Management of Metatarsalgia with Foot Orthotics

Transcription

1 /85/ $02.00/0 THE JOURNAL OF ORTHOPAEDIC AND SPORTS PHYSICAL THERAPY Copyright by The Orthopaedic and Sports Physical Therapy Sections of the American Physical Therapy Association Management of Metatarsalgia with Foot Orthotics GORDON E. DOXEY, BS, PT* Various disorders cause pain in the forefoot. Factors contributing to the development of metatarsalgia include: biomechanical alignment, foot biomechanics, anatomical structure of the foot and leg, physical activity, and pathological disease states. The foot functions to balance and support forward locomotion by acting as a mobile adaptor to the ground and as a rigid lever during propulsion at the early and late phases of stance. Forefoot pathomechanics results from an overload of the anterior support or from an irregular distribution of the metatarsal weightbearing load. Orthotic therapy may be provided with insoles made from flexible, semiflexible, or rigid materials. The orthotic should be individualized in each patient's case. The purpose of treatment is to increase weightbearing tolerance by balancing the metatarsal load, assisting proper foot biomechanics, and cushioning or protecting the metatarsal heads. Metatarsalgia is a common foot disorder. The term rnetatarsalgia refers to a pain syndrome in the forefoot and not to a specific diagnosi~.~' Many different diagnoses have been indentified as the cause of the painful forefoot. Excessive stress may result in ligamentous strain, synovitis, capsulitis, fracture, or degenerative arthritis. Metatarsalgia may be associated with cerebral palsy, stroke, multiple sclerosis, or other neurological diseases. Metatarsalgia results from pathological alterations in forefoot structure due to rheumatoid arthritis, osteomyelitis, or osteochondrosis. Circulatory or metabolic disorders may also produce metatar~algia.~~ The management of metatarsalgia requires identifying the etiology and treating the primary cause. Treatment may include medical, physical, or surgical therapies but only the use of foot orthotics will be discussed in this article. TYPES OF METATARSALGIA Metatarsalgia may present as an independent disorder or coexist with other foot pathology.14 The types of metatarsalgia may be grouped as primary, secondary, or as forefoot pain without associated plantar keratosis. Primary metatarsalgia is associated with metatarsal pain and reactive 'St. Benedict's Hospital, Ogden, UT. keratosis due to a chronic imbalance in the weight distribution between the metatarsals. This type may be either structural or functional depending upon whether the imbalance is osseous or due to inadequate muscular function.26 Neale et ahz2 refers to this type of mechanical imbalance as functional metatarsalgia. This imbalance overloads the metatarsals causing an inflammatory reaction in the metatarsalphalangeal joints. ScrantonZ6 considers adult onset static disorders, postoperative iatrogenic imbalances, hallux valgus, hallux rigidus, and Morton's foot to be primary metatarsalgias. Compression of the metatarsals is increased with rigid cavus or pes planus feet, metatarsal fixation, retraction or clawing of the toes, and metatarsal subluxation. Shearing across the metatarsals is increased with first or fifth metatarsal hypermobility, excessive pronation, or illfitting ~hoes.~'~~ Secondary metatarsalgia is associated with forefoot pain and reactive plantar keratosis due to factors other than the metatarsals themselves. The etiology is due to localized disease within the forefoot. A chronic equinus gait is also a prominent factor predisposing an individual to second ary metatarsalgia. S~ranton~~ considers rheumatoid arthritis, sesamoid disorders, posttraumatic imbalances, neurogenic and stress fractures to be secondary metatarsalgias. The contribution of 324

2 JOSPT MaylJune 1985 METATARSALGIA 325 localized disease to metatarsalgia development is illustrated with rheumatoid arthritis. This arthritic disease produces a chronic synovitis which causes erosion of the articular cartilage and bone, resulting in deformation of the joint capsule. Subsequent metatarsal subluxation, clawing of the toes, and dorsal displacement of the plantar fat pad expose the metatarsals to increased plantar stress and metatarsalgia results.30 It is important to recognize the distinction between disorders of mechanical imbalance across the metatarsals with loss of the fat pad and the presence of keratosis and other clinical disorders that are systemic or those that do not produce a keratic plantar reaction. S~ranton~~ considers Morton's neuroma, plantar fascitis, tarsal tunnel