medial underside of the calcaneum. A negative test does not rule out pathology, as often th e history is more sensitive. Full musculoskeletal examination is required to check for feat ures of SpA such as arthritis/ enthesitis elsewhere and sacroiliitis. Examine for midfoot lesions Identifying speci \201 c midfoot lesions is dif \201 cult, th ough bony landmarks and discrete tender areas can be noted: \200 Twisting the midfoot may elicit pain nonspeci \201 cally. Common lesions include gout, OA, and synovitis associated with RA and SpA. Bony tenderness alone without soft tissue swelling does not rule out synovitis of an adjacent joint. The midfoot is a typical site for neuroarthropathy in diabetes. \200 Bony lumps (exostose s) that may have formed at sites of pressure are common in the foot (e.g., medial or dorsal aspect of the \201 rst MTP joint, base or head of the \201 fth metatarsal, distal talus, or over the midfoot). In the elderly bony pain and skin sores may form at these sites. Both gout and infection result in swelling, skin erythema and localized tenderness. Gout of the \201 rst MTP joint occurs at any one time in 70% of patients with the condition. It can occur anywhere in the foot. Examine the forefoot Check for bony or other swelling, digit separation, and examine the so le of the foot. Squeezing the whole forefoot at the line of the MTP joints is a nonspeci \201 c but useful screening test for painful forefoot lesions: \200 Tender swelling of th e whole toe (dactylitis) occurs in SpA (see Chapter 8), sarcoid (see Chapter 18), and HIV infection (see Chapter 17). Swelling is soft not bony. Tender bony swelling suggests a bunion and is common on the dorsal aspect of the toes and the \201 rst and \201 fth MTP joints. Forefoot splaying and interdigital separation suggests MTP synovitis or interdigital bursitis. MTP joints may be individually tender (simultaneously palpated wi th thumb below and \201 nger above). LOWER LEG AND FOOT DISORDERS (ADULTS) 127 Tenderness between metatarsal heads is typical in Morton \200\231s metatarsalgia. There may be a sensory de \201 cit in the interdigital cleft. The different ial diagnosis (in adolescents) may be osteochondritis of the second and third metatarsal he ad. Check for hallux rigidus \200\224passive dorsi \202 exion should be at least 50 . Extendi ng the big toe passively can reveal an ability to form a medial longitudinal arch in patien ts with \202 at feet (Jack \200\231s test). Discrete bony tenderness without swelling occurs with stress fractures. Uneven callus distribution under the forefoot may suggest an abnormally focused area of wei ght bearing and an underlying mechanical abnormality. Rashes on the sole of the foot are uncommon but important to consider are: pompholyx, pustu lar psoriasis, and keratoderma blennorrhagica (see Reactive Arthropathy in Chapter 8). Loss of sensation under the forefoot may be due to an S1 root lesion, peripheral neuropathy (e.g., diabetes), mononeuritis (e.g., vasculitis \200\224 see Chapter 14), Sj gren \200 \231s syndrome (see Chapter 11), mixed connective tissue disease), or, rarely, tibial nerve entrapment (examine hindfoot). Neurologic examination Neurologic examination is essential in cases where pain is neurogeni c or there is weakness, numbness, or paresthesias (see Table 2.22). Diagnostic procedures Imaging of the lower leg \200 Suspected tibial abnormalities such a s stress fractures and pseudofractures in osteomalacia and Paget \200\231s disease have characteristic radiologica l appearances. Periosteal changes occur in trauma, psoriatic arthritis (above ankle), hypertrophic pulmonary osteoarthropathy (HPOA), and pachydermal periostitis. In athletes with exercise-related pain, a triple-phase bone scan is part of the work-up for anterior shin pain. In suspected (but radiograph-negative) cases of bony disease such as cortical stress fracture, periostitis, or cortical hyperostosis, a bone scan may be useful to identify subtle pathology. Imaging of the foot Information available on radiographs of the hindfoot includes: \200 I ncreased soft-tissue attenuation around the tendon insertion in cases of Achilles tendonitis or retrocalcaneal bursitis. Erosions or periostitis at the Achilles tendon insertion in enthesitis associated with SpA. Erosions in gout and RA-associated retrocalcaneal bursitis. \200 Axial radiographs of the hindfoot are useful in showing talocalcaneal joint abnormalities, e.g., in RA. If radiographs are normal in patients with posterior heel pain, US can show patterns of ten don and bursal in \202 ammation. MR can further characterize any discrete pattern of tendo n injury. CHAPTER 2 Regional musculoskeletal conditions 128 Table 2.22 Patterns of common abnormal examination \201 ndings in lower lumbar nerve root lesions Nerve root Abnormal \201 nding L4 Weakness of ankle dorsi \202 exion (tibialis