturers, e.g., Stromgen, combine the comfort of even compression by using Spandex, elastic, and Velcro strap combinations to restrict eversion, and inversion.  They have been used primarily for prophylaxis.

Bracing

Like taping, bracing can be used in an acute injury, during rehabilitation to prevent re-injury, prophylactically, and in chronically unstable ankles.  Braces come in 3 main types: casts, lace-up wraps, and plastic orthoses.  Casts can be either semi-rigid or rigid; lace-up braces and plastic orthoses are considered semi-rigid.

Braces have been shown to have several advantages over taping.  They can be used by persons who do not have access to a person skilled in taping techniques.  In some cases, they can be more cost-effective than taping.  But some braces may migrate during vigorous movement because of the lack of adhesion to skin.  This movement may cause the brace to fail to provide support.  But tape adhesion or straps to reduce migration may help.  During wear-and-tear, Velcro fasteners tend to fail and release, straps or buckles break, and elastic stretches out.  Off-the-shelf braces may not fit persons who are too tall, are obese, or deformed.  Custom-made braces are available, but are generally more expensive.

Rigid Plaster Casts

Rigid plaster casting, once a common treatment for acute ankle sprains, has now been generally abandoned for this use.  Plaster casting continues to be used in foot and ankle fractures.

Compared with taping, rigid plaster casting has been shown to increase the time to return to activity and has not been shown to produce a better outcome, even in patients with grade III ankle sprains (complete rupture of a ligament).

Still, rigid casting is an option to consider for the early post-operative phase or in cases of gross ankle instability.  When acute swelling subsides, the cast should be replaced with a better fitting one.  It should be replaced with semi-rigid bracing as soon as possible, usually within 1 to 2 weeks.

Rigid casting is not used to prevent re-injury during rehabilitation, for prophylaxis, or for chronic instability.

Soft (Semi-Rigid) Casts

Semi-rigid casting is done with a wrap that hardens somewhat after application but does not become completely rigid.  The Una (Unna's) boot (Graham Field, Inc., Hauppage, NY) is a semi-rigid cast that consists of a gauze bandage that contains glycerin and gelatin and is applied over a felt bone around the anklebone (the medial malleolus).  In an acute sprain, it provides some support and compression.  Ice is commonly applied around the boot, but no studies have demonstrated adequate tissue cooling with this technique.  In the treatment of acute ankle injuries, semi-rigid casts have not been shown to be more effective than tape.  Semi-rigid casting does not offer enough support to be used to prevent injury during rehabilitation, for prophylaxis, or for chronic instability.

Lace-Up Braces

Lace-up braces have been proven to be as effective as tape at restricting ankle range of motion, and unlike tape, lace-ups do not tend to lose their supportive ability during activity.  Lace-up braces are a cost-effective alternative to taping.  They are safe, easy to apply, and reusable.  They are not of much value in the acute stage of injury because they do not provide good uniform compression.  They are probably of some value in preventing re-injury during rehabilitation, for prophylactic use, and for use in patients with chronic ankle instability.

Air-Stirrups

The air-stirrup is a pre-fabricated semi-rigid orthosis.  The largest-selling brand is the Aircast air-stirrup ankle brace (Aircast, Summit, NJ), which is composed of a rigid outer plastic shell that fits up both sides of the leg and is connected under the heel.  It is lined with inner air bags and is attached to the leg with Velcro.  As with lace-up ankle supports, some clinicians combine use of the air-stirrup with taping.  The air-stirrup is an off-the-shelf device that does not require custom fitting.  It can be worn under regular shoes.

The air-stirrup decreases inversion and eversion, and protects the already injured ligament and soft tissues from re-injury, thereby decreasing rehabilitation time.  The pressure in the air-stirrup increases when weight-bearing, which is thought to provide intermittent compression during walking that aids in the milking out of edematous fluid.  The air-stirrup can also be readjusted to allow total contact fitting while swelling is fluctuating.

