Peroneus Tertius Syndrome: A Rare Cause of Anterolateral Ankle and Rearfoot Pain

Abstract

There is limited literature describing anterolateral ankle or rearfoot pain associated with the peroneus tertius tendon. The purpose of this study is to define peroneus tertius syndrome, in which the peroneus tertius tendon causes catching or locking over the anterolateral ankle or rearfoot with accompanying pain. We present a retrospective case series involving 4 patients diagnosed with peroneus tertius syndrome, discuss symptoms for clinical diagnosis, review radiographic imaging, and outline a minimally invasive operative technique for resection of the symptomatic tendon. Furthermore, we sought to evaluate postoperative outcomes and satisfaction scores after surgical management. All patients experienced resolution of symptoms by the fourth postoperative week. There was a statistically significant improvement in visual analog scale scores (average § SD, 7.75 § 0.96 preoperative to 0.75 § 1.19 postoperative) (p = .002). Overall patient satisfaction was 100%, with improved functional status and no evidence of recurrent symptoms at final follow-up (average 18.88 § 8.68 months). Our results demonstrate that excision of a symptomatic peroneus tertius provides resolution of symptoms, facilitates a quick return to activity, and has excellent patient outcomes. We suggest that during the evaluation of anterolateral ankle or rearfoot pain, peroneus tertius syndrome be considered as part of the differential diagnosis.

Imaging of Tendinous and Muscular Anatomical Variants Around the Ankle

“…The peroneus tertius muscle is the most frequent accessory muscle of the ankle with reported prevalence up to 95% in cadaveric studies and 80% in clinical studies. 1,11,23,24 Although no difference was found concerning the side of appearance, a mild male predominance was detected. 23 The peroneus tertius muscle is considered a weak ankle joint dorsiflexor; its primary function is eversion of the foot.…”

“…Although once considered a vital structure, current studies suggest the muscle is functionally insignificant. 24 The peroneus tertius muscle originates either from the anterior aspect of the distal fibula, the extensor digitorum longus (EDL) muscle, 1,2,11 or the intermuscular septum. 23 The tendon travels deep to the inferior extensor retinaculum, either in the same or different compartment as the EDL muscle.…”

“…1,2,11 The tendon typically has a broad fan-shaped insertion onto the dorsal aspect of the base of the fifth or, less frequently, fourth metatarsal. 23,24 Another additional slip to the dorsal aponeurosis of the fifth toe may sometimes be observed. 23 Anatomical scheme of the peroneus tertius and related muscles is presented on ►Fig.…”

Traumatic Rupture and Herniation of the Peroneus Tertius Muscle Leading to Compartment Syndrome and Entrapment of the Superficial Peroneal Nerve: A Case Report

“…[6][7][8][9][10][11] Overall, studies and literature of symptomatic PT is scarce and mainly associated with tendon problems, causing catching or locking over the anterolateral ankle or rear-foot and lesions such as split tears or ganglion cysts. [12][13][14] Hypertrophied PT muscle has also been reported to cause snapping and ankle pain. 15 The highly variable anatomical course of the SPN may expose it to damage during surgical incisions over the lateral malleolus, ankle arthroscopy, and forefoot surgery.…”

“… 6 7 8 9 10 11 Overall, studies and literature of symptomatic PT is scarce and mainly associated with tendon problems, causing catching or locking over the anterolateral ankle or rear-foot and lesions such as split tears or ganglion cysts. 12 13 14 Hypertrophied PT muscle has also been reported to cause snapping and ankle pain. 15 …”