title: Three-dimensional motion analysis of the human knee joint: comparison between intra- and post-operative measurements.
abstract: OBJECTIVE
  To compare intra-operative knee joint kinematic measurements immediately after total knee replacement with those of the same patients post-operatively at 6-month follow-up.
  
  
  METHODS
  Fifteen patients who underwent total knee arthroplasty were analysed retrospectively. Eight were implanted with one prosthesis design and seven with another. The intra-operative measurements were performed by using a standard knee navigation system. This provided accurate three-dimensional positions and orientations for the femur and tibia by corresponding trackers pinned into the bones. At 6-month follow-up, the patients were analysed by standard three-dimensional video-fluoroscopy of the replaced knee during stair climbing, chair rising and step-up. Relevant three-dimensional positions and orientations were obtained by an iterative shape-matching procedure between the silhouette contours and the CAD-model projections. A number of traditional kinematic parameters were calculated from both measurements to represent the joint motion.
  
  
  RESULTS
  Good post-operative replication of the intra-operative measurements was observed for most of the variables analysed. The statistical analysis also supported the good consistency between the intra- and post-operative measurements.
  
  
  CONCLUSIONS
  Intra-operative kinematic measurements, accessible by a surgical navigation system, are predictive of the following motion performance of the replaced knees as experienced in typical activities of daily living.
  
  
  METHODS
  Prognostic studies--investigating natural history and evaluating the effect of a patient characteristic, Level II.
authors.affiliation: Movement Analysis Laboratory, Centro di Ricerca Codivilla-Putti, Istituto Ortopedico Rizzoli, Via di Barbiano 1/10, 40136, Bologna, Italy, belvedere@ior.it.
authors.forename: C
authors.initials: C
authors.lastname: Belvedere
authors.forename: S
authors.initials: S
authors.lastname: Tamarri
authors.forename: D P
authors.initials: DP
authors.lastname: Notarangelo
authors.forename: A
authors.initials: A
authors.lastname: Ensini
authors.forename: A
authors.initials: A
authors.lastname: Feliciangeli
authors.forename: A
authors.initials: A
authors.lastname: Leardini
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D019645:Arthroplasty, Replacement, Knee / Q000295:instrumentation / Q000379:methods*; D001696:Biomechanical Phenomena; D005471:Fluoroscopy; D005500:Follow-Up Studies; D006801:Humans; D021621:Imaging, Three-Dimensional; D007432:Intraoperative Period; D007719:Knee Joint / Q000000981:diagnostic imaging / Q000503:physiopathology* / Q000601:surgery; D007720:Knee Prosthesis; D008875:Middle Aged; D017063:Outcome Assessment, Health Care; D011184:Postoperative Period; D016059:Range of Motion, Articular; D012189:Retrospective Studies; D025321:Surgery, Computer-Assisted / Q000295:instrumentation / Q000379:methods*; D014741:Video Recording