The air-stirrup can be used after acute ankle sprains and in the early stages of rehabilitation to prevent recurrent sprain.  It can also be used after rigid casting and for treatment of some fractures.  There is currently insufficient evidence for their use for prophylaxis or in chronic instability, although some newer variations of the splint have been designed for this purpose.

Other Semi-Rigid Orthoses

Other semi-rigid orthoses have not been studied adequately to make accurate comparisons with taping or with air-stirrups.  These include the following:

• DonJoy Ankle Ligament Protector (DonJoy, Carlsbad, CA) is a plastic brace that seems to restrict range of motion as well as the air-stirrup and possibly better than tape, although no head-to-head comparisons have been published.
• The Active Ankle (Active Ankle Systems, Louisville, KY) has a stirrup and air cell liner with a hinged ankle may also be useful.
• The Malleoloc (Bauerfiend USA, Kennesaw, GA) is a stabilizing ankle orthosis that uses a wrap-around ankle brace in conjunction with Velcro strapping.  Although it shows promise, definitive proof if its effectiveness is not yet available.

Other Ankle-Stabilizing Orthoses

• Non-Elastic Cloth Wrapping: Non-elastic cloth wrap (also known as the Louisiana heel lock) has been applied over socks to prevent ankle injury.  The advantage of this system is that the wrap can be washed or reused, thus reducing cost.  Cloth wrapping may improve position-sense, but it appears to offer less benefit than taping.  Its use in ankle injuries has not been adequately studied.
• Nylon and Nylon/Elastic Wrapping: Nylon or Nylon/Elastic heel wraps to be placed over socks may also improve position sense, but like non-elastic cloth wrapping, their use in ankle injuries has not been adequately studied.
• Orthoplast Stirrup: The orthoplast stirrup is a strip of thermoplastic material custom-fitted to run under the heel and up both sides of the leg.  The ankle bones (malleoli) and other bony prominences are covered with foam padding, and the stirrup is fitted with an elastic bandage.

Orthoplast is a low-temperature thermoplastic that becomes pliable when submerged in hot water.  It is applied directly to the patient and molded evenly around the ankle.  The fabrication is simple enough to be carried out in the office or clinic.

The orthoplast stirrup has been successfully used to treat ankle sprains, but because it is relatively hard, it does not adapt to reduction in swelling.  It has not been shown to decrease inversion range of motion more than tape, and is most commonly used in the acute or early rehabilitative stages.  Orthoplast deteriorates with long-term use, limiting its usefulness in prophylaxis and for chronic ankle sprains.

Stabilizing Shoes

Several shoe designs have been used for prevention and treatment of ankle sprains.

• Acute injury, rehabilitation, and chronic instability: The use of ankle-stabilizing shoes, such as the Kunzli line of shoes (Swiss Balance, Santa Monica, CA), to treat ankle sprain and to prevent re-injury have not been studied adequately to date.
• Prophylaxis: High-topped shoes have been shown to increase ankle stiffness in sports.  However, the advantage of high-topped shoes over low-topped shoes in prophylaxis has been shown to be relatively small.  The prophylactic benefits of various shoe types in sports have not been adequately investigated.

Cast-Braces

A number of hinged polypropylene cast braces have been used in the treatment of ankle sprains.  These involve have a foot section with heel stabilizer, a lateral ankle extension, and an articulating ankle joint joining the two.  An example is the Sarmiento cast brace, which is removable and fits in the patient's shoe.  They were designed primarily for long-term use in athletes who suffer from recurrent ankle sprains (i.e., prophylaxis and chronic instability).

Cast-braces require custom fitting by an orthotist for proper impression, fabrication, and fitting.  Fitting of a fresh ankle sprain with a cast-brace is usually not recommended because changes in swelling of the ankle during the initial recovery phase will compromise the cast-brace's fit.

Although these cast-braces have reportedly given good results in the treatment of ankle sprains, they are cumbersome, expensive, and have not been shown to offer any benefits over other forms of treatment.

The Boston Ankle System

The Boston Ankle System (Physical Support Systems, Boston, MA) is a custom-fitted ankle stabilizer.  The Boston Ankle System is made of polypropylene and requires an exact impression.  The services of an orthotist are often required for fine adjustment and accurate fitting.

