title: Evaluation of lower limb axial alignment using digital radiography stitched films in pre-operative planning for total knee replacement.
abstract: BACKGROUND
  For patients with knee osteoarthritis, even slight anatomical variations in the femur or the tibia could affect total limb alignment during total knee replacement (TKR). Our hypothesis implies that the femoral valgus correction angle (VCA) in patients indicated for TKR, is variable and higher than the reported norm of 6° utilized in most intramedullary instrumentation systems, and that tibial bowing may result to a disparity of the tibial mechanical axis to the anatomical axis.
  
  
  METHODS
  Our study is a retrospective review of 216 pre-operative arthritic knees, which investigated the lower limb axial alignment using digitally-stitched films. Patients excluded from the study are those with history of previous tibial or femoral osteotomy, secondary gonarthrosis, rheumatoid arthritis, previous femoral or tibial fracture, patients for bilateral TKR, or history of hip surgery.
  
  
  RESULTS
  The mean age was 68-years old (range 39-86 years). The mean VCA was 7° (4.7-9.3) for men and 6.6° (4.9-9) for women. However, 71 patients (33%) had more than 7° VCA. Subsequently, 46 patients (21%) had tibial bowing producing an angle >1.5° between its mechanical and anatomic axis.
  
  
  CONCLUSIONS
  The 6° standard when used as a guide may result in suboptimal prosthesis positioning during conventional TKR surgery. Therefore our findings suggest that the femoral valgus correction angle has a broad range, and using standard femoral intramedullary guides should not be overlooked.
authors.affiliation: Department of Orthopaedic Surgery, St. Vincent's Clinic, Darlinghurst, Sydney, New South Wales 2010, Australia.
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Neil
authors.affiliation: Department of Orthopaedic Surgery, St. Vincent's Clinic, Darlinghurst, Sydney, New South Wales 2010, Australia.
authors.forename: Jereme B
authors.initials: JB
authors.lastname: Atupan
authors.affiliation: Department of Orthopaedic Surgery, St. Vincent's Clinic, Darlinghurst, Sydney, New South Wales 2010, Australia.
authors.forename: Juan Paulo L
authors.initials: JP
authors.lastname: Panti
authors.affiliation: Department of Orthopaedic Surgery, St. Vincent's Clinic, Darlinghurst, Sydney, New South Wales 2010, Australia.
authors.forename: Robert A J
authors.initials: RA
authors.lastname: Massera
authors.affiliation: College of Medicine, University of Notre Dame, Darlinghurst, Sydney, New South Wales 2010, Australia.
authors.forename: Stewart
authors.initials: S
authors.lastname: Howard
keywords: Digital radiography; Total knee replacement; Valgus correction angle; Whole leg radiography