title: A systematic review of undisplaced femoral neck fracture treatments for patients over 65 years of age, with a focus on union rates and avascular necrosis.
abstract: BACKGROUND
  It remains unclear whether conservative treatment should be used to treat the common undisplaced femoral neck fractures that develop in the elderly. Herein, we systematically review the rates of union and avascular necrosis after conservative and surgical treatment of undisplaced femoral neck fractures.
  
  
  METHODS
  We searched the EMBASE, PubMed, OVID, Cochrane Library, Web of Science, and Scopus databases for randomized controlled trials or observational studies that assessed the outcomes of conservative or surgical treatments of undisplaced femoral neck fractures. No language or publication year limitation was imposed. Statistical analyses were performed with the aid of the chi-squared test. We evaluated the quality of each publication and the risk of bias.
  
  
  RESULTS
  Twenty-nine studies involving 5071 patients were ultimately included; 1120 patients were treated conservatively and 3951 surgically. The union rates were 68.8% (642/933) and 92.6% (635/686) in the former and latter groups, respectively (p < 0.001). The avascular necrosis rate in the conservatively treated group was 10.3% (39/380), while it was 7.7% (159/2074) in the surgically treated group (p = 0.09).
  
  
  CONCLUSIONS
  Surgery to treat undisplaced femoral neck fractures was associated with a higher union rate and a tendency toward less avascular necrosis than conservative treatment.
authors.affiliation: Department of Orthopaedic Surgery, The Second Affiliated Hospital, School of Medicine, Zhejiang University, Jie-fang Road 88, Hangzhou, 310009, People's Republic of China.
authors.forename: Dan-Feng
authors.initials: DF
authors.lastname: Xu
authors.affiliation: Department of Orthopaedic Surgery, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, 450001, People's Republic of China.
authors.forename: Fang-Gang
authors.initials: FG
authors.lastname: Bi
authors.affiliation: Department of Orthopaedic Surgery, The Second Affiliated Hospital, School of Medicine, Zhejiang University, Jie-fang Road 88, Hangzhou, 310009, People's Republic of China.
authors.forename: Chi-Yuan
authors.initials: CY
authors.lastname: Ma
authors.affiliation: Department of Orthopaedic Surgery, The Fourth Affiliated Hospital, School of Medicine, Zhejiang University, Yiwu, 322000, People's Republic of China.
authors.forename: Zheng-Fa
authors.initials: ZF
authors.lastname: Wen
authors.affiliation: Department of Orthopaedic Surgery, The Second Affiliated Hospital, School of Medicine, Zhejiang University, Jie-fang Road 88, Hangzhou, 310009, People's Republic of China. emilcai@163.com.
authors.forename: Xun-Zi
authors.initials: XZ
authors.lastname: Cai
mesh_terms: D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D005265:Femoral Neck Fractures / Q000150:complications / Q000601:surgery / Q000628:therapy*; D005271:Femur Head Necrosis / Q000209:etiology*; D005593:Fracture Fixation, Internal / Q000009:adverse effects / Q000379:methods*; D017102:Fracture Healing; D006801:Humans; D058866:Osteoporotic Fractures / Q000150:complications / Q000601:surgery / Q000628:therapy*
keywords: Avascular necrosis; Conservative treatment; Non-union; Secondary displacement; Surgical treatment; Undisplaced femoral neck fracture