Evaluation of limp in children

INTRODUCTION — The evaluation of the limping child is reviewed here. An overview of specific causes of limp in children is presented separately. (See "Overview of the causes of limp in children".)

EPIDEMIOLOGY — Limp is a relatively common complaint in childhood. Many conditions may manifest with a limp (table 1) [1,2]. Based upon small observational studies of presentations to the emergency department or primary care practice, the hip and the knee are the most common locations for pathology; minor trauma and toxic synovitis of the hip predominate as the typical cause for limp [3,4]. Thus, most children with limp who are evaluated in these primary or emergency care settings do not require specialty referral. The cause of limp usually can be determined through a careful history and physical examination with selected ancillary studies. While most cases of limp are caused by benign self-limiting conditions that resolve spontaneously [3], life- or limb-threatening conditions can occur and must be diagnosed promptly (table 2) [5].

NORMAL GAIT — Most children are able to walk with assistance by the time they are 12 months of age, to walk independently at 15 months, and to run by 18 months [2,6]. The normal gait is smooth, rhythmic, symmetric, and effortless (figure 1).

Relative to older children and adults, the gait of children younger than 3 to 3.5 years of age is notable for:

●Increased flexion of the hips, knees, and ankles, which provides a lower center of gravity and facilitates balance

●Rotation of the feet externally and more spread in relation to the shoulder width, providing a wider base of support

●A smaller percentage of the gait cycle spent in single limb stance

●A faster cadence but slower velocity because of shorter stride length

Children have typically achieved the adult pattern of gait by seven years of age. The biomechanics of a normal gait and the assessment of gait in athletes is discussed separately. (See "Clinical assessment of walking and running gait".)

DEFINITION OF LIMP — Limp is defined as an abnormality in gait that is caused by pain, weakness, or deformity [1,2,6,7]. In toddlers and young children, conditions that cause limp may present as a refusal to walk or stand. At times, ataxia may masquerade as a limp, but a careful examination usually distinguishes this condition based on the absence of tenderness, weakness, or deformity, and the presence of movements, often involving the trunk or upper extremities as well as the lower extremities, characteristic of cerebellar dysfunction.

Limp can be further described by gait pathology, which can help narrow the differential diagnosis (table 3):

●Antalgic gait – Antalgic gait is the most common type of limp encountered in children; it is characterized by a short stance phase on the affected extremity due to pain. An antalgic gait is associated with bone and soft tissue trauma, infection, inflammation, and bony lesions.

●Toe-walking gait – A child will toe-walk due to heel pain, calf pain, idiopathic heel cord tightness, or neurologic abnormality with increased flexor muscle tone in the lower leg. Examples of conditions that may present with toe-walking include cerebral palsy, peripheral neuropathy, hereditary spastic paraparesis, or spinal cord disorder [8]. Influenza A may cause acute calf myositis with self-limited toe-walking.

●Stooping gait – A stooping gait with hips flexed throughout the gait cycle suggests psoas muscle or obturator nerve irritation associated with appendicitis, psoas muscle abscess, pelvic inflammatory disease, ovarian torsion, or testicular torsion.

●Trendelenburg gait – Trendelenburg gait describes a downward pelvic tilt or shift toward the unaffected limb as it swings through caused by gluteus medius muscle weakness or spasm in the affected leg when it is in stance phase (picture 1). This gait frequently accompanies slipped capital femoral epiphysis, Legg-Calvé-Perthes disease, and developmental dysplasia of the hip.

●Steppage gait – Patients with a foot drop due to neurologic disease display exaggerated hip and knee flexion as the affected leg swings through to keep the foot from dragging on the floor. It is often accompanied by a slap of the foot during heel strike.

●Vaulting gait – Patients with limb length discrepancy or abnormal knee mobility maintain the knee hyperextended and locked at the end of stance phase and "vault" over the affected leg.

CAUSES — The causes of limp in children and differentiating features are provided separately (table 2). (See "Overview of the causes of limp in children".)

Etiologies of limp in children can also be organized according to age (table 4), the location of abnormal physical findings (table 1) or type of gait abnormality (table 3) [3,9-11].

In addition to pathology in the lower extremity, limp can also be caused by abnormalities of the nervous system, back, abdomen, or genitourinary tract (see 'Physical examination' below). The location of pain does not always reflect the location of pathology [2,3]:

●Hip conditions can cause pain in the knee or thigh

●Abdominal conditions may cause hip or thigh pain

●Back conditions may have referred pain down the back of the leg or to the lateral thigh

EVALUATION — A careful history and physical examination provide important information regarding the likely cause for the limp and guide the approach to radiographic studies and laboratory testing. Life-threatening or emergency conditions must be diagnosed promptly (table 2).

History — Several historical features help identify possible causes for limp (table 5) [1,2,7,12]:

●Age – Several conditions are much more likely, depending upon the patient's age (table 4).

●Duration – Limps of acute onset are typically due to trauma or acute infection.

Chronic limps more often arise from Legg-Calvé-Perthes disease, slipped capital femoral epiphysis (SCFE), rheumatic disease, malignancy, benign bone tumor, developmental dysplasia of the hip, overuse syndromes, apophysitis, osteochondrosis, leg length discrepancy, or neuromuscular disease.

Certain pathogens (eg, Kingella kingae and tuberculosis) can also cause indolent forms of osteomyelitis or bacterial arthritis.

●Trauma – Soft tissue injury (eg, superficial or deep muscle contusion, ligamentous sprain, or muscle strain) and fractures often have a history of prior trauma. Toddler's fractures are notable because the trivial trauma that can cause this injury may often be unknown or overlooked by the caregiver. A history of trauma may be absent or implausible in cases of child abuse.

A history of trivial trauma can be misleading in patients with an underlying osteomyelitis and delay diagnosis. (See "Hematogenous osteomyelitis in children: Clinical features and complications", section on 'Clinical features'.)