anterior) Patient \201 nds walking on their heel dif \201 cult (strong ankle dorsi \202 exion nee ded)* Reduced knee re \202 ex (L3 and L4) L5 Weakness of big toe dorsi \202 exion (extensor hallucis longus) Weakness of foot eversion (peroneal muscles, also S1) Sensory de \201 cit over dorsum of foot Reduced ankle re \202 ex (L5 and S1) S1 Weakness of ankle plantar \202 exion (gastrocnemius and soleus) Patient \201 nds walking on, or repeatedly rising onto, tiptoe dif \201 cult* Sensory de \201 cit over sole of foot Reduced ankle re \202 ex Maneuvers may be affected by pain, making interpretation dif \201 cult. Osteonecrosis of an os trigonum or posterior talar process or tarsal navicular may be ident i \201 ed by radiographs. It is invariably located by bone scan and can be characterized f urther, usually with soft tissue swelling, by MR. A plantar spur does not denote current plantar fasciitis. \200 Plantar heel pain may be d ue to a fracture in a spur. Erosions just above the spur may be seen. The thickness of heel fat pad can be gauged from its X-ray attenuation (thin = risk for plantar fasciitis). A fa t pad >23 mm thick in men and >21.5 mm thick in women is associated with acromegaly. Calcaneal fractures or an osteoid osteoma can be seen in some cases with radiographs alone. Bone scans/CT are more sensitive. \200 Patterns of joint, enthesi s, and tendon in \202 ammation can be documented using MR or bone scan. This is useful information when characterizing an arthrop athy. Bony abnormalities in the mid and forefoot are generally revealed by radiographs alone, tho ugh metatarsal stress fractures may be missed. MR can discriminate a plantar neuroma from i nterdigital bursitis and MTP joint synovitis. The former are probably best initially demons trated by US. Other Diagnostic procedures \200 Neurophysiology is a useful adjunct to clinical examinat ion in diagnosis of lower limb neuropathies, and can help discriminate between peripheral (common peroneal o r sciatic) or nerve root causes of foot drop, and also S1 root or tibial nerve entrapment c auses of paresthesias of the sole of the foot. LOWER LEG AND FOOT DISORDERS (ADULTS) 129 Joint/bursa \202 uid aspiration is mandatory in suspected cases of sepsis and should be s ent for culture (remember to consider gonococcus in young adults and TB in patients from en demic or inner-city areas). Fluid should be sent for polarized microscopy if a crystal-indu ced disease is suspected. Laboratory tests requested should re \202 ect suspicion of speci \201 c infective, in \202 ammatory, metabolic, or malignant pathology. Treatment Lower leg disorders \200 Anterior shin pain should be treated according to caus e. If there is also a problem of foot alignment then orthoses that support both the hind foot and mid arch may be very useful. Patients may volunteer that good walking shoes or sneakers help (as is the case with plantar fasciitis). Exercise-induced lower leg pain has a number of causes and includes shin splints and compar tment syndrome. The latter may require further investigation with pressure readings or exer cise scintigraphy ( 99m Tc-MIBI). In cases resistant to rest, analgesia, and modi \201 cat ion of triggering factors, decompressive surgery may be required. Patients with Paget \200\231s disease of the tibia may require treatment with high-dose bisphosphonates and will need a biomechanical assessment. Ankle and hindfoot disorders \200 Tendonitis around the ankle should respond to treatment of its underlying cause. Chronic posterior tibial tendonitis left untreated will eventually accele rate the development of hindfoot valgus. Consider heel and arch support orthotics early. Plantar fasciitis may respond to a number of conservative measures: heel pads and/or supportive shoes \200 modi \201 cation of weight-bearing activity \200 Achilles tendon stretching \200 hindfoot strapping \200 resting night splint (prevent ing ankle plantar \202 exion) \200 steroid injection around medial calcaneal tubercle \200 surgery Forefoot disorders \200 Localized forefoot pain, e.g., metatarsalgia, may respond to supp ort pads and a change to a wider, more supportive, low-heel shoe. The opinion of a podiatri st or orthopedic surgeon should be sought as required. \200 Forefoot stress fractures and metatarsal head osteochondritis require rest, supportive footwear and time to heal. Patients with chronic forefoot pain may bene \201 t from a podiatric assessment. \200\234 Stress of \202 oading \200\235 foot orthoses for metatarsalgia and other biomechanical abn ormalities (e.g., hallux rigidus) can be individually molded using thermoplastic materials. Steroid injections (see also Corticosteroid Injection Therapy) Steroid injections may be of value in the following: \200 Ankle joint in \202 ammation (e.g., RA, OA, gout) CHAPTER 2 Regional musculoskeletal conditions 130 Subtalar