title: [Case-control study on modified femoral prosthesis in reducing the incidence of patellar clunk syndrome after the initial posterior stabilized total knee arthroplasty].
abstract: OBJECTIVE
  To explore therapeutic effects of modified femoral prosthesis applied in the initial posterior stabilized total knee arthroplasty.
  
  
  METHODS
  From April 1, 2012 to January 1, 2013, 156 patients with knee osteoarthritis underwent posterior stabilized total knee arthroplasty by the same director of orthopedic surgeon. Sixty-one patients were treated with modified femoral prosthesis, including 7 males and 54 females, with an average age of (68.34 +/- 5.41) years old; and 95 patients were treated with conventional designed femoral prosthesis, including 14 males and 81 females, with an average age of (69.92 +/- 5.11) years old. Indexes including age, body mass index, Insall-Salvati index, type of prosthesis, occurrence rate of patella click syndrome, postoperative line of force of lower extremity and postoperative function of the knee joint were observed and recorded. And American Knee Society (AKS) score was used to evaluate the clinical results.
  
  
  RESULTS
  All the patients were followed up, and the duration ranged from 36 to 56 weeks, with a mean of 45.31 weeks. Among patients in the conventional designed femoral prosthesis group, 7 patients had patella click syndrome, but there was no patient having patellar click syndrome in the modified femoral prosthesis group. Postoperative knee activity of patients in the modified femoral prosthesis group was (110.98 +/- 10.32) degrees, which was better than (107.05 +/- 8.61) degrees in the conventional designed femoral prosthesis group. The AKS score in the modified femoral prosthesis group was 129.79 +/- 9.63 during 21 to 28 days after operation, which was higher than 126.85 +/- 7.79 in the conventional designed femoral prosthesis group.
  
  
  CONCLUSIONS
  New designed femoral components are effective to reduce the occurrence rate of postoperative patellar click syndrome and obtain better early functional recovery from knee surgery.
authors.forename: Yang-Bo
authors.initials: YB
authors.lastname: Liu
authors.forename: Jian-Dong
authors.initials: JD
authors.lastname: Yuan
authors.forename: Cheng-Wei
authors.initials: CW
authors.lastname: Chen
authors.forename: Chao
authors.initials: C
authors.lastname: Zhang
authors.forename: Kai
authors.initials: K
authors.lastname: Chen
authors.forename: Lei
authors.initials: L
authors.lastname: Chen
mesh_terms: D000368:Aged; D019645:Arthroplasty, Replacement, Knee / Q000009:adverse effects* / Q000295:instrumentation; D016022:Case-Control Studies; D005260:Female; D005269:Femur / Q000601:surgery*; D005500:Follow-Up Studies; D006801:Humans; D015994:Incidence; D007719:Knee Joint / Q000601:surgery*; D007720:Knee Prosthesis; D008297:Male; D008875:Middle Aged; D011183:Postoperative Complications / Q000453:epidemiology* / Q000209:etiology; D012189:Retrospective Studies