title: Does cruciate-retaining total knee arthroplasty enhance knee flexion in Western and East Asian patient populations? A meta-analysis.
abstract: BACKGROUND
  This study analyzed the published data to examine if CR TKAs can enhance the flexion and functional outcomes of the knee in the Western and East Asian populations using a meta-analysis approach.
  
  
  METHODS
  A systematic review of literature published through Medline and EMBASE was conducted. The inclusion criteria were: primary TKA, follow up duration greater than one year, a fixed bearing CR prosthesis, and data for maximum pre- and post-operative flexion along with standard deviations or errors. We estimated the weighted mean differences between pre- and post-operative flexion, extension and knee scores (KSS and HSS) via a random effect model.
  
  
  RESULTS
  Seventeen articles were selected and reviewed among 1229 studies that included 1090 knees of the Western and 516 knees of the East Asian. No significant difference was noted in maximal knee flexion pre- and post-operatively, when all the studies were pooled together (-0.17°, p=0.93, post-operative<pre-operative). The mean difference in flexion was -1.87° (p=0.2) and 2.03° (p=0.17), respectively in the both populations. However, the extension angle was significantly improved by -5.49° and -13.05° (p<0.05), respectively. KSS scores were significantly improved by 46.39 and 51.63, and HSS scores by 36.65 and 30.67 (p<0.05), respectively in the both populations.
  
  
  CONCLUSIONS
  The meta-analysis indicated that contemporary CR TKAs have not been shown to enhance post-operative flexion capability in the Western and East Asian. The extension angles of the knee and the knee scores were significantly improved in both populations.
authors.affiliation: Bioengineering Laboratory, Department of Orthopaedic Surgery, Massachusetts General Hospital and Harvard Medical School, Boston, MA, United States; Department of Orthopaedic Surgery, Nihon University School of Medicine, Tokyo, Japan.
authors.forename: Takanobu
authors.initials: T
authors.lastname: Sumino
authors.forename: Harry E
authors.initials: HE
authors.lastname: Rubash
authors.forename: Guoan
authors.initials: G
authors.lastname: Li
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D019645:Arthroplasty, Replacement, Knee / Q000009:adverse effects / Q000379:methods*; D001900:Boston; D005260:Female; D006801:Humans; D007564:Japan; D007720:Knee Prosthesis; D008297:Male; D008875:Middle Aged; D059351:Organ Sparing Treatments; D020370:Osteoarthritis, Knee / Q000000981:diagnostic imaging / Q000601:surgery*; D016119:Posterior Cruciate Ligament; D011183:Postoperative Complications / Q000503:physiopathology / Q000601:surgery; D011379:Prognosis; D011859:Radiography; D016059:Range of Motion, Articular / Q000502:physiology*; D020127:Recovery of Function; D018570:Risk Assessment
keywords: CR TKA; Cruciate retaining designs; Extension; Flexion; Meta-analysis; Total knee arthroplasty