Destin Hill, MD; John Whiteside, MD Limp in children: Diff erentiating St. Mary’s Family Medicine Residency, St. Mary’s Hospital and Regional Center, benign from dire causes Grand Junction, Colo john.whiteside@stmarygj. Key decision points in the stepwise approach presented org here can make your investigation more effi cient and The authors reported no potential confl ict of interest productive. relevant to this article. mother brings her 4-year-old son to the offi ce because PRACTICE he has been limping. She isn’t aware of a specifi c trau- RECOMMENDATIONS A ma. But the boy and his twin brother, while recovering › Use radiographs to identify from “colds,” were rough-housing in their room when this son bone changes from disease complained of pain. He is afebrile and points to his knee as the (as well as fracture) when area of pain. evaluating a limp. C Although limping in children is common—the incidence › Consider growth plate is roughly 2 per 10001—it is never normal. It indicates pain, injuries as well as tod- weakness, or structural abnormality.2 Most cases result from dler’s fracture; both may trauma.1 Limp usually resolves with little intervention and be radiographically occult no sequelae. However, the diff erential diagnosis is broad and and require immobiliza- daunting (TABLE 1), and some causes of limp are associated tion for treatment. C with signifi cant morbidity. › Consider child abuse if the patient has an isolated mid-shaft tibial fracture. C Helpful tips for your initial assessment › Assess for fever, elevated Many textbook authors have described some causes of limp as sedimentation rate, elevated “painless.” However, truly painless limp is rare, seldom acute, C-reactive protein, and and usually the result of mechanical or neuromuscular disor- leukocytosis when radio- ders.1 A more likely explanation for acute “painless” limp is that graphs are unrevealing or a young child with pain is unable to express pain or accurately when a patient has systemic symptoms associated with identify its location. Further, the child may instinctively avoid limp. Th ese factors are predic- painful positions or movements and, thus, may present only tors of septic arthritis. B with decreased movement of an extremity or refusal to bear weight.3 Strength of recommendation (SOR) With a child who has knee pain, remember the pediatrics A Good-quality patient-oriented maxim: “Knee pain equals hip pain,”3 underscoring the diag- evidence nostic diffi culty with limp. B Inconsistent or limited-quality patient-oriented evidence Also bear in mind that children of diff erent ages tend to C Consensus, usual practice, have diff erent etiologies of limp TABLE( 2). For example, sep- opinion, disease-oriented evidence, case series tic arthritis, osteomyelitis, and transient synovitis occur more commonly in children under 10 years. Legg-Calve-Perthes dis- ease and leukemia are more common in children between the ages of 4 and 10. Slipped capital femoral epiphysis (SCFE) is more common in boys over the age of 11. CONTINUED JFPONLINE.COM VOL 60, NO 4 | APRIL 2011 | THE JOURNAL OF FAMILY PRACTICE 193 TABLE 1 Fracture Possible causes of limp Fracture is a possibility across all age rang- 1-3,17 es, necessitating radiographs if suspected. in a child Beyond detecting fractures, x-ray fi lms can Traumatic/mechanical identify bony changes associated with dis- ease (eg, Legg-Calve-Perthes disease, SCFE). Fractures, stress fractures Radiographs can also identify a clinically sig- Muscle injuries nifi cant joint eff usion at the hip.4 However, Sprains/strains x-ray results may be falsely negative for some Contusions fracture types. ❚ Salter-Harris Type I fractures are trans- Developmental dysplasia of the hip verse fractures through the growth plate with Slipped capital femoral epiphysis epiphyseal separation from the metaphy- Tarsal coalition sis.5 Typical fi ndings are a history of trauma Child abuse and point tenderness over the epiphyseal Overuse injuries plate. Type I fractures are radiographically occult, making the injury easy to mistake Leg length discrepancy as a sprain. Nonetheless, growth plate in- Infectious juries are common in children, requiring Salter-Harris Septic arthritis immobilization. ❚ Toddler’s fracture Type 1 Osteomyelitis was fi rst described as fractures are a spiral, oblique undisplaced fracture of the Lyme disease radiographically distal tibial shaft in children from 9 months occult, making Psoas abscess to 3 years of age.6 It results from a rotational the injury easy Diskitis or twisting force through the tibia while the leg rotates internally on a planted foot.7,8 to mistake as Infl ammatory a sprain. Th is is the most common tibial fracture in in- Transient synovitis fants and young children.9 Th e incidence has Juvenile rheumatoid arthritis been reported as 0.6 to 2.5 per 1000 pediat- Ankylosing spondylitis ric visits.10 Accurate diagnosis is important Reiter syndrome because current treatment