- Email: [email protected]
Orthotics and insoles for the forefoot: The European way
Foot Ankle Clin N Am 8 (2003) 671 – 682
Orthotics and insoles for the forefoot: The European way Gerd M. Ivanic, MD Hospital for Orthopaedic Surgery Stolzalpe, 8852 Stolzalpe, Austria
Foot problems have been known since early mankind. Because of man’s upright gait, the feet have constant contact with the environment. Hippocratics wrote about orthopedic technical devices for the foot in 400 BC. At the end of the seventeenth century, reports of technical devices for foot problems were found again in Europe. During the reign of Napoleon, the business of technical foot devices was booming. A specialist of these days was J. G. Heine who founded the orthopedic sanatorium in Wu¨rzburg, Germany. In 1835, the oldest continuously operating orthopedic hospital in the world, the so-called ‘‘Paulinenhilfe’’ was built. In 1860, there were reports of the treatment of foot deformities. In the following years, it was important for the hospitals to have orthopedic workshops and the patients also wanted these orthopedic workshops. It was prestigious for a hospital to have its own orthopedic technician. At the beginning of the twentieth century, people like Florian Beely, Royal Whitman, Fritz Lange, H.-A. Berkemann, and Hermann Gocht were responsible for the development of shoe insoles. During the twentieth century, people like Hans Spitzy, Carl Mau, and Georg Hohmann put a lot of work into the development of orthotics. After World War II, Wolfgang Marquardt gained a reputation in this field [1]. During the last two centuries, much work has been done to improve shoe insoles. There is an increasing demand for fashionable and stylish footwear for all age groups. The well-known orthopedic adapted shoe or the custom made orthopedic shoe, in its traditional form, is no longer accepted. Manufacturing of footwear has changed considerably. Special insoles and modular foot systems have changed the products, as well. It is the goal that special custom-made insoles should be used and fitted into manufactured ready-made shoes. Further improvement should be achieved through physical body functions over proprioception. Through the proprioception of the foot (Plantar) an influence in the gait and body movement is given. Thus orthotics can influence gait and movement disorders. Because of
E-mail address: [email protected] 1083-7515/03/$ – see front matter D 2003 Elsevier Inc. All rights reserved. doi:10.1016/S1083-7515(03)00149-9
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G.M. Ivanic / Foot Ankle Clin N Am 8 (2003) 671–682
the ongoing specialization in orthopedic foot surgery, the requirement of alternatives to an operation, as well as postoperative management, become necessary. Because of today’s long life expectancy, it is possible that some pathologies become problematic. Peripheral vascular disease or the increasing incidence of diabetes mellitus with the associated diabetic foot syndrome require further treatment strategies to avoid lower limb amputation.
Functions of insole The basic functions of insoles are to provide support, bedding (padding), and correction. Especially in the domain of correction, a change from passive to active correction can be noted as a result of the increasing importance of proprioception.
Examination It is well known that the examination of the foot includes looking for corns and callosities that are representative of points of high pressure. Also, the patient’s most often used shoes need to be examined. A lot of information about the gait and the load to the feet can be taken from the condition of these shoes. Often, the wear of the shoe gives a useful suggestion about the necessary treatment or orthotic device. The inspection of technical devices during therapy are mandatory [2]. It is important to look at whether the device still fits properly and if the desired function is being achieved. With this information, any modification of the device, as well as new devices, can be accomplished. The condition of the device also gives information about its use. Overloaded areas and pressure points can also be recognized (Fig. 1).
Fig. 1. Sweat spurs show pressure peaks under the second and third metatarsal head in severe metatarsalgia.
G.M. Ivanic / Foot Ankle Clin N Am 8 (2003) 671–682
673
A few guidelines: Every device must be worn without pain. Pressure points are strictly forbidden. The shoe and the technical device must fit. An orthotic must not compensate for bad or unsuitable footwear. Exact placement of orthotics within the shoe are a basic requirement. The insole must not slip in the shoe and needs a proper fit to the inner sole. The insert should be thin at the heel to prevent slipping of the heel. Slipping of the orthotic within the shoe can be prevented with a rough base or Velcro. The gait should be examined with and without the device. Examine the foot. Look for corns and callosities and compare with the device and sweat spurs (signs of pressure peaks on a device which are produced by sweat and the pressure) on it. Modification of the device, if necessary. The device must not be hollow under the metatarsal bones. The orthotic and the foot need a proper fit. The material used for the orthotic should fit the indication. Generally, the material should not be too stiff. The insoles need to be the optimal length according to the indication (eg, forefoot problems need long insoles from the heel to the toes).
Fitting and examination of orthotics The knees should be flexed and the feet should be positioned neutrally. The orthotic should be tested on the foot without weight bearing and while it is bare. Then it should be tested in dorsiflexion and plantarflexion. These observations should be repeated while the patient is weight bearing. It is important to know that the foot is bigger under load.
