Background
Initiatives led by the American Academy of Orthopaedic Surgeons and the American Association of Hip and Knee Surgeons (AAHKS) have indicated a number of clinical risk factors associated with total joint arthroplasty that might reflect the complexity of contemporary hip and knee care. This study sought to examine the prevalence of specific International Classification of Diseases, Ninth Revision (ICD-9), coding with respect to an AAHKS-endorsed list of comorbidity codes.