joint in \202 ammation \200 Tarsal tunnel syndrome \200 Achilles peritendinit is (local steroid injections for Achilles \200\231 nodules should be avoided if possible as the risk of rupture is high. The same concern, though prob ably lesser risk, applies to Achilles \200\231 peritendinitis) Calcaneal apophysitis (Sever \200\231s disease \200\224Achilles \200\231 tendon insertion) \200 Retrocalcaneal bursitis \200 Plantar fasciitis \200 Gout/OA/enthesitis at \201 rst MTP joint Surgery \200 Minor surgical techniques can be curative in tarsal tunnel sy ndrome and in excising an interdigital (Morton \200\231s) neuroma. Consider excision of pai nful exostoses and troublesome rheumatoid nodules and amputation of deformed or overriding toes. Major surgical procedures with good outcomes in appropriate patients include fusion of hind foot joints and forefoot arthroplasty in chronic in \202 ammatory arthritides. Osteotomy r ealignment of a hallux valgus deformity can be successful in the long term. This page intentionally left blank CHAPTER 2 Regional musculoskeletal conditions 132 Child and adolescent foot disorders For a review of classi \201 cation criteria of autoimm une juvenile arthritides see Chapter 7. Background Lower limb and foot deformities of babies may be noticed \201 rst by parents. Diagnostic evaluation needs to focus on ruling out major congenital dis- ease and exploring biomechanical factors. \200 Neonatal deformities of the leg are uncommon. \200 Talipes equinovarus (club foot) is an important deformity, which presents at birth. It is most commonly idiopathic and it is associated with wasting of the lower leg muscles. Causes to consider and rule out are spina bi \201 da, spinal dysraphism , cerebral palsy, and arthrogryposis. With babies, persistence of certain sleeping postures is associated with patterns of angular and torsion deformity involving the whole leg. Postures include pr one sleeping with knees tucked up under the chest, hips extended, or in a \200\234frog \200\231s-legs \200\235 position. In children able to walk, the most common conditions that present to pediatric orthopedic c linics are in-toeing and \202 at feet, though serious causes of \202 at feet usually af fect only older children. Important points in evaluating an in-toeing deformity and \202 at feet are shown in Table 2.23. Some deformities in this group have been associated with p ersistence of sitting postures, e.g., cross-legged or \200\234reverse tailor \200\235 ( \202 oor sitting, knees bent and legs splayed out/back) positions. Achiness in the feet is the typical symptom in young children with torsional leg deformities of signi \201 cance. If the biomechanical problem is suf \201 c iently severe, shoes can wear out quickly. Regional musculoskeletal lesions in children <3 years of age are rare but most in \202 amm atory arthritides can affect foot joints. Pain from an in \202 amed joint results in a mis erable child and a refusal to walk. Periosteal pain (hyperostosis) in the tibia and other long bones occurs in Caffey \200\231s disease. There is usually symmetric limb enlargement in this rare condition, which usually occurs before the baby is 6 months old. Taking a history Ask about the site and quality of the pain \200 Lower leg pain may be du e to one of the causes of \200\234shin splints \200\235, a bone lesion, or complex regional pain syndrome. Localized anterior lower leg pain occurs in lesions of the anterior tibia e.g., stress frac tures, periostitis, tibial tubercle osteochondritis, but deeper more diffuse anterior pain (often also medial) occurs in \200\234shin splints \200\235 (see below). Minimal or nontraumatic tibial fracture associated with fracture or bony deformity elsewhere raises the possibility of osteogenesis imperfecta. Localized or diffuse burning pain suggests a neurogenic cause. In children, disc prolapse is rare. Super \201 cial burning pain may be due to peripheral neu ropathy or complex regional pain syndrome. CHILD AND ADOLESCENT FOOT DISORDERS 133 Table 2.23 Common patterns of foot deformity in babies and infants Deformity Most common causes Features In-toeing Metatarsus varus Presents age 0 \200\2233 months or when starts to walk. Examination: forefoot varus only (h eel is in neutral or valgus). Over 80% correct without surgery though predicting which will is dif \201 cult: \200\234wait and see until age 3 \235 is appropriate Torsional lower limb deformity \200\224medial tibial torsion and/or excessive femoral antev ersion Often related to regular prone knee \200\223chest (fetal) sleeping position in babies andto ddlers, and persistently sitting on the \202 oor with legs forward internally rotatedand knees bent out/backwards in children (see Fig. 2.21) Cerebral palsy Most often caused by excessive femoral anteversion Spinal dysraphism Rare Flat feet (pes planus) Idiopathic or familial, hereditary