Foot measurement There are various techniques of foot measurement [3] for the manufacturing of individual custom made insoles: Plantar pressure measure with tracing-paper; this is a static procedure. It is also possible to measure the plantar pressure by computerization in the sense of pedobarography. The technique allows the dynamic examination of the plantar foot pressure by the use of special pressure trays. A variety of systems are available. The sponge footprint: three-dimensional molds of the weight-bearing foot can be obtained. The foot negative with plaster cast: this technique has the advantage that a negative mold of the foot can be obtained with the foot in a corrective posi-
674
G.M. Ivanic / Foot Ankle Clin N Am 8 (2003) 671–682
tion. It is possible to get a positive mold of the foot in its corrective position. Using this technique, one has to consider that real weight bearing of the foot, together with correction of the foot deformity, is only possible to a certain degree. This must be considered during the manufacturing of the insoles. There have been recent reports of new computerized scanning systems that are still in development. Although early studies show promising results, they are not yet sophisticated enough for general application.
The making of insoles There are some basic principles of insole manufacturing in which the use of padding must be mentioned. With padding, pressure release of certain areas of the foot can be achieved. If necessary, padding can increase the load to certain areas of the foot. In general, it is important to avoid pressure peaks while using these devices. Materials and the mixture of different materials are important to achieve the indicated function of the orthotics. Newer methods for making orthotics use plate materials. Thermo moldable plates are heated and put over a corrected foot model of plaster of Paris. The advantage is the ability to produce a single-piece insole in which the needed corrections are built. The disadvantage is the ready defined orthotic (after the molding process the orthotic’s form cannot be changed). Additional corrections are not possible or the single-piece advantage is lost. The other possibility is to use this insole as a base on which the different pads can be put. Pads Pads are a big help in the design of shoes and orthotics for achieving the desired function. To obtain these functions, the shape and the position of the pads have to fit the indication of the device [4,5]. Thus, it is important to control the position of the pads. If they are too close to the area that should be supported, pain can result; also, the desired function is not obtained. The same is valid for pads if they are too far away from the area that should be supported. A good example of incorrect procedure is the so-called ‘‘medical footwear.’’ Serial insoles respectively so called ‘‘healthy foot bedding’’ have standard pads for the retrocapital support of the metatarsal heads. Normally, these pads are situated too far proximally because direct contact of the metatarsal heads with the pads may cause pain, but usually this does not cause further problems. The support of the longitudinal arch of the foot should reach its highest point underneath the sustentaculum of the talus. This support should drop off proportionately to get a correct position of the hindfoot. Depending on the pathology, different adjustments are possible. In the normal, ready-to-wear shoe, the balance of the longitudinal arch is put too far distally, because otherwise, pain in the hindfoot may occur while wearing these shoes. To avoid this problem, this support is put more distally. This may cause forefoot supination, which then can cause other
G.M. Ivanic / Foot Ankle Clin N Am 8 (2003) 671–682
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Fig. 2. Heart-shaped and kidney-shaped pads.
problems. These problems should be avoided in ready-to-wear shoes with adequate support, as well as in serial manufactured insoles. It is essential, therefore, to clinically follow up the patients and check the insoles after delivery. The main indication for such paddings is the retrocapital support of the metatarsal heads in the event of metatarsalgia to relieve the pain caused by pressure. The ideal padding must be customized for each patient; no padding suits every patient and meets all requirements. In the case of retrocapital support of the metatarsal heads, the padding must be adapted to the individual form of the foot. The length of the metatarsal bones has to be considered. Therefore, two main padding forms may be used, heart-shaped pads or kidney-shaped pads (Fig. 2). These pads have to be adapted to the individual shape of the foot. In special cases, it might be sensible to make a metatarsal crest that is oriented to the length of each of the metatarsal bones (Fig. 3). The radius of the pads has to fit the supported foot. Pads that are too sharp, too hard, or too high pads can cause troubles. The height of the pads depends on the shoe. ‘‘Sport insoles’’ should have only a fraction of the correction of pads that are used in walking shoes. Diseases such as diabetes also have to be considered. Material Another important point in the field of insole manufacturing is the choice of the proper material. Depending on the material, the function of the insoles can be improved considerably. There is the risk that a well-manufactured insole can be compromised by material that is of bad quality. Hard synthetic materials, such as plastics and Plexidur should be avoided. Hard plastic material causes pressure sores. The microclimate around the foot should have good circulation. Depending
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G.M. Ivanic / Foot Ankle Clin N Am 8 (2003) 671–682
Fig. 3. Metatarsal crest.
on pathology, various materials like ‘‘cork’’, ‘‘leather’’, ‘‘plastizote’’ up to most of the modern synthetic plastic material can be used. All of these materials, alone or in combination, make it possible to produce an individual insole that has positive effects.
Prescription and follow-up Examination of the feet should always include the observation of the patient’s gait pattern, with and without his/her foot wear, as well as the condition of the shoes themselves.
Rocker soles Shoe modifications are not the subject of this article but should be mentioned; a rocker sole is often needed in combination with orthotics. A rocker sole should be combined with a stiffening of the sole to achieve optimal results.
