The arthritis that may be a part of Lyme disease, a spirochetal
infection transmitted by ticks, has not been widely reported in the
orthopaedic literature. Established chronic arthritis in patients who have
Lyme disease most commonly affects the knee and may cause erosive joint
disease. Antibiotics given early in the course of the disease can prevent
chronic arthritis. When the arthritis is established, penicillin
administered intravenously is curative in as many as 55 per cent of
patients, but medical therapy alone may be insufficient to successfully
treat the chronic stage of arthritis.