Progressive pes adductus caused by an accessory calcaneus: a case report

Os calcaneus secundarius, a relevant differential diagnosis to fracture or pseudarthrosis of processus anterior of the calcaneus: a CT morphologic description

PURPOSE

A fracture or a pseudarthrosis of the processus anterior calcanei (PAC) as well as a traumatized Os calcaneus secundarius (OCS) is often overlooked. A clinical or conventional radiological differentiation of these is uncertain. Therefore, a CT scan is recommended. The aim of the study was to identify CT morphological differentiators between OCS and pathologies of PAC.

METHODS

All CT scans at our trauma center level I from 2010 to 2014, which imaged the entire foot, performed after acute trauma or postoperative control were retrospectively re-examined for OCS, other accessory ossicles (oAOS), fracture or pseudarthrosis of PAC and analyzed for specifiers.

RESULTS

In 611 CT examinations, 14 (2.3%) accessory ossicles (AOS) at the PAC were detected. 12 (86%) were identified as typical OCS and 2 (14%) as oAOS. 56 (9.2%) pathologies were detected. Of these, 44 (79%) were declared as fractures and 12 (21%) as pseudarthrosis. 7 OCS (58%) and 25 (46%) of the pathologies were not mentioned in the initial CT reports. The main differentiators of OCS to fracture of PAC were the anteromedial localization into a concave notch at the calcaneal facet at PAC and the continuous corticalization. With increasing size, radiological osteoarthritic signs at the OCS were frequent (p ≤ 0.05).

CONCLUSIONS

The study confirms that AOS or pathologies at the PAC often are not exactly described in CT report. In the context of foot trauma, attention should be paid to this region. Based on the presented differentiation criteria, a precise distinction can be made with the help of a CT.

Calcaneus secundarius--a relevant differential diagnosis in ankle pain: a case report and review of the literature

Introduction

Accessory ossicles of the foot are a common finding. Although mostly asymptomatic, they can gain clinical relevance by trauma or stress on the complex biomechanical system of the foot. There are few reports on the entity of symptomatic calcaneus secundarius. Furthermore, the current literature does not address the need for awareness of calcaneus secundarius as a differential diagnosis in cases of persistent posttraumatic ankle pain.

Case presentation

We present the case of a 51-year-old Indo-European man with a medical history of persistent load-dependent ankle pain over 3 decades. At presentation after an acute ankle sprain, we diagnosed a traumatized calcaneus secundarius. Surgical excision led to a complete recovery. More than 1 year postoperative he is still asymptomatic.

Conclusions

With the presented case and review of the literature we demonstrate the clinical relevance of calcaneus secundarius. Depending on size and alignment, calcaneus secundarius can alter the biomechanics in the subtalar region generating pain at the ankle. If a patient has persistent sinus tarsi syndrome, a painful limited subtalar range of motion or repetitive ankle sprains, then calcaneus secundarius should be considered in differential diagnosis. Likewise when a fracture of the anterior process of the calcaneus or a calcaneonavicular coalition is suspected, calcaneus secundarius should be considered a possible diagnosis by all clinicians confronted with foot and ankle pain.

Acquired cavo-varus deformity caused by an accessory calcaneus: a case report and literature review

We describe an unusual cause of an acquired cavo-varus foot deformity produced by progressive enlargement of an accessory calcaneal ossicle. A 13-year-old boy with constitutional plano-valgus flat feet noted a gradual change in foot shape associated with lateral ankle pain on ambulation following an inversion injury 2 years earlier. CT and MRI scans confirmed a large accessory calcaneal ossicle lying within the sinus tarsi, with associated marrow oedema. Following surgical excision of the ossicle, the foot returned to its original shape and the symptoms were alleviated. This is the fifth reported case of an accessory calcaneal ossicle, but the only case that has occurred in a flatfooted individual. We also present the first reported MRI images of the lesion confirming pathological marrow oedema as a response to mechanical stress.