Keywords:
Normal variants, Diagnostic procedure, Ultrasound, MR, Conventional radiography, Musculoskeletal system, Musculoskeletal bone, Extremities, Education and training
Authors:
J. Desimpel1, M. S. Posadzy2, F. M. H. M. Vanhoenacker3; 1Duffel/Antwerp/BE, 2Poznań/PL, 3Duffel/Antwerp/Ghent/BE
DOI:
10.1594/essr2017/P-0214
Purpose
Ankle pain may result from a variety of diseases. An underestimated cause of chronic lateral ankle pain is the presence of a hypertrophic tuberculum peroneum (TP). [1] As the differential diagnosis with more frequent causes of ankle pain solely based on clinical findings is often impossible, imaging is very useful for evaluation of the size of a TP and its effect on the surrounding structures.
The aim of this exhibit is to review the clinical and imaging features of symptomatic hypertrophic (TP) in a cohort of symptomatic patients.
Introduction
The TP is located on the lateral surface of the calcaneus,
anteriorly to the eminentia retrotrochlearis ( Fig. 1 ). Anatomically, the TP has an oblique course from postero-superior to antero-inferior. The peroneus longus and brevis tendon run respectively under and above the TP, separating their tendon sheaths.
It functions as fulcrum directing the peroneus longus tendon towards the cuboid. Furthermore the inferior peroneal retinaculum inserts on the TP. [2]
Its size is defined by width,
height and length. Because conventional radiography (CR) is usually not accurate for precise evaluation of the size of the TP,
measurements are far better performed on ultrasound (US),
CT or MRI. [3] The width of the TP is the most easy parameter to evaluate on oblique coronal US images and on axial or coronal CT or MR images ( Fig. 2 and Fig. 3 ). Hyer et al. [3] examined human skeletons focusing on the characteristics of the tuberculum peroneum. Their measurements revealed an average width of 3.13 mm.
Hypertrophy of the TP will cause friction and mechanical irritation which may lead to peroneal tenosynovitis causing lateral ankle pain. Anatomically,
the peroneus longus tendon is at risk for tenosynovitis because of its long excursion and changing direction. The peroneus brevis tendon is less frequently affected. [4,5]
Despite multiple previous case reports and small studies,
a uniform definition of a hypertrophic tuberculum peroneum is still debated. Based on those small reports a width exceeding 5 mm is considered as being hypertrophic predisposing to tenosynovitis. [6]