connective tissue diseases, hindfoot disease: tarsal coa litions, arthritis, osteochondritis, infection etc. Very common \200\224often asymptomatic. Children often develop medial arch withtime (passiv e big toe extension or standing on toes often reveals it). It is associated with conditions of general tissue laxity. If it occurs with pain and/or stiff \202 at feet look for pero neal muscle spasm and hindfoot pathology as the cause Talipes equinovarus (club-foot) Idiopathic, spina bi \201 da, spinal dysraphism, tibial dysplasia, cerebral palsy, arthrog ryposis Incidence 1 \200\2232:1000 overall. Presents at birth. Idiopathic (etiology unknown) is mos t common. Often a family history. Examination: calf wasting, hindfoot and forefoot in equin us (plantaris) and varus Pes cavus Idiopathic, peroneal muscular atrophy High arch (medial and lateral sides), toe clawing. Associated with neurologic disease rarel y e.g., Friedrich \200\231s ataxia Complex regional pain syndrome (see Chapter 18) typically gives burning pain, although it can occur with dull, aching pain or paroxysms. Pain often disturb s sleep. In children it is more common in the lower leg and foot than in the upper limb. Di ffuse swelling and skin changes may be present. In many cases trauma is a triggering event but anything from simple sprains to arthroscopic knee surgery can trigger it; 25% are idiop athic. In children, complex regional pain syndrome may occur in the limb distal to an arthritic joint. CHAPTER 2 Regional musculoskeletal conditions 134 Unremitting, sleep-disturbing pain that is worse on weight bearing suggests bone or bone marrow pathology e.g., bone tumors, osteomyelitis, or periost itis (hypertrophic pulmonary osteoarthropathy, Gaucher \200\231s disease). Ask about pain onset during sports There are typical sports injuries of the lower leg that occur relatively often in active children and adolescents. Ask about pain onset during spor ts or recurrence during or after speci \201 c activities: \200 Adolescents may refer to \200\234shin splints. \200\235 Possible conditions include: tibial stress fracture, Osgood \200\223Schlatter \200\231s disease, tibialis posterior fasciitis, compartment syndrome, p opliteal artery stenosis, and malalignment of the hind- and midfoot. Tibial fascial in \202 ammation and pain typically occurs as running begins. Patients can run through it, but it often returns severely after exercise and takes days to wear off. It is associated with hyperpronation of the foot (which increases stretch forces on the tendo n). Compartment syndrome may be acute (due to muscle necrosis) or chronic. The chronic form occ urs almost exclusively in endurance sports. Pain is absent at rest but builds as exercise p rogresses. It diminishes gradually \200\224usually within a few hours. The pattern of pain and \201 ndings from perfusion scintigraphy suggest the cause of pain is ischemic. Increa sed compartment pressures can be demonstrated by invasive monitoring. Pain from major vessel ischemia (i.e., claudication) typically occurs with exercise. Muscle or a \201 brous band in the popliteal fossa can compress the popliteal artery. Stress fractures occur in young athletes. In girls there may be an association with amenorrhea and generalized osteopenia. Are there regional traumatic lesions? In the foot, regional traumatic lesions are quite com mon, particularly in active children and athletes. Chronic arthritides should be considered : \200 Apophysitides (osteochondritides) are quite common (see Table 2.24). Most present with localized pain during exercise. There is tenderness and often swelling and pain on res isted movement of the appropriate tendon. Proximal midfoot pain may be caused by an accessory navicular, navicular osteochondritis (K hler \200\231s disease), and tarsal coalitions (abnormal joins between bones leading to joint hypomobility, bilateral in 50% of cases). All lesions may be associated with a rigid \202 at foot (peroneal spastic \202 at foot) and will be more painful on weight bearin g. Joint synovitis (pain with immobility-related stiffness) is often dif \201 cult to detect clinically. Ankle synovitis is the easiest to be con \201 dent about. Soft or sp ringy swelling with tenderness over the dorsal skin crease often suggests an effusion. Syno vial thickening can be felt in \202 orid cases circumferentially or just around the lower margins of the malleoli. In oligoarticular JIA the ankle joint is sometimes painlessly swo llen. \200 Juvenile SpA/ERA is rare in children aged <8, and up until that age oligo/poly articular JIA is a more likely cause of joint synovitis in the CHILD AND ADOLESCENT FOOT DISORDERS 135 Table 2.24 Localized painful foot disorders speci \201 c to school-age children and adoles cents. Tumors are rare but osteoid osteoma should be considered Site of pain Disorder Characteristics of