A Peculiar Case of the Navicular Bone

Abstract Background: The tarsal navicular is the most frequently injured of the lesser tarsal bones and a critical component of the medial longitudinal arch and transverse tarsal locking mechanism. Its central one-third has relatively poor vascularization, supplied variably by branches of the dorsalis pedis and posterior tibial arteries, which predisposes the bone to osteonecrosis and stress fracture. Navicular stress fractures account for approximately 14–35% of all stress fractures, yet early radiographic findings are often subtle or absent, contributing to frequent diagnostic delays. Case Presentation: A 40-year-old woman presented in 2009 with tenderness over the medial aspect of the left foot, reporting an occupational injury fourteen months prior. Initial physical examination revealed edema over the lateral malleolus, a dropped arch, limited subtalar inversion and eversion, and pain on ambulation. Initial radiographs were unremarkable, and the patient was managed conservatively with rest, ice, compression, elevation, oral analgesics, and a podiatry referral for custom orthotics. Seven years later, in 2016, she returned with progressively worsening medial foot pain. Repeat imaging demonstrated deformity of the anterior process of the talus, loss of volume of the navicular bone, and talonavicular osteoarthritis, with bone scan findings consistent with the healing phase of avascular necrosis. Intervention: The patient was referred to orthopedic surgery and underwent subtalar–talonavicular joint fusion combined with naviculocuneiform fusion. Six weeks postoperatively, imaging demonstrated bony bridging across the talonavicular joint with associated soft tissue calcification, prompting a revision procedure for hardware removal and placement of an autograft bone graft. Postoperative management included physiotherapy and celecoxib for analgesia. Outcome: The patient achieved full functional recovery but was left with a permanent limp. Discussion: This case highlights the diagnostic challenges associated with navicular pathology, particularly when initial radiographs are negative and symptoms are attributed to soft-tissue injury. The relative avascularity of the central navicular, combined with disruption of microvascular and macrovascular supply following trauma, can precipitate avascular necrosis, which progresses rapidly to osteoarthritis and structural deformity. Earlier use of advanced imaging (CT or MRI) may identify osseous changes before they are visible on plain radiographs and may reduce the likelihood of progression to end-stage joint disease requiring fusion. Conclusion: Post-traumatic avascular necrosis of the tarsal navicular is an underrecognized cause of chronic medial foot pain following occupational and sports-related injuries. A high index of suspicion, early advanced imaging, and timely orthopedic referral are essential to prevent progression to talonavicular arthritis and the need for arthrodesis. Keywords: tarsal navicular; avascular necrosis; osteonecrosis; talonavicular arthritis; subtalar fusion; naviculocuneiform fusion; post-traumatic; case report; foot and ankle surgery