gms | German Medical Science

Deutscher Kongress für Orthopädie und Unfallchirurgie, 75. Jahrestagung der Deutschen Gesellschaft für Unfallchirurgie, 97. Tagung der Deutschen Gesellschaft für Orthopädie und Orthopädische Chirurgie, 52. Tagung des Berufsverbandes der Fachärzte für Orthopädie und Unfallchirurgie

25. - 28.10.2011, Berlin

Combined genu valgum and increased knee version: an anatomical configuration pre-disposing to patellofemoral instability?

Meeting Abstract

  • M.O. Heller - Charité-Universitätsmedizin, Julius Wolff Institut, Berlin, Germany
  • E. Kornaropoulos - Charité-Universitätsmedizin Berlin, Julius Wolff Institut, Centrum für Sportwissenschaft und Sportmedizin Berlin, Berlin, Germany
  • S. Scheffler - Charité-Universitätsmedizin Berlin, Centrum für Musculoskeletale Chirurgie, CMSC, Berlin, Germany
  • G. Diederichs - Charité Berlin, Standort Campus Virchow Klinikum, Klinik für Radiologie, Berlin, Germany
  • W.R. Taylor - Charité-Universitätsmedizin Berlin, Julius-Wolff Institut, Centrum für Sportwissenschaft und Sportmedizin Berlin, Berlin, Germany
  • G.N. Duda - Charité-Universitätsmedizin Berlin, Centrum für Muskuloskeletale Chirurgie, Berlin, Germany

Deutscher Kongress für Orthopädie und Unfallchirurgie. 75. Jahrestagung der Deutschen Gesellschaft für Unfallchirurgie, 97. Tagung der Deutschen Gesellschaft für Orthopädie und Orthopädische Chirurgie, 52. Tagung des Berufsverbandes der Fachärzte für Orthopädie. Berlin, 25.-28.10.2011. Düsseldorf: German Medical Science GMS Publishing House; 2011. DocWI32-504

DOI: 10.3205/11dkou170, URN: urn:nbn:de:0183-11dkou1705

Veröffentlicht: 18. Oktober 2011

© 2011 Heller et al.
Dieser Artikel ist ein Open Access-Artikel und steht unter den Creative Commons Lizenzbedingungen (http://creativecommons.org/licenses/by-nc-nd/3.0/deed.de). Er darf vervielfältigt, verbreitet und öffentlich zugänglich gemacht werden, vorausgesetzt dass Autor und Quelle genannt werden.


Gliederung

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Questionnaire: Torsional deformities of the femur or the tibia, as well as genu valgum can all increase the Q angle, thereby lateralize the force vector acting on the patella and possibly increase the risk of lateral dislocation. A detailed evaluation of lower limb anatomy to identify the location and degree of a possible underlying patho-anatomy is therefore an essential step in the diagnosis and treatment of PF instability. Hypothesis of this study was that patients with PF instability possess both significantly increased knee valgus and an internally rotated knee, and further, that the main patho-anatomy was on the femur.

Methods: An MRI protocol using a T2-HASTE sequence and a dedicated lower limb angiography coil was developed, with the entire scanning process lasting less than 4min. In a study approved by the local ethics committee, 15 healthy subjects and 15 patients with PF instability were evaluated. After 3D reconstruction of the MRI scans in Amira (Visage Imaging GmbH, Berlin, Germany), bony landmarks where defined in order to calculate the following read-out parameters: femoral torsion, tibial torsion, the knee version (the relative rotation between the distal femur and the proximal tibia), and the mechanical femoral tibial angle (mFTA). Negative values for the mFTA are interpreted as knee valgus. Greater values for either femoral or tibial torsion mean a greater internal rotation of the distal end of the respective segment. Negative values for the knee version are interpreted as relative internal rotation of the distal femur.

Results and conclusions: Patients with PF instability had significantly more valgus knees (p< 0.01) than the control subjects (Figure 1 [Fig. 1]). Additionally, significantly (p<0.01) higher femoral torsion and knee version angles (Figure 1 [Fig. 1]) were observed in the patient cohort in comparison to the controls, while no significant differences where observed for the tibial torsion between the two groups. Using this novel protocol to determine 3D limb alignment from MRI we found that the patients with PF instability exhibited a significantly more valgus knee, and also possessed significantly increased knee version. Both frontal plane as well as rotational malalignment in our patients increase the Q-angle and can therefore increase the lateralizing forces acting on the patella. The specific multi-planar anatomical configuration observed in our patients might thus predispose to PF instability. While future studies should aim to identify whether increased knee version is an independent risk factor for PF instability, our results confirm that at least a subgroup of patients with PF instability might particularly benefit from treatment options that focus on this aspect.