syndrome, tumors, gout, and circulatory disorders within this group. CLINICAL EXAMINATION The goal of the clinical examination and supplementary studies is to correlate the clinical evidence into a treatment plan by determining the etiology of the disorder, by examining individual biomechanical, alignment and anatomical structure, and by analyzing biomechanical foot function during gait. The physical examination of the foot and ankle is outlined elsewhere ~17~22.29 It is important to attempt to correlate the clinical and biomechanical evidence with respect to what is occurring during dynamic foot function. Grayg has observed that clinical evidence with respect to pain, callosities, and biornechanical structure of the foot may not be closely correlated to what occurs dynamically, due to contributing factors within the proximal lower extremity. For example, some patients who upon clinical examination present a rigid first metatarsal ray, in fact, demonstrate a hypermobile first metatarsal ray during level walking due to rearfoot pathomechanics when analyzed by the Electrodynogramo (Electrodynogram, Langer Laboratories, Deer Park, NY) gait system. In summary, it is important to identify factors that are intrinsic to the foot or that are extrinsic within the lower extremity that produces gait dysfunction. Generally, primary and secondary metatarsalgia is aggravated with weightbearing, ambulation, tip toe activity, and forefoot manipulation. Plantar keratosis may also be present at areas where significant stress is occurring. Observation of the patient's gait reveals an apropulsive pushoff, a decreased stride, prolonged midstance, and decreased heel rise and toe dorsifle~ion.~~'~ NORMAL BIOMECHANICS OF THE FOOT The function of the foot during walking is that of balance and support with forward locomotion maintained by the lower extremities and momentum of the upper body.25 The foot acts as a mobile adaptor to the ground at heel strike and early stance phase and then stabilizes to function in propulsion at pushoff. Identifying abnormality in the lower extremity requires an understanding of normal biomechanics. Variations in anatomical structure and alignment are important to identify, especially with mechanical disorders. The biomechanics of the whole lower extremity has been described by other author^."^^^^'^^^^ Body weight is accepted into the foot at heel strike and transferred anteriorly during foot flat and pushoff. The stance phase of gait occurs for 62% of the gait cycle. Initial foot contact occurs at heel strike, foot flat at 7%, heeloff at 34%, and toeoff at 62% of the gait cy~le.'~ The metatarsals and hallux are weightbearing for 85 and 60% of the stance phase.12 The heel first contacts the ground in an inverted position. The adaptation of the foot to the ground occurs by eversion of the calcaneus and pronation of the subtalar and midtarsal joints. The medial longitudinal arch undergoes structural change during early stance phase by accepting weight from the talas as it assumes a plantarflexed and adducted position. This mechanism of pronation normally only occurs during early stance phase. At midstance, external rotation of the lower extremity initiates supination of the foot. The calcaneus inverts and the talas moves into abduction and dorsiflexion, thereby locking the midtarsal joint, allowing the foot to become more rigid during pu~hoff.'~~'~ Supination is further assisted by the oblique axis between the second and fifth metatarsals (called the metatarsal break) which causes the midfoot to supinate passively as weight is shifted onto the metatarsals. The foot also becomes more stable at pushoff due to the windlass mechanism of the plantar fasica and the activity of the gastrocsoleus muscle group. These mechanisms stabilize the medial forefoot and allow the first ray (first metatarsal and first cuneiform) to participate max imally during push off.2.' The kinetics of lower extremity function during gait are summarized in Figure 1. The forefoot adapts to the ground through the

