Orthoses in the treatment of rearfoot problems

Abstract

Orthotic management is helpful in the treatment of most orthopedic conditions involving the rearfoot, including plantar fasciitis, Achilles tendon disorders, posterior tibial tendon dysfunction, flatfoot, ankle sprains, and problems associated with diabetes, arthritis, and equinus disorders. A review of the effectiveness of orthoses in the treatment of these conditions is presented here. An in-depth analysis of the orthotic management of plantar fasciitis and a critical review of foot orthoses for the pronated foot are presented. Also discussed are the rationale and effectiveness of the tension night splint in the treatment of plantar fasciitis, orthotic devices for the different stages of posterior tibial tendon dysfunction, and the various categories of orthoses for off-loading the diabetic foot. The modern ankle brace, the effectiveness of prefabricated versus prescription foot orthoses, and recent developments in the ankle-foot orthosis are also reviewed.

The rearfoot-ankle complex is subject to numerous orthopedic disorders ranging from such extremely common entities as plantar fasciitis and posterior tibial tendon dysfunction to such severe orthopedic problems as Charcot’s arthropathy, rheumatoid arthritis, neuromuscular disease, and amputations. Orthotic therapy has been extensively employed in the treatment of all of these conditions.

Plantar Fasciitis

Plantar fasciitis, the most common cause of plantar heel pain, is an overuse injury characterized by heel pain that is especially severe when the patient first arises from bed [1,2,3,4,5,6,7,8,9]. Management involves treating the inflammation, removing the aggravating factors, and rehabilitating the patient to allow a return to normal activities [10]. A variety of orthotic devices are used to manage this condition. Some of the most common ones are presented here.

Heel Pads, Cushions, and Insoles

Soft heel cups both cushion and contain the plantar calcaneal fat pad [5]. In patients with heel pain caused by fat-pad atrophy, hard-plastic heel cups (M-F Heel Protectors, M-F Athletic Co, Cranston, Rhode Island) position the heel pad underneath the calcaneus, which restores the natural cushioning and compressibility of the heel [11,12]. The Viscoheel SofSpot (Bauerfeind USA, Inc, Kennesaw, Georgia) is a silicone heel cushion that has a built-in area of softer durometer that is designed to disperse weight around the plantar medial tubercle of the calcaneus, the site of inflammation in plantar fasciitis. Viscoelastic heel pads have been reported to reduce the impact of heel strike on the leg and low back by as much as 50% [13,14,15,16,17]. In one study, all patients who wore viscoelastic heel inserts for treatment of plantar and posterior heel pain improved rapidly [18]. In another report, reduction or absence of heel pain was experienced in 73% of 30 patients who wore the Viscoheel SofSpot for 1 month [19].

Although the sorbothane material used in viscoelastic heel pads is widely used and considered to be an excellent shock absorber, shoe inserts made of sponge rubber were found to be more shock-absorbent than sorbothane inserts in a carefully controlled study testing the shock absorption of shoe-insert materials [20]. Patients with sports-induced Achilles tendinitis that was treated with sponge-rubber heel pads and physical therapy were also observed to have more improvement in gait than those treated with viscoelastic-polymer sorbothane heel pads and physical therapy [21]. Poron (Rogers Corp, East Woodstock, Connecticut) insoles have been found to be effective in the treatment of heel pain, although there was no significant difference in relief of heel pain when magnetic foil was added to the Poron insole [22].

Custom-Made and Prefabricated Foot Orthoses

Ligament-cutting experiments in cadavers have shown that the plantar fascia is the primary ligamentous restraint to arch collapse, [23] and sectioning the plantar fascia causes arch sag in individuals operated on for intractable plantar fasciitis [24]. The plantar fascia is in tension when the foot is loaded in weightbearing. During weightbearing, the body weight is distributed between the two feet and converted into tensile force in the plantar fascia [25]. A decrease in strain should occur with an adequate foot orthosis [26]. In a study of arch stability, foot orthoses improved stability in 14 loaded cadaveric specimens as compared with loading in cadavers in the barefoot state [27]. Kogler and associates [26] found that the University of California Biomechanics Laboratory (UCBL) orthosis, a custom-made soft full-foot orthosis casted in a semiweightbearing position, and a custommade semirigid full-foot orthosis casted in a semiweightbearing position significantly decreased the strain in the plantar aponeurosis compared with the barefoot control and were considered effective arch supports. In contrast, the Root functional foot orthosis, a prefabricated foot orthosis, and a shoe alone did not significantly decrease strain in the plantar aponeurosis as compared with the same barefoot control.

