title: The effect of tibial rotation on knee medial and lateral compartment contact pressure.
abstract: OBJECTIVE
  The progression of knee osteoarthritis (OA) is determined in part by mechanical effects on local structures. The mechanical influences of limb malalignment on cartilage loss are well known; however, the effect of rotational deformities on knee OA is not yet known. The aim of the current study was to evaluate the effect of tibial rotation on knee medial and lateral compartment contact pressure.
  
  
  METHODS
  The left knees of six fresh whole-body cadavers were used in this study. Fujifilm Prescale super-low type film was used for contact pressure measurement. The films were inserted into the joint after arthrotomy. The cadavers were stabilized with a custom-made device, and axial force of half body weight specific to each cadaver was applied to the plantar surface of the feet. The examination was repeated after osteotomy of the fibula and tibia, and the tibia was then rotated 15° or 30° internally (IR) or externally (ER) and securely fixed. The resulting films were scanned, and CP was determined using appropriate software.
  
  
  RESULTS
  The p values for increased medial compartment contact pressure at 15° and 30° IR and 30° ER were 0.016, 0.025, and 0.025, respectively. For decreased medial compartment contact pressure at 15° ER, the p value was 0.020. The p values for increased lateral compartment contact pressure at 15° and 30° ER were 0.010 and 0.030, respectively. In this compartment, contact pressure changes at 15° and 30° IR were not significant.
  
  
  CONCLUSIONS
  This experimental study demonstrated that 15° IR of the tibial shaft increased contact pressure and 15° ER decreased contact pressure over the knee medial compartment.
authors.affiliation: Department of Knee Surgery, Firoozgar Hospital, School of Medicine, Iran University of Medical Science, Tehran, Iran. Dr.Yazdi88@yahoo.com.
authors.forename: Hamidreza
authors.initials: H
authors.lastname: Yazdi
authors.affiliation: Biomechanics Department, School of Mechanical Engineering, Iran University of Science and Technology, Tehran, Iran.
authors.forename: Mohammadreza
authors.initials: M
authors.lastname: Mallakzadeh
authors.affiliation: Biomechanics Department, School of Mechanical Engineering, Iran University of Science and Technology, Tehran, Iran.
authors.forename: Sara
authors.initials: S
authors.lastname: Sadat Farshidfar
authors.affiliation: Shafa Rehabilitation Hospital, School of Medicine, Iran University of Medical Science, Tehran, Iran.
authors.forename: Behrooz
authors.initials: B
authors.lastname: Givehchian
authors.affiliation: Legal Medicine Research Center, Legal Medicine Organization, Tehran, Iran.
authors.forename: Hamidreza
authors.initials: H
authors.lastname: Daneshparvar
authors.affiliation: Department of Orthopedic Surgery, Medical University Innsbruck, Innsbruck, Austria.
authors.forename: Hannes
authors.initials: H
authors.lastname: Behensky
mesh_terms: D001696:Biomechanical Phenomena; D017760:Bone Malalignment / Q000503:physiopathology*; D002102:Cadaver; D005260:Female; D005360:Fibula / Q000601:surgery; D006801:Humans; D007719:Knee Joint / Q000503:physiopathology*; D020370:Osteoarthritis, Knee / Q000503:physiopathology*; D010027:Osteotomy; D011312:Pressure; D012399:Rotation; D013977:Tibia / Q000503:physiopathology* / Q000601:surgery
keywords: Contact pressure; Knee; Osteoarthritis; Tibial rotation