3 DOXEY JOSPT Vol. 6, No. 6 PELVIS FEMUR WALKING CYCLE INITIAL INITIAL FLOOR LIFT FLOOR CONTACT OFF CONTACT m 15% jo( &% 60% 80% loox ~~~~~~& EXTERNAL ROTATION 0 ~~~~ TIBIA ANKLE JOINT PLANTAR ~~~:~ OORSIFLEXION 3LEXION+ DORSlFLEXlON WBTALAR JOINT EVERSIOH+ INVERSION EVERSION TRANSVERSE TARSAL JOINT TALONAVICULAR JOINT INTRINSIC MUSCLES WET IBlAL MUSCLES CALF MUSCLES UNSTABLW INCREASING INACTIVE+ ACTIVE INACTIVE* FLOOR CONTACT REACTION "INCREASING 4blNACTIVE 1 4 STANCE PHASE ACTIVE MID STANCE Fig. 1. Diagram illustrating the joint rotations and muscle activity in the lower extremity during a complete gait cycle. Reproduced with permission from Mann RA, Mechanics of the foot. In: American Academy of Orthopaedic Surgeons: Atlas of orthotics, CV Mosby Co. mobility of the first and fifth metatarsals. The other metatarsals, especially the second, are more firmly articulated at their bases and are only capable of movement in the sagittal plane. The stability of the second, third, and fourth metatarsals results from osseous articulation and normal muscle f un~tion.~*~~~~~~~~ The neutral position of the subtalar joint is used as a reference to determine the alignment of the foot. Ideal nonweightbearing foot alignment is present when the forefoot is perpendicular to the sagittal calcaneus and when the calcaneus is parallel to the axis of the lower leg.''.17 The first metatarsal should assume a position level with the lesser metatarsals and be capable of an equal amount of plantarflexion and dorsiflexion, but is generally less flexible than the fifth metatarsal." The angle from the ground for the first, second, third, fourth, and fifth metatarsal shafts is 1825, 15, 10, 8, and 5O, re~pectively.~~ The foot may be classified by toe and metatar TERMINAL STANCE STABILITY ACTIVITYol, I PRE WING UNSTABLE INACTIVE* A C T I V E ' INACTIVE INITIAL WING TERMINAL SWING 4 SWINCi MASE r sal length. Referring to the foot as square, Greek, or Egyptian depends upon whether the first toe is the same, shorter, or longer than the second. The metatarsal length formulas are: index plus, 1 > 2 > 3 > 4 > 5; index plus minus, 1 r 2 > 3 > 4 > 5; and index minus, 2 > 1 > 3 > 4 > 5. Vilad~t~~ examined 1,000 feet and observed 16% index plus, 26% index plus minus, and 56% index minus; considering the Greek and index plus minus formula to be ideal. The weight distribution across the metatarsals differs in stance and level walking. The distribution of 12 units of load, as outlined by Morton, is transferred so that the heel accepts 6, the first metatarsal 2, and each of the lesser digits 1.I4 Recently, research has demonstrated that the middle metatarsals accept high pressures and that the heel accepts greater than 50% of the load. In stance, the second and third metatarsals accept significant load^.'.'^,^^ During walking, the ground reaction forces in

4 JOSPT MaylJune 1985 METATARSALGIA 327 toes; 3) heel, midfoot, and forefoot; 4) forefoot and toes; 5) toes; and 6) great toe. The weightbearing stress at the metatarsals is partly relieved by the muscular activity of the toe flexors which counteracts forces occurring at the metatarsals during pushoff. The metatarsals are further protected by the plantar skin, fat pads, and ligamentous structures which act as a natural cushioning mechanism (Fig. 3).20*37 PATHOMECHANICS OF THE FOREFOOT Fig. 2. Diagram illustrating the center of pressure in the foot during level walking. The numbers along the line represent the percentage of the stance phase of gait that the pressure is present at one location. Reproduced with permission of Mann18 and WB Saunders Co. each foot segment varies during different phases of the gait cycle. Weight distribution moves through a line of central pressure. Generally. the center of pressure begins at the lateral heel, moves forward into the midfoot, and then shifts medially where it exits between the first and second toes at ~ushoff (Fig. 2). However variability of the center of pressure exit from the forefoot has been recorded by Stott et a1.34 The ground reaction forces exit between the first and second or second and third toes in subjects who have an index plus or index minus metatarsal formula. The center of pressure demonstrates to which areas of the foot the forces are distributed and the approximate time they remain at one location. The center of pressure moves rapidly through the heel and midfoot and then slows significantly at the forefo~t.'~.'~ Weight is present at the forefoot for a longer period of time, requiring the weightbearing function of the metatarsals and toes to be three times that of the rearfo~t.'~~'~~~~ At pushoff all of the ground reaction forces are concentrated on the metatarsals and toes. This force has been calculated to be 120% of body eight.'^^^^ The force acting on just the toes is approximately 40% of body weight.33 The forefoot load is carried to a greater degree at the medial forefoot in younger subjects, while older subjects carry the forefoot load more equally between the medial and lateral forefo~t.'~.