Limp

A limp is a type of

A limp is a type of asymmetric abnormality of the gait. When due to pain it is referred to as an antalgic gait, in which the foot is in contact with the ground for a shorter duration than usual; in severe cases there may be a refusal to walk.^[2] Hip deformities with associated muscular weakness, on the other hand, may be present with a Trendelenburg gait, with the body shifted over the affected hip.^[2]

Differential diagnosis

The causes of limping are many and can be either serious or non-serious. It usually results from pain, weakness, neuromuscular imbalance, or a skeletal deformity.

Septic arthritis can be difficult to separate from less serious conditions such as transient synovitis. Factors that can help indicate septic arthritis rather than synovitis include a WBC count greater than 12×10⁹/l, fever greater than 38.5 °C (101.3 °F), ESR greater than 40 mm/h, CRP greater than 2.0 mg/dL, and refusal to walk.^[4] People with septic arthritis usually look clinically toxic or sick.^[5] Even in the absence of any of these factors, however, septic arthritis may be present.^[6] Joint aspiration is required to confirm the diagnosis.^[6]

Other

Other infections that classically lead to a limp include Lyme disease (a bacterial infection spread by deer ticks) and osteomyelitis (an infection of the bone).^[7]

Mechanical

Trauma

Accidental or deliberate

Transient synovitis is a reactive arthritis of the hip of unknown cause.^[2] People are usually able to walk and may have a low grade fever.^[2] They usually look clinically nontoxic or otherwise healthy.^[5] It may only be diagnosed once all other potential serious causes are excluded. With symptomatic care it usually resolves over one week.^[2]

Juvenile rheumatoid arthritis

The diagnosis of the cause of a limp is often made based on history, physical exam findings, laboratory tests, and radiological examination. If a limp is associated with pain it should be urgently investigated, while non-painful limps can be approached and investigated more gradually.[5] Young children have difficulty determining the location of leg pain, thus in this population, knee pain equals hip pain.^[7] SCFE can usually be excluded by an x-ray of the hips.^[2] An ultrasound or x-ray guided aspiration of the hip joint maybe required to rule out an infectious process within the hip.^[2]

Epidemiology

A limp at one hospital emergency department was the presenting complaint in 4% of children.^[1] It occurs twice as commonly in boys as in girls.^[3]

References