recommenda- tions suggest a long leg cast for 3 to 5 weeks, Lupus followed by a short leg cast for a total of Vascular 6 weeks.11 Legg-Calve-Perthes disease Despite being the most common tibial fracture, toddler’s fracture is easily missed. Osteonecrosis Initial radiographs are only 53% sensitive.7,10 Hemoglobinopathies (sickle cell disease) Th is implies that nearly 50% of children with Neoplastic tibial fracture will have an initially negative Leukemia, lymphoma x-ray result. However, nearly 94% of children with a confi rmed toddler’s fracture have been Malignant/lytic tumors (Ewing sarcoma, 12 osteogenic sarcoma, etc.) unable to bear weight. Evidence suggests that despite negative radiographs, patients Metabolic with point tenderness over the tibia and an Rickets inability to bear weight should be treated for 12 Hyperparathyroidism presumed toddler’s fracture. Another confusing aspect of toddler’s Neuromuscular fracture is that the causative injury is often Muscular dystrophy considered insignifi cant by parents—eg, Cerebral palsy tripping, falling from a modest height, or a 7,8 Peripheral neuropathy twisting motion. Th ese events may occur countless times during the average day of a 194 THE JOURNAL OF FAMILY PRACTICE | APRIL 2011 | VOL 60, NO 4 LIMP IN CHILDREN TABLE 2 Common causes of limp according to child’s age1 <3 years 3-10 years 11-18 years Foreign body Legg-Calve-Perthes disease Juvenile arthritis Osteomyelitis Osteomyelitis Slipped capital femoral epiphysis Septic arthritis Septic arthritis Trauma (physeal fracture) Toddler’s fracture Transient synovitis Tumor Transient synovitis Trauma (physeal fracture) Tumor Tumor toddler. Often parents do not witness the in- tis or transient synovitis (FIGURE). Both may jury and are unable to describe the mecha- present with limp and fever as well as pain, nism of injury.7 decreased range of motion, bone tenderness, ❚ When to suspect child abuse. When a swelling, and warmth.15 child presents with fracture after an unwit- ❚ Transient synovitis is the most common A midshaft tibial nessed trauma and the story does not match cause of hip pain in children up to 10 years fracture may be the injury pattern, consider child abuse. With of age, with a 3% risk of occurrence through an indication of tibial fractures, the location of the fracture childhood.16,17 Its cause is unclear, but many child abuse. can help distinguish a result of abuse from a experts have proposed a viral agent.17 Tran- toddler’s fracture. Toddler’s fracture is clas- sient synovitis universally resolves without sically described as a distal tibial fracture. sequelae in 1 to 2 weeks. Th erefore, prescribe In contrast, a midshaft tibial fracture often rest and nonsteroidal anti-infl ammatory suggests child abuse.8,13 In a small retrospec- drugs (NSAIDs) for symptomatic relief, and tive study of 37 children diagnosed with tod- reassure parents.16 dler’s fracture, 4 midshaft tibial fractures ❚ Septic arthritis, although often similar were found.8 Child abuse was confi rmed in in presentation to transient synovitis, requires 2 of these cases.8 However, other authors, hospitalization, operative drainage, and par- including Dr. Dunbar in his sentinel article,6 enteral antibiotics.18 A delay in diagnosis is assert that toddler’s fracture may occasion- associated with poor outcome, including os- ally extend into the midshaft of the tibia. teonecrosis, growth arrest, permanent loss of Consequently, a midshaft tibial fracture is joint function, and sepsis.3,18 not pathognomonic for child abuse. But the Several studies have shown children with diagnosis should be considered. Perform a septic arthritis usually appear more acutely ill careful examination for other signs of abuse than those with transient synovitis.4,18-21 Th ey or neglect, and do not hesitate to report sus- are described as toxic-appearing, and have pected child abuse to the proper local and leukocytosis, a high erythrocyte sedimenta- state authorities.14 tion rate (ESR), and a high fever.19 However, no single marker or specifi c laboratory value consistently identifi es septic arthritis. Many Transient synovitis studies have been performed in an eff ort to vs septic arthritis identify a collection of factors, or an algo- A child who limps or refuses to bear weight rithm, that can predict the probability of sep- on a limb often has associated symptoms tic arthritis. of acute illness. In these cases, or when ra- Fever, an elevated ESR, and leukocytosis diographs have ruled out apparent abnor- are independent multivariate clinical predic- malities such as Legg-Calve-Perthes disease, tors for septic arthritis. Th e prediction algo- SCFE, and fracture, consider septic arthri- rithm published by Jung et al is the only study JFPONLINE.COM VOL 60, NO 4 | APRIL 2011 | THE JOURNAL OF FAMILY PRACTICE 195 FIGURE Diagnostic algorithm for pediatric limp3,4,6,8-12,15 A child presents with limp with Order x-rays to detect fracture or Yes or without joint pain.