~~ 334 Vilad~t~~ studied the sequence of foot contact during gait in 100 subjects and observed that in 70% of the cases, ground contact occurred as follows: 1) heel; 2) heel, metatarsals, and distal Biomechanical metatarsalgia results from alterations in the weightbearing distribution of forces at the forefoot where the metatarsals become overloaded relative to their neighbors. Alteration in anatomical structure and alignment are major etiological factors. Foot type may contribute to metatarsalgia. Metatarsal weightbearing is increased with the cavus foot because a disproportionate amount of weight is borne by the heel and forefoot. It is not uncommon to observe retracted or clawed toes with cavus feet, thus decreasing the toes' contribution to unload the metatarsals at pushoff. The pes planus foot type (resulting from genu valgum, rearfoot valgus, or forefoot varus) remains pronated during midstance and inhibits proper supination, thus compromising the propulsive function of the forefoot. Alterations in forefoot alignment may compromise foot function. Forefoot varus may be present where the medial forefoot is inverted relative to the rearfoot when the subtalar joint is in a neutral position. This malalignment decreases the medial stability of the forefoot and causes excessive foot pronatlon, as does rearfoot varus. Forefoot valgus may be present where the medial forefoot is everted relative to the rearfoot when the subtalar joint is in a neutral position. This malalignment may result from the first metatarsal that is plantarflexed in a rigid position." Figure 4 illustrates the normal and abnormal nonweightbearing positions for the forefoot. These alignment problems may increase and alter the stress acting at the metatarsals, but may not be clinically significant unless the alignment is excessive or rigid." Emphasis should be placed upon examining the rearfoot, forefoot, and lower extremity for malalignment, since the biomechanics of the foot is dependent upon all foot and leg segments. Foot force analysis has been more commonly performed on subjects with rheumatoid arthritis or hallux valgus deformities. Compared to controls free of foot pathology, these subjects dem

5 DOXEY JOSPT Vol. 6, No. 6 fibrous flexor sheath lirst lunibrical and scptunl plantar ligament trancrerse mctatars;~i liga~~~t*t~t vertical fihres R Fig. 3. Illustration of the anatomical structures beneath the metatarsals. Reproduced with permission of MollerZ0 JB Lippincott Co. I Fig. 4. illustrations of the normal and abnormal nonweightbearing forefoot alignment types when the subtalar joint is in the neutral position. A, normal relationship; B, forefoot varus; C, plantarflexed first ray; D, forefoot valgus. PATHOMECHANICS weakness of the toes. Simkin30 determined that the force concentration at the metatarsals was a better indicator of local stress than the quantity of the force because rheumatoid arthritis patients maintained lower forefoot force by decreasing their walking speed and by prolonging midstance. The preceding research demonstrates the significant role of the hallux in weightbearing. The weightbearing capacity of the first metatarsal progressively decreases as the hallux valgus deformity progre~ses.~ Hallux valgus results from rheumatoid arthritis, neurological disbases, biomechanical alignment problems, or develops by an idiopathic process or other Hypermobility of the first ray results in a clinical problem where a lack of support compromises its ability to assume adequate weightbearing loads.17 Patients with metatarsalgia should be examined for associated disorders of the hallux. ScrantonZ6, in his series, concluded that 34 of 78 patients with either primary or secondary metatarsalgia had coexisting hallux disorders. Any painful condition of the hallux will shift weightbearing to the lesser metatarsals, particularly the second or third.*' CLASSIFICATION OF METATARSAL onstrate an inadequate propulsive role of the forefoot resulting from the center of pressure exiting more laterally, between the second and third or the third and fourth toes10~12~28~3032~34 and greater stress at the metatarsals due to decreased toe flexor muscle activity, particularly in subjects with hallux valgus.10~12~28~3032 Sharma et al2' concluded that the lack of medial weightbearing at pushoff in rheumatoid arthritis patients was due to either inadequate pronation or flexor muscle Vilad~t~~ has classified metatarsal pathomechanics as an overload of anterior support or an irregular distribution of the metatarsal load. Irregular metatarsal load syndromes are further separated into the following four groups: l) first ray overload, 2) first ray insufficiency, 3) central ray overload, and 4) central ray insufficiency. The different patterns of weight distribution in the irregular metatarsal load syndromes are illustrated with pedographs (Fig. 5).

