title: Stemmed tibial revision component alignment: Does an anatomic conflict exist?
abstract: BACKGROUND
  Obtaining satisfactory coronal plane alignment is important for success in revision total knee arthroplasty (TKA). The study objective was to determine tibial coronal plane alignment after TKA when a tibial stem was used and assess if there was an anatomic conflict in tibial stemmed component alignment.
  
  
  METHODS
  A radiographic review of 88 revision TKA cases was performed. Full length leg radiographs were examined for varus/valgus alignment, defined as greater than or equal to three degrees from neutral 180 degrees, canal or non-canal filling tibial stems, and any native tibial bow.
  
  
  RESULTS
  In tibias with a native valgus alignment of three or more degrees, a canal-filling stem allowed little flexibility to improve final positioning of the tibial stem and resulted in a valgus alignment of the tibial stem in 87.5% of cases, where a canal filling stem was utilized. A non-canal filling stem utilized in native valgus tibias allowed on average a two-degree improvement in tibial alignment and 64.7% of cases resulted in a neutral placement of the tibial stem.
  
  
  CONCLUSIONS
  Implanting the tibial component in a desired position is limited by type of stem and the native angulation of the tibia. When anatomic conflict exists between tibial mechanical axis and the intramedullary canal, canal filling stems may compromise coronal alignment.
authors.affiliation: Houston Methodist Orthopedics & Sports Medicine, 6445 Main St., Outpatient Center, Suite 2500, Houston, TX 77030, United States. Electronic address: kmsmith@houstonmethodist.org.
authors.forename: Kevin M
authors.initials: KM
authors.lastname: Smith
authors.affiliation: Houston Methodist Orthopedics & Sports Medicine, 6445 Main St., Outpatient Center, Suite 2500, Houston, TX 77030, United States. Electronic address: Amoorman5@gmail.com.
authors.forename: Andrew
authors.initials: A
authors.lastname: Moorman
authors.affiliation: The Institute of Orthopedic Research Education, 6550 Fannin, Houston, TX 77030, United States. Electronic address: isamaily@bcm.edu.
authors.forename: Sabir K
authors.initials: SK
authors.lastname: Ismaily
authors.affiliation: Houston Methodist Orthopedics & Sports Medicine, 6445 Main St., Outpatient Center, Suite 2500, Houston, TX 77030, United States. Electronic address: SJincavo@houstonmethodist.org.
authors.forename: Stephen J
authors.initials: SJ
authors.lastname: Incavo
mesh_terms: D019645:Arthroplasty, Replacement, Knee / Q000379:methods*; D017760:Bone Malalignment / Q000000981:diagnostic imaging / Q000517:prevention & control*; D006801:Humans; D007720:Knee Prosthesis; D011474:Prosthesis Design; D012086:Reoperation; D012189:Retrospective Studies; D013977:Tibia / Q000000981:diagnostic imaging / Q000601:surgery*
keywords: Canal filling tibial stems; Coronal plane alignment, tibial mechanical axis; Non-canal filling tibial stems; Revision total knee arthroplasty; Tibial component