title: Fixed flexion deformity following total knee arthroplasty. A prospective study of the natural history.
abstract: BACKGROUND
  Stiffness following total knee arthroplasty (TKA) is a disabling problem resulting in pain and reduced function.
  
  
  OBJECTIVE
  The aim of our study was to evaluate the natural course of fixed flexion deformity (FFD ) following primary total knee arthroplasty.
  
  
  METHODS
  Prospective review of 1626 patients undergoing primary TKA from 2001 to 2006 with a minimum of 4 year follow up. Demographic data included post-operative range of motion; type of prosthesis used, treatment modalities for stiffness and the final range of motion were recorded. FFD was defined as class 1(5-15 degrees) and Class 2 (> 15 degrees). Patients with a pre-operative FFD of >15, infection, stiffness treated with manipulation or revision surgery were excluded from the study.
  
  
  RESULTS
  Of the 1626 patients evaluated, 170 (10.5%) presented with a FFD. 18 patients were excluded from the study and 16 were lost to follow up. 124 (91.2%) were class 1 and 12 (8.8%) were class 2. FFD improved from a mean of 8.8 degrees to 0.4 degrees (p<0.0001) in 11.4 months. In 94.1% patients the FFD completely resolved (i.e. < 5 degrees) at a mean of 10.8 months (p<0.0001). In the remaining 5.9% of patients, FFD improved from a mean of 16.4 to 6.9 degrees at a mean follow up of 21.5 months (p<0.0001).
  
  
  CONCLUSIONS
  A gradual improvement in the FFD can be expected up to 2 years and a small residual flexion contracture does not cause functional deficit.
  
  
  METHODS
  Prospective cohort study, level 3.
authors: Royal Derby Hospital, Derby, Uttoxeter Road, DE223NE, UK. conalquah@yahoo.com
authors: Conal
authors: C
authors: Quah
authors: Girish
authors: G
authors: Swamy
authors: James
authors: J
authors: Lewis
authors: John
authors: J
authors: Kendrew
authors: Nitin
authors: N
authors: Badhe
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D019645:Arthroplasty, Replacement, Knee / Q000009:adverse effects*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D016916:Joint Deformities, Acquired / Q000209:etiology* / Q000503:physiopathology; D007719:Knee Joint / Q000503:physiopathology* / Q000601:surgery; D008297:Male; D008875:Middle Aged; D020370:Osteoarthritis, Knee / Q000601:surgery*; D011379:Prognosis; D011446:Prospective Studies; D016059:Range of Motion, Articular / Q000502:physiology*; D013997:Time Factors