6 5= JOSPT MaylJune 7985 METATARSALGIA 329 '..., c:. t b&.k&s dk metatarsal frontal plane malalignment, subluxa 3 tion, dislocation, claw or hammer toes, or congen itally long central metatarsals are predisposing % factors.37 The position and function of the central + metatarsals is commonly disturbed by the malposition and malfunction of their respective digits as they are pinned down by digital retraction or subl~xation.~~ I 7 % Lesser metatarsal overload is caused by inad _ /._ equate weightbearing of the first ray. A short first 7, metatarsal, forefoot, or rearfoot varus can result.. in excessive pronation. First metatarsal varus and hypermobility of the first ray are also predisposing.. factors to pronatory problems.29q37. L _ These syndromes are identified by patient com =+maz ' plaint, palpation, callus formation, anatomical rf; e:k p r >? I;: Fig. 5. Pedographs representing the different syndromes of irregular load distribution at the metatarsals: A, first ray overload; B, first ray insufficiency; C, central ray overload; 0, central ray insuffi6iency. Overload of anterior support occurs from imbalances between the rearfoot and forefoot in the sagittal plane. Footwear with high heels shifts weight anteri~rly.~~ Inflexible posterior calf musculature resulting in an equinus position predisposes an individual to anterior overload and compensatory pronation at the subtalar and midtarsal joints during midstance. Obesity, occupational weightbearing stress, tip toe activities, and pregnancy further increase the weightbearing function of the forefoot. Excessive pressure at the first metatarsal results in the first ray overload syndrome. A long first metatarsal, forefoot valgus, a rigid plantarflexed first ray, the cavus foot type, and forefoot weightbearing activities predispose an individual to develop this cor~dition.~~ Inadequate weightbearing at the central metatarsals with overload at the first and fifth metatarsals causes the central ray insufficiency syndrome. A first or fifth plantarflexed ray, neurological cavus feet and iatrogenic imbalance from previously failed forefoot surgery are contributing structure and alignment, pedograph and xray examination. The Electrodynogram is being uti lized with increasing frequency to objectively ana 3) ~3: 71 lyze the quantity and duration of segmental and. vertical foot forces with computer analysis of foot biomechanics from foot sensor data.g The temporal and distance variables of aait can be anaiyzed by utilizing the Footswitc~Stride Analyzer (6 & L Engineering, Santa Fe Springs, CA.) with Fig. 6. Therapeutic forefoot extensions for balancing the met Central ray overload results from excessive atarsal load: A, first ray overload; 8, first ray insufficiency; C, pressure at any of the central metatarsals. Central central ray overload; 0, central ray insufficiency.