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Forefoot (toe-only rocker sole) The apex is proximal to the metatarsophalangeal (MTP) joints, perpendicular to the gait direction (Fig. 4). This increases the step length, makes the roll-off more difficult, and causes hyperextension in the knee. Midfoot The apex is under the midfoot (Fig. 5). This relieves the Chopart and Lisfranc joint and causes slight extension of the knee joint. Entire foot (heel-to-toe rocker sole) The apex of the rocker sole should be made according to the radius of the circle between the knee and the sole. This results in total relief of the ankle joint with no effect to the knee joint.
Indications and pathologies in the forefoot for the use of orthotics Splayfoot Symptoms: broadened forefoot in the MTP joint area with pain and shoe conflict, hallux valgus, hammer toes, claw toes, metatarsalgia, corns and callosities plantar to the heads of the second through fourth metatarsal bones, lateral to the fifth metatarsal, troubles with ready-made footwear Therapy: pain relief through pressure decrease with retrocapital support of the metatarsal heads, could be combined with semi-rolls under the Proximal InterPhalangeal Distal InterPhalangeal (PIP-DIP) joints in claw and hammer toes Pressure relief of the so-called ‘‘transverse arch’’ (wrong description but still widely used [6]) Retrocapital support Decrease of pressure in the roll-off phase
Fig. 4. Rocker sole under the forefoot.
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G.M. Ivanic / Foot Ankle Clin N Am 8 (2003) 671–682
Fig. 5. Rocker sole under the midfoot.
Orthotics: butterfly insoles according to Wolfgang Marquardt [1] in the acute phase (Fig. 6; retrocapital support with pads. CarboPlus (Rathgeber-Bioform, OFA-Bamberg, Bamberg, Germany)(Fig. 7) (see Metatarsalgia) Bandages: splayfoot bandages with metatarsal pads (changeable pads, with different heights, soft or hard, are recommended).
Fig. 6. Butterfly orthotic with a pressure release under the second through fourth metatarsal heads.
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Fig. 7. CarboPlus orthotics with a built-in elastic roll-off support.
Orthopedic shoes: rocker soles, butterfly-style insoles for a better pressure decrease under the second through fourth metatarsal heads in combination with orthotics. It is important that the pads are in the correct position. What are the indications for pads? According to the pain, treatment in different stages is necessary. The initial treatment could be done with butterfly insoles (see Fig. 6) for pain relief (with a high pressure relief under the second through fourth metatarsal heads). When the ache subsides, a provocation test with splayfoot bandages with soft pads is recommended. If this goes well then orthotics are possible. The transverse arch of the insoles should be built step by step. Hallux valgus Symptoms: pain medial to the first MTP joint (at the bunion). Problems with the shoes (pressure and rubbing). Weakness in the toe-off phase during roll-off. Therapy: traction and stretching of the hallux joint to improve the range of motion. Shoes: the shoe conflict has to be resolved. Often the shoes are too small and too tight. Orthopedic shoes: deepening (to build a whole groove under the MTP joint) under the first MTP joint, good heel hold. The vamp and the toe box has to be broad enough. The foot needs a perfect hold at the Chopart level. Slipping of the foot inside the shoe is strictly forbidden. Technical aids: avoidance of pressure to the joint and the bunion. Orthoses and bandages to adduct the hallux. Schede developed a splint in 1923 [1]. The same style is used in the so-called ‘‘hallux valgus night bandages’’. Special taping techniques and newer products, like a hallux valgus belt. All of these products can be useful in postoperative care, mainly to prevent relapses; the hallux valgus cannot be treated by them.
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G.M. Ivanic / Foot Ankle Clin N Am 8 (2003) 671–682
Fig. 8. Hallux valgus compression stocking.