The functional foot orthosis has been recommended as a treatment modality in cases of severe plantar fasciitis [28,29]. The most common indication for prescription foot orthoses in symptomatic runners was excessive pronation and plantar fasciitis [30]. A foot orthosis should support the arch, relieve pressure in the tender area, and provide cushioning [31]. Biomechanically, the foot orthosis should maintain the subtalar joint in its neutral position and the midtarsal joint in the stable pronated position, [32] which will theoretically improve abnormal lower-extremity function [33]. Foot orthoses for the management of plantar fasciitis in athletes are evaluated in terms of their ability to reduce heel and arch pain, reduce pronation, and return athletes to normal sports activities. In the treatment of 43 painful heels using customized rigid-plastic foot orthoses, 81% had complete relief after the orthosis was worn for 3 months [34]. Similarly, in a retrospective study of 222 runners, 74% of symptomatic runners with plantar fasciitis obtained great or complete relief with orthotic shoe inserts, while 8% had slight or no improvement and 6% said the orthoses made their condition worse; the remaining 12% developed a new foot problem [30]. Patients with plantar fasciitis who were treated with a functional foot orthosis using either a Root neutral negative-impression casting technique or a Blake 25° inverted casting technique reported an 80% reduction in pain [33].

Orthotic devices have been shown to be effective in returning injured athletes to full functioning. In one study, 78% of runners who sustained running injuries were able to return to their previous running programs with the use of foot orthotic devices [35]. The orthoses used in this study resulted in a significant reduction in maximum pronation compared with a barefoot control group of six runners [35]. Similarly, 70% of injured recreational athletes were able to return to previous levels of activity after receiving semirigid functional foot orthoses [36].

A comparative study found that custom-made foot orthoses reduced heel pain from plantar fasciitis significantly better than viscoelastic heel cups or antiinflammatory therapy [37]. In another study comparing insert materials, there was no significant difference in 40 patients treated for heel spur syndrome with either Rohadur (Teltscher Corp, Mt Kisco, New York) or TL-61 (Medical Material, Westlake Village, California) functional foot orthoses [38]. Eighty-five percent of patients in this study had improvement of their conditions.

In several studies, subjects running with semirigid orthoses in their shoes demonstrated significant decreases in maximal pronation as compared with subjects running in shoes without inserts [35,39,40,41]. Rigid orthoses and orthoses inverted 25° also reduced pronation in runners [42]. Maximal pronation during walking has also been reported to decrease in subjects wearing shoes with orthoses when compared with the same subjects wearing shoes alone [39,43,44]. In contrast, Rodgers and Leveau [45] found that pronation was not significantly reduced in runners wearing a functional polypropylene foot orthosis in the shoe. There was no significant difference in reduction in rearfoot pronation in patients wearing Spenco (Spenco Medical Corp, Waco, Texas) inserts versus custom-made foot orthoses [46] or between casted foot orthoses and low-density polyethylene thermoplastic (Vitralene, Stanley Smith & Co, London, England) over-the-counter arch supports [47]. Rearfoot orthotic devices were found to reduce vertical and anteroposterior ground-reactive forces during ambulation [48]. However, the authors thought that the rearfoot orthoses theoretically should have reduced medial and anteroposterior ground-reactive forces [48].

A rearfoot varus post has frequently been added to a functional foot orthosis in order to allow normal but not excessive subtalar joint pronation during the contact phase of gait [49]. Empirically, the effect of adding a rearfoot post to the functional foot orthosis is variable. In one study, a semirigid, total-contact foot orthosis reduced forefoot vertical forces; however, adding a 6° rearfoot varus post had no effect on the results [50]. The orthosis in this study was made of Aliplast XPE (AliMed, Inc, Dedham, Massachusetts) [50]. Rearfoot posts made of methyl methacrylate (rigid) and Birko cork (Birkenstock Footprint Sandals, Inc, Novato, California) (compressible) were found to decrease initial pronation velocity in runners, which is associated with lower-extremity injuries [51]. However, there were no differences in control of pronation between the two kinds of posting materials. In another study, both forefoot and rearfoot posts or rearfoot posts alone controlled abnormal pronation better than forefoot posts used in the shoes of subjects during ambulation [52]. Finally, Tollafield and Pratt [53] found that externally posting the rearfoot more than 4° actually increased pronation as the foot rotated on the device.

