Orthopaedic manifestations of Lyme disease.

Lyme disease is caused by the spirochete Borrelia burgdorferi and is transmitted by the Ixodes tick. Early diagnosis is difficult because the tick bite may go unnoticed and the distinguishing rash, erythema chronicum migrans, often does not occur. Serologic tests are both sensitive and specific in the later stages of the disease but not in stage 1. Thus diagnosis of Lyme disease remains clinical. Knowledge of the orthopaedic manifestations of Lyme disease may aid in early diagnosis and help differentiate from possible cases of juvenile rheumatoid arthritis and septic arthritis. If septic arthritis is suspected, appropriate antibiotic therapy should be initiated while awaiting serology for Lyme disease. Recurrence of Lyme arthritis following antibiotic treatment is rare. Lyme disease should be considered in any patient with arthritis and a history of rash, fever, or neurologic or cardiac abnormality.