disorder Posterior heel Calcaneal apophysitis (Sever \200\231s disease) Traction osteochondritis. Both sexes age 8 \200\22310 years Dorsal midfoot Accessory navicular Common \201 nding in all children (50%). In 75% it fuses with main navicular. Majority no t painful. Rarely it is associated with exercise-related pain Navicular osteochondritis (K hler \200\231s disease). Boys > girls. Presents with pain, limp and weight bearing on the outside of the foot Tarsal coalitions Asymptomatic or with peroneal spastic (rigid) \202 at foot (8 \200\22316 years) Medial side of foot (may be diffuse) Hypermobile \202 at foot Children 1 \200\2235 years. May have generalized tissue laxity Lateral side of foot 5th metatarsal base osteochondritis (Iselin \200\231s disease) Children 10 \200\22312 years. Possibly due to tendon ossi \201 cation and related to tight shoes Dorsal and plantar distal midfoot Stress fracture (rare) Adolescents \200\2242nd/3rd metatarsal Metatarsal head osteochondritis (Freiberg \200\231s disease) Commonly 2nd metatarsal head. Affects active adolescent girls most frequently foot. Juvenile SpA/ERA may present with synovitis in a single lower limb joint, enthesitis at the Achilles tendon insertion or plantar fasciitis. Dactylitis ( \200\234sausage toe \200\235) raises the possibility of psoriatic arthritis or sarcoid. History usually discriminates the pattern of arthritis that helps in the differen tial diagnosis. The most common other arthritides to involve foot joints are viral and poststreptococcal arthritis and Lyme disease. Diffuse foot swelling occasionally occurs with synovitis in oligo/ polyarticular JIA. The m ajor differential is complex regional pain syndrome. Both pains are worse at night. Sensory symptoms are prominent and skin changes common in established complex regional pain syndro me. Forefoot pain in adolescents may be due to an interdigital neuroma (Morton \200\231s metata rsalgia) or osteochondritis of a metatarsal head (Freiberg \200\231s osteochondritis). Neur oma pain is often associated with dysesthesia and numbness between the toes. Big toe pain from hallux rigidus (<50 passive dorsi \202 exion) is rare but can occur after injury and prevent running. Unlike in adults, gout occurs rarely in children and usually only in the context of renal f ailure, glucose 6-phosphatase de \201 ciency (von CHAPTER 2 Regional musculoskeletal conditions 136 Gierke \200\231s), malignancy, or X chromosome-linked disorders of uric acid metabolism. Examination Observe the lower legs from front and back while the patient is standing: \200 Lower leg muscle wasting occurs in hereditary sensorimotor neuropathy (bilateral) and typically accompanies spinal dysraphism. Diffuse muscle hypertro phy might suggest muscular dystrophy. \200 Extremity swelling occurs in some forms of JIA (see Chapter 7), vasculitis (e.g., Henoch \200\223Sch nlein purpura (HSP) \200\224see Chapter 14) and sep sis (see Chapter 17). Note the appearance and distribution of any rashes. Skin conditions from venous abnormaliti es are common. Other skin lesions that may be relevant include purpura (HSP) and panniculit is over the shins (erythema nodosum/sarcoid \200\224see Chapter 18). Observe the feet from front and back while the patient is standing \200 Look for swelling and patterns of deformity. Patterns of deformity may require detailed orthopedic assessment. Check the gait. Look for localized edema \200\224an occasional sign of underlying JIA but also present in n ephrotic syndrome and in systemic vasculitides. \200 Some torsional leg deformities are c linically signi \201 cant. The most common pattern is with the hip internally rotated (usually excessive femoral anteversion), the tibia compensating in external rotation, and associated hindfoot valgus and forefoot va rus. Flat feet are often asymptomatic and familial, and regress as the child grows (the medial a rch becomes evident standing on tiptoe and with passive big toe dorsi \202 exion). Hindfoo t pathology may be a cause. Examine the sitting patient With the patient sitting on the edge of the couch, check for ti bial torsion: \200 Tibial torsion is measured as the angle between an imaginary line through the tibial tubercle in the sagittal plane and the perpendicular of an imaginary lin e through the malleoli (see Figure 2.22). Examine the supine patient With the patient supine on the couch, examine the lower leg: \200 Check for bruising, swelling, and tenderness around the \201 bular head in patients with foot drop (peroneal nerve palsy). Localized anterior tibial tenderness is often found in patients with stress fractures. Examine for swellings in the foot \200 Bony lumps (exostoses) that may have formed at sit es of pressure (e.g., a \200\234pump bump \200\235 at the posterior heel). Swelling, skin erythema and localized tenderness suggests infection, although synovitis, sk