title: An assessment of femoral rotational alignment of mini-incision total knee arthroplasty: A comparison based on the transepicondylar line from the kneeling view and the intraoperative posterior condylar line.
abstract: BACKGROUND
  Rotational alignment of the distal femur is important in total knee arthroplasty. The purpose of this study is to use a roentgenographic technique to evaluate the accuracy of mini-incision total knee arthroplasty (MIS TKA) performed based on the transepicondylar line from the kneeling view.
  
  
  METHODS
  Totally 32 patients (aged from 64 to 80 years with an average of 70.9 years) with 46 cases of knee osteoarthritis received MIS TKA were registered. Before surgery, the condylar twist angle was measured from the kneeling view. The bone cut for the external rotation was completed, with regard to the condylar twist angle. The control group including 26 patients (aged from 50 to 89 years with an average of 69.7 years) with 42 cases of knee osteoarthritis underwent TKA with built-in cutting jig design 3 degrees of femoral external rotation. This study is a prospective continuous-time duration analysis study. The level of evidence is IIc.
  
  
  RESULTS
  The mean condylar twist angle was 5.1° in the experimental group and 5.4° in the control group. The mean postoperative angle between the clinical epicondylar axis and the posterior condylar line of the femoral component was 0.46°. The same postoperative angle of the built-in external rotation in the control group was 2.7°. The condylar twist angle was significantly more accurate than the built-in design.
  
  
  CONCLUSIONS
  Our result substantiates that the kneeling view is practicable and reproducible as the cutting reference for femoral external rotation. The accuracy of the kneeling view shows that the epicondylar axis can be used in smaller wound surgery, such as MIS TKA.
  
  
  METHODS
  Level IIc.
authors.affiliation: Department of Orthopaedic Surgery, Taiwan Adventist Hospital, Taipei 10556, Taiwan.
authors.forename: Hwa-Chang
authors.initials: HC
authors.lastname: Liu
authors.affiliation: Department of Orthopedics, School of Medicine, Tzu Chi University, Hualien 97004, Taiwan; Department of Orthopedic Surgery, Hualien Tzu Chi Hospital, The Buddhist Tzu Chi Medical Foundation, Hualien 97004, Taiwan.
authors.forename: Wen-Tien
authors.initials: WT
authors.lastname: Wu
authors.affiliation: School of Dental Technology, College of Oral Medicine, Taipei Medical University, Taipei 11031, Taiwan; Laboratory of Organ and Tissue Reconstruction, Institute for Frontier Life and Medical Sciences, Kyoto University, Kyoto 606-8507, Japan; Department of Orthopedic Surgery, Taipei Tzu Chi Hospital, The Buddhist Tzu Chi Medical Foundation, New Taipei City 23142, Taiwan.
authors.forename: Kai-Chiang
authors.initials: KC
authors.lastname: Yang
authors.affiliation: Department of Orthopedics, School of Medicine, Tzu Chi University, Hualien 97004, Taiwan; Department of Orthopedic Surgery, Hualien Tzu Chi Hospital, The Buddhist Tzu Chi Medical Foundation, Hualien 97004, Taiwan.
authors.forename: Kuang-Ting
authors.initials: KT
authors.lastname: Yeh
authors.affiliation: Laboratory of Organ and Tissue Reconstruction, Institute for Frontier Life and Medical Sciences, Kyoto University, Kyoto 606-8507, Japan.
authors.forename: Shoichiro
authors.initials: S
authors.lastname: Sumi
authors.affiliation: Department of Orthopedics, School of Medicine, Tzu Chi University, Hualien 97004, Taiwan; Department of Orthopedic Surgery, Taipei Tzu Chi Hospital, The Buddhist Tzu Chi Medical Foundation, New Taipei City 23142, Taiwan. Electronic address: xavier-wang@yahoo.com.tw.
authors.forename: Chen-Chie
authors.initials: CC
authors.lastname: Wang
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D059925:Anatomic Landmarks; D019645:Arthroplasty, Replacement, Knee / Q000379:methods; D002358:Cartilage, Articular / Q000000981:diagnostic imaging / Q000601:surgery; D005260:Female; D005269:Femur / Q000000981:diagnostic imaging / Q000601:surgery*; D005500:Follow-Up Studies; D006801:Humans; D007719:Knee Joint / Q000000981:diagnostic imaging / Q000601:surgery*; D007720:Knee Prosthesis; D008297:Male; D008875:Middle Aged; D019060:Minimally Invasive Surgical Procedures / Q000379:methods*; D016343:Monitoring, Intraoperative / Q000379:methods*; D020370:Osteoarthritis, Knee / Q000175:diagnosis / Q000601:surgery*; D011446:Prospective Studies; D014057:Tomography, X-Ray Computed; D014102:Torsion Abnormality / Q000175:diagnosis / Q000517:prevention & control*