title: Clinical outcome using a ligament referencing technique in CAS versus conventional technique.
abstract: OBJECTIVE
  Computer-assisted surgery (CAS) for total knee arthroplasty (TKA) has become increasingly common over the last decade. There are several reports including meta-analyses that show improved alignment, but the clinical results do not differ. Most of these studies have used a bone referencing technique to size and position the prosthesis. The question arises whether CAS has a more pronounced effect on strict ligamentous referencing TKAs.
  
  
  METHODS
  We performed a prospective cohort study comparing clinical outcome of navigated TKA (43 patients) with that of conventional TKA (122 patients). Patients were assessed preoperatively, and 2 and 12 months postoperatively by an independent study nurse using validated patient-reported outcome tools as well as clinical examination.
  
  
  RESULTS
  At 2 months, there was no difference between the two groups. However, after 12 months, CAS was associated with significantly less pain and stiffness, both at rest and during activities of daily living, as well as greater overall patient satisfaction.
  
  
  CONCLUSIONS
  The present study demonstrated that computer-navigated TKA significantly improves patient outcome scores such as WOMAC score (P=0.002) and Knee Society score (P=0.040) 1 year after surgery in using a ligament referencing technique. Furthermore, 91% were extremely or very satisfied in the CAS TKA group versus 70% after conventional TKA (P=0.007).
authors.affiliation: Klinik für Orthopädische Chirurgie und Traumatologie des Bewegungsapparates, Rorschacherstrasse 97, 9007, St. Gallen, Switzerland.
authors.forename: K
authors.initials: K
authors.lastname: Lehnen
authors.forename: K
authors.initials: K
authors.lastname: Giesinger
authors.forename: R
authors.initials: R
authors.lastname: Warschkow
authors.forename: M
authors.initials: M
authors.lastname: Porter
authors.forename: E
authors.initials: E
authors.lastname: Koch
authors.forename: M S
authors.initials: MS
authors.lastname: Kuster
mesh_terms: D000368:Aged; D019645:Arthroplasty, Replacement, Knee / Q000009:adverse effects / Q000379:methods*; D016009:Chi-Square Distribution; D015331:Cohort Studies; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007593:Joint Instability / Q000517:prevention & control; D007720:Knee Prosthesis; D007902:Length of Stay / Q000639:trends; D008023:Ligaments, Articular / Q000502:physiology; D008297:Male; D008875:Middle Aged; D020370:Osteoarthritis, Knee / Q000175:diagnosis / Q000601:surgery*; D010147:Pain Measurement; D011183:Postoperative Complications / Q000503:physiopathology; D011300:Preoperative Care / Q000379:methods; D011446:Prospective Studies; D011474:Prosthesis Design; D011475:Prosthesis Failure; D016059:Range of Motion, Articular / Q000502:physiology*; D025321:Surgery, Computer-Assisted / Q000009:adverse effects / Q000379:methods*; D016896:Treatment Outcome