title: [Influence of the insert design on clinical results and kinematics of the knee after total knee arthroplasty].
abstract: OBJECTIVE
  To investigate the influence of the insert design of knee prosthesis on clinical results and kinematics of the knee after total knee arthroplasty (TKA).
  
  
  METHODS
  Forty-two knees in 28 patients with knee osteoarthritis undergoing TKA using the GENESIS II from July 2007 to June 2009 were included in this study, mean follow-up of 27.7 months. The cases were divided into 2 groups according to the type of insert, one was high flexion insert group (23 knees) and the other was standard insert group (19 knees). Two groups were compared by clinical ratings of knee function. The motion of flexion and extension of the two groups was observed by cyclic fluoroscopy and the data was analyzed by mapping software. The influence of the insert design of knee prosthesis on kinematics of the knee after TKA was investigated by comparing the parameters of the two groups during the movement of knee joint, including femoral roll back and extensor mechanism arm.
  
  
  RESULTS
  The range of motion of standard insert group and high flexion insert group was 120° and 123° respectively with no difference between them. There was no difference of knee society clinical rating system in both groups. Feller score of high flexion insert group was higher than the standard insert group, the difference was significant statistically (P = 0.012). In the imaging measurement, the two groups had no differences in femoral rollback and extensor mechanism arm during the 0 to 120° range of movement. The two groups appeared significant statistically (P = 0.034) in the extensor mechanism arm when flexion extended to 130°.
  
  
  CONCLUSIONS
  The high flexion improved design may play a certain role on reducing anterior knee pain and improving knee function after TKA. However, the improved design may be reduced the extensor mechanism arm when high flexion, so that affecting the work ability of quadriceps.
authors.affiliation: Department of Adult Joint Reconstruction Surgery, Beijing Jishuitan Hospital, Beijing 100035, China.
authors.forename: Song-jie
authors.initials: SJ
authors.lastname: Ji
authors.forename: Yi-xin
authors.initials: YX
authors.lastname: Zhou
authors.forename: Yu-jun
authors.initials: YJ
authors.lastname: Li
authors.forename: Qing-hua
authors.initials: QH
authors.lastname: Liu
authors.forename: Ye
authors.initials: Y
authors.lastname: Huang
mesh_terms: D000368:Aged; D019645:Arthroplasty, Replacement, Knee; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007719:Knee Joint / Q000503:physiopathology; D007720:Knee Prosthesis; D008297:Male; D008875:Middle Aged; D011184:Postoperative Period; D011474:Prosthesis Design; D016896:Treatment Outcome