in vasculitis and panniculitis (e.g., erythema nodosum) should also be considered. Examine the hindfoot In the hindfoot, examine for joint and tendon synovitis, palpate speci \201 c structures, and test passive hindfoot joint mobility: CHILD AND ADOLESCENT FOOT DISORDERS 137 Synovitis of hindfoot joints is not always easily detected. With ankle joint synovitis thic kened tissue may be felt anteriorly in the ankle crease (where there may be a \200\234spri ngy fullness \200\235, like foam rubber) or laterally around the malleoli. The pain of plantar fasciitis may be elicited by \201 rm palpation of the medial undersid e of the calcaneum. ERA should be ruled out. Posterior tibial and peroneal tendonitis are associated with soft tissue swelling of the me dial and lateral hindfoot, respectively. Synovial thickening from ankle and talocalcaneal j oints may also be felt there and synovitis of structures may coexist in JIA or ERA. Resisti ng a tendon \200\231s movement to elicit speci \201 c tendon pain may not be a speci \201 c test. Painful posterior heel structures are usually easily palpated, though pain may be due to a number of causes including Achilles \200\231 enthesitis, mechanical damage to the tendon, r etrocalcaneal bursitis, and apophysitis. The loss of passive hindfoot movements is not speci \201 c. Often due to ankle synovitis, stiffness may also occur in other causes of joint pain (e.g., osteochondritis dissecans) an d cases of peroneal spastic \202 at foot. The hindfeet of children are more mobile than t hose of adults. \200 Peroneal spastic (rigid) \202 at foot syndrome should be distingui shed from \202 exible \202 at foot (when the medial longitudinal arch reappears when st anding on the toes or with passive big toe dorsi \202 exion). Pain is centered on the dors omedial side of the foot. The medial longitudinal arch is de \201 cient. Associated perone al muscle spasm may be painful. The age of presentation depends on the etiology, the most c ommon cause being tarsal coalition. It is always important to consider cerebral palsy and s pinal dysraphism as well as local lesions: tumors (e.g., osteoid osteoma of calcaneum); nav icular osteochondritis (K hler \200\231s); local osteomyelitis or pyogenic arthritis; an kle or talocalcaneal joint synovitis (e.g., JIA). AP, lateral, oblique, and axial talocalca neal radiographs, a three-phase bone scan, and hindfoot CT may all be useful in de \201 ni ng associated hindfoot lesions. Examine the midfoot In the midfoot determine any sites of tenderness and stiffness: \200 Twisting the midfoot may elicit pain from lesions, although this can be nonspeci \201 c. The major condition to rule out in teenagers is tarsal coalitions. These are \201 brous, cartilaginous, or osseous joins between bones resulting in no or little mobility. The most commonly involved joints are the calcaneonavicular and the talocalcaneal. They may be tende r. Passive movement with inversion is usually painful and increases spasm in peroneal muscl es. A tender navicular may also be due to osteochondritis. \200 Synovitis associated with som e forms of JIA can occur at any joint. The precise location is often dif \201 cult to identify clinically. CHAPTER 2 Regional musculoskeletal conditions 138 (a) (b) (c) (d) (e) Fig. 2.22 Femoral anteversion, retroversion, and tibial torsion. (a) Where the femoral neck angulates excessively forward relative to an imaginary axis through the femoral condyles, the hip is anteverted. (b) Femoral neck anteversion can lead to a greater-than-usual range of hip internal rotation and a toe-in gait. (c) and (d) Retroversion, where the femoral nec k angulates posteriorly relative to a femoral condyle axis, can cause a toe-out gait. (e) T oeing can also be caused by excessive medial tibial torsion. Normally the ankle mortise fac es 15 externally relative to a sagittal plane axis through the tibial tubercle (arrow) bu t in medial torsion it faces forward or internally. CHILD AND ADOLESCENT FOOT DISORDERS 139 Examine the forefoot Check for bony or other swelling, look for digit separation, examine t he digits and the sole of the forefoot. Squeezing the whole forefoot at the line of MTPs is a useful but nonspeci \201 c screening test for painful forefoot lesions: \200 Dactylit is (psoriatic arthritis or sarcoid) swelling is soft, not bony. \200 Forefoot splaying an d interdigital separation suggests MTP synovitis. MTPs may be tender when palpated (simulta neously with thumb below and \201 nger above). Tenderness between two metatarsal heads is typical in Morton \200\231s neuroma. The differential (in adolescents) may be osteochondritis of the second or third me tatarsal head. Extending the big toe passively can reveal an ability to form a medial longitudinal arch in patients with \202 at feet (Jack \200\231s test). Discrete bony tenderness without swelling may occur with