Ice Pack with Air-Stirrup

The Cryo/Strap (Aircast, Summit, NJ) ice pack with air-stirrup uses a U-pad for compression of the soft tissue around the ankle.  The pad contains a liquid that can be frozen and is held in place by an elastic strap.  A modified air-stirrup is worn over this device.  This system has been shown to provide uniform compression and to decrease skin temperature for up to 90 mins.  It has not been shown, however, to improve long-term outcomes.

Ankle-Foot Orthoses (AFOs) and Knee-Ankle-Foot Orthoses (KAFOs)

Ankle-foot orthoses (AFOs) extend well above the ankle (usually to near the top of the calf) and are fastened around the lower leg above the ankle.  These features distinguish them from foot orthotics, which are shoe inserts that do not extend above the ankle.

Below the knee, the components of a KAFO are the same as those of an AFO.  However, the KAFO extends to the knee joint and thigh.

A non-ambulatory ankle-foot orthosis may be either an ankle contracture splint or a foot drop splint.

Figueiredo et al (2008) performed a literature review evaluating the quality of current research on the influence of AFO on gait in children with cerebral palsy (CP).  Two between-group and 18 within-group studies met the inclusion criteria indicating a low level of evidence.  Between-group studies each scored "4" on the PEDro Scale, and 17 within-group studies scored "3" and 1 scored "2", indicating low-quality.  Standard terminology for AFO was not used and only 6 studies described functional status using appropriate instruments.  The authors concluded that studies using high-quality methods are still needed to support evidence-based decisions regarding the use of AFO for this population.

The Intrepid Dynamic Exoskeleton Orthosis (IDEO) is a custom molded energy-storing AFO that was reportedly developed for individuals who have suffered massive tissue, nerve and bone damage to supposedly return capabilities to the injured ankle. Purportedly, the individual can return to a high level of activity, such as running. The IDEO device is molded out of lightweight black carbon that includes a foot plate and a strut that runs up the back of the calf to a cuff that is situated just below the knee. Reportedly, when force is applied to the foot plate, the strut bends. As the individual steps down, it bends the foot plate, transferring energy forward.

Microprocessor-Controlled KAFOs

Microprocessor activated mobility devices combine electronic components with specialized orthotic braces to reportedly provide assistance in walking to individuals with back injuries or leg muscle weakness. Examples of microprocessor activated devices include, but may not be limited to, the C-Brace Orthotronic Mobility System or the Sensor Walk Stance Control knee brace.

Irby et al (2005) noted that individuals with weak or absent quadriceps who wish to walk independently were prescribed KAFOs.  New stance control orthosis (SCO) designs automatically release the knee to allow swing phase flexion and extension while still locking the joint during stance.  A total of 21 subjects were fitted unilaterally with the Dynamic Knee Brace System (DKBS), a non-commercial SCO -- 13 were experienced KAFO users (average of 28 +/- 18 years of experience) while 8 were novice users.  Novice users demonstrated increased velocity (55 versus 71 cm/sec, p = 0.048) and cadence (77 versus 85 steps/min, p < 0.05) when using the DKBS over the traditional locked KAFO.  Experienced KAFO users tended to have reduced velocity and cadence measures when using the SCO (p < 0.10).  Knee range of motion was significantly greater for the novice group than for the experienced group (55.2 +/- 4.8 versus 42.6 +/- 3.8 degrees, p = 0.05).  Peak knee extension moments tended to be greater for the experienced group (0.29 +/- 0.21 versus 0.087 +/- 0.047 Nm/kg, p = 0.09).  This report described gait changes during the introductory phase of DKBS adoption.  Experienced KAFO users undoubtedly had ingrained gait patterns designed to compensate for walking with a standard locked KAFO.  These patterns may have limited the ability of those users from taking full and immediate advantage of the SCO capabilities.  Also, alternate SCO systems may engender different results.  The authors concluded that comparison studies and longer term field studies are needed to clarify benefits of the various bracing options.

