Peroneal tubercle hypertrophy refers to the presence of an unusually large peroneal tubercle.
Dependent on the definition, the incidence of enlarged peroneal tubercle has been reported to be from 20.5 - 24% 2.
Two bony projections or protuberances may be seen from the lateral wall of the calcaneus – the peroneal tubercle and the retrotrochlear eminence.
The peroneal tubercle is present immediately inferior to the fibular malleolus, lying in between the two tendons, it separates the tendons of peroneus brevis and the peroneus longus. The common synovial sheath that covers the two tendons proximal to the tubercle divides into two slips to individually enclose the peroneal tendons at the tubercle and beyond. The peroneus brevis lies superior to the tubercle, and the peroneus longus lies inferior to the tubercle.
The retrotrochlear eminence is located posterior to the peroneal tubercle and the peroneal tendons. It is seen to be prominent in individuals with hypertrophied peroneus quartus muscle, the most frequently reported accessory peroneal muscle. The muscle arises from the inferolateral aspect of the fibula and has variable insertions, one of them being the retrotrochlear eminence.
Some consider the height of the peroneal tubercle of 5 mm or more being a cutoff for diagnosis of hypertrophied peroneal tubercle 2.
- the enlarged tubercle may impinge upon the peroneus tendons and result in stenosing tenosynovitis
- the tendon sheaths may show thickening and fluid within them
- at times an adventitial bursa can develop over the tubercle due to repeated friction, which may become symptomatic
Treatment and prognosis
The initial management of the condition when symptomatic is conservative, but surgical resection is indicated in those who do not respond to conservative management.
- 1. Saupe N, Mengiardi B, Pfirrmann CW et-al. Anatomic variants associated with peroneal tendon disorders: MR imaging findings in volunteers with asymptomatic ankles. Radiology. 2007;242 (2): 509-17. doi:10.1148/radiol.2422051993 - Pubmed citation
- 2. Lui TH. Endoscopic Resection of Peroneal Tubercle. (2017) Arthroscopy techniques. 6 (5): e1489-e1493. doi:10.1016/j.eats.2017.06.006 - Pubmed
- 3. Ochoa LM, Banerjee R. Recurrent hypertrophic peroneal tubercle associated with peroneus brevis tendon tear. (2007) The Journal of foot and ankle surgery : official publication of the American College of Foot and Ankle Surgeons. 46 (5): 403-8. doi:10.1053/j.jfas.2007.05.006 - Pubmed