stress fractures. Loss of sensation under the forefoot is rare. Full back and neurologic leg examination may be necessary. Diagnostic procedures Imaging of the lower leg \200 Radiographs of the lower leg have cha racteristic patterns of abnormality in osteogenesis imperfecta, rickets, and some periosteal conditions, e.g., from stress fracture or periostitis, etc. Bone scan is a sensitive investigation for radiograph-negative cases of suspected bone dise ase. It is also a useful initial investigation in adolescents with shin splints as it will rule out stress fractures and can show tibialis fasciitis. Treadmill or cycle ergometer exercise scintigraphy using 99m Tc-MIBI can be useful in revealing compartmental perfusion defects in athletes with ischemic-type p ain during exercise (another cause of shin splints). Imaging of the foot Local lesions require investigation with radiographs, but in patients w ith in \202 ammatory or bony lesions, further imaging may be necessary: \200 Routine AP and lateral hindfoot radiographs will reveal most cases of Sever \200\231s disease and oste ochondritis dissecans of the ankle. Some cases of talocalcaneal coalition will require extr a views and CT for diagnosis. In patients with a rigid \202 at foot, additional oblique and axial view radiographs of the hindfoot help show osteoarticular abnormalities if routine AP and latera l views do not. The gold-standard investigation is CT which is used to plan for surgery. Forefoot radiographs are a good screening test in those with forefoot pain. Radiographs are insensitive for detecting early synovitis, but are useful for identifying osteochondritide s, hallux abnormalities, and the pattern of established arthritis. It is important to check a radiograph for \201 rst MTP osteochondritis dissecans in those with hallux rigidus. Isolated soft tissue swelling may be due to complex regional pain syndrome, underlying syno vitis, or infection. Radiographs are CHAPTER 2 Regional musculoskeletal conditions 140 mandatory. Bone scan may be nonspeci \201 c in this setting, but can be useful to diagnose complex regional pain syndrome. MR of the whole foot or swollen area is the quickest way to an advanced differential diagnosis. Where swelling, pain, and tenderness coexist, infection must be ruled out using imaging. If it cannot and suspicion remains, tissue or \202 uid sampling should be undertaken. In mo st cases it is appropriate to do this under general anesthesia. Complex regional pain syndr ome should be excluded before any intervention. Laboratory tests Any possibility of joint synovitis (most likely at the ankle), enthesitis, ten- donitis, or infection requires investigation with laboratory tests: \200 ESR and CR P are likely to be raised in cases of in \202 ammatory arthritis and infection, and are more likely to be normal or only slightly increased in oligoarticula r JIA and juvenile ERA compared with polyarticular and systemic JIA or infection. Normochromic anemia ( mild microcytosis) is a nonspeci \201 c sign of a systemic conditi on. CBC may be normal in oligoarticular JIA. Leukocytosis is typical with infection, with s teroids and in systemic JIA. Thrombocytosis can be seen in all forms of JIA. If the ESR and CRP are elevated, but the pl atelet count is low, malignancy should be considered. Moderately elevated titers of ANA may be present in 40 \200\22375% of patients with oligoar ticular JIA; a positive ANA is a risk factor for associated uveitis. Even minimally symptom atic uveitis can threaten vision if not treated. Check for circulating rheumatoid factor (RF) and anti-citrullinated protein antibodies (ACP A) in cases of synovitis. High titers are expected in (RF+) polyarticular JIA. Treatment Lower leg disorders \200 Anterior shin pain should be treated according to caus e. \200 Treat foot alignment problems with appropriate orthotics. \200 Review diagnosis if conservative treatment fails, e.g., is there an underlying stress fracture or periostitis? Consider obtaining a bone scan. Ankle and foot disorders \200 The management of bony anomalies/deformities should be disc ussed with an orthopedic surgeon and physical therapist early, to avoid missing an opportun ity to prevent growth abnormalities. Be aware that soft-tissue steroid injection of a presumed local lesion may impair healing/g rowth at apophyses and may aggravate the symptoms of (missed) complex regional pain syndrom e. \200 Consider intra-articular steroid injection of speci \201 c joints in oligoarticular JIA if joints can be clearly identi \201 ed by bone scan or MR. Use of seda tion (adolescents) or light general anesthesia (toddlers/ children) may be appropriate. This page intentionally left blank CHAPTER 2 Regional musculoskeletal conditions 142 Corticosteroid injection therapy Background \200 Local anesthetic and steroid injection i nto joints or soft tissues is