Hip fracture surgery: is the pre-operative American Society of Anesthesiologists (ASA) score a predictor of functional outcome?

Abstract

Many studies have identified specific demographic, social, health or life-style pre-operative indicators of long-term outcome among older hip fracture patients who underwent surgical treatment. The purpose of this study was to determine the predictive value of peri- and intra-operative factors, and more specifically of the pre-operative American Society of Anesthesiologists (ASA) score on functional outcome in these patients. A questionnaire designed to assess pre-fracture functional and health status was administered to surgically treated hip fracture patients. Post-fracture functional and health status was further ascertained by in-home interview one year after the operation. Among 140 consecutive eligible patients older than 65 years, 10 either refused subsequent interviews or could not be contacted; an additional 16 patients died during the year of follow-up, leaving 114 patients available for this study. The average age of the patients was 82.4 years. Almost two-thirds of them suffered from severe systemic disease, whether or not incapacitating (ASA grades III-IV). Subjects classified in these categories presented more frequently with cardiovascular disorders, were more frequently disoriented, and already had some pre-fracture difficulty with ambulation. The mortality at one year was almost nine times higher in severely impaired patients (grades III-IV) than in healthy or mildly affected patients (grades I-II). Functional outcome and/or ambulatory ability assessed at one year did not reveal any statistically significant difference between the ASA I-II and III-IV groups. The most pronounced difference was noticed for the functional independence measured by the ADL score (p = 0.236). Better prognoses were consistently recorded for patients with an intracapsular fracture, for those who were operated within 24 hours, for those treated with a prosthesis as opposed to internal fixation, and for those whose operating time was less than 1 1/2 hours. Although the ASA classification is a good predictor of long-term mortality, the findings of the present investigation do not conclusively associate ASA score with post-operative restoration of mobility and functional independence.