title: Mini-midvastus total knee arthroplasty does not result in superior gait pattern.
abstract: OBJECTIVE
  Previous studies dealing with gait after minimally invasive surgery (MIS) total knee arthroplasty (TKA) are rare and insufficient. It was the purpose of the study to determine in a prospective, comparative setting whether MIS influences the outcome of TKA in terms of typical 3D gait parameters.
  
  
  METHODS
  Patients scheduled for TKA or MIS TKA were invited to participate. MIS TKA was defined as TKA with shorter skin incision, mini-midvastus arthrotomy, special instruments, and avoidance of tibiofemoral dislocation and patella eversion. All other intra- and perioperative aspects were identical for both groups. A 3D gait analysis was performed with a VICON system 1 month preoperative and 8 weeks post-operative. A multivariate analysis of variance was conducted including the main effects time (pre- and post-surgery) and surgical group and the group-by-time interaction effect.
  
  
  RESULTS
  Seventeen MIS TKA patients and 20 TKA patients were eligible for the final analysis. We determined neither inter-group differences nor time × group interactions for any gait variables (temporospatial, ground reaction forces, joint angles and joint moments)—except for the varus-valgus knee kinematics. In pre- to post-operative comparison, the maximum valgus sway increased in the MIS group, whereas it decreased in the conventional group (p = 0.001).
  
  
  CONCLUSIONS
  From our findings, it was concluded that MIS TKA does not result in a superior walking pattern 8 weeks post-operative. Because we previously also observed mini-midvastus MIS TKA to have equal or slightly inferior results with regard to knee scores, knee torque, radiographic outcome and tourniquet/operating time, we discontinued the procedure.
  
  
  METHODS
  Prospective comparative study, Therapy, Level II.
authors.affiliation: Department of Orthopaedic Surgery, Innsbruck Medical University, Anichstrasse 35, 6020, Innsbruck, Austria, michael.liebensteiner@i-med.ac.at.
authors.forename: M C
authors.initials: MC
authors.lastname: Liebensteiner
authors.forename: M
authors.initials: M
authors.lastname: Thaler
authors.forename: J M
authors.initials: JM
authors.lastname: Giesinger
authors.forename: S
authors.initials: S
authors.lastname: Fischler
authors.forename: D C
authors.initials: DC
authors.lastname: Coraça-Huber
authors.forename: M
authors.initials: M
authors.lastname: Krismer
authors.forename: E
authors.initials: E
authors.lastname: Mayr
mesh_terms: D000368:Aged; D019645:Arthroplasty, Replacement, Knee / Q000379:methods*; D001696:Biomechanical Phenomena / Q000502:physiology; D005260:Female; D005684:Gait / Q000502:physiology*; D006801:Humans; D021621:Imaging, Three-Dimensional; D007719:Knee Joint / Q000503:physiopathology; D008297:Male; D019060:Minimally Invasive Surgical Procedures; D011446:Prospective Studies