title: Do high flexion posterior stabilised total knee arthroplasty designs increase knee flexion? A meta analysis.
abstract: OBJECTIVE
  This systematic literature review analysed the change in range of knee flexion from pre-operative values, following conventional posterior stabilised (PS) and high-flexion (H-F) PS total knee arthroplasty (TKA).
  
  
  METHODS
  We calculated the weighted mean differences of pre- and postoperative flexion using meta-analysis with random effect modelling. Eighteen studies met our inclusion criteria. These data included a total of 2,104 PS knees that received conventional implants and 518 knees that received H-F implants.
  
  
  RESULTS
  The pooled gain in flexion was 4.70° in the conventional group (p <0.0001) and 4.81° in the H-F group (p = 0.0008). In the subgroup analysis, the Western patient group showed significant difference in the gain of flexion with both implants. In contrast, no significant gain in flexion was observed in the Asian patient group.
  
  
  CONCLUSIONS
  These results suggest that improvement of preoperative flexion after TKA using current H-F PS prostheses is similar to that of conventional PS prostheses.
authors.affiliation: Department of Orthopaedic Surgery, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA.
authors.forename: Takanobu
authors.initials: T
authors.lastname: Sumino
authors.forename: Hemanth R
authors.initials: HR
authors.lastname: Gadikota
authors.forename: Kartik M
authors.initials: KM
authors.lastname: Varadarajan
authors.forename: Young-Min
authors.initials: YM
authors.lastname: Kwon
authors.forename: Harry E
authors.initials: HE
authors.lastname: Rubash
authors.forename: Guoan
authors.initials: G
authors.lastname: Li
mesh_terms: D000368:Aged; D019645:Arthroplasty, Replacement, Knee / Q000295:instrumentation* / Q000379:methods*; D005260:Female; D006801:Humans; D007719:Knee Joint / Q000503:physiopathology / Q000601:surgery*; D007720:Knee Prosthesis; D008297:Male; D008962:Models, Theoretical; D011474:Prosthesis Design; D016059:Range of Motion, Articular / Q000502:physiology*; D016896:Treatment Outcome