●Fever – Fever suggests possible osteomyelitis and septic arthritis. Toxic synovitis may also present with an associated viral illness and fever. Acute rheumatic fever, systemic juvenile idiopathic arthritis (JIA), systemic lupus erythematosus, and leukemia are rare causes of fever and chronic limp. Fever may also be present among children with myositis due to viral infection, such as influenza.

Occasionally, an intercurrent febrile illness may obscure the diagnosis of a traumatic injury.

●Pain characteristics – Children with limp often have difficulty describing and localizing pain. However, certain pain features can help narrow the anatomic region and diagnoses of concern:

•Constant severe pain that is localized and consistently reproducible is seen with fractures, septic arthritis, osteomyelitis, and sickle cell disease.

•In addition to knee pathology, knee pain may signify referred pain from hip pathology (eg, SCFE or Legg-Calvé-Perthes disease) rather than knee joint disease.

•Back conditions may refer pain down the back of the leg or to the lateral thigh.

•The preference to crawl or walk on the knees in toddlers may indicate foot pain.

•Intermittent, less severe pain is characteristic of JIA, Legg-Calvé-Perthes disease, SCFE, Osgood-Schlatter disease, and transient synovitis.

•Cyclic pain that occurs at night or wakens the child suggests malignancy (eg, leukemia, osteogenic sarcoma, Ewing sarcoma) or benign bone tumors (eg, osteoid osteoma). (See "Overview of common presenting signs and symptoms of childhood cancer" and "Nonmalignant bone lesions in children and adolescents", section on 'Osteoid osteoma'.)

•Bilateral calf or thigh pain may indicate myositis, particularly in the setting of current infection with influenza.

•Lateral thigh pain may reflect sciatica and indicate a lumbar spine abnormality (eg, discitis, ruptured lumbar disc, vertebral osteomyelitis, spondylolisthesis, epidural abscess, or spinal cord tumor). (See "Approach to hip pain in childhood".)

•Pain that worsens with activity suggests stress fracture, overuse injury (eg, osteochondrosis or apophysitis), or hypermobility syndrome.

•Pain that improves with activity is characteristic of rheumatologic conditions and complex regional pain syndrome (reflex sympathetic dystrophy). Complex regional pain syndrome is also suggested by pain that is out of proportion to the history.

●Associated symptoms – Associated symptoms can help suggest specific etiologies:

•Morning stiffness ("gel phenomenon") is often found in patients with oligoarticular JIA.

•Incontinence, sciatica, or leg weakness suggests a spinal cord problem (eg, acute flaccid myelitis, epidural abscess, closed spinal dysraphism with a tethered cord, or spinal cord tumor).

•Abdominal pain accompanies immunoglobulin A vasculitis (Henoch-Schönlein purpura), appendicitis with periappendiceal abscess, psoas abscess, pelvic inflammatory disease, or ovarian torsion.

•Back pain may indicate discitis, vertebral osteomyelitis, spondylolysis, spondylolisthesis, spinal epidural abscess, or a herniated disc.

•Migratory arthralgias are characteristic of acute rheumatic fever and gonococcal arthritis.

•Rash with a limp may be seen in patients with:

-Immunoglobulin A vasculitis (Henoch-Schönlein purpura, palpable purpura (picture 2 and picture 3)) (see "IgA vasculitis (Henoch-Schönlein purpura): Clinical manifestations and diagnosis")

-Serum sickness and serum sickness-like reactions (urticaria (picture 4) and/or erythema multiforme minor (picture 5 and picture 6)) (see "Serum sickness and serum sickness-like reactions")

-Systemic lupus erythematosus (malar rash) (see "Clinical manifestations and diagnosis of systemic lupus erythematosus in adults")

-Gonococcal arthritis (pustular or vesicular pustular lesions on palms and soles (picture 7)) (see "Disseminated gonococcal infection")

●Past medical history – Pertinent past medical history includes:

•Upper respiratory viral illness may precede transient synovitis.

•Recent use of antibiotics (eg, penicillin, cefaclor, amoxicillin, or trimethoprim-sulfamethoxazole) is associated with serum sickness and serum sickness-like reactions; they may also alter the presentation of septic arthritis or osteomyelitis.

•Antecedent urogenital or gastrointestinal bacterial infection points to reactive arthritis.

•History of sickle cell disease supports vaso-occlusive crisis.

•History of hemophilia suggests spontaneous hemarthrosis.

•Patients with hypothyroidism, panhypopituitarism, and hypogonadism are at increased risk for developing SCFE. (See "Evaluation and management of slipped capital femoral epiphysis (SCFE)".)

Physical examination — A careful physical examination helps to narrow the differential diagnosis of the limping child, especially when physical findings suggest a likely site of abnormality either in the lower extremity or elsewhere (eg, the abdomen, spinal column, or neuromuscular system (table 1)).

Approach — Older children and adolescents usually can cooperate with the physical examination. For patients in significant pain, analgesia appropriate to the degree of pain should be provided before examination. (See "Pain in children: Approach to pain assessment and overview of management principles".)

The young and apprehensive or uncooperative child presents a significant challenge to obtaining a useful physical examination and requires patience on the part of the examiner. Pain may be the underlying cause of patient irritability or refusal to cooperate; judicious use of nonopioid analgesics (eg, ibuprofen or acetaminophen) may permit a better examination in some patients.

Children who refuse to bear weight on the leg should not be forced to walk until further assessment has excluded fracture or other serious pathology (eg, SCFE), which may be worsened by weight-bearing. Otherwise, the physician should enlist the parent or caregiver to help with gait evaluation by having them take the child for a walk in the room or hallway so that the gait can be observed. (See 'Gait' below.)

After evaluation of the gait or if gait evaluation is deferred, further examination is best performed with the young child sitting in the caregiver's lap. The physician should start by observing the child's appearance and positioning from a distance and observing how they hold or move the lower extremities. If the child is upset, the physician should permit time for the parent to calm the child. Distraction with a toy or bright object may also be useful. If a specific site of pain is suggested by the history, it should be examined last. In an uncooperative child, it is sometimes useful to have the parent palpate down the normal leg, and then palpate down the painful leg. This can often localize the painful area without the fear of the examiner.

If the source of the limp cannot be localized clearly by the history and simple observation (which is often the case in the young or nonverbal child), the clinician must perform a systematic physical examination of the spine, central and peripheral nervous system, hips, knees, ankles, and feet [7]. In addition, the abdomen and external genitalia should be examined to identify unusual causes of limp (eg, psoas abscess, pelvic inflammatory disease, or testicular torsion). Obvious traumatic injury on examination in the absence of a credible history suggests child abuse. (See "The pediatric physical examination: Back, extremities, nervous system, skin, and lymph nodes", section on 'Extremities' and "Evaluation of nontraumatic scrotal pain or swelling in children and adolescents" and "Emergency evaluation of the child with acute abdominal pain" and "Physical child abuse: Recognition".)

General appearance — Ill appearance or significant pain suggests a more serious cause of limp (table 2). Infectious or inflammatory etiologies are often associated with fever.

Gait — The particular type of gait abnormality helps to localize the problem, narrow the differential diagnosis, and direct the evaluation (table 3).

To examine the child's gait, the child should be asked to walk up and down the corridor several times with the legs exposed, permitting observation of several gait cycles. When the physician suspects pathology in the foot or toes, the feet should be bare, as well, or in socks. The child may need to be distracted to achieve the natural gait (versus trying to walk correctly for the examiner). Having the parents point out their specific concerns is also helpful [3].

When examining the child's gait, the examiner should pay particular attention to the following features:

●With an antalgic gait, the stance phase is shorter on the affected side.

●Circumduction (circular movement of the limb during swing phase) suggests an ankle or foot problem.

●Downward pelvic tilt during the swing phase (Trendelenburg gait) suggests hip pathology (eg, developmental dysplasia of the hip, SCFE, or idiopathic avascular necrosis of the hip [Legg-Calvé-Perthes disease]).

●Toe-to-heel sequence (toe-walking gait, as opposed to the normal heel-to-toe pattern) may indicate a neurologic problem, cerebral palsy, or idiopathic heel cord tightness.

●Lack of full knee extension in the stance phase implies knee pathology or possible limb length discrepancy.

Listening to the gait can also provide clues to particular gait abnormalities [13,14]. The cadence may be irregular because of an uneven or asymmetric gait. A foot slap may be heard in patients with a foot drop. Scraping may be heard in patients with spasticity.

Asking the child to run may unmask an abnormality that is caused by weakness or otherwise hidden by the child's compensation or self-consciousness. Asking the child to hop on one leg and then the other, and to walk on his or her heels and then toes (if developmentally able), may also disclose otherwise undetected weakness.

Abdomen and genitalia — Abdominal tenderness, rebound, guarding, or a positive psoas sign suggests appendicitis. Right lower quadrant pain may masquerade as right hip pain, especially in the toddler or preschool child. (See "Acute appendicitis in children: Clinical manifestations and diagnosis".)

Testicular torsion manifests with an exquisitely painful, swollen testicle and loss of the cremasteric reflex. Adolescent boys may not reveal significant testicular pain on history and often walk with a wide-based shuffling gait. (See "Evaluation of nontraumatic scrotal pain or swelling in children and adolescents".)

Penile or vaginal discharge may accompany gonococcal arthritis in the sexually active adolescent. (See "Disseminated gonococcal infection".)

Spine — The spine should be examined for abnormal curvature (kyphosis or scoliosis) or limited range of motion in flexion or extension. Limitations or asymmetry on forward bending may indicate spinal cord tumors or discitis. Midline abnormalities (eg, hair tuft, dimple, vascular or pigmentary lesions) may indicate an underlying spinal dysraphism [2,12].

Lower extremity — The examination should proceed from areas of least concern to the site of suspected pathology [9].

Inspection often helps to localize the cause:

●Bruising, swelling, or deformity supports bone or soft tissue injury after trauma.

●Physiologic or pathologic bowing of the tibias (genu varum) (figure 2) or knock knees (genu valgum) (figure 3) are straightforward findings. (See "Approach to the child with knock-knees" and "Approach to the child with bow-legs", section on 'Physiologic varus'.)

●The soles of the feet may demonstrate blisters, bruises, open wounds, foreign bodies, or plantar warts. Inspection of the shoes can indicate a wear pattern that suggests a particular gait abnormality (eg, toe walking) or a rough surface that is causing pain. Claw toes or a high arch (pes cavus) suggests an underlying neurologic condition, particularly if these findings are unilateral [12].

Joint swelling and limitation of motion may be present in several conditions that cause limp:

●Swelling and inflammation of a single joint, particularly in a febrile child, is suggestive of septic or Lyme arthritis.

●Swelling and pain in multiple joints suggests a rheumatologic condition, but less frequently can represent bacterial infection (eg, Neisseria gonorrhoeae).

●Joint swelling and pain in a child with no history or a history of minor trauma may be infectious or may indicate hemarthrosis as the initial presentation of a bleeding disorder [2].

Hemarthrosis is very common in children with hemophilia. Bleeding occurs most frequently in the ankle for the small child, but after age 5, hemarthrosis occurs more frequently in the knee and the elbow. (See "Clinical manifestations and diagnosis of hemophilia", section on 'Joints and muscle'.)

Limited range of motion of the hip is seen with SCFE, idiopathic avascular necrosis of the hip (Legg-Calvé-Perthes disease), transient synovitis, and a septic hip. Typically, the septic hip is exquisitely tender with any attempted range of motion, while patients with SCFE, idiopathic avascular necrosis, or transient synovitis tend to permit some range of motion.

Point tenderness of the bone or apophysis may indicate fracture, osteomyelitis, or an apophysitis or osteochondrosis such as:

●Osgood-Schlatter disease (tibial tuberosity) (see "Osgood-Schlatter disease (tibial tuberosity avulsion)")

●Sever disease (base of the calcaneus) (see "Heel pain in the active child or skeletally immature adolescent: Overview of causes", section on 'Calcaneal apophysitis (Sever disease)')

●Köhler disease (navicular bone of the foot) (see "Forefoot and midfoot pain in the active child or skeletally immature adolescent: Overview of causes", section on 'Köhler disease (navicular osteochondrosis)')

●Freiberg disease (head of the second metatarsal) (see "Forefoot and midfoot pain in the active child or skeletally immature adolescent: Overview of causes", section on 'Freiberg disease (metatarsal avascular necrosis)')

●Sinding-Larsen-Johannson syndrome (inferior patella) (see "Approach to chronic knee pain or injury in children or skeletally immature adolescents", section on 'Sinding-Larsen-Johansson disease (patellar apophysitis)')

●Iselin’s disease (fifth metatarsal) (see "Forefoot and midfoot pain in the active child or skeletally immature adolescent: Overview of causes", section on 'Iselin disease (fifth metatarsal traction apophysitis)')

●Osteochondrosis of the medial cuneiform

Muscle tenderness without bony tenderness supports myositis and primary pyomyositis (image 1).

Severe soft tissue pain and swelling in the setting of bruise or crush injury may indicate compartment syndrome; the affected muscle may feel hard to palpation and pain is increased by passive extension of the affected area and is often out of proportion to external findings. (See "Acute compartment syndrome of the extremities", section on 'Clinical features'.)

Limb length discrepancy should be assessed by measuring the length of the leg from the anterior superior iliac spine to the medial malleolus of the ankle. This finding may become apparent in young children with developmental dysplasia of the hip at the time they begin to walk. Young children with developmental dysplasia of the hip also have limited abduction of the affected hip, asymmetry in the position or number of the inguinal, thigh, or gluteal skin folds (figure 4 and figure 5), and a positive Trendelenburg test (figure 6) as described in greater detail separately (table 6). (See "Developmental dysplasia of the hip: Clinical features and diagnosis".)

Comparison of the thigh and calf circumference between the affected and unaffected limbs may reveal atrophy (more than 1 to 2 cm difference between sides) in patients whose function has been limited for more than one to two months [3].

Provocative testing — Provocative tests help to identify pathology of the hip and sacroiliac joint:

●Hip rotation – Evaluation of hip rotation helps to differentiate problems in the hip joint from periarticular hip disease. One method of evaluating hip rotation in children is to roll the thigh of the child while he or she is in the supine position. Rotation usually produces pain in all traumatic, infectious, or inflammatory conditions of the hip (figure 7).

Evaluation of internal rotation of the hips is performed with the child in the prone position and with the knees flexed; the ankles and feet are then rotated away from the body to compare the amount of internal rotation in the symptomatic versus the asymptomatic hip. The pelvis must be kept flat on the examining table; otherwise, asymmetry of internal rotation may not be appreciated. Decreased or absent hip rotation, a "lag of internal rotation," is particularly useful in raising the suspicion for SCFE and Legg-Calvé-Perthes disease; children with septic arthritis of the hip and even transient synovitis of the hip usually cannot tolerate this maneuver because of pain (figure 8).

●Galeazzi test – The Galeazzi test (also known as Allis or Perkins test) is useful in diagnosing developmental hip dysplasia or leg length discrepancy. This test is performed by putting the child in a supine position and then flexing the hips and knees. The feet should be placed side-by-side with the heels touching the buttocks [3]. The test is positive when the knees are of different heights (figure 9). (See "Developmental dysplasia of the hip: Clinical features and diagnosis", section on 'Asymmetry'.)

Leg length discrepancy can be caused by abnormal shortening or lengthening of either leg. Abnormal shortening of the leg can be caused by congenital aplasia or hypoplasia, developmental dysplasia of the hip, clubfoot, disuse or paralysis, ischemia, Legg-Calvé-Perthes disease, physeal injury or malunion after trauma, or a tumor that involves the physis. Abnormal lengthening of the leg can be caused by hyperplasia (eg, in hemihypertrophy syndromes), arteriovenous fistula, vascular tumors, and fractures (through distraction or stimulation) [15]. (See "Overview of the causes of limp in children".)

●Trendelenburg test – Asking the child to stand on the affected leg (the Trendelenburg test) causes a pelvic tilt (the unaffected hip is lower) in children with SCFE, Legg-Calvé-Perthes disease, or developmental dysplasia of the hip because of gluteal muscle weakness in the affected side (figure 6) [16].

●FABERE test – The sacroiliac joint is examined with the "figure of four" maneuver (also referred to as the Patrick or FABERE test). This maneuver consists of Flexion of the hip and knee, with ABduction and External Rotation at the hip, so that the ankle of one leg is on top of the opposite knee (a figure four configuration) (figure 10) [17]. Downward force is applied simultaneously to the bent knee and the opposite hip causing Extension of the sacroiliac joint. Pain with this maneuver in the absence of pain with passive hip joint motion suggests discomfort arising from the sacroiliac joint, although the sensitivity and specificity of the maneuver are limited [18].

Nervous system — Important findings on neurologic examination include:

●Pain radiating from the back to the lateral thigh with numbness suggests spinal nerve root impingement at the lumbar spine from a herniated disc, spondylolisthesis, or other pathology of the spinal column.

●Distal bilateral pain and paresthesias with weakness and diminished or absent deep tendon reflexes point to an acquired peripheral neuropathy. (See "Overview of acquired peripheral neuropathies in children".)

●Symmetric proximal muscle weakness in a young child with calf enlargement and normal reflexes supports the diagnosis of muscular dystrophy. Asymmetric weakness with diminished or absent reflexes characterizes acute flaccid myelitis. Ascending paralysis with decreased or absent deep tendon reflexes supports tick paralysis. (See "Etiology and evaluation of the child with weakness".)

Skin — Examination of the skin may reveal the characteristic rash of serum sickness, immunoglobulin A vasculitis (Henoch-Schönlein purpura), acute rheumatic fever (picture 8A-B), or Lyme disease (picture 9). (See "IgA vasculitis (Henoch-Schönlein purpura): Clinical manifestations and diagnosis" and "Diagnosis of Lyme disease" and "Acute rheumatic fever: Clinical manifestations and diagnosis".)

DIAGNOSTIC APPROACH — The history and physical examination should guide further evaluation.

Laboratory studies and/or imaging are usually not indicated in the child with an obvious cause for a limp such as:

●Superficial soft tissue injury

●Insect bite or sting

●Plantar wart

●Painful plantar vesicles of hand, foot, and mouth disease

●Friction blister

In addition, an afebrile child with a history of an acute limp but a normal physical examination, including a normal gait, does not typically warrant further investigation at the initial visit.

Otherwise, further evaluation is warranted in the limping child, especially in patients with the following features [1,2,11,19]:

●Three years of age and younger

●Signs of infection (eg, fever; exquisite joint tenderness with marked limitation of motion; or localized redness, warmth, or swelling)

●Limitation of joint movement on examination, especially at the hip

●Inability to walk

●History of chronic or intermittent limp

Acute limp — For this discussion, acute limp refers to patients with the new onset of limp within the previous 48 hours and without a history of previous unexplained episodes of limp.

Signs of infection — The evaluation of acute limp with signs of infection is further determined by whether tenderness is localized to the lower extremity or also involves the abdomen or back:

●Findings localized to the bone or joint – All patients with an acute limp and localized lower extremity signs of bacterial infection such as fever; exquisite joint tenderness with marked limitation of motion; focal bone tenderness; or localized redness, warmth, or swelling should undergo evaluation for osteomyelitis or septic arthritis that includes laboratory studies and imaging [1,2,11,19,20].

Recommended ancillary studies to add in diagnosis of osteomyelitis or septic arthritis in children are provided separately:

•(See "Hematogenous osteomyelitis in children: Evaluation and diagnosis".)

•(See "Bacterial arthritis: Clinical features and diagnosis in infants and children".)

Diagnostic studies for Lyme disease are also warranted if the child has arthritis and lives in or has traveled to a Lyme-endemic area. (See "Diagnosis of Lyme disease" and "Lyme disease: Clinical manifestations in children", section on 'Arthritis'.)

For children with concern for a septic hip, which can cause rapid joint destruction within hours and long-term morbidity, emergency ultrasonography is required to facilitate rapid diagnosis and emergency arthrocentesis. Ultrasonography is the preferred imaging study in these patients. Bedside ultrasonography by an appropriately trained physician should be performed whenever available because it is diagnostic and can also be used to guide emergency arthrocentesis. (See "Approach to hip pain in childhood", section on 'Septic arthritis'.)

By contrast, small effusions in patients who are able to bear weight often occur when the limp is caused by transient synovitis or Lyme arthritis. Joint aspiration is not indicated for the diagnosis or treatment of these conditions. (See "Approach to hip pain in childhood", section on 'Transient synovitis' and "Treatment of Lyme disease", section on 'Arthritis'.)

When joint aspiration is performed, synovial fluid analysis should include white blood cell count, Gram stain, anaerobic and aerobic cultures, and measurement of protein and glucose. Teenagers with synovial fluid suggesting bacterial arthritis and findings of disseminated gonorrhea (eg, tenosynovitis, dermatitis, or polyarthritis) should also undergo appropriate testing for genital gonococcal infection. (See "Synovial fluid analysis" and "Disseminated gonococcal infection", section on 'Laboratory and microbiologic testing'.)

●Findings of infection localized to soft tissue only – Patients with cellulitis or abscess involving a puncture wound on the sole of the foot or complicating an open wound in other regions may warrant imaging (ultrasonography and/or plain radiographs) to assess for a foreign body. (See "Minor wound evaluation and preparation for closure", section on 'Foreign body' and "Infectious complications of puncture wounds", section on 'Imaging'.)

Ultrasonography, often performed at the bedside, is also helpful for distinguishing a cellulitis from a cutaneous abscess. (See "Techniques for skin abscess drainage", section on 'Bedside ultrasonography'.)

Additional evaluation of cellulitis and abscess in the afebrile patient, including indications for culture are discussed separately. (See "Cellulitis and skin abscess: Epidemiology, microbiology, clinical manifestations, and diagnosis", section on 'Diagnosis'.)

Most children with benign acute myositis can be diagnosed clinically without additional evaluation. Patients with severe pain and marked limp or difficulty walking warrant evaluation for rhabdomyolysis including serum creatine kinase; serum calcium, phosphate, uric acid, electrolytes, blood urea nitrogen, and creatinine; and urine dipstick with urinalysis. (See "Rhabdomyolysis: Clinical manifestations and diagnosis", section on 'Laboratory findings'.)

Pyomyositis should be suspected on clinical findings and confirmed by magnetic resonance imaging (MRI) and/or culture of pus obtained during muscle drainage. (See "Primary pyomyositis".)

●Abdominal or back tenderness – Patients with fever, abdominal tenderness, and referred pain to the hip or thigh may have appendicitis or another acute abdominal process and warrant appropriate evaluation as described separately. (See "Acute appendicitis in children: Clinical manifestations and diagnosis", section on 'Evaluation and diagnosis' and "Emergency evaluation of the child with acute abdominal pain".)

Sexually active adolescent females with limp, lower abdominal and/or back pain, and vaginal discharge should undergo evaluation for pelvic inflammatory disease. (See "Pelvic inflammatory disease: Clinical manifestations and diagnosis", section on 'Acute symptomatic PID'.)

Fever in a patient with severe, localized back pain, especially if the pain is worsened by palpation or percussion, points to a diagnosis of spinal epidural abscess. If untreated, the patient typically develops nerve root pain ("shooting" or "electric shocks" in the distribution of the affected nerve root). Without intervention, symptoms may progress to neurologic deficits (sensory changes, motor weakness, and bowel of bladder dysfunction) and paralysis, which can quickly become irreversible. (See "Spinal epidural abscess".)

Localized findings, no signs of infection — In patients with localized findings to the lower extremity and no signs of infection, plain radiographs of the site of pain or tenderness usually are obtained first because they are readily available and are specific for fractures, destructive lesions, and avascular necrosis [2,19]. Both anteroposterior (AP) and lateral views should be obtained. Children with knee, ankle, or foot pain may warrant other views if a fracture is suspected (table 7). Patients with knee pain and limitation of motion at the hip should undergo knee and hip films to evaluate for hip pathology such as slipped capital femoral epiphysis (SCFE) with referred pain to the knee.

With the exception of radiographic evaluation of the hip, comparison views of the unaffected extremity are typically not necessary [2,19]. When imaging the hip, anteroposterior (AP) and frog leg views of the pelvis are the correct radiographs to obtain. The clinician should not order a unilateral hip series because a small SCFE could be missed in the absence of a direct comparison with the opposite hip. (See "Approach to hip pain in childhood", section on 'Imaging'.)

Males with limp and localized testicular pain should undergo evaluation for testicular torsion in consultation with a urologist with pediatric expertise. (See "Causes of scrotal pain in children and adolescents", section on 'Testicular torsion'.)

Acute compartment syndrome may rarely present with a complaint of acute limp. The key finding is pain out of proportion to the injury and localized to a tense muscle compartment. Paresthesias, diminished sensation, pallor, and paralysis are late findings that are variably present. The clinician should obtain an emergency orthopedic consultation to assist with direct measurement and interpretation of muscle compartment pressure. (See "Acute compartment syndrome of the extremities".)

No localized findings, no signs of infection — For young nonverbal children in whom there is no concern for infection and the specific area of pain or tenderness extremity cannot be identified, AP and lateral plain radiographs of the tibia and fibula of the affected side are appropriate initial studies to evaluate for a toddler's fracture [2,19]. Depending upon the history or gait pattern, radiography of the femur or foot may also be appropriate, especially if radiographs of the tibia and fibula are normal.

Alternatively, two-view (AP and lateral) hip to toe series of the affected extremity can be performed as the initial imaging study.

The prevalence of occult radiographic findings in children without a history of trauma and a normal physical examination has not been determined in prospective studies, and the prevalence in retrospective studies is inconsistent [10,21]. Nevertheless, even when a history of antecedent trauma and/or other localizing abnormalities on physical examination are lacking, up to 20 percent of such children may have an occult fracture, especially toddlers [10].

Subacute, chronic, or intermittent limp — For this discussion, subacute limp is defined as a limp present up to two weeks, chronic limp refers to a limp persisting beyond two weeks, and an intermittent limp is a limp with similar presenting features occurring at least two separate times.

Localized bone pain — Pain characteristics and physical findings determine the diagnostic approach:

●Nighttime pain or pain at rest – Patients with nighttime pain or pain at rest should undergo plain radiographs of the site to evaluate for primary malignant tumors of the bone or bony changes suggestive of other malignancies, such as leukemia, lymphoma, or neuroblastoma, or benign tumors, such as osteoid osteoma. In addition, the clinician should also obtain a complete blood count with differential and peripheral smear, ESR or CRP, serum alkaline phosphatase, and serum lactate dehydrogenase. (See "Overview of common presenting signs and symptoms of childhood cancer", section on 'Bone and joint pain'.)

Children with radiograph findings suggesting bone marrow infiltration or with additional findings of fever, pallor, bruising, lymphadenopathy, or a palpable spleen or liver should undergo further evaluation for leukemia or lymphoma as described separately (see "Overview of the clinical presentation and diagnosis of acute lymphoblastic leukemia/lymphoma in children"). Children with hypertension, an abdominal mass, proptosis, Horner syndrome, or opsoclonus-myoclonus syndrome warrant a diagnostic evaluation for neuroblastoma. (See "Clinical presentation, diagnosis, and staging evaluation of neuroblastoma".)

●Pain increased with activity – Pain that increases with activity, improves with rest, and does not interfere with sleep is characteristic of traction apophysitis, osteochondrosis, osteochondritis dissecans, and stress fractures. Specific findings determine further evaluation:

•Patients with apophysitis of the tibial tuberosity (Osgood Schlatter disease), lower pole of the patella (Sinding-Larsen-Johansson disease), or calcaneus (Sever disease) may be diagnosed clinically without plain radiographs. (See "Osgood-Schlatter disease (tibial tuberosity avulsion)" and "Heel pain in the active child or skeletally immature adolescent: Overview of causes", section on 'Calcaneal apophysitis (Sever disease)' and "Approach to chronic knee pain or injury in children or skeletally immature adolescents", section on 'Sinding-Larsen-Johansson disease (patellar apophysitis)'.)

•Otherwise, plain radiographs of the region of pain and/or tenderness should be obtained. They establish the diagnosis of Köhler disease (navicular osteochondrosis) and Freiberg disease (metatarsal avascular necrosis) and help to differentiate Iselin disease (traction apophysitis of the fifth metatarsal) from a fifth metatarsal fracture.

Plain radiographs are also often diagnostic for osteochondritis dissecans (OCD) of the knee and ankle. Because of the high prevalence of bilateral disease, radiographic views of both joints should be obtained. Detection of OCD of the knee warrants specialized views (tunnel, and Merchant [or sunrise] views) in addition to AP and lateral views. Oblique, mortise, and plantar-flexed views should be performed if OCD of the ankle is suspected. (See "Osteochondritis dissecans (OCD): Clinical manifestations, evaluation, and diagnosis", section on 'Imaging'.)

Plain radiographs often do not identify stress fractures. The approach to imaging and assessment of stress fractures is discussed separately (algorithm 1). (See "Overview of stress fractures", section on 'Imaging studies'.)

●Pain at site of bone deformity – Patients with suspected tarsal coalition, pathologic varus (bow legs), and pathologic valgus (knock knees) warrant plain radiographs and additional evaluation according to the specific abnormality as discussed separately. (See "Forefoot and midfoot pain in the active child or skeletally immature adolescent: Overview of causes", section on 'Tarsal coalition' and "Approach to the child with bow-legs", section on 'Evaluation' and "Approach to the child with knock-knees", section on 'Evaluation'.)

Joint pain and/or swelling — Chronic joint pain and/or swelling raises the possibility of:

●Inflammatory arthritis (eg, reactive arthritis, immunoglobulin A vasculitis [Henoch-Schönlein purpura], or serum sickness)

●Rheumatologic disease such as JIA

●Chronic infection (eg, Lyme disease, Kingella kingae, or tuberculous arthritis).

The diagnostic approach to children with limp and chronic joint pain and/or swelling is discussed separately. (See "Evaluation of the child with joint pain and/or swelling", section on 'Diagnostic studies'.)

Trendelenburg gait — Plain radiographs of the pelvis are the initial study for children with Trendelenburg gait or a positive Trendelenburg test (figure 6) to evaluate for:

●Slipped capital femoral epiphysis (SCFE) (see "Evaluation and management of slipped capital femoral epiphysis (SCFE)", section on 'Evaluation')

●Avascular necrosis of the hip (Legg-Calvé-Perthes disease) (see "Approach to hip pain in childhood", section on 'Legg-Calvé-Perthes and secondary avascular necrosis')

●Unilateral developmental dysplasia of the hip (see "Developmental dysplasia of the hip: Clinical features and diagnosis")

Ataxia or weakness — Ataxia or weakness that presents or is interpreted as a limp by caretakers suggests central or peripheral nervous system, neuromuscular, or muscular pathology. The evaluation of acute, intermittent ataxia or weakness is discussed separately. (See "Approach to the child with acute ataxia" and "Etiology and evaluation of the child with weakness".)

Back or abdominal pain — Limp with back and/or abdominal pain suggests:

●Psoas abscess

●Spinal column conditions such as discitis, spondylolysis or spondylolisthesis

●Closed spinal dysraphism with tethered cord

●Disc herniation

Any of these conditions may cause referred pain to the hip or thigh.

Exacerbation of pain with hip extension (psoas sign) and decreased pain with hip flexion supports a psoas abscess. The diagnosis is confirmed by computed tomography (CT) or MRI. (See "Psoas abscess", section on 'Diagnosis'.)

Tenderness on palpation of the spine and/or with limited back range of motion points to a spinal column condition. Plain radiographs may be useful to identify spondylolysis or closed spinal dysraphism, but patients with neurologic symptoms warrant more advanced imaging. (See "Spondylolysis and spondylolisthesis in child and adolescent athletes: Clinical presentation, imaging, and diagnosis" and "Closed spinal dysraphism: Clinical manifestations, diagnosis, and management".)

Patients with signs of disc herniation may require MRI. (See "Back pain in children and adolescents: Causes", section on 'Intervertebral disc herniation'.)

Pain or functional disability out of proportion to clinical findings — Lower extremity pain out of proportion to clinical findings and accompanied by at least one sign of functional disability (ie, coolness, cyanosis, edema, or increased sweating) fulfills the diagnosis of complex regional pain syndrome. (See "Complex regional pain syndrome in children".)

Rarely, children with somatic symptom disorder (conversion disorder) may present with abrupt and paroxysmal limp that may be intermittent or nonprogressive. Physical examination is usually not consistent with underlying pathology and may demonstrate false weakness (giving way), sensory abnormalities not corresponding to normal dermatomes, or functional disability out of proportion to clinical findings.

The diagnosis of complex regional pain syndrome or somatic symptom disorder is clinical and no testing is necessary. If either diagnosis is suspected but the clinician is uncertain, then initial studies should be limited to a complete blood count with differential, C-reactive protein, and plain radiographs. (See "Somatic symptom disorder: Assessment and diagnosis".)

MANAGEMENT — Management is dictated by the specific diagnosis. Most children have a benign cause for their limp and can be managed as outpatients with appropriate medical follow-up:

●Afebrile children with normal radiographs and pain managed by a nonsteroidal anti-inflammatory medication (eg, ibuprofen) may be discharged to home with follow-up by the primary care provider to ensure that symptoms resolve.

●Patients in whom a toddler's fracture is suspected but not apparent on plain radiograph should undergo immobilization of the affected leg (eg, short leg splint, controlled ankle movement [CAM] walker boot, or short leg cast) and, if pain and limp persist, outpatient follow-up in 7 to 10 days with reimaging (typically a repeat plain radiograph) and evaluation by an orthopedic surgeon (image 2). Patients who are asymptomatic out of immobilization can discontinue immobilization without further imaging or follow-up.

●Febrile children without joint effusion and with normal radiographic and blood studies may also be followed as an outpatient if clinical findings are most suggestive of myositis or transient synovitis [22].

●Children in whom a provisional diagnosis that does not require emergency management is apparent or being considered (eg, juvenile idiopathic arthritis [JIA], Legg-Calvé-Perthes disease, or tarsal coalition) should have follow-up arranged with the appropriate specialist.

Specialty consultation and/or hospital admission should occur for children whose findings indicate life-threatening or emergency conditions (table 2). Examples include:

●Septic hip – Surgical drainage of a septic hip should occur as soon as possible once the diagnosis is made. Treatment of bacterial arthritis in other joints varies according to the site and should also take into account the likelihood of Lyme arthritis, which does not usually require drainage. (See "Bacterial arthritis: Treatment and outcome in infants and children" and "Musculoskeletal manifestations of Lyme disease", section on 'Late Lyme disease'.)

●Osteomyelitis – Osteomyelitis warrants timely evaluation for the likely pathogen and administration of antibiotics. The evaluation and treatment of osteomyelitis is discussed separately. (See "Hematogenous osteomyelitis in children: Management".)

●Slipped capital femoral epiphysis (SCFE) – Children with a slipped capital femoral epiphysis (SCFE) require immediate non-weightbearing and urgent referral to an orthopedic surgeon for operative stabilization. (See "Evaluation and management of slipped capital femoral epiphysis (SCFE)", section on 'Management'.)

●Malignancy – A child with a likely oncologic process (eg, leukemia or bone tumor) needs admission for staging work-up and initiation of treatment. (See "Bone tumors: Diagnosis and biopsy techniques" and "Overview of the clinical presentation and diagnosis of acute lymphoblastic leukemia/lymphoma in children".)

●Occult fracture (child abuse) – Children with fractures concerning for child abuse should undergo further evaluation as described separately. (See "Physical child abuse: Diagnostic evaluation and management".)

INFORMATION FOR PATIENTS — UpToDate offers two types of patient education materials, "The Basics" and "Beyond the Basics." The Basics patient education pieces are written in plain language, at the 5^th to 6^th grade reading level, and they answer the four or five key questions a patient might have about a given condition. These articles are best for patients who want a general overview and who prefer short, easy-to-read materials. Beyond the Basics patient education pieces are longer, more sophisticated, and more detailed. These articles are written at the 10^th to 12^th grade reading level and are best for patients who want in-depth information and are comfortable with some medical jargon.

Here are the patient education articles that are relevant to this topic. We encourage you to print or e-mail these topics to your patients. (You can also locate patient education articles on a variety of subjects by searching on "patient info" and the keyword(s) of interest.)

●Basics topics (see "Patient education: Transient synovitis (The Basics)")

SUMMARY AND RECOMMENDATIONS

●Definition and causes – Limp is defined as an abnormality in gait that is caused by pain, weakness, or deformity. The tables summarize the causes of limp in children (table 2), highlighting the common presentations based on age (table 4), location of physical findings (table 1) or type of gait (table 3). (See 'Definition of limp' above and 'Causes' above.)

In addition to pathology in the lower extremity, limp can also be caused by abnormalities of the nervous system, back, abdomen, or genitourinary tract. The location of pain does not always reflect the location of pathology:

•Hip conditions can cause pain in the knee or thigh

•Abdominal conditions may cause hip or thigh pain

•Back conditions may have referred pain down the back of the leg or to the lateral thigh

●History – During the history, the clinician should determine the duration of the limp (acute, subacute, or chronic), presence of fever, whether there is a history of trauma, any focal site of pain, pain characteristics, and associated symptoms, such as abdominal pain, back pain, joint pain, morning stiffness, recent illness, ataxia, or weakness (table 5). (See 'Evaluation' above.)

Bone pain that occurs at night or at rest and without a history of trauma is found more commonly in patients with neoplastic conditions (eg, leukemia, osteogenic sarcoma, Ewing sarcoma) and benign tumors (eg, osteoid osteoma). Ill appearance or significant pain also suggests a more serious cause of limp. Infectious or inflammatory etiologies are often, but not always, associated with fever. (See 'History' above and 'General appearance' above.)

●Physical examination – A careful physical examination helps to narrow the differential diagnosis of the limping child, especially when physical findings suggest a likely site of abnormality either in the lower extremity or elsewhere (eg, the abdomen, spinal column, or neuromuscular system (table 1)). (See 'Physical examination' above.)

Older children and adolescents usually can cooperate with the physical examination. Children who refuse to bear weight on the leg should not be forced to walk until further assessment has excluded fracture or other serious pathology that may be worsened by weight-bearing. (See 'Approach' above.)

If the source of the limp cannot be localized clearly by the history and simple observation (which is often the case in the young or nonverbal child), the examiner must proceed systematically through examination of the central nervous system (CNS), spine, peripheral nervous system, hips, knees, ankles, and feet. In addition, the abdomen and external genitalia should be examined to identify unusual causes of limp (eg, psoas abscess, pelvic inflammatory disease, or testicular torsion). The examination should proceed from areas of least concern to the site of suspected pathology. (See 'Approach' above.)

●Diagnostic approach – The history and physical examination should guide further evaluation. Laboratory studies and/or imaging are usually not indicated in the child with an obvious cause for a limp such as a superficial soft tissue injury; insect bite or sting; plantar wart; hand, foot, and mouth disease; or blister. In addition, an afebrile child with a history of an acute limp but a normal physical examination, including a normal gait, does not typically warrant further investigation at the initial visit. (See 'Diagnostic approach' above.)

Otherwise, further evaluation, as described above, is warranted in the limping child, especially in patients with the following features (see 'Acute limp' above and 'Subacute, chronic, or intermittent limp' above):

•Three years of age and younger

•Signs of infection (eg, fever; exquisite joint tenderness with marked limitation of motion; or localized redness, warmth, or swelling)

•Limitation of joint movement on examination, especially at the hip

•Inability to walk

•History of chronic or intermittent limp

●Management – The management of the child with a limp depends upon the results of the initial evaluation. Specialty consultation and/or hospital admission should occur for children whose findings indicate life- or limb-threatening conditions (table 2). Most children have a benign or nonurgent cause for their limp and can be managed as outpatients with appropriate medical follow-up. (See 'Management' above.)