University of California Biomechanics Laboratory Orthosis

The orthosis made at the University of California Biomechanics Laboratory (UCBL) was originally designed to maintain a flexible paralytic valgus foot deformity in the corrected position [54]. However, its use has been extensively expanded to treat flexible flatfoot, plantar fasciitis, and calcaneal spurs [55,56,57,58]. The UCBL orthosis is casted in the semiweightbearing position [54]. The device elevates the arch by holding the foot in a position of forefoot adduction and rearfoot inversion. In one study, patients who wore a UCBL orthosis for 3 months had 60% to 100% relief of heel pain [55]. The UCBL orthosis was found to reduce the degree and duration of abnormal pronation during the stance phase of gait in eight patients with flatfoot [59]. The UCBL orthosis with medial posts has been successfully used to treat posterior tibial tendon dysfunction [60].

Posterior Splint

Recently, the tension posterior night splint has been used in the treatment of recalcitrant cases of plantar fasciitis (Fig. 1) [61,62,63,64,65,66,67]. During sleep, the unbraced foot and ankle assume a plantarflexed position because of the normal tone in the gastrocnemius and soleus muscles. This nonfunctional, plantarflexed position results in tightness of the posterior muscle group and the plantar fascia and is thought to account for the severe pain that patients with plantar fasciitis experience with their first step in the morning as the plantar fascia resumes its functional weightbearing length [61]. Stress relaxation is the decrease in stress with time once a material under loaded condition has deformed to a constant length [68]. This is due to the viscoelastic nature of all biological tissues. Similarly, when the plantar fascia is kept in a dorsiflexed, stretched position by the night splint, the biomechanical phenomenon of stress relaxation occurs and the plantar fascia relaxes in the new stretched position. The tension night splint maintains the foot in a dorsiflexed state while the patient is sleeping, thereby preventing tightness and contracture of the Achilles tendon and plantar fascia that occur as a result of the plantarflexed posture of the foot during sleep.

Figure 1. Tension posterior night splint (Early Fit Night Splint, AliMed, Inc, Dedham, Massachusetts).

Figure 1. Tension posterior night splint (Early Fit Night Splint, AliMed, Inc, Dedham, Massachusetts).

The tension night splint is typically used in combination with other treatments for heel pain. A study by Batt et al [61] showed that the night splint in conjunction with stretching, viscoelastic heel pads, and nonsteroidal anti-inflammatory medications was more effective in the treatment of plantar fasciitis than the same treatments without the night splint. This study used an office-made plaster night splint constructed with the ankle in maximum dorsiflexion. The authors thought that their splint produced both ankle dorsiflexion and toe extension, which they considered critical to maintain tension in the plantar fascia.

Eleven of 14 patients (79%) with 1 year or more of heel pain had complete resolution of pain in less than 4 months with treatment using a polypropylene anklefoot orthosis set in 5° of dorsiflexion, stretching, Tuli heel cups (International Comfort Products Ltd, San Marcos, California), and nonsteroidal anti-inflammatory medication [67]. The 11 patients were all asymptomatic at the 9-month follow-up. Of the three patients who did not improve, excessive weight and noncompliance were considered factors in continuation of the problem.

Mizel and associates [63] treated 57 patients who had been symptomatic for at least 10 months with a combination of a molded ankle-foot orthosis and a rocker-bottom shoe. At an average follow-up time of 16 months, symptoms were completely resolved in 59% of patients and improved in 18%.

In a prospective, crossover study, Powell and colleagues [65] treated 37 patients with recalcitrant plantar fasciitis using a dorsiflexion night splint. In this study, the night splint was worn for 1 month and used alone, with no supporting treatment; thus the night splint was evaluated as a single treatment modality. This is in contrast to previous studies, which used shoe modification, [63] exercises, heel cups, and nonsteroidal antiinflammatory medication along with the splint [61,67]. The night splint in this study was a polypropylene ankle-foot orthosis with the ankle placed in 5° of dorsiflexion and wedging at the forefoot, which provided 30° of dorsiflexion at the metatarsophalangeal joints. Eighty-eight percent of patients reported improvement at the 6-month follow-up.

