title: The benefits of computer-assisted total knee arthroplasty on coronal alignment with marked femoral bowing in Asian patients.
abstract: BACKGROUND
  Mechanical alignment guides are designed to compensate for variations in the valgus alignment angle; however, these guides may not be adequate when a patient has coronal alignment with marked bowing deformity. Previous study demonstrates better radiographic results, but the clinical benefits are a matter of speculation. The aim of this study was to investigate whether radiographic benefits of computer-assisted surgery total knee arthroplasty (CAS-TKA) would translate to clinical outcomes.
  
  
  METHODS
  Patients with osteoarthritis and coronal alignment with marked bowing deformity who underwent total knee arthroplasty (TKA) at our institution between January 2005 and June 2012 were entered into this retrospective study. Patients were divided into three groups: patients with coronal alignment with marked bowing deformity treated with CAS-TKA; with coronal alignment with marked bowing deformity treated with conventional TKA; and without marked coronal bowing deformity treated with conventional TKA. The computer-assisted navigation and the conventional technique were then compared by radiographic parameters. The International Knee Society (IKS) scores and patellar score were obtained for all patients preoperatively and at the last follow-up visit.
  
  
  RESULTS
  One hundred and thirty-seven patients (198 knees) met the inclusion criteria. For patients with osteoarthritic knees with marked femoral bowing deformity, the reconstructed mechanical axis (MA) was significantly closer to normal in the CAS-TKA group (P = 0.002) than in the conventional group. Significant differences in the reconstructed MA after conventional TKA were noted between patients without bowing and those with bowing (P = 0.003). Using the patellar score and IKS score, at a mean follow-up of 52.2 months, the differences did not achieve statistical significance among the three groups.
  
  
  CONCLUSIONS
  CAS-TKA was an effective alternative for obtaining proper alignment in patients with coronal alignment with marked bowing deformity. However, there was no statistically significant difference in clinical function between patients treated with CAS-TKA and conventional TKA. Long-term follow-up will be needed to determine if the improvement in radiographic results translates to better clinical outcomes.
authors.affiliation: Department of Orthopaedic Surgery, Chang Gung Memorial Hospital, 6, West Section, Chia-Pu Road, Pu-Tz City, Chia-Yi Hsien, 613, Taiwan. chienyin@gmail.com.
authors.forename: Chien-Yin
authors.initials: CY
authors.lastname: Lee
authors.affiliation: Department of Orthopaedic Surgery, Chang Gung Memorial Hospital, 6, West Section, Chia-Pu Road, Pu-Tz City, Chia-Yi Hsien, 613, Taiwan. b9002092@adm.cgmh.org.tw.
authors.forename: Shih-Jie
authors.initials: SJ
authors.lastname: Lin
authors.affiliation: Department of Orthopaedic Surgery, Chang Gung Memorial Hospital, 6, West Section, Chia-Pu Road, Pu-Tz City, Chia-Yi Hsien, 613, Taiwan. 8902078@adm.cgmh.org.tw.
authors.forename: Liang-Tseng
authors.initials: LT
authors.lastname: Kuo
authors.affiliation: Department of Orthopaedic Surgery, Chang Gung Memorial Hospital, 6, West Section, Chia-Pu Road, Pu-Tz City, Chia-Yi Hsien, 613, Taiwan. mr3497@adm.cgmh.org.tw.|Chang Gung University, 259 Wen-Hwa 1st Road, Kwei-Shan, Tao-Yuan, 333, Taiwan. mr3497@adm.cgmh.org.tw.
authors.forename: Kuo-Ti
authors.initials: KT
authors.lastname: Peng
authors.affiliation: Department of Orthopaedic Surgery, Chang Gung Memorial Hospital, 6, West Section, Chia-Pu Road, Pu-Tz City, Chia-Yi Hsien, 613, Taiwan. kc2672@adm.cgmh.org.tw.|Chang Gung University, 259 Wen-Hwa 1st Road, Kwei-Shan, Tao-Yuan, 333, Taiwan. kc2672@adm.cgmh.org.tw.
authors.forename: Kuo-Chin
authors.initials: KC
authors.lastname: Huang
authors.affiliation: Department of Orthopaedic Surgery, Chang Gung Memorial Hospital, 6, West Section, Chia-Pu Road, Pu-Tz City, Chia-Yi Hsien, 613, Taiwan. b8601081@adm.cgmh.org.tw.|Chang Gung University, 259 Wen-Hwa 1st Road, Kwei-Shan, Tao-Yuan, 333, Taiwan. b8601081@adm.cgmh.org.tw.
authors.forename: Tsan-Wen
authors.initials: TW
authors.lastname: Huang
authors.affiliation: Department of Orthopaedic Surgery, Chang Gung Memorial Hospital, 6, West Section, Chia-Pu Road, Pu-Tz City, Chia-Yi Hsien, 613, Taiwan. mellee@cgmh.org.tw.|Chang Gung University, 259 Wen-Hwa 1st Road, Kwei-Shan, Tao-Yuan, 333, Taiwan. mellee@cgmh.org.tw.
authors.forename: Mel S
authors.initials: MS
authors.lastname: Lee
authors.affiliation: Department of Orthopaedic Surgery, Chang Gung Memorial Hospital, 6, West Section, Chia-Pu Road, Pu-Tz City, Chia-Yi Hsien, 613, Taiwan. wwh@cgmh.org.tw.|Chang Gung University, 259 Wen-Hwa 1st Road, Kwei-Shan, Tao-Yuan, 333, Taiwan. wwh@cgmh.org.tw.
authors.forename: Robert Wen-Wei
authors.initials: RW
authors.lastname: Hsu
authors.affiliation: Po-Cheng Orthopaedic Institute, 100 Bo-ai 2nd Road Zuoying District, Kaohsiung, Taiwan. w2212@ms14.hinet.net.
authors.forename: Wun-Jer
authors.initials: WJ
authors.lastname: Shen
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D019645:Arthroplasty, Replacement, Knee / Q000379:methods*; D044466:Asian People; D005260:Female; D005269:Femur / Q000002:abnormalities* / Q000601:surgery; D006801:Humans; D007719:Knee Joint / Q000000981:diagnostic imaging; D008297:Male; D008875:Middle Aged; D011859:Radiography; D012189:Retrospective Studies; D025321:Surgery, Computer-Assisted / Q000379:methods*; D016896:Treatment Outcome