Methods: Patients with a clinical and radiographic diagnosis of basal joint arthritis who are appropriate and willing candidates for injection therapy will be selected. The primary symptom indicating need for injection would be pain not controlled with more conservative measures (e.g. nonsteroidal anti-inflammatory drugs (NSAIDs), splinting, physical therapy, etc.) Weakness and impaired functioning are also considered. Exclusion criteria will include any injection within the last 12 months or surgical treatment. All patients will undergo Eaton staging radiographically prior to treatment. Informed consent will be obtained and patients will be randomly assigned to one of three groups. One group will receive BTX-A injections, the second group will receive triamcinolone plus lidocaine injections, and the third group will receive saline plus lidocaine injections of the thumb CMC joint. Prior to treatment, patients' baseline function will be assessed with pinch, grip, and range of motion measurements, and the affect of their disease will be measured with a visual analog pain scale and the Disabilities of the Arm, Shoulder, and Hand (DASH) questionnaire. Pain scales and DASH questionnaires will be completed at twenty-four hours, ten days, twelve weeks, six months, and one year after treatment. Pain scales will be recorded for average pain and maximum pain. Clinical evaluations with pinch, grip, and range of motion measurements will occur ten days, twelve weeks, six months, and one year after treatment. All patients will be asked to return when sufficient symptoms recur to warrant further treatment.