Short-Leg Walking Cast

Thirty-two patients with heel pain of more than 1 year’s duration were treated with a short-leg walking cast for an average of 6 weeks (range, 1 to 12 weeks) [69]. At an average follow-up time of 15 months, 25% of the patients had complete resolution of heel pain and 61% reported improvement. The authors concluded that casting should be tried prior to surgical intervention. In another study of the outcome of nonsurgical treatment for plantar fasciitis, a short-leg walking cast was the most effective of numerous conservative therapies including steroid injection, rest, ice, running shoe, crepe-soled shoe, and Tuli heel cup [70].

Posterior Tibial Tendon Dysfunction

The symptoms of posterior tibial tendon dysfunction consist of pain, tenderness, and swelling in the medial aspect of the rearfoot that are aggravated by weightbearing [71,72,73,74,75,76]. Posterior tibial tendon dysfunction is divided into four stages; orthotic treatment is described for each of these stages [72]. Orthotic treatment for posterior tibial tendon dysfunction is based on the flexibility of the foot, which becomes increasingly rigid as the stages progress (Fig. 2). In the first and second stages of posterior tibial tendon dysfunction, there is flatfoot deformity with heel valgus and forefoot abduction; however, the rearfoot remains flexible. For patients with stage I and II dysfunction, a full-length, semirigid foot orthosis in a running shoe provides arch support and corrects the flexible deformity [71,74]. The orthosis may be constructed of leather or plastic. Medial posts may be placed along the rearfoot. The UCBL orthosis with a rearfoot varus post has been recommended as a treatment modality for stage II posterior tibial tendon dysfunction [60]. The orthosis and rearfoot varus wedge correct the flexible rearfoot valgus deformity and prevent the subfibular impingement that is seen in stage II posterior tibial tendon dysfunction [60]. However, this orthosis may be uncomfortable and may not be tolerated by the patient because of the pressure of the arch against the orthosis [77].

Figure 2. In a case of traumatic posterior tibial tendon rupture, treatment after surgical reattachment of the tendon consisted of an Aircast ankle brace (Aircast, Inc, Summit, New Jersey) and reinforcing the arch.

Figure 2. In a case of traumatic posterior tibial tendon rupture, treatment after surgical reattachment of the tendon consisted of an Aircast ankle brace (Aircast, Inc, Summit, New Jersey) and reinforcing the arch.

In stages III and IV posterior tibial tendon dysfunction, there is fixed flatfoot deformity with rigid heel valgus. Pain is more pronounced laterally at the tip of the fibula than medially on weightbearing because of the rigid valgus angulation of the calcaneus [76]. A solid ankle-foot orthosis made of 3/16-inch polypropylene has been recommended for treatment of a rigid stage III deformity [74]. However, the prominence of the head of the talus may cause the foot to press against the orthosis; although the orthosis may be comfortable at first, once collapse of the arch has occurred, patients may not be able to tolerate the orthosis [78]. If there is significant swelling or rearfoot pain in stage III or IV posterior tibial tendon dysfunction, a double-upright or patellar-tendon-bearing brace might be considered. The patellar-tendon-bearing orthosis has been recommended for use in elderly patients with extreme collapse of the longitudinal arch and painful rearfoot arthrosis [74].

Posterior Heel Disorders

Achilles peritendinitis is the most common injury in runners; it is caused by repetitive irritation during running, walking, and jumping [79,80,81,82,83,84,85,86]. A firm heel lift of approximately 1/4 to 3/8 inch or higher may be used to shorten the distance between the origin and insertion of the gastrocnemius-soleus complex, which relaxes the tension in the Achilles tendon [87,88] The primary function of the foot orthosis is to reduce pressure on the Achilles tendon. For patients with Achilles tendinitis who have excessively pronated feet, the Achilles tendon exhibits less “whipping and bowstring action” with the use of orthoses because the tendon remains medial to the subtalar joint axis, which reduces the pronatory influence of the Achilles tendon [89].

Orthoses for Ankle Instability

Individuals with cavus feet are more prone to lateral ankle inversion sprains. Theoretically, rigid forefoot valgus forces the rearfoot into inversion when the patient bears weight, which stresses the lateral ankle [90]. An orthosis will ease stress on the ankle by balancing the forefoot and stabilizing the rearfoot with 0° rearfoot posts and extrinsic forefoot valgus posts [91]. Individuals with cavus feet and frequent ankle sprains may also be prescribed orthoses with full-foot valgus posts. Custom-made orthotic devices have been shown to restrict undesirable motion at the foot and ankle and enhance joint mechanoreceptors to detect perturbations and provide structural support in patients with injured ankles [92].