Postoperative care: according to recent studies, the recommended shoe type is a forefoot pressure relief shoe (wedged sole) [7]. Wooden-soled shoes should not be used because they cause more pressure to the forefoot than ready-made shoes or sneakers. Compression stockings, in a Japanese style, that are especially made for the postsurgical phase of hallux are useful, fashionable, and enjoyed by the patients (Fig. 8) (Gilofa 2000, Ofa Bamberg, Bamberg, Germany). Hallux rigidus Symptoms: arthrosis of the first MTP joint. It begins with painful dorsal extension in that joint. Radiographs show the typical changes of an arthrotic joint with a dorsal exostoses. Painful toe-off and the exostoses are the most common reasons why patients seek medical care. Therapy: depends on the stage of the rigidus. Treatment for early stage hallux rigidus should include: (1) thermotherapy with ice, or most often with warm compresses supported with ointments for a better circulation and a reduction in pain
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and (2) tractions and functional movement, especially dorsiflexion (rotation gliding, side bending) and infiltration with local anesthetics, rarely combined with steroids. Treatment for acute, later stage hallux rigidus includes shoes that relieve forefoot pressure (eg, wooden-soled shoes with a roll-off support like Dutch shoes). Shoes: forefoot stiffening, roll-off support, deepening (to build a whole groove under the MTP joint) of the shoe under the first MTP. Orthotics: rigidus spring (insole with a steel shank under the first MTP— obsolete and no longer recommended). CarboPlus (see Fig. 7) is comfortable and can be used in sneakers and ready-made shoes. Metatarsalgia Symptoms: pain in the forefoot. The main problems appear in the area of the metatarsal heads and the MTP joints. The most common causes are splayfoot, transfer metatarsalgia, hallux valgus, and hallux rigidus, as well as vasopathic, angiopathic, and rheumatic feet. Therapy: the therapy should be determined by the cause of the problem. In many cases, surgery is unavoidable. Conservative therapy algorithms should look for pressure relief in the painful forefoot area. Shoes: stiffening of the sole in the forefoot area (ie, steel shanks) and roll-off supports that are added to the sole. Orthotics: retrocapital pads to support the so-called ‘‘transverse arch’’ to take pressure of the metatarsal heads. ‘‘Butterfly orthotics’’ for the acute phase (see Fig. 6), CarboPlus for a painfree roll-off and relief of contractures (see Fig. 7). CarboPlus is a newly developed orthotic design that has elastic stiffening and a roll-off support built in [8– 10]. The orthotic is composed of three layers: (1) a cork layer from the heel to the midfoot, (2) a drop-shaped carbonfiber layer that is connected to the plantar side of the cork at midfoot level, and (3) a top surface of plastizote. The narrower part of the carbon layer lies under the midfoot and the broadest part lies under the MTP joints. Thus, pressure on the midfoot is relieved and is spread onto the whole forefoot. The carbonfiber is also molded like a wave, which gives the function of a rocker bottom and additionally relieves high pressure to the mid- and forefoot. The plastizote also helps to decrease peak pressures. Therapy algorithm in metatarsalgia A forefoot pressure relief shoe (eg, Darco Ortho Wedge, Darco Int., Inc., Huntington, West Virginia) is recommended until pain subsides. CarboPlus orthotics (see Fig. 7) should be used afterward to achieve a physiologic gait. Before orthotics and when the major pain comes from the second to the fourth metatarsal heads, butterfly orthotics (see Fig. 6) are a reasonable choice of therapy. These orthotics are not recommended for permanent use because the total decompression of the intermediate heads can lead to further problems. When the pain subsides and when the corns become smaller, CarboPlus orthotics can be tried or, before it, splayfoot bandages with soft and low pads for a retrocapital support. When the bandages are tolerated for a longer period of time, orthotics can be prescribed.
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Summary Technical aids in the treatment of foot problems have been known for hundreds of years. In the German-speaking countries, especially, shoemakers, prosthetists, and orthotists are well respected. They have great skills and provide the orthopedic surgeon with alternatives to surgery. Also, the combination of surgery and technical aids is important because suboptimal surgical results can be improved by a good orthopedic device.
References [1] Marquardt W. Die theoretischen Grundlagen der Orthopaedie Schuhmacherei [Theoretical basics for the making of orthopaedic shoes.] Geislingen, Germany: Maurersche Buchdruckera; 1951. [2] Grifka J. Einlagen - indikation, verordnung, ausfu¨hrung [Orthotics; indication, prescription, production.] Bu¨cherei des orthopa¨den Band 55. Stuttgart (Germany): Enke Verlag; 1993 [in German]. [3] Hughes J, Kriss S, Kienerman L. A Clinician’s view of foot pressure: a comparison of three different methods of measurement. Foot Ankle 1987;7:277 – 84. [4] Hayda R, Tremaine MD, Tremaine K, Banco S, Teed K. Effect of metatarsal pads and their positioning: a quantitative assessment. Foot Ankle 1994;15:561 – 6. [5] Holmes GB, Timmermann L. A quantitative assessment of the effect of metatarsal pads on plantar pressures. Foot Ankle 1990;11:141 – 5. [6] Jacob HAC. Zur belastung des fußes beim gehen und stehen - hat die ‘‘dreipunkttheorie’’ noch bestand? Med Orth Tech 2000;120:100 – 5 [in German]. [7] Trnka H-J, Parks BG, Ivanic GM, Chu IT, Easley ME, Schon LC, et al. Six first metatarsal shaft osteotomies: mechanical and immobilization comparisons. Clin Orthop 2000;381:256 – 65. [8] Ivanic GM, Trnka H-J, Homann NC. Metatarsalgie - eine neue klassifikation und korrelierende orthopa¨dietechnische therapiemo¨glichkeiten [Metatarsalgia - a new classification with a correlating theraphy algorithm with technical devices.] Orthop Praxis 2000;36(8):497 – 502 [in German]. [9] Ivanic GM, Trnka H-J, Homann NC. Die posttraumatische metatarsalgie - erste behandlungserfahrungen mit einer neuen einlage. Unfallchirurg 2000;103:507 – 10 [in German]. [10] Ivanic GM, Homann NC, Trnka H-J. Das diabetische fußsyndrom - therapie und prophylaxe mit carbonfaser-kork-einlagen. Med Orth Tech 2002;122:101 – 4.
