Figure 1. Anteroposterior radiograph of the right foot.
Figure 2. An image of the bump on the medial side of the patient’s foot.
A 14-year-old girl presents for evaluation of a painful prominence over her right medial midfoot that has been present for the past 2 years. She is a hockey player and the pain is made worse while wearing skates. She has tried nonsteroidal anti-inflammatory drugs (NSAIDs) and orthotic inserts, but neither provides relief. An anteroposterior radiograph of her right foot identifies the painful prominence (Figure 1). The bump on the medial side of her foot can be clearly seen on physical examination (Figure 2). The bump is firm, nonmobile, and tender to palpation.
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The patient is presenting with a symptomatic accessory navicular. An accessory navicular is a normal variant found in about 12% of the population and consists of an extra ossicle or sesamoid bone on the medial side of the foot.1
The accessory navicular can vary in size ranging from a small round bone within the substance of the tibialis posterior tendon (Type 1), a large bony synchondrosis connected to the navicular body (Type 2), or a large ossicle completely fused to the navicular body (Type 3).2 In a study by Wynn et al, Type 2 accessory navicular was found to be much more frequent (73%) than either Type 1 (9.7%) or Type 3 (17.4%).2
Most patients will remain asymptomatic but some patients, particularly athletes, may complain of pain after an injury or with wearing tight shoes.3 The most common complaint is pain to palpation over the medial prominence of the foot. Most patients can be treated successfully with a period of rest, NSAIDs, pads to cushion the bony prominence, and immobilization if necessary.2
Indications for surgical excision include persistent pain while wearing shoes and pain with athletic activities.2,3 Excision generally involves complete resection of the accessory ossicle with re-attachment of the tibialis posterior tendon if necessary.3
Dagan Cloutier, MPAS, PA-C, practices in a multispecialty orthopedic group in the southern New Hampshire region and is editor in chief of the Journal of Orthopedics for Physician Assistants.
- Coskun N, Yuksel M, Cevener M, et al. Incidence of accessory ossicles and sesamoid bones in the feet: a radiographic study of the Turkish subjects. Surg Radiol Anat. 2009;31(1):19-24. doi:10.1007/s00276-008-0383-9
- Wynn M, Brady C, Cola K, Rice-Denning J. Effectiveness of nonoperative treatment of the symptomatic accessory navicular in pediatric patients. Iowa Orthop J. 2019;39(1):45-49.
- Murphy RF, Van Nortwick SS, Jones R, Mooney JF 3rd. Evaluation and management of common accessory ossicles of the foot and ankle in children and adolescents. J Am Acad Orthop Surg. 2021;10.5435/JAAOS-D-20-00218. doi:10.5435/JAAOS-D-20-00218