The shoe for a patient with ankle instability might have an outflared lateral heel—that is, the heel should be broadened laterally to provide an “outrigger” effect, making it more difficult to turn over on the ankle. Lateral buttressing and a valgus wedge may also have this effect. High-top shoes provide maximum ankle stability.

Ankle braces prevent active and passive inversion at the ankle, [93,94] improve proprioceptive capability, and have been shown to be more effective than taping (Fig. 3) [95]. Athletes also report that an Aircast brace is more comfortable than adhesive ankle taping [96]. More importantly, ankle braces have not been shown to inhibit athletic performance [96,97]

Ankle braces are effective in the treatment of lateral ankle instability and ankle fractures. Traditionally, the treatment for nondisplaced lateral ankle fractures was a below-the-knee walking cast that was worn for 5 to 6 weeks after the trauma [98]. In one study, 66 adult patients with supination external-rotation ankle fractures were successfully treated with either an Aircast ankle brace or a DonJoy R.O.M.-Walker brace (DonJoy Co, Vista, California) for 5 weeks, with an average time until return to work of 6 weeks [98]. At 4 weeks, 70% to 80% of patients were able to walk without pain. In a study of 20 patients with acute inversion ankle sprains, 10 patients were treated with an orthopedic ankle brace after a 10-day plaster cast immobilization and a control group of 10 patients was treated with a weightbearing short-leg plaster cast for 25 days. An earlier and more functional recovery occurred in the ankle-brace group [99]. Similarly, patients treated with an Aircast ankle brace were more mobile and used less sick-leave time than patients who were treated with a compression bandage [100].

Figure 3. Laced canvas ankle brace (Swede-O Ankle Lok, Swede-O, North Branch, Minnesota).

Figure 3. Laced canvas ankle brace (Swede-O Ankle Lok, Swede-O, North Branch, Minnesota).

Ankle-Foot Orthoses for Rearfoot Equinus

Ankle-foot orthoses are widely used for the treatment of different types of motor disorders [101,102,103,104,105,106,107]. Plastic ankle-foot orthoses have now largely replaced the metal ones, with the most common materials being polypropylene and laminated plastics [108,109,110]. However, patients requiring bracing who are also insensate should be fitted for an ankle-foot orthosis with a metal shoe attachment so that the brace is not in direct contact with sensitive skin (Fig. 4) [110]. The posterior leaf spring ankle-foot orthosis is indicated for patients with peripheral nerve injuries resulting in flaccid footdrop, where all that is needed is toe clearance during the swing phase of gait. This orthosis is fabricated by cutting the ankle trim lines behind the malleoli, resulting in a flexible brace that provides minimal mediolateral stability and may control mild spasticity (Fig. 5A). The posterior leaf spring orthosis was found to improve ankle function in the gait of 31 children with cerebral palsy; it reduced excessive equinus during the swing phase, but did not improve ankle function for push-off during the stance phase [106]. The rigid, solid ankle-foot orthosis restricts all motion at the ankle and is useful for treatment of traumatic arthritis of the ankle or other conditions in which complete immobilization of the ankle is required (Fig. 5B). It is also indicated for control of severe spasticity and is therefore useful in the treatment of stroke patients. The solid ankle-foot orthosis has the ankle trim lines cut anterior to the malleoli, which results in a rigid orthosis. Most patients have a semirigid ankle-foot orthosis with the trim lines intermediate between those of the solid and the posterior leaf spring orthoses, thereby providing enough control for significant spasticity and support for weak muscles, yet maintaining a degree of flexibility.

Figure 4. Double-upright ankle-foot orthosis.

Figure 4. Double-upright ankle-foot orthosis.

Figure 5. A, Posterior leaf spring ankle-foot orthosis. Note that the trim line at the ankle joint is behind the malleoli. B, Solid ankle-foot orthosis with trim lines cut anterior to the malleoli.

Figure 5. A, Posterior leaf spring ankle-foot orthosis. Note that the trim line at the ankle joint is behind the malleoli. B, Solid ankle-foot orthosis with trim lines cut anterior to the malleoli.