a very effective treatment for localized pain. Injection offers a local maximal anti-in \202 ammatory effect with minimal systemic absorption. The indications for local steroid injection include: to reduce in \202 ammation in joints, entheses, tendon sheaths and bursa; to relieve pain from in \202 ammatory ligament lesions; to relieve in \202 ammation at sites of nerve compression; to attempt to reduce the size of nodules and ganglia; to relieve pain at trigger points; a nd as part of epidurals. The contraindications are: Absolute: \200\224 septic arthritis/septicemia \200\224 febrile patient, cause unknown \200\224 se rious allergy to previous injection \200\224 sickle cell disease Relative: \200\224 neutropenia, thrombocytopenia \200\224 anticoagulation or bleeding disorder. Hydrocortisone acetate is a short-acting, weak anti-in \202 ammatory, useful for super \201 cial lesions such as tendons and bursae. A dose of 25 mg is typical. Methylprednisolone acetate (40 mg/ml), prednisolone acetate (25 mg/ ml), and triamcinolone acetonide (10 and 40 mg/ml) are long-acting synthetic agents suitable for joint injections. Small joints accept only a small volume; thus, for IPs, MCPs, MTPs, ACs, and TMs, 0.5 ml of triamcinolone acetate (10 mg) is appropriate. All other joints shou ld accept at least 1ml. Choice of strength of steroid remains empiric. There may be merit i n diluting the steroid in sterile saline, to increase volume for better distribution in lar ger joints. The patient should be warned of potential, though uncommon, side- effects: \200 exacerbation of pain for 24 \200\22348 h \200 septic arthritis and reacti vation of TB \200 tissue atrophy (less likely with hydrocortisone than others) \200 dep igmentation \200 anaphylaxis \200 nerve damage \200 tendon rupture \200 avascular n ecrosis \200 cartilage damage \200 soft-tissue calci \201 cation \200 temporary exac erbation of hyperglycemia in diabetes. As a general rule it is recommended that any one joint should not be injected more than fou r times in 12 months and there are at least 6 weeks between injections. Children and some adolescents usually require a light general anesthetic for most joint injections given the procedure can be quite CORTICOSTEROID INJECTION THERAPY 143 traumatic. An alternative for older children or those who have had many injections done bef ore is to use local anesthetic gel pads (e.g., EMLA patch) to numb skin adequately befor e the injection. Principles of injection techniques The procedure need not necessarily be done in a sterile environment. Some steps below illustrate the need to maintain relatively aseptic conditions : \200 Mark the exact spot of needle insertion. \200 Wash hands. Use sterile gloves for procedure. \200 Clean the skin with povidone-iodine and allow to dry. \200 Anesthetize the skin (either with local anesthetic or refrigerant alcohol spray). Insert clean needle with empty syringe and aspirate back. \200 Leave needle in place, det ach syringe, and place syringe containing drug onto end of needle. Pull back syringe plunger again before injecting to con \201 rm placement. \200 Introduc tion of steroid should be effortless. Resistance implies that the needle is in the wrong space. On completion, remove syringe and needle and throw away \200\234sharps \200\235. \200 Co ver the injection site with clean gauze or bandage. \200 Re-emphasize possible side effec ts and bene \201 ts. The glenohumeral joint \200 The anterior route gives reliable acces s in patients with adhesive capsulitis. It is also better suited for aspiration of joint ef fusions. Palpate the coracoid process anteriorly and the acromion posteriorly. The injection is made just lateral to the coracoid with the needle pointing toward the acromion. The posterior route requires the clinician to palpate the spine of the scapula with the thu mb to its lateral end where it bends forward as the acromion. With the fore \201 nger then palpate the coracoid anteriorly. The line between \201 nger and thumb then marks the pos ition of the joint line. The needle is advanced from behind, 1 cm below the acromion, and t oward the coracoid. There should be no resistance. \200 Withdrawing the needle slightly, and redirecting 30 upward will allow you to reach the rotator cuff with the same procedure! Subacromial articulation and acromioclavicular joint \200 The subacromial bursa is approa ched from the lateral side. To inject this space, the arm is placed in a neutral position, hanging to the side, and the gap between the acromion and the humeral head is palpated. The needle is directed medially and slightly posterior and not too deep (see Plate 13). The AC joint is located by following the clavicle laterally. The joint is often tender to p alpate. The patient lies supine and a small gauge needle with 0.5 ml of steroid is directed into the joint at about 45 anteriorly.