Zissimopoulos et al (2007) noted that users of traditional KAFOs walk with either locked or unlocked knee joints depending on the level of stability required.  Some users may benefit from new stance-control KAFOs that prevent stance-phase knee flexion but allow swing-phase flexion.  These researchrs collected data from 9 non-disabled adults who walked with KAFOs that incorporated the Horton Stance-Control Orthotic Knee Joint (SCOKJ) in the locked, unlocked, and auto (which provides knee stability during stance phase and knee flexion during swing phase) modes to investigate the biomechanical and energetic effects of stance-control orthoses.  Studying non-disabled subjects allowed these researchers to analyze the effects of stance-control orthoses in a homogenous population.  In general, gait kinematics for the auto and unlocked modes were more similar than for the auto and locked modes.  Despite the elimination of hip hiking in the auto mode, oxygen cost was not different between the auto and locked modes (p > 0.99).  The SCOKJ allowed non-disabled subjects to walk with a more normal gait pattern; however, future research should explore the effect of stance-control orthoses on persons with gait pathology.

Ankle Contraction Splints / Static Dynamic AFOs

According to Medicare Durable Medical Equipment Carrier Guidelines, a static-dynamic AFO is a pre-fabricated AFO that has all of the following characteristics:

1. Applies a dorsiflexion force to the ankle , and
2. Designed to accommodate either plantar fasciitis or an ankle with a plantar flexion contracture up to 45^°, and
3. Has a soft interface, and
4. Used by a patient who is minimally ambulatory or non-ambulatory.

Ankle flexion contracture is a condition in which there is shortening of the muscles and/or tendons that plantarflex the ankle with the resulting inability to bring the ankle to 0 degrees by passive range of motion.  (0 degrees ankle position is when the foot is perpendicular to the lower leg.)

Foot Drop Splint

A foot drop splint/recumbent positioning device is a pre-fabricated AFO, which has all of the following characteristics:

1. Designed to maintain the foot at a fixed position of 0^° (i.e., perpendicular to the lower leg), and
2. Has a soft interface, and
3. Not designed to accommodate an ankle with a plantar flexion contracture, and
4. Used by a patient who is non-ambulatory.

Foot drop is a condition in which there is weakness and/or lack of use of the muscles that dorsiflex the ankle but there is the ability to bring the ankle to 0 degrees by passive range of motion.

Foot and Ankle Orthoses for Rheumatoid Arthritis

Hennessy and colleagues (2012) evaluated the evidence for the effectiveness of custom orthoses for the foot and ankle in rheumatoid arthritis.  Studies were identified in appropriate electronic databases (from 1950 to March 2011).  The search term "rheumatoid arthritis" with "foot" and "ankle" and related terms were used in conjunction with "orthoses" and synonyms.  Included studies were quantitative longitudinal studies and included randomized controlled trials (RCTs), case-control trials, cohort studies, and case series studies.  All outcome measures were investigated.  Quality assessment was conducted using the Cochrane Collaboration criteria with additional criteria for sample population representativeness, quality of statistical analysis, and compliant intervention use and presence of cointerventions.  Meta-analyses were conducted for outcome domains with multiple RCTs.  Qualitative data synthesis was conducted for the remaining outcome domains.  Levels of evidence were then assigned to each outcome measure.  The inclusion criteria were met by 17 studies -- 2 studies had high-quality for internal validity and 3 studies had high-quality for external validity.  No study had high-quality for both internal and external validity.  Six outcome domains were identified.  There was weak evidence for custom orthoses reducing pain and forefoot plantar pressures.  Evidence was inconclusive for foot function, walking speed, gait parameters, and reducing hallux abductovalgus angle progression.  The authors concluded that custom orthoses may be beneficial in reducing pain and elevated forefoot plantar pressures in the rheumatoid foot and ankle.  However, they stated that more definitive research is needed in this area.