The articulated ankle-foot orthosis is a plastic brace with joints at the ankle (Fig. 6). Hinged orthoses with a dorsiflexion stop to prevent plantarflexion beyond a right angle of the foot to the leg are frequently employed for tone reduction to reduce spasticity in children with spastic ankle equinus [111,112]. Ankle-foot orthoses have been shown to increase velocity, stride length, and single-support percentage as compared with walking barefoot in children with spastic equinus and crouch gait [113]. However, the results of studies comparing the various ankle-foot orthoses for spastic equinus conditions in children and adults are conflicting. In a case study comparing solid and hinged ankle-foot orthoses in a child with cerebral palsy, the solid ankle-foot orthosis was found to block the needed foot and ankle mobility [114]. Articulated orthoses decreased the sit-to-stand time in preambulatory children with cerebral palsy [115]. In a study of 14 children with spastic hemiplegia, both a hinged ankle-foot orthosis with plantarflexion stop and a solid anklefoot orthosis improved cadence, velocity, and step length; however, the hinged orthosis produced a more dynamic and physiologic gait pattern [116]. Similarly, in another study, both orthoses with a plantarflexion stop and solid ankle-foot orthoses increased stride length and temporal-distance characteristics equally in children with spastic cerebral palsy [117].

Figure 6. Articulated ankle-foot orthosis (center). Note the ankle joint built into the plastic orthosis. The orthosis on the left is a solid ankle-foot orthosis. Note the high medial flanges built into the foot plate and the additional two straps on the ankle and distal foot, all of which are tone-reducing features. The orthosis on the right is a total-contact ankle-foot orthosis with a tone-reducing anterior shell.

Figure 6. Articulated ankle-foot orthosis (center). Note the ankle joint built into the plastic orthosis. The orthosis on the left is a solid ankle-foot orthosis. Note the high medial flanges built into the foot plate and the additional two straps on the ankle and distal foot, all of which are tone-reducing features. The orthosis on the right is a total-contact ankle-foot orthosis with a tone-reducing anterior shell.

A dorsiflexion-assist modification may be added to an ankle-foot orthosis to spring the foot into dorsiflexion automatically when the foot enters the swing phase of gait. However, in a study of five hemiplegic adults using dorsiflexion-assist orthoses versus orthoses without spring loading, no significant differences in 10-m walking time were found [118]. The cylinder of the assist device was heavy and noisy, and patients did not like it; they preferred their old orthoses. The authors concluded that the dorsiflexionassist ankle-foot orthosis was not superior to the orthosis with no assist device [118]. In a study of children with spastic equinus, the supramalleolar orthosis appeared to offer no improvement in gait over the solid ankle-foot orthosis [119]. In conclusion, although new developments in orthoses are often helpful, the new orthosis is not automatically more effective than the original orthosis simply because it is new [58,120]

Orthotic Devices for Treatment of Arthritis of the Subtalar Joint

It is estimated that the ankle and subtalar joint are involved in 10% to 56% of patients with rheumatoid arthritis [121,122,123]. Shoes are the most important conservative treatment for patients with rheumatoid arthritis [124,125]. The shoes should be lightweight and have extra depth, with a high toe box to accommodate the contracted digits. Metatarsal bars shift weightbearing away from tender or high-pressure areas. The insert and sole of the shoe may be excavated about bony prominences such as the deviated talar head, which occurs in the valgus foot. Shoe modifications that provide stability to the rearfoot include a strong counter, a longitudinal arch support, and a 1/4-inch medial heel and sole wedge [126]. Spenco may be used as an insert to decrease shear, and Plastazote (Apex Foot Products, South Hackensack, New Jersey) may be used to disperse weightbearing by providing more total contact. The purpose of the orthosis for the patient with severe arthritis is generally accommodative and supportive, and to provide cushioning. Heel cups and the UCBL orthosis have been recommended for patients with rheumatoid arthritis who have heel pain, [127] although the fragile skin of the foot in such patients may not tolerate a UCBL orthosis [128].