Orthotics and insoles for the forefoot: The European way Gerd M. Ivanic, MD Hospital for Orthopaedic Surgery Stolzalpe, 8852 Stolzalpe, Austria
Foot problems have been known since early mankind. Because of man’s upright gait, the feet have constant contact with the environment. Hippocratics wrote about orthopedic technical devices for the foot in 400 BC. At the end of the seventeenth century, reports of technical devices for foot problems were found again in Europe. During the reign of Napoleon, the business of technical foot devices was booming. A specialist of these days was J. G. Heine who founded the orthopedic sanatorium in Wu¨rzburg, Germany. In 1835, the oldest continuously operating orthopedic hospital in the world, the so-called ‘‘Paulinenhilfe’’ was built. In 1860, there were reports of the treatment of foot deformities. In the following years, it was important for the hospitals to have orthopedic workshops and the patients also wanted these orthopedic workshops. It was prestigious for a hospital to have its own orthopedic technician. At the beginning of the twentieth century, people like Florian Beely, Royal Whitman, Fritz Lange, H.-A. Berkemann, and Hermann Gocht were responsible for the development of shoe insoles. During the twentieth century, people like Hans Spitzy, Carl Mau, and Georg Hohmann put a lot of work into the development of orthotics. After World War II, Wolfgang Marquardt gained a reputation in this field [1]. During the last two centuries, much work has been done to improve shoe insoles. There is an increasing demand for fashionable and stylish footwear for all age groups. The well-known orthopedic adapted shoe or the custom made orthopedic shoe, in its traditional form, is no longer accepted. Manufacturing of footwear has changed considerably. Special insoles and modular foot systems have changed the products, as well. It is the goal that special custom-made insoles should be used and fitted into manufactured ready-made shoes. Further improvement should be achieved through physical body functions over proprioception. Through the proprioception of the foot (Plantar) an influence in the gait and body movement is given. Thus orthotics can influence gait and movement disorders. Because of
E-mail address: [email protected] 1083-7515/03/$ – see front matter D 2003 Elsevier Inc. All rights reserved. doi:10.1016/S1083-7515(03)00149-9
672
G.M. Ivanic / Foot Ankle Clin N Am 8 (2003) 671–682
the ongoing specialization in orthopedic foot surgery, the requirement of alternatives to an operation, as well as postoperative management, become necessary. Because of today’s long life expectancy, it is possible that some pathologies become problematic. Peripheral vascular disease or the increasing incidence of diabetes mellitus with the associated diabetic foot syndrome require further treatment strategies to avoid lower limb amputation.
Functions of insole The basic functions of insoles are to provide support, bedding (padding), and correction. Especially in the domain of correction, a change from passive to active correction can be noted as a result of the increasing importance of proprioception.
Examination It is well known that the examination of the foot includes looking for corns and callosities that are representative of points of high pressure. Also, the patient’s most often used shoes need to be examined. A lot of information about the gait and the load to the feet can be taken from the condition of these shoes. Often, the wear of the shoe gives a useful suggestion about the necessary treatment or orthotic device. The inspection of technical devices during therapy are mandatory [2]. It is important to look at whether the device still fits properly and if the desired function is being achieved. With this information, any modification of the device, as well as new devices, can be accomplished. The condition of the device also gives information about its use. Overloaded areas and pressure points can also be recognized (Fig. 1).
Fig. 1. Sweat spurs show pressure peaks under the second and third metatarsal head in severe metatarsalgia.
G.M. Ivanic / Foot Ankle Clin N Am 8 (2003) 671–682
673
A few guidelines: Every device must be worn without pain. Pressure points are strictly forbidden. The shoe and the technical device must fit. An orthotic must not compensate for bad or unsuitable footwear. Exact placement of orthotics within the shoe are a basic requirement. The insole must not slip in the shoe and needs a proper fit to the inner sole. The insert should be thin at the heel to prevent slipping of the heel. Slipping of the orthotic within the shoe can be prevented with a rough base or Velcro. The gait should be examined with and without the device. Examine the foot. Look for corns and callosities and compare with the device and sweat spurs (signs of pressure peaks on a device which are produced by sweat and the pressure) on it. Modification of the device, if necessary. The device must not be hollow under the metatarsal bones. The orthotic and the foot need a proper fit. The material used for the orthotic should fit the indication. Generally, the material should not be too stiff. The insoles need to be the optimal length according to the indication (eg, forefoot problems need long insoles from the heel to the toes).
Fitting and examination of orthotics The knees should be flexed and the feet should be positioned neutrally. The orthotic should be tested on the foot without weight bearing and while it is bare. Then it should be tested in dorsiflexion and plantarflexion. These observations should be repeated while the patient is weight bearing. It is important to know that the foot is bigger under load.