AFOs and KAFOs for Knee Instability Related to Neuromuscular and Central Nervous System Disorders

In a pilot study, Arazpour and co-workers (2016) determined the effect of a powered KAFO on the physiological cost index, walking speed and the distance walked in people with poliomyelitis compared to when walking with a KAFO with drop lock knee joints.  A total of 7 subjects with poliomyelitis volunteered for the study and undertook gait analysis with both types of KAFOs.  Walking with the powered KAFO significantly reduced walking speed (p = 0.015) and the distance walked (p = 0.004), and also, it did not improve physiological cost index values (p = 0.009) compared to walking with the locked KAFO.  The authors concluded that using a powered KAFO did not significantly improve any of the primary outcome measures during walking for poliomyelitis subjects.  They stated that this powered KAFO design did not improve the physiological cost index of walking for people with poliomyelitis when compared to walking with a KAFO with drop lock knee joints.  This may have been due to the short training period used or the bulky design and additional weight of the powered orthosis; further research is therefore warranted.

In a Health Technology Assessment on “Orthotic management of instability of the knee related to neuromuscular and central nervous system disorders: systematic review, qualitative study, survey and costing analysis”, O’Connor and associates (2016) concluded that various types of orthoses (KAFOs [mainly carbon fiber], stance control KAFO and hip KAFOs) were used in the United Kingdom Nation Health Service to manage patients with neuromuscular disorder (NMD)/central nervous system (CNS) conditions (e.g., inclusion body myositis, post-polio syndrome, post-stroke, and spinal cord injury [SCI]) and knee instability, both custom-made and pre-fabricated, of variable cost.  They stated that evidence on the effectiveness of the orthoses was limited, especially in relation to the outcomes that were important to orthoses users.

Kobayashi and colleagues (2016) noted that genu recurvatum (knee hyperextension) is a common issue for individuals post-stroke; AFOs are used to improve genu recurvatum, but evidence is limited concerning their effectiveness.  These researchers examined the effect of changing the plantarflexion resistance of an articulated AFO on genu recurvatum in patients post-stroke.  Gait analysis was performed on 6 individuals post-stroke with genu recurvatum using an articulated AFO whose plantarflexion resistance was adjustable at 4 levels.  Gait data were collected using a Bertec split-belt instrumented treadmill in a 3D motion analysis laboratory.  Gait parameters were extracted and plotted for each subject under the 4 plantarflexion resistance conditions of the AFO.  Gait parameters included peak ankle plantarflexion angle, peak ankle dorsiflexion moment, peak knee extension angle and peak knee flexion moment.  A non-parametric Friedman test was performed followed by a post-hoc Wilcoxon Signed-Rank test for statistical analyses.  All the gait parameters demonstrated statistically significant differences among the 4 resistance conditions of the AFO.  Increasing the amount of plantarflexion resistance of the AFO generally reduced genu recurvatum in all subjects.  However, individual analyses showed that the responses to the changes in the plantarflexion resistance of the AFO were not necessarily linear, and appeared unique to each subject.  The authors concluded that plantarflexion resistance of an articulated AFO should be adjusted to improve genu recurvatum in patients post-stroke; and future studies should examine what clinical factors would influence the individual differences.

In a pilot study, Kobayashi and associates (2016) studied the mechanical properties of a novel articulated AFO with adjustable plantarflexion resistance, dorsiflexion resistance and alignment, and its effect on ankle and knee joint kinematics and kinetics in an individual post-stroke during gait.  The mechanical properties of the AFO were quantified.  Gait analysis was performed using a 3D motion capture system with a split-belt instrumented treadmill under 12 different settings of the mechanical properties of the AFO [i.e., 4 plantarflexion resistances (P1<P4), 4 dorsiflexion resistances (D1<D4), 4 initial alignments (A1<A4)].  The AFO demonstrated systematic changes in moment-angle relationship in response to changes in AFO joint settings.  The gait analysis demonstrated that the ankle and knee angle and moment were responsive to changes in the AFO joint settings.  Mean ankle angle at initial contact changed from -0.86° (P1) to 0.91° (P4) and from -1.48° (A1) to 4.45° (A4), while mean peak dorsiflexion angle changed from 12.01° (D1) to 6.40° (D4) at mid-stance.  The authors concluded that the novel articulated AFO appeared effective in influencing lower-limb joint kinematics and kinetics of gait in the individual post-stroke.  The findings of this pilot study need to be further investigated.

