A limp is a type of asymmetric abnormality of the gait. Limping may be caused by pain, weakness, neuromuscular imbalance, or a skeletal deformity. The most common underlying cause of a painful limp is physical trauma; however, in the absence of trauma, other serious causes, such as septic arthritis or slipped capital femoral epiphysis, may be present. The diagnostic approach involves ruling out potentially serious causes via the use of X-rays, blood tests, and sometimes joint aspiration. Initial treatment involves pain management. A limp is the presenting problem in about 4% of children who visit hospital emergency departments.
Definition
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. In 30% of cases, the underlying cause remains unknown after appropriate investigations. Other important causes are infectious arthritis, osteomyelitis, and slipped capital femoral epiphysis in children.
Infection
Septic arthritis
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 12×10<sup>9</sup>/l, fever greater than , ESR greater than 40 mm/h, CRP greater than 2.0 mg/dL, and refusal to walk. People with septic arthritis usually look clinically toxic or sick. Joint aspiration is required to confirm the diagnosis. Treatment involves non-weight-bearing movement and surgery. Young children have difficulty determining the location of leg pain, thus in this population, knee pain equals hip pain.