Related Experiment Video
Updated: Aug 30, 2026

Treatment of Ankle Osteoarthritis with Total Ankle Replacement Through a Lateral Transfibular Approach
Published on: January 24, 2018
The role of a posteriorly positioned fibula in ankle sprain
Osman Tugrul Eren1, Metin Kucukkaya, Yavuz Kabukcuoglu
1First Department of Orthopaedic Surgery, Sisli Etfal Research and Training Hospital, Istanbul, Turkey.
Background:
Specific anatomic variations of the ankle mortise may predispose people to ankle sprains.
Hypothesis:
There is a correlation between a higher malleolar index (posteriorly positioned fibula) and incidence of ankle sprain.
Study Design:
Prospective case control study.
Methods:
We compared the malleolar index (transverse plane of the talus) on computerized axial tomographic images of 61 patients with ankle sprain with that of 101 normal controls. A positive number for the malleolar index meant that the lateral malleolus was posterior to the plane of the medial malleolus. A negative number meant that the lateral malleolus was actually anterior to the plane of the medial malleolus.
Results:
The average malleolar index of the patients with ankle sprain was +11.5 degrees with a standard deviation of 7 degrees. Malleolar relationships varied from -6 degrees to +39 degrees, a range of 45 degrees. The average malleolar index in the control group was +5.85 degrees with a standard deviation of 4.9 degrees, which varied from -8 degrees to +16 degrees. However, there was no correlation between recurrence of sprains and malleolar index values.
Conclusion:
Patients with an ankle sprain were more likely to have a posteriorly positioned fibula, possibly predisposing them to ankle sprain.
Related Concept Videos
Ankle Joint
Muscles of the Leg that Move the Foot and Toes
Anterior Compartment
The anterior compartment includes muscles that contribute to the dorsiflexion of the foot. This compartment houses the tibialis anterior, extensor hallucis longus, and extensor digitorum longus muscles.
Bones of the Lower Limb: Tibia and Fibula
Bones of the Lower Limb: Femur and Patella
Muscles that Move the Leg
Anterior Compartment
The quadriceps femoris, the most visible muscle of the anterior compartment, is integral for leg extension and thigh flexion. It is formed by merging four distinct muscles — the vastus lateralis, vastus medialis, vastus intermedius, and rectus femoris. The quadriceps tendon, a shared tendon of the four quadriceps muscles, is affixed to...
Fractures: Bone Repair
Minor fractures with no bone displacement are treated by immobilizing the fractured bone using a cast or splint. However, in the case of fractures with displaced bones, the broken bones are repositioned before immobilization to ensure successful healing without deformation and loss of function. The realignment of fractured bone ends is performed through a process called reduction. If the procedure...

