title: Predictive factors for knee stiffness after periarticular fracture: a case-control study.
abstract: BACKGROUND
  Knee stiffness is an important complication after periarticular fracture, but a systematic evaluation of risk factors for this complication and outcomes of treatment has not been undertaken, to our knowledge. The aims of this study were to evaluate risk factors for knee stiffness requiring manipulation after periarticular fracture and to document the clinical outcomes of the manipulation.
  
  
  METHODS
  This study was designed as a case-control study in which patients requiring manipulation under anesthesia after periarticular fracture were compared with those who did not require manipulation. Using billing data from a regional level-I trauma center, we identified twenty-four knees requiring manipulation for refractory stiffness over a six-year period. These were matched, on the basis of the AO/OTA classification, with forty-three control knees that did not develop stiffness requiring manipulation. Descriptive statistics were used for frequency and mean analysis.
  
  
  RESULTS
  Univariate analysis revealed that extensor mechanism disruption (chi square = 0.05), fasciotomy (chi square = 0.020), wounds requiring ongoing management and precluding knee motion (p = 0.001), and the need for more than two surgical procedures to achieve definitive fracture fixation and soft-tissue coverage (p = 0.003) all placed patients at increased risk for knee stiffness requiring manipulation. The mean improvement in knee motion following all procedures targeting knee stiffness was 62°. Mean final flexion was significantly less in the case group (107°) compared with the control group (124°; p=0.01).
  
  
  CONCLUSIONS
  To our knowledge, this is the first study to systematically evaluate the risk factors for knee stiffness after periarticular fracture and document the outcomes of manipulation under anesthesia. It demonstrates that injury characteristics that delay or prevent postoperative knee motion place patients at increased risk for refractory knee stiffness. Although knee motion remains compromised, late surgery aimed at improving knee motion leads to improvements in flexion
authors.affiliation: Department of Orthopaedic Surgery, Stanford University School of Medicine, Redwood City, CA 94063, USA. jabishop@stanford.edu
authors.forename: Julius
authors.initials: J
authors.lastname: Bishop
authors.forename: Julie
authors.initials: J
authors.lastname: Agel
authors.forename: Robert
authors.initials: R
authors.lastname: Dunbar
mesh_terms: D000328:Adult; D016022:Case-Control Studies; D005260:Female; D050723:Fractures, Bone / Q000503:physiopathology / Q000601:surgery*; D006801:Humans; D007718:Knee Injuries / Q000503:physiopathology / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D011183:Postoperative Complications / Q000503:physiopathology*; D011184:Postoperative Period; D011379:Prognosis; D016059:Range of Motion, Articular / Q000502:physiology*; D012307:Risk Factors