title: Regulation of the patellofemoral contact area: an essential mechanism in patellofemoral joint mechanics?
abstract: Although the relationship between contact area and pressure under physiological loading has been described in the feline patellofemoral joint, this interaction has only been examined under simplified loading conditions and/or considerably lower forces than those occurring during demanding activities in humans. We hypothesized that patellofemoral contact area increases non-linearly under an increasing joint reaction force to regulate patellofemoral pressure. Eight human cadaveric knees were ramp loaded with muscle forces representative of the stance phase of stair climbing at 30° knee flexion. Continuous pressure data were acquired with a pressure sensitive film that was positioned within the patellofemoral joint. While pressure was linearly dependent upon the resulting joint reaction force, contact area asymptotically approached a maximum value and reached 95% of this maximum at patellofemoral forces of 349-723N (95% CI). Our findings indicate that the regulatory influence of increasing contact area to protect against high patellofemoral pressure is exhausted at relatively low loads.
authors: Julius Wolff Institute and Center for Musculoskeletal Surgery, Charité - Universitätsmedizin Berlin, Center for Sports Science and Sports Medicine Berlin (CSSB) Philippstr. 13, Haus 11, 10115 Berlin, Germany.
authors: Ioannis G
authors: IG
authors: Goudakos
authors: Christian
authors: C
authors: König
authors: Philip B
authors: PB
authors: Schöttle
authors: William R
authors: WR
authors: Taylor
authors: Jan-Erik
authors: JE
authors: Hoffmann
authors: Berry M
authors: BM
authors: Pöpplau
authors: Navrag B
authors: NB
authors: Singh
authors: Georg N
authors: GN
authors: Duda
authors: Markus O
authors: MO
authors: Heller
mesh_terms: D000818:Animals; D001696:Biomechanical Phenomena; D002415:Cats; D005684:Gait / Q000502:physiology; D006801:Humans; D066298:In Vitro Techniques; D008954:Models, Biological; D017711:Nonlinear Dynamics; D057071:Patellofemoral Joint / Q000502:physiology*; D011312:Pressure; D016059:Range of Motion, Articular / Q000502:physiology; D013314:Stress, Mechanical; D016474:Weight-Bearing / Q000502:physiology