Studies have shown that prefabricated foot orthoses and off-the-shelf orthopedic shoes are as effective for individuals with rheumatoid arthritis as more expensive orthoses and shoes. In a well-controlled study conducted over a 3-year period, functional posted foot orthoses provided no significant benefit over placebo orthoses in limiting disability and pain [129]. Groups wearing both types of orthoses reported improvement. In this study, the functional orthosis consisted of a custom-made Rohadur material that had posts at the rearfoot and forefoot. The placebo orthosis was a thin polyvinylchloride shoe insert without posts. It should be noted that Rohadur has never been the material of choice for use in shoes of patients with rheumatoid arthritis, and a more accommodating, shock-absorbing, custom-made semirigid foot orthosis might have been more effective than placebo orthoses. In another study, patients with rheumatoid arthritis who wore off-the-shelf orthopedic footwear for a 2-month period had significantly less pain and better function than patients in a control group who did not receive any special shoe [130].

When arthritis affects the ankle, a solid ankle-foot orthosis made of either plastic or metal may be indicated. A solid orthosis may also be indicated for treatment of a totally collapsed arch with a painful bursa under the talar head or for severe instability of the subtalar and/or ankle joint (Figs. 4 and 5B) [131]

Orthotic Devices for Treatment of the Diabetic Rearfoot

Orthotic devices for treatment of the diabetic foot reduce pressure and redistribute it more evenly throughout the foot. Orthoses for the diabetic foot include insoles and foot orthoses, prefabricated walking braces, total-contact casts, ankle-foot orthoses, and prostheses for the amputated foot. Foot orthoses for patients with diabetes are most commonly soft and accommodative and have good cushioning. The orthosis and the shoe must work together to disperse callosities and protect the foot from hard walking surfaces.

Total-contact casting is the treatment currently recommended for Wagner stage 1 and 2 neuropathic plantar ulcers. This casting provides equalization of plantar foot pressures and generalized off-loading of the foot [132]. However, no significant differences were found in plantar pressure measurements between conventional short-leg casts and total-contact casts in healthy volunteers, [133] or in patients with Charcot’s midfoot collapse and rocker-bottom deformity [134]. The prefabricated below-the-knee walking brace can sometimes be substituted for cast treatment for neuropathic ulcers and immobilization of Charcot’s foot in diabetic patients (Fig. 7) [135]. No significant differences in peak pressure were found in ten healthy male subjects wearing a prefabricated walking brace and a total-contact cast [132]. The authors concluded that the prefabricated walking brace was a convenient and useful treatment for neuropathic plantar ulcerations of the foot.

Figure 7. Prefabricated walking brace (Equalizer, Royce Medical Co, Camarillo, California) for patient with Charcot foot deformity.

Figure 7. Prefabricated walking brace (Equalizer, Royce Medical Co, Camarillo, California) for patient with Charcot foot deformity.

The prefabricated walking brace (Fig. 7) and the ankle-foot orthosis (Figs. 4 and 5 A and B) are commonly used in the treatment of patients with diabetic foot problems. The ankle-foot orthosis has been recommended for closing ulcers in the diabetic foot and preventing their recurrence [136]. The walking brace provides the necessary stability while allowing easy donning and doffing for physical therapy sessions and during washing and sleeping. A rocker-bottom sole or ankle joints may be added to facilitate ambulation. The total-contact, bivalved, rocker-bottomsole ankle-foot orthosis was shown to be effective in controlling complications in 14 individuals with Charcot’s foot [137]. Recently, the Charcot Restraint Orthotic Walker orthosis (Orthotic Service, Brea, California) has been found useful in treating patients with neuroarthropathy. The Charcot Restraint Orthotic Walker is a rigid, custom-made, full-foot-enclosure ankle-foot orthosis (Fig. 8) [138]. It provides immobilization and protection during the prolonged healing of diabetic neuroarthropathy. In a study of the effects of the Charcot Restraint Orthotic Walker orthosis, 18 patients rated it good to excellent and none reported significant activity restrictions while wearing the orthosis; all patients believed that their quality of life was markedly improved by use of the orthosis [138]. In a more recent report, all patients wearing the Charcot Restraint Orthotic Walker orthosis noted varying measures of improvement in symptoms and function at an average 12-month follow-up [139].

Figure 8. Charcot Restraint Orthotic Walker orthosis for treatment of patients with a severely deformed foot.

Figure 8. Charcot Restraint Orthotic Walker orthosis for treatment of patients with a severely deformed foot.