7 330 DOXEY JOSPT Vol. 6, No. 6 TABLE 1 General considerations for the selection of materials for foot orthotics and pads Flexible Semiflexible Rigid Materials Plastazote #I, 2 (1) Polypropylene (1)t PPP (3) Thermolast IIQ (rohadurl)t SpencoQ (1) Coylene" (1)t SorbothaneQ (4) Polyethylene (1)t Soft Birkocork" (2)$ Rigid Birkocorkm (2)t Orthoplast (1)' Polyflex II" (1)' Patient age Any age Any age Treatment indication Pathology Use on all parts of the plantar foot ' Cushioning * Reducing shear Increase weightbearing surface of foot ' Forefoot alignment Mild control of pronation * Temporary padding for most foot conditions Use at midfoot and rearfoot * Flexible support of midfoot and rearfoot Moderate control of pronation Useful with patients who have biomechanical and local disorders of the foot while providing better tolerance for physiologically old or rigid feet Limited use with physiologically old patients or any patient with rigid feet Use at midfoot and rearfoot * Firm control of midfoot and rearfoot ' Maximum control of pronation ' Useful with patients who have biomechanical or local disorders ' May need to combine with flexible materials Use with the following: Use with the following: Use with the following: Bone prominences ' Mild or moderate arthritis ' Foot malalignment Severe keratosis ' Mild foot hypersensitivity Flexible or semiflexible ' Diabetic or ischemic plantar ' Motion related inflammations foot types ulcerations of the foot and leg 'Obese * Arthritis with deformity ' Arch support Motion related inflam ' Foot hypersensitivity mations ' Arch support Durability months 424 months 24 or more months (1) Distributed by Paramedical Distributors, Kansas City, MO. (2) Birkenstock, Novato, CA. (3) Professional Technology, Inc., Deer Park, NY. (4) Distributed by IEM Orthopaedics, Aurora, OH. ' These low temperture thermoplastics may be molded directly to the foot. They can be used as temporary foot orthotics due to their limited durability. t These higher temperature thermoplastics require forming on a plaster foot cast. $ Soft Birkocork is particularly useful as a moldable posting material. 5 Durability depends upon the orthotic material characteristics, fabrication, and patient activity. microcomputer analysis from compression closing footswitches. ORTHOTIC FABRICATION The purpose of orthotic therapy is to increase the metatarsalgia patient's tolerance to weightbearing, assist proper foot function, and normalize gait. Orthotics may be utilized as a primary conservative treatment with patients with primary and secondary metatarsalgia. The orthotic is fabri cated in order to balance the weight distribution across the metatarsals by compensating for the biomechanical malalignment that alters foot biomechanics. Therapeutic forefoot extensions used with the irregular distribution of metatarsal load syndromes are illustrated in Figure 6. Emphasis should be directed toward fabricating the orthotic so that any malalignment is corrected, thus normalizing foot biomechanics and prescribing orthotics according to the diagnosis in each particular case.

8 JOSPT MaylJune 1985 METAT PRINCIPLES OF ORTHOTIC FABRICATION Successful orthotic therapy depends upon material selection, fabrication technique, and using appropriate footwear. The selection of materials for the construction of the orthotic is determined by factors that are outlined in Table 1. Jahss13 has recommended the following rules for orthotic fabrication: 1 ) never attempt to correct a fixed plantar deformity by attempting to add support underneath and raise it, 2) bring the floor up to the foot by adding support in order to increase weightbearing at an area, 3) remove stress from areas that demonstrate excessive pressure, and 4) create excavations under painful areas. Failure to comply with these rules will only result in increasing the patient's symptoms or preventing the patient from becoming tolerant to the orthotics. An orthotic fabricated following these principles will balance the foot segments, unload the painful areas, and increase weightbearing in insufficient areas (Fig. 7). Other fabrication considerations include: adding midfoot support, using a toe crest, making adjustments according to the patient's foot type, and correcting alignment problems. The disproportionately high weightbearing areas in the cavus foot is reduced by adding support along the lateral and medial longitudinal arches. The pes planus foot requires Fig. 7. The types of techniques for making forefoot extension modifications. Example, central ray overload: A, adding cushioning materials; B, placing support adjacent to the painful metatarsal; C, making an excavation under the painful metatarsal; D, placing support proximal to the painful metatarsal head; E, adding a toe crest under the proximal part of the phalanx; F, a combination. Fig. 8. The types of support for temporary or permanent orthotic therapy. Example, central ray overload: A, temporary padding with flexible materials at the forefoot; B, simple flat insole of flexible material; C, full foot insole with second layer of flexible material adjacent to the painful metatarsal; D, forefoot extension added to a prefabricated, semiflexible, Birkocork orthotic (Birkenstock, Novato, CA): E, forefoot extension added to a molded rigid polypropylene orthotic with a rearfoot varus post of epoxy putty. In summary, the forefoot extension should include modifications to balance the metatarsal load and unload the painful metatarsals. The orthotic is completed by covering it with a top layer of flexible material from heel to toe. control of forefoot or rearfoot varus by medial p~sting.