Painful os talus secundarius: a case report and imaging findings

Talus Secundarius: Case Series

BACKGROUND

Talus secundarius is a very rare accessory bone at the lateral border of the foot. It is attached via a synchondrosis or small synostosis to the lateral aspect of the talar body and has additional facets to the tip of the lateral malleolus and the superior aspect of the calcaneus.

METHODS

Over a period of 8 years, we have seen 5 patients with 6 cases of talus secundarius with an average age of 17 years at first presentation to the senior author. One ossicle was an incidental finding and completely asymptomatic. In the other 5 cases, the average duration of symptoms was 21 months at that time. In 3 cases, additional accessory bones were seen around the talus.

RESULTS

The average size of the ossicles was 18 × 12 × 8 mm. Complete removal resulted in considerable pain reduction without further functional restriction in 4 cases. Two cases (1 asymptomatic, 1 with mild intermittent symptoms) were treated nonoperatively. The average Foot Function Index improved from 22.6 to 4.8 in all patients and from 31.0 to 4.5 in the patients treated with excision for symptomatic talus secundarius (P < .01).

CONCLUSION

The knowledge of accessory bones at the foot is important, as missed diagnosis may lead to prolonged course of pain and unnecessary protection in the affected patients. Resection of symptomatic ossicles substantially reduces pain, but patients have to be counseled that some symptoms may prevail in a congenital deformity.

LEVEL OF EVIDENCE

Level IV, prospective case series.

Symptomatic os talus secundarius: a case report and review of the literature

Os talus secundarius is an extremely rare accessory ossicle located at the lateral aspect of the talus just anterior to the fibula. Although rarely seen, it may cause lateral-sided chronic ankle pain. Only a few cases of symptomatic os talus secundarius have been reported to date. Herein, a 42-year-old male patient with symptomatic os talus secundarius is presented, and its imaging findings, differential diagnosis, and treatment are discussed.

LEVEL OF EVIDENCE

Level IV.

A rare cause of lateral ankle pain: A symptomatic talus secundarius

The talus secundarius is one of the rarest accessory tarsal bones, being present in 0.01% of all ankles. It is located at the lateral side of the talus, distally to the tip of the fibula. Hitherto, only five cases of a symptomatic talus secundarius have been described in literature. We presented a case of bilateral symptomatic talus secundarius in a young gymnast. There was a difference in size of the two accessory bones. The large talus secundarius in the left ankle was fixated, in the right ankle the fragment was excised. Both excision and fixation in the presented patient led to satisfactory results, both in the short and long term outcome.

Accessory Ossicles of the Foot and Ankle: Disorders and a Review of the Literature

Accessory ossicles of the foot and ankle are normal variants of bone development that usually remain asymptomatic. However, they may be involved in various disorders and become a source of pain such as in fractures, dislocations, degenerative changes, osteonecrosis, osteoarthritis, osteochondral lesions, avascular necrosis, and irritation or impingement of adjacent soft tissues. Hence, during the assessment of the situations above, knowledge about these little-known ossicles could be very important to reach the correct diagnosis. Recent studies in the literature have mostly focused on the most frequent 9-12 accessory bones. In this review, 24 types of accessory ossicle are described. These ossicles are accessory navicular bone, os peroneum, os trigonum, os intermetatarseum, os vesalianum. os subfibulare, os subtibiale, os calcaneus secundarius, os calcanei accessorium, os supratalare, os sustentaculi, os talotibiale, os tali accessorium, talus secundarius, os subcalcis, os cuboideum secundarium, os supranaviculare, os infranaviculare, os paracuneiforme, os intercuneiforme, os cuneometatarsale I tibiale, os cuneometatarsale plantare, os cuneo–I metatarsale-II dorsale, and os aponeurosis plantaris. The clinical importance of these bones should be known thoroughly to reduce unnecessary orthopedic consultations and misdiagnosis. This article describes the clinical importance of the accessory ossicles and their possible pathological conditions. Understanding the possible disorders of the accessory ossicles of the foot and ankle can provide a more accurate diagnostic process.