Foot measurement There are various techniques of foot measurement [3] for the manufacturing of individual custom made insoles: Plantar pressure measure with tracing-paper; this is a static procedure. It is also possible to measure the plantar pressure by computerization in the sense of pedobarography. The technique allows the dynamic examination of the plantar foot pressure by the use of special pressure trays. A variety of systems are available. The sponge footprint: three-dimensional molds of the weight-bearing foot can be obtained. The foot negative with plaster cast: this technique has the advantage that a negative mold of the foot can be obtained with the foot in a corrective posi-
674
G.M. Ivanic / Foot Ankle Clin N Am 8 (2003) 671–682
tion. It is possible to get a positive mold of the foot in its corrective position. Using this technique, one has to consider that real weight bearing of the foot, together with correction of the foot deformity, is only possible to a certain degree. This must be considered during the manufacturing of the insoles. There have been recent reports of new computerized scanning systems that are still in development. Although early studies show promising results, they are not yet sophisticated enough for general application.
The making of insoles There are some basic principles of insole manufacturing in which the use of padding must be mentioned. With padding, pressure release of certain areas of the foot can be achieved. If necessary, padding can increase the load to certain areas of the foot. In general, it is important to avoid pressure peaks while using these devices. Materials and the mixture of different materials are important to achieve the indicated function of the orthotics. Newer methods for making orthotics use plate materials. Thermo moldable plates are heated and put over a corrected foot model of plaster of Paris. The advantage is the ability to produce a single-piece insole in which the needed corrections are built. The disadvantage is the ready defined orthotic (after the molding process the orthotic’s form cannot be changed). Additional corrections are not possible or the single-piece advantage is lost. The other possibility is to use this insole as a base on which the different pads can be put. Pads Pads are a big help in the design of shoes and orthotics for achieving the desired function. To obtain these functions, the shape and the position of the pads have to fit the indication of the device [4,5]. Thus, it is important to control the position of the pads. If they are too close to the area that should be supported, pain can result; also, the desired function is not obtained. The same is valid for pads if they are too far away from the area that should be supported. A good example of incorrect procedure is the so-called ‘‘medical footwear.’’ Serial insoles respectively so called ‘‘healthy foot bedding’’ have standard pads for the retrocapital support of the metatarsal heads. Normally, these pads are situated too far proximally because direct contact of the metatarsal heads with the pads may cause pain, but usually this does not cause further problems. The support of the longitudinal arch of the foot should reach its highest point underneath the sustentaculum of the talus. This support should drop off proportionately to get a correct position of the hindfoot. Depending on the pathology, different adjustments are possible. In the normal, ready-to-wear shoe, the balance of the longitudinal arch is put too far distally, because otherwise, pain in the hindfoot may occur while wearing these shoes. To avoid this problem, this support is put more distally. This may cause forefoot supination, which then can cause other
G.M. Ivanic / Foot Ankle Clin N Am 8 (2003) 671–682
675
Fig. 2. Heart-shaped and kidney-shaped pads.
problems. These problems should be avoided in ready-to-wear shoes with adequate support, as well as in serial manufactured insoles. It is essential, therefore, to clinically follow up the patients and check the insoles after delivery. The main indication for such paddings is the retrocapital support of the metatarsal heads in the event of metatarsalgia to relieve the pain caused by pressure. The ideal padding must be customized for each patient; no padding suits every patient and meets all requirements. In the case of retrocapital support of the metatarsal heads, the padding must be adapted to the individual form of the foot. The length of the metatarsal bones has to be considered. Therefore, two main padding forms may be used, heart-shaped pads or kidney-shaped pads (Fig. 2). These pads have to be adapted to the individual shape of the foot. In special cases, it might be sensible to make a metatarsal crest that is oriented to the length of each of the metatarsal bones (Fig. 3). The radius of the pads has to fit the supported foot. Pads that are too sharp, too hard, or too high pads can cause troubles. The height of the pads depends on the shoe. ‘‘Sport insoles’’ should have only a fraction of the correction of pads that are used in walking shoes. Diseases such as diabetes also have to be considered. Material Another important point in the field of insole manufacturing is the choice of the proper material. Depending on the material, the function of the insoles can be improved considerably. There is the risk that a well-manufactured insole can be compromised by material that is of bad quality. Hard synthetic materials, such as plastics and Plexidur should be avoided. Hard plastic material causes pressure sores. The microclimate around the foot should have good circulation. Depending
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G.M. Ivanic / Foot Ankle Clin N Am 8 (2003) 671–682
Fig. 3. Metatarsal crest.
on pathology, various materials like ‘‘cork’’, ‘‘leather’’, ‘‘plastizote’’ up to most of the modern synthetic plastic material can be used. All of these materials, alone or in combination, make it possible to produce an individual insole that has positive effects.
Prescription and follow-up Examination of the feet should always include the observation of the patient’s gait pattern, with and without his/her foot wear, as well as the condition of the shoes themselves.
Rocker soles Shoe modifications are not the subject of this article but should be mentioned; a rocker sole is often needed in combination with orthotics. A rocker sole should be combined with a stiffening of the sole to achieve optimal results.