In a RCT, Nikamp and co-workers (2017) examined the 6-month clinical effects of providing AFOs at different moments (early or delayed) in (sub)acute stroke; this was a follow-up to a published trial.  Participants were unilateral hemiparetic stroke subjects maximal 6 weeks post-stroke with indication for AFO use.  Subjects were randomly assigned to early (at inclusion; week 1) or delayed provision (8 weeks later; week 9).  Functional tests assessing balance and mobility were performed bi-weekly for 17 weeks and at week 26.  A total of 33 subjects were randomized.  No differences at week 26 were found between both groups for any of the outcome measures.  However, results suggested that early provision led to better outcomes in the first 11 to 13 weeks. Berg Balance Scale (p = 0.006), Functional Ambulation Categories (p = 0.033) and 6-minute walk test (6MWT; p < 0.001) showed significantly different patterns over time.  Clinically relevant but statistically non-significant differences of 4 to 10 weeks in reaching independent walking with higher balance levels were found, favoring early provision.  The authors concluded that no 6-month differences in functional outcomes of providing AFOs at different moments in the early rehabilitation after stroke were found.  Moreover, they stated that these findings suggested that there was a period of 11 to 13 weeks in which early provision may be beneficial, possibly resulting in early independent and safe walking.  However, they noted that this study was under-powered; further investigation including larger numbers of subjects is needed.

In a systematic review, McDaid and colleagues (2017) evaluated the effectiveness of orthotic devices for the management of instability of the knee in adults with a NMD or CNS disorder.  Interventions employed were orthoses (e.g., AFOs, KAFOs, and knee orthoses or mixed design with no restrictions in design or material) with the clinical aim of controlling knee instability.  Outcomes included condition-specific or generic patient-reported measures assessing function, disability, independence, activities of daily living (ADLs), quality of life (QOL) or psychosocial outcomes; pain; walking ability; functional assessments; biomechanical analysis; adverse effects; usage; patient satisfaction and the acceptability of a device; as well as resource utilization data.  A total of 21 studies including 478 patients were included.  Orthotic devices were evaluated in patients with inclusion body myositis, post-polio syndrome, post-stroke syndrome, and SCI).  The review included 2 RCTs, 3 non-RCTs and 16 case series.  Most were small, single-center studies with only 6 of 21 following patients for 1 year or longer.  They met between 1 and 5 of 9 quality criteria and reported methods and results poorly.  They mainly assessed outcomes related to gait analysis and energy consumption with limited use of standardized, validated, patient-reported outcome measures.  There was an absence of evidence on outcomes of direct importance to patients such as reduction in pain and falls.  The authors concluded that there is a need for high-quality research, especially RCTs, on the effectiveness of AFOs, KAFOs and other orthotic devices for managing knee instability related to NMD and CNS conditions.  They stated that this research should address outcomes that are important to patients; and there may also be value in developing a national registry.

In a systematic review, Daryabor and associates (2018) evaluated the efficacy of different designs of AFOs and comparison between them on the gait parameters of individuals with hemiplegic stroke.  The search strategy was based on the population intervention comparison outcome (PICO) method.  A search was performed in PubMed, ISI Web of Knowledge, Scopus, Science Direct, and Google Scholar databases.  A total of 27 articles were found for the final evaluation.  All types of AFOs had positive effects on ankle kinematic in the first rocker and swing phases, but not on knee kinematics in the swing phase, hip kinematics or the third rocker function.  All trials, except 2, assessed immediate or short-term effects only.  The articulated passive AFO compared with the non-articulated passive AFO had better effects on some aspects of the gait of patients with hemiplegia following stroke, more investigations are needed in this regard though.  The authors concluded that an AFO can immediately improve the dropped foot in the stance and swing phases.  Moreover, they stated that the effects of long-term usage and comparison among the different types of AFOs need to be evaluated.

The above policy is based on the following references: