Limping in Children Case File

Limping in Children Case File

Eugene C. Toy MD, Donald Briscoe, MD, FA  AFP, Bruce Britton, MD, Joel J. Heidelbaugh, MD, FA  AFP, FACG

Case 37

A 12-year-old boy is brought to the physician's office with right thigh pain and a limp. His mother has noticed him limping for the past week or so. He denies any injury to his leg but says that it hurts some when he plays basketball with his friends. He denies back pain, hip pain, or ankle pain. He occasionally gets some pain in the right knee but does not have any swelling or bruising. He has no significant medical history, does not take any medications regularly, and otherwise feels fine. On examination, he is an overweight adolescent. His vital signs and a general physical examination are normal. When you have him walk, he has a prominent limp. You note that he seems to keep his weight on his left leg for a greater proportion of his gait cycle than he does on the right leg. Examination of his back reveals a full range of motion, no tenderness, and no muscle spasm. He gets pain in the right hip when it is passively internally rotated. When the hip is passively flexed, there is a noticeable external rotation. There is no thigh muscle atrophy. His right knee and the remainder of his orthopedic examination are normal.

⯈ What is the most appropriate test to order first for this patient?

⯈ What is the most likely diagnosis?

⯈ What complication could occur if this problem is not diagnosed and treated?

ANSWER TO CASE 37

Limping in Children

Summary: An overweight 12-year-old boy presents for evaluation of a limp and thigh pain. There is no history of injury or trauma. He is found to have pain on internal rotation of the hip and his hip externally rotates when passively flexed. He bears weight more on his left leg than his right while walking.

• Most appropriate test to order: X-ray of the right hip
• Most likely diagnosis: Slipped capital femoral epiphysis
• Complication for which he is at risk: Avascular necrosis of the hip

ANALYSIS

Objectives

1. Develop a differential diagnosis of the most likely causes of leg pain and limping in children.
2. Know common causes of leg pain and limping in children of different ages.
3. Know appropriate examination, laboratory, and radiologic evaluation for the limping child.

Considerations

Leg pain is a common complaint in childhood. The most common causes of leg pain in children are acute trauma (sprains, strains, contusions) or overuse injuries. However, leg pain and limping can be a sign of a more serious, even life threatening, pathology. Learning an approach to the evaluation and the common diagnoses involved may help in the identification of these problems earlier, when a better outcome is more likely.

To understand a limp, it is first important to understand the normal gait. Gait is composed of two phases: the "swing" and the "stance'' phases. The stance phase is the weight-bearing phase and accounts for approximately 60% of the gait cycle. The swing phase is the non-weight-bearing phase, when the foot lifts off the ground and is propelled forward. The antalgic gait occurs when the stance phase of gait is shortened on the side of pain, usually because of pain during weight bearing. Antalgic gait is the most common type of limp and is the type of gait described in this case.

There are many causes of limp with pain in children; some of the more common causes may be broadly categorized as being primarily orthopedic, reactive, infectious, rheumatologic, or neoplastic. The prevalence of the specific diagnoses also varies by age. Limp without pain is usually due to congenital orthopedic anomalies or neuromuscular disorders.

In the specific case presented, there are several symptoms and signs that make the diagnosis of slipped capital femoral epiphysis (SCFE) likely. The absence of a specific injury is significant, as SCFE is the most common nontraumatic hip pathology in adolescents. The initial complaint of thigh pain may lead to other considerations, but hip pathology will frequently present with pain in the groin, thigh, or even the knee. The patient's age and body habitus are typical for SCFE, which is classically described as occurring most often in overweight adolescent males. Pain with internal rotation of the hip and the finding of external rotation on passive flexion of the affected hip are also suggestive of SCFE.

Approach To:

Limping With Pain in Children

DEFINITIONS

AVASCULAR NECROSIS: Death of living bone tissue caused by disruption of blood flow

DYSPLASIA: Abnormal growth or development

CLINICAL APPROACH

As always, the initial approach should include a good focused history and physical. The clinician should ask questions about recent trauma, onset, and duration of limp, recent illnesses (viral, pharyngitis, rashes, tick bites, diarrhea, urethritis). Past medical history, previous levels of function, and family history of musculoskeletal disorders can help with diagnosis. Associated symptoms like fever, weight loss, anorexia, or pain are especially important. A key characteristic in the evaluation of the child with a limp is assessing whether there is pain or no pain. In an antalgic gait, the cause of the pain may range from the back to the foot (Table 37-1). Therefore, unless there is an obvious source of pain, the examination should include assessment of the back, pelvis, buttock, leg, and foot. In the child who clings to the parent, separating the child from the parent will allow the clinician to observe the child's gait when they walk back to the parent. The child who walks stiffly may be avoiding moving the spine indicating a possible discitis. Those with nonantalgic gait abnormalities (Trendelenburg gait, inability to dorsiflex the foot, locked knees, toe walking) can have congenital, neurologic, or limb length disorders. Inspecting the feet may show clawing of the toes or cavus deformity, which are signs of neuromuscular conditions.

Because hip pathology often presents with vague pain and hip conditions are likely to need emergent treatment, evaluation of the hip may be the most important part of the examination of a patient in whom the site of pathology is not immediately obvious. Restricted internal rotation appears to be the most sensitive marker of hip pathology in children, followed by a lack of abduction. Internal rotation of the hip increases the intracapsular pressure within the acetabulum. Pain during a leg roll (supine child with extended hip and knee; one examiner stabilizes the pelvis while another rolls leg internally and externally) and limited internal rotation of less than 30 degrees may indicate infectious or orthopedic hip pathology. The FABER test (Hexion, ABduction, External Rotation-the ipsilateral ankle placed

on the contralateral knee and mild downward pressure placed on the ipsilateral knee) can find pathology located in the sacroiliac joint, often seen in rheumatologic disorders. Bone pain or point tenderness can indicate osteomyelitis or malignancy. Limps from overuse injuries of the foot (eg, Sever disease) and knee disorders (eg, Osgood-Schlatter disease) can occur. If there is significant abdominal pain on history or examination, consider an acute abdomen or psoas abscess.

X-rays should be obtained when the differential indicates a likelihood of bony abnormalities. An ultrasound of the hip is more sensitive for an effusion of the hip and can be considered. In nonverbal children, x-rays from hip to feet can find a fracture in a significant minority of children with limp. A complete blood count (CBC) should be drawn if there is concern of an infection, inflammatory arthritis, or malignancy. An erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) should be considered in evaluating infectious and rheumatologic etiologies. Consider Lyme disease in endemic areas, as this can mimic both infectious and rheumatologic causes of hip disorders. If there was a recent pharyngitis, consider antistreptolysin (ASO) titers. In teens with history of urethritis or febrile diarrhea, consider urine chlamydia! antigens or stool cultures for possible Reiter syndrome. Any joint where septic arthritis is considered should have a joint aspiration and evaluation of synovial fluid. Fever greater than 99.5°F and ESR greater than 20 is

Data from Hollister JR. Rheumatic diseases. In: Hay WW, Levin Ml, Sondheimer JM, et al, eds. Current Pediatric Diagnosis

and Treatment. 15th ed. New York, NY: McGraw-Hill; 2001 :734; Leet Al, Skaggs DL. Evaluation of the acutely limping child.

Am Fam Physician. 2000;61: 1011-1018; and Crawford AH. Orthopedics. In: Rudolph CD, Rudolph AM, Hostetter MK, eds.

Rudolph's Pediatrics. 21st ed., New York, NY: McGraw-Hill; 2003: 2419-2458.

97% sensitive for septic hip joint. Testing of the fluid should include culture for gonorrhea in teens that are sexually active.

The evaluation of limping without pain (Table 37-2) should include measurements for leg length discrepancies (measure umbilicus to medial malleolus) and observation for muscular atrophy or limb deformity. Barlow (hip and knee flexed 90 degrees, hold the knee and attempt to displace the thigh posterior), Ortolani (guided abduction), and Galeazzi (knee height discrepancy when patient lies supine with ankles to buttocks and hips and knees flexed) tests can be used to assess for congenital hip abnormalities and femoral length discrepancies.

Infants and Toddlers

Common causes of limping in children in this age group are septic arthritis, fractures, and complications of congenital hip dysplasia. Septic arthritis is usually monoarticular and associated with systemic signs such as fever. In young infants, the symptoms may be less obvious, such as crying, irritability, and poor feeding. Children who are ambulatory (crawlers or walkers) will often refuse to do anything that puts weight on the affected joint because of pain. Infection of a joint causes a septic effusion, which raises the pressure inside of the joint capsule. Children with a septic hip joint will often lay with their hip flexed, abducted, and externally rotated, which helps to reduce the pain, and they will have significant pain with any internal rotation or extension of the joint. Children with a septic joint will usually have an elevated white blood cell (WBC) count, ESR, and CRP. Definitive diagnosis comes from joint aspiration. Any suspected septic joint must be aspirated. In younger infants (4 months or younger), group B Streptococcus and Staphylococcus aureus are the most common pathogens involved. In older infants and children under the age of 5, S aureus and Streptococcus pyogenes are the usual causes. Treatment is urgent surgical irrigation and debridement, along with antibiotics.

Unsuspected fractures-either stress fractures or traumatic fractures-can present with pain and limping. Abuse must be suspected if the injury is inconsistent with the history presented, if the history changes with repeated questioning, if the child is said to have performed an act outside of his developmental ability, or if a fracture usually associated with abuse is found (see Case 36). However, the history

Data from Perry DC, Bruce C. Evaluating the child who presents with an acute limp. BMJ. 2010 Aug 20;341 :c4250. doi:

10.1136/bmj.c4250.

may not reveal the source of the injury, as a child may fall outside of the view of the parent (see Table 3 7 -3). A traumatic injury may not result in limping or in complete immobility, but may cause a change in how the child ambulates. For example, a child who previously walked and now refuses to walk but will crawl, may have an injury of the lower leg or foot.

A toddler's fracture is one example of an unsuspected fracture that may present primarily as a limp or a refusal to walk. This fracture is a spiral fracture of the tibia that results from twisting while the foot is planted. The diagnosis may be suspected in the setting of an acute limp or change in ambulation, a normal examination of the knee and upper leg, and tenderness of the tibia. It can be confirmed with a plain film x-ray. Undiagnosed congenital developmental dysplasia of the hip (DDH) may present as a painless limp that is present from the time that the child learns to walk. All newborns and infants should have their hips examined for instability or dislocation. If undiagnosed, contractures may form that limit movement of the hip. When the child learns to walk, the child will have a painless limp. The diagnosis may be confirmed by x-rays showing abnormal hip alignment. If the problem is found in the first few weeks of life, the child can be treated with splinting of the hip and normal development usually follows. If diagnosed late, the treatment is often surgical.

Young Children

Transient synovitis is a self-limited inflammatory response that is a common cause of hip pain in children. It occurs typically in children ages 3 to 10, is more common in boys than in girls, and often follows a viral infection. It is frequently seen as gradually increasing hip pain that results in a limp or refusal to walk. These children have a low-grade or no fever, a normal WBC count, and a normal ESR. On examination, there is pain with internal rotation of the hip and the overall range of motion is limited by pain. X-rays are either normal or show some nonspecific swelling. In a situation where the patient is afebrile, has pain-free rotation of hip greater than 30 degrees, has a normal WBC count, normal ESR, CRP, and short-term follow up can be assured, the patient can be followed clinically and should improve in a few days. If these conditions are not met and the diagnosis of a septic joint is considered, or if a patient followed expectantly continues to worsen, an aspiration should be done. Kocher criteria are often utilized to assess risk for septic arthritis in children. The four criteria are fever greater than 101.3°F (38.5°C), non-weightbearing, ESR greater than 40, WBC count greater than 12,000. Zero criteria present equals less than 0.2% risk, one criteria is 3%, two criteria is 40%, three criteria is 93%, and four criteria is almost 100% chance of septic arthritis. A septic joint will have a purulent aspirate with a WBC count greater than 50,000/ μL; transient synovitis will have a yellow I clear aspirate with a lower WBC count ( <10,000 I μL ).

Legg-Calve-Perthes (LCP) disease is an avascular necrosis of the femoral head that typically occurs in children ages 4 to 8. It is much more common in boys than in girls. Any disruption of blood flow to the femoral capital epiphysis, such as trauma or infection, may cause avascular necrosis. In LCP disease, the etiology of the disruption of blood flow is unknown. Children typically have a gradual onset of hip, thigh, or knee pain, and limping over a few months. Early in the course, x-rays of the hip may appear normal. Later radiographic findings include collapse, flattening, and widening of the femoral head. Bone scans or magnetic resonance imaging (MRI) may be necessary to confirm the diagnosis. The treatment is usually conservative, with protection of the joint and efforts to maintain range of motion. Children who develop more severe necrosis or who develop the disease at older ages may have a worse outcome and a higher risk of developing degenerative arthritis.

Adolescents

The capital femoral epiphysis is the growth plate that connects the metaphysis (femoral head) to the diaphysis (shaft of the femur). A slipped capital femoral epiphysis is a separation of this growth plate, which results in the femoral head being medially and posteriorly displaced. This may be caused by an acute injury, but more often is not. It is most often seen in overweight adolescent boys and presents as pain in the hip, thigh, or knee along with a limp. Examination reveals limited internal rotation and obligate external rotation when the hip is passively flexed. Early x-rays may show only widening of the epiphysis; later x-rays can show the slippage of the femoral head in relation to the femoral neck. The treatment is surgical pinning of the femoral head. These patients must be closely followed, as approximately 20% to 50% will develop avascular necrosis and 33% will develop SCFE in the contralateral hip.

Other causes of limb pain are common in adolescents. Sprains, strains, and overuse injuries are the most common cause of limb pain in this population, and are usually readily diagnosed on history and examination (see Case 12). Sexually active adolescents or teens are at risk for sexually transmitted diseases (STDs) and their complications, including gonococcal arthritis. In this population, an appropriate history, sexual history, and review of systems are necessary.

All Ages

Septic arthritis, fractures, neuromuscular disorders, and neoplasms can cause a limp in children of all ages. Night sweats, anorexia, weight loss, and pain that wakens the child at night are suspicious for malignancy. "Growing pains" is a diagnosis of exclusion. It should be considered if the pain is only at night, is bilateral, is not present during the day, and if no other pathology is found.

CASE CORRELATION

• See also Cases 3 (Joint Pain) and 5 (Well-Child Care).

COMPREHENSION QUESTIONS

37.1 A 6-year-old young boy is brought in for evaluation of a painful hip. He has been limping and not wanting to walk for the past 2 days. He has had no obvious injury. He feels a little better if he is given some ibuprofen. He has not had a fever and does not have any other current symptoms, although he had "the flu" last week. On examination, his vital signs are normal. His right hip has some pain with internal rotation. He walks with a pronounced limp.

Which of the following statements is most appropriate?

A. He can be sent home with a prescription for ibuprofen.

B. He should have a CBC and ESR.

C. He should have an aspiration of his hip in the office.

D. If he has a normal x-ray, no further workup is needed.

37.2 An 18-month-old African-American girl is brought into your office because she has been crying and stopped walking today. She will crawl, however. Her mother denies any injury to the child. On examination, she is crying but consolable in her mother's arms. She has bruising and swelling just proximal to the left ankle. An x-ray reveals a spiral fracture of the tibia. Which of the following best describes your advice to the mother of the patient?

A. You are going to report this to child protective services as suspected abuse.

B. You are going to refer the child for a bone biopsy because this is a pathologic fracture that may represent a neoplasm.

C. This is a common fracture resulting from twisting on a planted foot.

D. You should draw blood to evaluate for sickle cell disease, which may cause infarction of the bone.

37.3 A 2-year-old boy is brought in with fever and poor feeding. He started getting sick yesterday and has worsened significantly today. He has had no recent illnesses or injuries, and no known ill contacts. On examination, his temperature is 101°F (38.3°C), is tachycardic, and appears ill. He is lying on his back with his left leg flexed and abducted at the hip. A head, ears, eyes, nose, and throat (HEENT) examination is normal, the heart is tachycardic but regular, and the lungs are clear. The abdomen is nontender and has normal bowel sounds. He screams in pain when you move his left leg from its resting position. Blood work reveals an elevated WBC count of 15,000 mm3 and an ESR of 45 mm/h (normal: 0-10). An x-ray of his left hip shows a widened joint space but no fractures. Which of the following is your next step at this point?

A. Oral antibiotic and follow-up in 1 day

B. MRI of the hip and referral to an orthopedist

C. Anti-inflammatory medication and close follow-up

D. Hip joint aspiration

37.4 A 6-year-old boy appears in the office with a 2-month history of slight limp. He has no significant past medical history and takes no medications. He has normal vital signs and is noted to have antalgic gait and decreased range of motion in the left hip (internal rotation more limited). He has mild pain on palpation of the anterior capsule on the left side. X-ray shows fragmentation of the femoral head. Which of the following is the most likely diagnosis?

A. Toxic synovitis of hip

B. Avascular necrosis of hip (Legg-Calve-Perthes)

C. Slipped capital femoral epiphysis

D. Femoral shaft fracture

ANSWERS

37.1 B. The case presented is suspicious for transient synovitis following a viral illness. A CBC and ESR should be drawn. With a normal CBC and ESR, and if follow-up can be assured, this child could be treated expectantly, given an oral nonsteroidal anti-inflammatory drug (NSAID) with the expectation of a recovery in a few days.

37.2 C. The case presented is classic for a toddler's fracture. Spiral fractures of other long bones (femur, humerus) are more suspicious for abuse. Orthopedic referral is appropriate for management, but a bone biopsy or further workup is not necessary at this time.

37.3 D. The child in this case has all of the symptoms and signs of a septic hip joint. This situation demands a joint aspiration to confirm the diagnosis. If it is confirmed, he should be promptly referred for urgent surgical management.

37.4 B. This child is in the correct gender and age group with signs, symptoms, and radiologic findings associated with Legg-Calve-Perthes disease. It is often a self-healing disorder. Treatment is focused on limiting pain and avoiding functional loss. Depending on severity and age, treatment may include watchful waiting, physical therapy, casting, and surgery.

CLINICAL PEARLS

⯈ Hip pathology may not cause hip pain; it may cause groin, thigh, or knee pain instead.

⯈ Because of the high risk of bilateral disease, follow-up in SCFE cases should include examination and x-rays of the unaffected hip until the growth plate closes .

⯈ A limp that is nonantalgic usually does not need urgent evaluation.

REFERENCES

HerringJA. The musculoskeletal system. In: Rudolph CD, Rudolph AM, Lister G, et al., eds. Rudolph's Pediatrics. 22nd ed. New York, NY : McGraw-Hill; 2011:839-876. 

Peck M. Slipped capital femoral epiphysis: diagnosis and management. Am Fam Physician. 2010 Aug 1;82(3):258-262. 

Perry DC, Bruce C. Evaluating the child who presents with an acute limp. BM]. 2010 Aug 20;341:c4250. 

Sawyer JR, Kapoor M. The limping child: a systematic approach to diagnosis. Am Fam Physician. 2009 Feb 1;79(3):215-224.

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