Effects of Intraarticular Botulinum Toxin A in Ankle Osteoarthritis

Inclusion Criteria: * an age of 20-85 years with diagnosis of ankle osteoarthritis * unilateral ankle pain that had lasted for at least 6 months, with no significant benefit from conservative treatment or with an inability to tolerate the side effects of medications * ankle radiographs taken within 6 months equivalent to grade 2 on the Kellgren-Lawrence grading system * a current total Ankle Osteoarthritis Scale (AOS) score of \>3 and \< 9 (possible range, 0-10) * a normal activity level-i.e., not bedridden or confined to a wheelchair, and are able to walk 30 meters without the aid of a walker, crutches or cane * no changes in shoes or orthotic devices during the study period. Exclusion Criteria: * pregnancy or lactation in women * lower leg trauma other than ankle trauma * previous surgery involving the spine, hip or knee * the presence of an active joint infections of foot or ankle * previous surgery or arthroscopy on the ankle within 12 months * history of chicken or egg allergy * intraarticular steroid or hyaluronate injection in the treated ankle within the previous 6 months * treatment with anticoagulants or immunosuppressives * a history of rheumatoid arthritis, gout, or any other inflammatory arthropathy * the presence of other comorbidity (such as neoplasms, diabetes mellitus, paresis or recent trauma) or poor health status that would interfere with the clinical assessments during the study.