The patellar-tendon-bearing orthosis is one of the original orthoses for off-loading the rearfoot and leg [140]. It has a pretibial component in which the patient rests the upper leg and knee during ambulation (Fig. 9). Patients are trained to walk by sinking their weight into the pretibial shell, and the weight is transferred down the uprights to the floor, bypassing the leg and rearfoot. When patients are trained to walk properly with the patellar-tendon-bearing orthosis, it has been found to reduce weightbearing on the leg and rearfoot up to 60% [141]. The patellar-tendon-bearing orthosis is indicated for patients with fractures of the leg and rearfoot, and to remove weight in a painful diabetic Charcot rearfoot. The orthosis is available in metal and plastic varieties, and it must have a solid ankle to work properly [142,143].

Figure 9. Patellar-tendon-bearing orthosis for treatment of Charcot’s foot with dislocated ankle joint.

Figure 9. Patellar-tendon-bearing orthosis for treatment of Charcot’s foot with dislocated ankle joint.

Prostheses for the Rearfoot Stump

The goals for biomechanical management of partial foot amputations are to restore stability, maintain support, and protect function in the residual foot [144].

The shoe, stocking, and orthosis work together as a unit in protecting a patient with a partially amputated foot [145,146]. For example, silicone-insole socks have been shown to be more effective in reducing horizontal shear than cotton socks (Fig. 10) [145]. Amputations involving one or more digits or a lateral ray usually can be managed with just a good shoe and insert. When the amputation is through the metatarsal heads, it is managed with a foot orthosis with a filler. However, when the amputation is more proximal to the metatarsal heads, an above-the-ankle partial foot prosthesis is required [147,148]. This can be in the form of an ankle-foot orthosis with forefoot filler (Fig. 11). If the amputation is through the midtarsal joint with only the rearfoot remaining, equinus contractures are likely to occur, and a Chopart’s amputation prosthesis may be necessary (Fig. 12) [149] Ground-reactive forces have been shown to be reduced in patients with Chopart’s amputations who walk with a Chopart’s amputation prosthesis [150] Syme’s amputation involves removal of the entire foot and requires utilization of a Syme’s amputation prosthesis (Fig. 13 A and B) [151].

Figure 10. An elastic cotton stocking with silicone stump liner (ComfortZone Partial Foot Sock, Silipos Co, Buffalo, New York) is used for patients with midfoot amputation to protect the distal stump.

Figure 10. An elastic cotton stocking with silicone stump liner (ComfortZone Partial Foot Sock, Silipos Co, Buffalo, New York) is used for patients with midfoot amputation to protect the distal stump.

Figure 11. Proximal, transmetatarsal amputation requires treatment with an ankle-foot orthosis with forefoot filler.

Figure 11. Proximal, transmetatarsal amputation requires treatment with an ankle-foot orthosis with forefoot filler.

Figure 12. A clamshell Chopart’s prosthesis is used for patients with Chopart’s amputation with equinus contractures.

Figure 12. A clamshell Chopart’s prosthesis is used for patients with Chopart’s amputation with equinus contractures.

Figure 13. A, Syme’s amputation prosthesis. Note the medial window that opens. Syme’s amputation traditionally left patients with a large, bulbous stump, and the medial window was necessary for patients to insert the foot into the narrow waist of the orthosis. B, Same patient shown in A wearing the Syme’s amputation prosthesis.

Figure 13. A, Syme’s amputation prosthesis. Note the medial window that opens. Syme’s amputation traditionally left patients with a large, bulbous stump, and the medial window was necessary for patients to insert the foot into the narrow waist of the orthosis. B, Same patient shown in A wearing the Syme’s amputation prosthesis.

Summary

Foot orthoses have been shown to relieve pain, reduce rearfoot pronation, and improve function in patients with orthopedic conditions involving the rearfoot. However, several studies have found that prefabricated foot orthoses are often as effective as custommade foot orthoses in the treatment of plantar fasciitis and rheumatoid arthritis. Orthoses for the diabetic foot serve to accommodate and off-load high-pressure areas. The prefabricated walking brace has been shown to be as effective in equalizing plantar pressures as the total-contact cast in the diabetic foot. In cases of neuromuscular disease, the dorsiflexion-assist ankle-foot orthosis and the supramalleolar orthosis offered no advantage over the solid ankle-foot orthosis. In contrast, a hinged ankle-foot orthosis was more effective than a solid ankle-foot orthosis in improving gait in children with cerebral palsy.