The American Chiropractic Association's (ACA) Board of Governors mas voted to join an existing class action lawsuit against UnitedHealthcare (United) initiated by the Ohio State Chiropractic Association, the Congress of Chiropractic State associations and others. aca's involvement will expand the litigation to include problems with united's claims review, tierĀing and payment policies. ACA urges providers who believe that they and/or their patients have been affected by United or Optum's unfair practices to visit the Chiropractic Networks Action Center (CN AC), where they will find instructions and forms that can be used to submit a complaint. CN AC can be accessed by going to: http://www.acatoday.org/CNAC.