title: [Soft tissue balanced navigation of total knee arthroplasties].
abstract: OBJECTIVE
  Implantation of a total knee arthroplasty with a correct mechanical axis, a rectangular joint gap and a reconstructed joint line by use of an imageless computer navigation device
  
  
  METHODS
  Symptomatic gonarthrosis if non operative treatment or joint preserving operations remains ineffective
  
  
  METHODS
  Infections; soft tissue damage in the approach area; massive instability of the collateral ligaments
  
  
  METHODS
  Medial parapatellar approach to the knee joint; diminution of the patella; fixation of the reference arrays in tibia and femur; registration of leg axis, ligament balance and surface of the knee joint by use of the navigation system; tibial resection perpendicular to the mechanical axis; ligament balancing to achieve a rectangular extension gap; femoral implant planning to maintain the original joint line and reconstruct an equal joint gap in extension and flexion; femora resection perpendicular to the mechanical axis; reconstruction of the rectangular flexion gap by rotation of the femoral resection; two stage cementing technique for fixation of the original implants; check of the final mechanical axis and symmetry of the joint gap over the whole range of motion; wound closure.
  
  
  METHODS
  Physiotherapy; continuous passive motion treatment; mobilization with 20 kg weight bearing with 2 crutches for 2 weeks, thereafter with 2 crutches and incremental full weight bearing for 4 weeks.
  
  
  RESULTS
  The analysis of 582 consecutive navigated total knee arthroplasties showed one case of extension gap instability  > 3 mm (0.2%) and 8 patients with flexion gap instability  > 3 mm (1.4%). A too tight flexion gap was registered in 23 patients (4.4%), a too wide flexion gap in 13 cases (2.5%). The joint line was reconstructed with an average inaccuracy of 0 mm, in 17 patients the joint line was elevated  > 3 mm (2.9%).
authors.affiliation: LVR Klinik für Orthopädie, Horionstr. 2, 41749, Viersen, Deutschland. christophschnurr@gmx.de
authors.forename: C
authors.initials: C
authors.lastname: Schnurr
authors.forename: I
authors.initials: I
authors.lastname: Stolzenberg
authors.forename: J
authors.initials: J
authors.lastname: Nessler
authors.forename: P
authors.initials: P
authors.lastname: Eysel
authors.forename: P
authors.initials: P
authors.lastname: König
mesh_terms: D019645:Arthroplasty, Replacement, Knee / Q000295:instrumentation* / Q000379:methods*; D006801:Humans; D007593:Joint Instability / Q000175:diagnosis* / Q000601:surgery*; D007720:Knee Prosthesis; D012189:Retrospective Studies; D025321:Surgery, Computer-Assisted / Q000379:methods*; D016896:Treatment Outcome