People with Lyme arthritis should limit their level of physical activity to avoid damaging affected joints, and in case of limping should use crutches. Pain associated with Lyme disease may be treated with nonsteroidal anti-inflammatory drugs (NSAIDs). Corticosteroid joint injections are not recommended for Lyme arthritis that is being treated with antibiotics. People with Lyme arthritis treated with intravenous antibiotics or two months of oral antibiotics who continue to have joint swelling two months after treatment and have negative PCR test for Borrelia DNA in the synovial fluid are said to have antibiotic-refractory Lyme arthritis; this is more common after infection by certain Borrelia strains in people with certain genetic and immunologic characteristics. Antibiotic-refractory Lyme arthritis may be symptomatically treated with NSAIDs, disease-modifying antirheumatic drugs (DMARDs), or arthroscopic synovectomy. Physical therapy is recommended for adults after resolution of Lyme arthritis.