title: Navigation did not improve the precision of minimally invasive knee arthroplasty.
abstract: Potential advantages of minimally invasive total knee arthroplasty (TKA) include decreased pain, faster recovery, and increased quadriceps muscle strength. Computer-assisted navigation has been associated with more accurate component alignment. We evaluated two groups of 50 patients who had minimally invasive TKAs performed with and without navigation by two surgeons. A comparison of 50 previous TKAs by each of the two surgeons showed similar results. The mean operative times for the navigation and nonnavigation groups were 112 minutes (range, 63-297 minutes) and 54 minutes (range, 35-86 minutes), respectively. The mean estimated blood losses, mean Knee Society pain as well as functional scores and mean component alignments were similar. The number of knees that deviated by more than 3 degrees from the normal anatomic axis was three and one in the navigated and nonnavigated groups, respectively. Complication rates were 6% and 4% in the navigated and nonnavigated groups, respectively. Our data demonstrate no distinct advantage of navigation when combined with a minimally invasive approach.
  
  
  METHODS
  Level II, therapeutic study. See the Guidelines for Authors for a complete description of levels of evidence.
authors.affiliation: Bonutti Clinic, Effingham, IL, USA.
authors.forename: Peter M
authors.initials: PM
authors.lastname: Bonutti
authors.forename: Daniel A
authors.initials: DA
authors.lastname: Dethmers
authors.forename: Mike S
authors.initials: MS
authors.lastname: McGrath
authors.forename: Slif D
authors.initials: SD
authors.lastname: Ulrich
authors.forename: Michael A
authors.initials: MA
authors.lastname: Mont
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D019645:Arthroplasty, Replacement, Knee / Q000379:methods*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D019060:Minimally Invasive Surgical Procedures / Q000379:methods*; D020370:Osteoarthritis, Knee / Q000601:surgery*; D011446:Prospective Studies; D015203:Reproducibility of Results; D025321:Surgery, Computer-Assisted / Q000379:methods*; D016896:Treatment Outcome