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Forefoot (toe-only rocker sole) The apex is proximal to the metatarsophalangeal (MTP) joints, perpendicular to the gait direction (Fig. 4). This increases the step length, makes the roll-off more difficult, and causes hyperextension in the knee. Midfoot The apex is under the midfoot (Fig. 5). This relieves the Chopart and Lisfranc joint and causes slight extension of the knee joint. Entire foot (heel-to-toe rocker sole) The apex of the rocker sole should be made according to the radius of the circle between the knee and the sole. This results in total relief of the ankle joint with no effect to the knee joint.
Indications and pathologies in the forefoot for the use of orthotics Splayfoot Symptoms: broadened forefoot in the MTP joint area with pain and shoe conflict, hallux valgus, hammer toes, claw toes, metatarsalgia, corns and callosities plantar to the heads of the second through fourth metatarsal bones, lateral to the fifth metatarsal, troubles with ready-made footwear Therapy: pain relief through pressure decrease with retrocapital support of the metatarsal heads, could be combined with semi-rolls under the Proximal InterPhalangeal Distal InterPhalangeal (PIP-DIP) joints in claw and hammer toes Pressure relief of the so-called ‘‘transverse arch’’ (wrong description but still widely used [6]) Retrocapital support Decrease of pressure in the roll-off phase
Fig. 4. Rocker sole under the forefoot.
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Fig. 5. Rocker sole under the midfoot.
Orthotics: butterfly insoles according to Wolfgang Marquardt [1] in the acute phase (Fig. 6; retrocapital support with pads. CarboPlus (Rathgeber-Bioform, OFA-Bamberg, Bamberg, Germany)(Fig. 7) (see Metatarsalgia) Bandages: splayfoot bandages with metatarsal pads (changeable pads, with different heights, soft or hard, are recommended).
Fig. 6. Butterfly orthotic with a pressure release under the second through fourth metatarsal heads.
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Fig. 7. CarboPlus orthotics with a built-in elastic roll-off support.
Orthopedic shoes: rocker soles, butterfly-style insoles for a better pressure decrease under the second through fourth metatarsal heads in combination with orthotics. It is important that the pads are in the correct position. What are the indications for pads? According to the pain, treatment in different stages is necessary. The initial treatment could be done with butterfly insoles (see Fig. 6) for pain relief (with a high pressure relief under the second through fourth metatarsal heads). When the ache subsides, a provocation test with splayfoot bandages with soft pads is recommended. If this goes well then orthotics are possible. The transverse arch of the insoles should be built step by step. Hallux valgus Symptoms: pain medial to the first MTP joint (at the bunion). Problems with the shoes (pressure and rubbing). Weakness in the toe-off phase during roll-off. Therapy: traction and stretching of the hallux joint to improve the range of motion. Shoes: the shoe conflict has to be resolved. Often the shoes are too small and too tight. Orthopedic shoes: deepening (to build a whole groove under the MTP joint) under the first MTP joint, good heel hold. The vamp and the toe box has to be broad enough. The foot needs a perfect hold at the Chopart level. Slipping of the foot inside the shoe is strictly forbidden. Technical aids: avoidance of pressure to the joint and the bunion. Orthoses and bandages to adduct the hallux. Schede developed a splint in 1923 [1]. The same style is used in the so-called ‘‘hallux valgus night bandages’’. Special taping techniques and newer products, like a hallux valgus belt. All of these products can be useful in postoperative care, mainly to prevent relapses; the hallux valgus cannot be treated by them.
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Fig. 8. Hallux valgus compression stocking.