~ The construction of the orthotic is further determined by the nature of the patient's pathology, symptoms, age, and the length of time therapy is needed. Temporary problems may be treated with flexible materials taped to the foot or by using a simple flat insole. If only symptomatic forefoot management is needed then a flat insole with the appropriate forefoot extension is used.35 The fabrication of plastazote insoles has been thoroughly described by Glass et al.' The management of arthritic patients by using prefabricated semiflexible orthotics, flexible forefoot extensions, and extra depth shoes has been described by Moncur and shield^.^' If midfoot padding, longitudinal arch support or biomechanical control is indicated then the forefoot modifications are added to a %length orthotic shell made from appropriate materials (Fig. 8). Particular attention should be paid to the rearfoot, as many forefoot conditions are caused or augmented by rearfoot pathomechanics. The

9 332 DOXEY JOSPT Vol. 6, No. 6 orthotic is fabricated according to biomechanical pathology; then following the establishment of biomechanical control, appropriate forefoot extensions are added. A variety of methods may be used to alter the weightbearing load at the metatarsals. Shaft padding relieves the symptomatic metatarsal head by transferring the load to the proximal metatarsal shaft. The first, second, and fifth metatarsals can be padded with flexible materials, while the third and fourth metatarsals can be supported with pearshaped metatarsal pads.lg The success of shaft padding requires placing the support just proximal to the metatarsal head and not underneath it.5,6 Medial or lateral longitudinal arch support can be used to provide support along the first or fifth metatarsal shafts and midfoot, thus increasing the total amount of foot contact with the cavus foot and controlling excessive motion with the pes planus foot. Forefoot extensions can be added to increase weightbearing under nonsymptomatic metatarsal heads. The fabrication considerations for constructing forefoot extensions are outlined in Table 2. Orthotic therapy should only be used with suitable footwear. Metatarsalgia patients should use shoes with a low heel, a stiff sole, and a large, rounded toe box.8~10827 The sole of the shoe may be modified by adding a metatarsal bar, which transfers part of the load to the proximal metatarsal shafts and midfoot. Shoes with a wedge sole allow a srrooth transition of force along the foot and support the medial arch. The rocker bottom sole is thicker at the rearfoot and midfoot but then tapers to form a high toe spring, so a natural rolling may occur across the metatarsal heads and toes. Extra depth orthopaedic shoes are par Syndrome First ray overload First ray insufficiency Central ray overload Central ray insufficiency ticularly indicated with patients that demonstrate moderate to severe forefoot deformity or with patients who only tolerate the more bulky, flexible orthotic materials. Intolerance to orthotic therapy may result from problems related to: the stage of foot pathology, foot pathomechanics, patient activity, prefabrication orthotic planning, fabrication, and footwear. The following sequence should be followed as an outline to the steps for orthotic therapy: 1) perform a complete clinical examination, 2) establish a diagnosis, 3) determine what orthotic features would provide adequate treatment, 4) fabricate the orthotic from the correct materials, 5) determine the therapeutic benefit of each of the orthotic's features by patient trial, 6) analyze the patient's gait, and 7) reevaluate the orthotic periodically. When prescribed and fabricated correctly, orthotic therapy will decrease pain, reduce callus formation, improve foot biomechanics, increase the patient's functional tolerance to activity, and delay the development of deformity in the foot. Orthotic therapy is a valuable treatment modality but should not be used at the expense of medical or surgical therapy that could provide a permanent solution to the problem. < SUMMARY The goals of orthotic management with metatarsalgia patients are to increase weightbearing tolerance, assist proper foot biomechanics, and normalize gait. Each orthotic must be individualized to each patient with respect to pathology, symptoms, and foot pathomechanics. Simkin3' concluded that metatarsalgia patients can be treated with "suitable insoles which reduce the TABLE 2 Considerations for fabrication of forefoot extensions with metatarsal syndromes* Metatarsal Arch Metatarsal and Metatarsal Shaft Padding support Toe Extension Head Excavation First Medial Secondfifth First First Medial Firstthird Under painful lesser metatarsal Second Optional First and fifth Under painful fourth central metatarsal First and fifth Medial Second First and/or fifth and fourth lateral * These guidelines are intended for balancing the metatarsal load at the metatarsals. Appropriate correction of the biomechanical function of the foot should be done on the 3hlength orthotic shell for varus or valgus alignments at the forefoot or rearfoot when present.

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