title: [Value of predicting preoperative risk in orthopedic surgery by using POSSUM].
abstract: OBJECTIVE
  To assess the use of Physical and Operative Severity Score for the Enumeration of Mortality and Morbidity (POSSUM) scoring system in predicting outcomes of patients undergoing orthopedic surgery and provide guidance for operation treatment decisions.
  
  
  METHODS
  From April 2009 to September 2010, a total of 779 cases went operation in Beijing Hospital were collected.They were divided into two groups according to the presence or absence of complications.The patients' postoperative complications were predicted by POSSUM and compared to the actual morbidity to verify the effectiveness of the equation.Logistic regression was taken to make appropriate improvements for the POSSUM equation.ROC curve was drawn to describe the compliance of the original and new equations.
  
  
  RESULTS
  In the 779 cases, the morbidity predicted by POSSUM is 212 cases while the actual morbidity is 65 cases.Of all risk factors, echocardiography ejection fraction showed a close relationship with postoperative complications (P<0.01). In the original equation, actual complication group compared with non-complication group, the difference was statistically significant (P<0.01). In the modified equation, complication group compared with non-complication group, the difference was statistically significant (P<0.01). Compared with the original one , the modified POSSUM had better predictive value on postoperative morbidity, and the comparison of AUC between the two groups was statistically significant ((0.67 ± 0.12) vs (0.75 ± 0.08), P<0.01).
  
  
  CONCLUSIONS
  POSSUM over predicted morbidity of patients undergoing orthopedic surgery, it can be more accurate when modified appropriately.
authors.affiliation: Department of Orthopedics, Beijing Hospital, Beijing 100730, China.
authors.forename: Deming
authors.initials: D
authors.lastname: Bao
authors.affiliation: Email: xueqingyun163@163.com.
authors.forename: Qingyun
authors.initials: Q
authors.lastname: Xue
authors.forename: Yichong
authors.initials: Y
authors.lastname: Xu
mesh_terms: D006801:Humans; D009017:Morbidity; D019637:Orthopedic Procedures; D011183:Postoperative Complications; D011184:Postoperative Period; D011379:Prognosis; D012372:ROC Curve; D012307:Risk Factors