Normal parameters of ankle joint in x ray

NEET PG Orthopaedics
#1

Normal parameters of ankle joint in x ray…

  • Tibiofibular overlap.
    measure at point of maximum overlap.
    normal >6 mm on AP view.
    normal >1 mm on mortise view.

  • Medial clear space
    normal ≤ 4 mm on mortise or stress view.

  • Tibiofibular clear space (lateral clear space).
    measure clear space 1 cm above joint.
    normal <6 mm on both AP and mortise views.

  • Talocrural angle.
    measured by bisection of line through tibial anatomical axis and another line through the tips of the malleoli.
    shortening of lateral malleoli fractures can lead to increased talocrural angle.
    talocrural angle is not 100% reliable for estimating restoration of fibular length.

Other measures of fibular length:

  • Shenton line.
  • Dime sign.