title: Intrinsic and extrinsic risk factors for nonunion after nonoperative treatment of midshaft clavicle fractures.
abstract: BACKGROUND
  The optimal treatment of midshaft clavicle fractures remains controversial. Nonunion is usually considered to be an uncommon complication following a nonoperatively treated clavicle fracture.
  
  
  OBJECTIVE
  Not every midshaft clavicular fractures shares the same risk of developing nonunion after nonoperative treatment. The present study was performed to identify the intrinsic and extrinsic independent factors that are independently predictive of nonunion in patients with midshaft clavicular fractures after nonoperative treatment.
  
  
  METHODS
  We performed a retrospective study of a series of 804 patients (391 men and 413 women with a median age of 51.3 years) with a radiographically confirmed midshaft clavicle fracture, which was treated nonoperatively. There were 96 patients who underwent nonunion. Putative intrinsic (patient-related) and extrinsic (injured-related) risk factors associated with nonunion were determined with the use of bivariate and multivariate statistical analyses.
  
  
  RESULTS
  By bivariate analysis, the risk of nonunion was significantly increased by several intrinsic risk factors including age, sex, and smoking and extrinsic risk factors including displacement of the fracture and the presence of comminution (P<0.05 for all). On multivariate analysis, smoking (OR=4.16, 95% CI: 1.01-14.16), fracture displacement (OR=7.81, 95% CI: 2.27-25.38) and comminution of fracture (OR=3.86, 95% CI: 1.16-13.46) were identified as independent predictive factors.
  
  
  CONCLUSIONS
  The risk factors for nonunion after nonoperative treatment of midshaft clavicle fractures are multifactorial. Smoking, fracture displacement and comminution of fracture are independent predictors for an individual likelihood of nonunion. Further studies are still required to evaluate these factors in the future.
  
  
  METHODS
  Level III, case-control study.
authors.affiliation: Department of orthopedics, Huai'an First People's Hospital, Nanjing Medical University, 6, Beijing Road West, Huai'an, Jiangsu 223300, PR China.
authors.forename: W
authors.initials: W
authors.lastname: Liu
authors.affiliation: Department of orthopedics, The 101st Hospital of Chinese PLA, No. 101 North Xingyuan Road, Wuxi, Jiangsu 214044, PR China.
authors.forename: J
authors.initials: J
authors.lastname: Xiao
authors.affiliation: Department of orthopedics, Huai'an First People's Hospital, Nanjing Medical University, 6, Beijing Road West, Huai'an, Jiangsu 223300, PR China. Electronic address: habest163@126.com.
authors.forename: F
authors.initials: F
authors.lastname: Ji
authors.affiliation: Department of orthopedics, Huai'an First People's Hospital, Nanjing Medical University, 6, Beijing Road West, Huai'an, Jiangsu 223300, PR China.
authors.forename: Y
authors.initials: Y
authors.lastname: Xie
authors.affiliation: Department of orthopedics, Huai'an First People's Hospital, Nanjing Medical University, 6, Beijing Road West, Huai'an, Jiangsu 223300, PR China.
authors.forename: Y
authors.initials: Y
authors.lastname: Hao
mesh_terms: D000293:Adolescent; D000328:Adult; D016022:Case-Control Studies; D002968:Clavicle / Q000293:injuries*; D005260:Female; D005500:Follow-Up Studies; D017102:Fracture Healing; D050723:Fractures, Bone / Q000628:therapy*; D018460:Fractures, Comminuted / Q000601:surgery*; D006801:Humans; D008297:Male; D008875:Middle Aged; D019637:Orthopedic Procedures / Q000379:methods*; D012189:Retrospective Studies; D012307:Risk Factors; D016896:Treatment Outcome; D055815:Young Adult
keywords: Clavicle fracture; Multivariate analysis; Nonunion; Risk factor; Treatment