The Surgical Apgar Score in Hip and Knee Arthroplasty

Abstract

Background A 10-point Surgical Apgar Score, based on patients' estimated blood loss, lowest heart rate, and lowest mean arterial pressure during surgery, was developed to rate patients' outcomes in general and vascular surgery but has not been tested for patients having orthopaedic surgery. Questions/purposes For patients undergoing hip and knee arthroplasties, we asked (1) whether the score provides accurate risk stratification for major postoperative complications, and (2) whether it captures intraoperative variables contributing to postoperative risk based on the three parameters independent of preoperative risk. Patients and MethodsWe retrospectively reviewed the electronic records for all 3511 patients who underwent a hip or knee arthroplasty from March 2003 to August 2006 and extracted data to calculate a Surgical Apgar Score. We evaluated the relationship between scores and likelihood of major postoperative in-hospital complications and assessed its discrimination and calibration. Results Complication rates increased monotonically as the score decreased. Even after controlling for preoperative risk, each 1-point decrease in the score was associated with a 34.0% increase (95% confidence interval, 0.66-0.84) in the odds of a complication. The overall discriminatory performance of the score was a c-statistic of 0.61. Seventysix percent of all major complications occurred in patients classified as low risk with scores of 7 or greater.

Can the Surgical Apgar Score predict morbidity and mortality in general orthopaedic surgery?

“…It could be hypothesised that the limited utility of the SAS in this cohort of patients undergoing orthopaedic surgery could be secondary to a smaller complication rate compared to general and vascular surgery, since it is not unusual to have a significant number of patients with a risk of death greater than 70 % in general surgery [13]. Our cohort exhibited a lower complication rate compared with the general and vascular surgery validation cohort (5.2 versus 22 %); a low in-hospital complication rate was also reported in a retrospective study assessing the SAS in patients undergoing hip and knee arthroplasties [11]. Nonetheless, that study may have underestimated their complications, since relatively high readmission rates have been observed within 30 days after joint arthroplasties [14].…”

“…Previously, only two publications had assessed this score in the orthopaedic field. A retrospective study evaluating patients undergoing hip and knee arthroplasties showed that although the score contained relevant intra-operative information regarding the risk of complications, on its own it did not provide a comprehensive postoperative risk stratification [11]. Nevertheless, that study could only determine the inhospital complications, which do not account for all the cases that presented major complications and mortality 30 days after surgery; in addition, as a retrospective study, the accuracy of the data acquired at the end of surgery could be imperfect.…”

“…Only two studies have evaluated the utility of this score in the orthopaedic field, and only for specific operations: a retrospective study evaluating patients undergoing hip and knee arthroplasties showed that even though the score obtained relevant intra-operative information regarding risk of complications, on its own it did not provide a comprehensive postoperative risk stratification [11]. Another study aiming to evaluate the utility of the SAS in a district general hospital in the UK found that the score did not demonstrate statistical significance for the prediction of major complication or death in patients undergoing lower limb arthroplasty or femoral neck fracture treatment [9].…”

Implementing the Surgical Apgar Score in patients with trauma hip fracture

“…Although this score has been validated in selected orthopaedic procedures (10,11,12,13,14) we also wanted to observe the utility of the SAS in the trauma hip fracture surgery patients. Hip fracture surgery repairs are operations of different magnitude.…”

Intensive care monitoring after total joint replacement

“…The authors have looked at factors that might guide postoperative admission to the ICU and thus develop a predictive model of risk for unplanned ICU admission. This might be analogous to a TJR Apgar score, used to assess new born babies, 11,12 and other work predicting post-operative risks after hip fracture surgery. 13 Undertaking any safety study involves a multi-disciplinary effort (Fig.…”