title: No difference between tibia-first and femur-first techniques in TKA using computer-assisted surgery.
abstract: OBJECTIVE
  The measured resection technique and the gap-balancing technique are two philosophies used in total knee surgery. It is still unknown whether one or the other technique provides superior results when computer-assisted surgery is performed. We hypothesized that the gap-balancing technique improves joint stability because the technique relies primarily on the soft tissue.
  
  
  METHODS
  A prospective controlled study was performed in 116 patients using the tibia-first or femur-first technique. The Columbus(TM) total knee system and the Orthopilot(®) (Aesculap(®) AG, Tuttlingen, Germany) navigation system were used in all cases. Sixty-three patients were allocated to the femur-first technique (group F) and 53 patients to the tibial first technique (group T). The mean follow-up time was 11.4 ± 1.1 months. The KSS, KOOS and SF-36 were taken prior to surgery and at the time of follow-up for clinical assessment. Long-leg weight-bearing radiographs were performed to assess ligament alignment. Radiographs in varus and valgus stress were performed using the Telos(®)-Instrument (Telos(®) GmbH, Greisheim, Germany) under a force of 15 N at the time of follow-up for the assessment of medial-lateral stability. The nonparametric t test (Mann-Whitney U-test) was used in order to compare the ligament stability and the scores between group F and group T.
  
  
  RESULTS
  The lateral joint space opening for groups F and T was 3.4° ± 1.4° and 3.9° ± 1.7°, respectively (n.s.), and the medial joint space opening for groups F and T was 4° ± 1.4° and 4.1° ± 1.7°, respectively (n.s.). The femorotibial mechanical axis for groups F and T revealed 1.4° ± 1.2° and 0.7° ± 2.0° of varus, respectively (p = 0.138). The clinical assessment showed significant improvement according to KSS, KOOS and SF-36 in all subscales. Neither of the sores showed significant differences between the two groups.
  
  
  CONCLUSIONS
  The surgeon should use his/her preferred surgical technique providing the implantation is performed with computer assistance. It remains unclear whether the same findings will occur after conventional surgery.
  
  
  METHODS
  II.
authors.affiliation: Department of Orthopaedic and Trauma Surgery, City Hospital Brandenburg, Hochstrasse 26, 14770, Brandenburg an der Havel, Germany. roland_becker@yahoo.de
authors.forename: Roland
authors.initials: R
authors.lastname: Becker
authors.forename: Markus
authors.initials: M
authors.lastname: Malzdorf
authors.forename: Christian
authors.initials: C
authors.lastname: Stärke
authors.forename: Pirtkien
authors.initials: P
authors.lastname: Randolf
authors.forename: Christoph
authors.initials: C
authors.lastname: Lohmann
mesh_terms: D000368:Aged; D019645:Arthroplasty, Replacement, Knee / Q000379:methods*; D005260:Female; D005269:Femur / Q000601:surgery*; D005500:Follow-Up Studies; D006801:Humans; D007719:Knee Joint / Q000000981:diagnostic imaging / Q000502:physiology / Q000601:surgery; D008297:Male; D008875:Middle Aged; D020370:Osteoarthritis, Knee / Q000601:surgery*; D016119:Posterior Cruciate Ligament / Q000502:physiology / Q000601:surgery; D011446:Prospective Studies; D011859:Radiography; D016059:Range of Motion, Articular; D025321:Surgery, Computer-Assisted; D013977:Tibia / Q000601:surgery*; D016896:Treatment Outcome