Postoperative care: according to recent studies, the recommended shoe type is a forefoot pressure relief shoe (wedged sole) [7]. Wooden-soled shoes should not be used because they cause more pressure to the forefoot than ready-made shoes or sneakers. Compression stockings, in a Japanese style, that are especially made for the postsurgical phase of hallux are useful, fashionable, and enjoyed by the patients (Fig. 8) (Gilofa 2000, Ofa Bamberg, Bamberg, Germany). Hallux rigidus Symptoms: arthrosis of the first MTP joint. It begins with painful dorsal extension in that joint. Radiographs show the typical changes of an arthrotic joint with a dorsal exostoses. Painful toe-off and the exostoses are the most common reasons why patients seek medical care. Therapy: depends on the stage of the rigidus. Treatment for early stage hallux rigidus should include: (1) thermotherapy with ice, or most often with warm compresses supported with ointments for a better circulation and a reduction in pain
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and (2) tractions and functional movement, especially dorsiflexion (rotation gliding, side bending) and infiltration with local anesthetics, rarely combined with steroids. Treatment for acute, later stage hallux rigidus includes shoes that relieve forefoot pressure (eg, wooden-soled shoes with a roll-off support like Dutch shoes). Shoes: forefoot stiffening, roll-off support, deepening (to build a whole groove under the MTP joint) of the shoe under the first MTP. Orthotics: rigidus spring (insole with a steel shank under the first MTP— obsolete and no longer recommended). CarboPlus (see Fig. 7) is comfortable and can be used in sneakers and ready-made shoes. Metatarsalgia Symptoms: pain in the forefoot. The main problems appear in the area of the metatarsal heads and the MTP joints. The most common causes are splayfoot, transfer metatarsalgia, hallux valgus, and hallux rigidus, as well as vasopathic, angiopathic, and rheumatic feet. Therapy: the therapy should be determined by the cause of the problem. In many cases, surgery is unavoidable. Conservative therapy algorithms should look for pressure relief in the painful forefoot area. Shoes: stiffening of the sole in the forefoot area (ie, steel shanks) and roll-off supports that are added to the sole. Orthotics: retrocapital pads to support the so-called ‘‘transverse arch’’ to take pressure of the metatarsal heads. ‘‘Butterfly orthotics’’ for the acute phase (see Fig. 6), CarboPlus for a painfree roll-off and relief of contractures (see Fig. 7). CarboPlus is a newly developed orthotic design that has elastic stiffening and a roll-off support built in [8– 10]. The orthotic is composed of three layers: (1) a cork layer from the heel to the midfoot, (2) a drop-shaped carbonfiber layer that is connected to the plantar side of the cork at midfoot level, and (3) a top surface of plastizote. The narrower part of the carbon layer lies under the midfoot and the broadest part lies under the MTP joints. Thus, pressure on the midfoot is relieved and is spread onto the whole forefoot. The carbonfiber is also molded like a wave, which gives the function of a rocker bottom and additionally relieves high pressure to the mid- and forefoot. The plastizote also helps to decrease peak pressures. Therapy algorithm in metatarsalgia A forefoot pressure relief shoe (eg, Darco Ortho Wedge, Darco Int., Inc., Huntington, West Virginia) is recommended until pain subsides. CarboPlus orthotics (see Fig. 7) should be used afterward to achieve a physiologic gait. Before orthotics and when the major pain comes from the second to the fourth metatarsal heads, butterfly orthotics (see Fig. 6) are a reasonable choice of therapy. These orthotics are not recommended for permanent use because the total decompression of the intermediate heads can lead to further problems. When the pain subsides and when the corns become smaller, CarboPlus orthotics can be tried or, before it, splayfoot bandages with soft and low pads for a retrocapital support. When the bandages are tolerated for a longer period of time, orthotics can be prescribed.
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Summary Technical aids in the treatment of foot problems have been known for hundreds of years. In the German-speaking countries, especially, shoemakers, prosthetists, and orthotists are well respected. They have great skills and provide the orthopedic surgeon with alternatives to surgery. Also, the combination of surgery and technical aids is important because suboptimal surgical results can be improved by a good orthopedic device.
References [1] Marquardt W. Die theoretischen Grundlagen der Orthopaedie Schuhmacherei [Theoretical basics for the making of orthopaedic shoes.] Geislingen, Germany: Maurersche Buchdruckera; 1951. [2] Grifka J. Einlagen - indikation, verordnung, ausfu¨hrung [Orthotics; indication, prescription, production.] Bu¨cherei des orthopa¨den Band 55. Stuttgart (Germany): Enke Verlag; 1993 [in German]. [3] Hughes J, Kriss S, Kienerman L. A Clinician’s view of foot pressure: a comparison of three different methods of measurement. Foot Ankle 1987;7:277 – 84. [4] Hayda R, Tremaine MD, Tremaine K, Banco S, Teed K. Effect of metatarsal pads and their positioning: a quantitative assessment. Foot Ankle 1994;15:561 – 6. [5] Holmes GB, Timmermann L. A quantitative assessment of the effect of metatarsal pads on plantar pressures. Foot Ankle 1990;11:141 – 5. [6] Jacob HAC. Zur belastung des fußes beim gehen und stehen - hat die ‘‘dreipunkttheorie’’ noch bestand? Med Orth Tech 2000;120:100 – 5 [in German]. [7] Trnka H-J, Parks BG, Ivanic GM, Chu IT, Easley ME, Schon LC, et al. Six first metatarsal shaft osteotomies: mechanical and immobilization comparisons. Clin Orthop 2000;381:256 – 65. [8] Ivanic GM, Trnka H-J, Homann NC. Metatarsalgie - eine neue klassifikation und korrelierende orthopa¨dietechnische therapiemo¨glichkeiten [Metatarsalgia - a new classification with a correlating theraphy algorithm with technical devices.] Orthop Praxis 2000;36(8):497 – 502 [in German]. [9] Ivanic GM, Trnka H-J, Homann NC. Die posttraumatische metatarsalgie - erste behandlungserfahrungen mit einer neuen einlage. Unfallchirurg 2000;103:507 – 10 [in German]. [10] Ivanic GM, Homann NC, Trnka H-J. Das diabetische fußsyndrom - therapie und prophylaxe mit carbonfaser-kork-einlagen. Med Orth Tech 2002;122:101 – 4.