summary Acessory Navicular is a common idiopathic condition of the foot that presents with an enlargement of the navicular bone. Diagnosis is made with plain radiographs of the foot showing a plantar medial enlargement of the navicular bone. Treatment is generally conservative with shoe modifications and a short period of cast immobilization in patients with symptoms. Surgical excision is indicted for patients with progressive pain that have failed extended nonoperative management. Epidemiology Incidence accessory navicular is a normal variant seen in up to 12% of population majority of patients are asymptomatic Demographics more commonly symptomatic in females Etiology Pathophysiology pathoanatomy occurs as a plantar medial enlargement of the navicular bone exists as accessory bone or as completely ossified extension of the navicular Genetics inheritance pattern autosomal dominant Associated conditions flat feet posterior tibial tendon insufficiency Anatomy Osteology navicular bone normally has a single center of ossification ossifies at age 3 in girls and 5 in boys and fuses at 13 years of age an accessory navicular is a normal variant from which the tuberosity of the navicular develops from a secondary ossification center that fails to unite during childhood the accessory navicular does not begin to ossify prior to age 8 Muscles tibialis posterior inserts onto the tuberosity (medial) of the navicular bone innervated by tibial nerve Ligament plantar calcaneonavicular (spring) ligament originates from sustentaculum tali and inserts on to navicular plantar support for head of talus bifurcate ligament attaches the anterior process of the calcaneus to the navicular and cuboid bones lateral support dorsal talonavicular ligament connects the neck of the talus to the dorsal surface of the navicular bone dorsal support Blood Supply dorsalis pedis artery (dorsal aspect) medial plantar artery (plantar aspect) anastomosis between dorsalis pedis and medial plantar arteries (medial surface of tuberosity) Classification Radiographic Classification Type 1 Sesamoid bone in the substance of the tibialis posterior insertion Type 2 Separate accessory bone attached to native navicular via synchondrosis Type 3 Complete bony enlargement Presentation Symptoms asymptomatic majority of patients are asymptomatic medial arch pain often worse with overuse due to repeated microfracture at the synchondrosis or from inflammation of the posterior tibialis tendon insertion Physical exam inspection may have swelling in region medial foot tenderness firm and tender at the medial and plantar aspect of the navicular bone Imaging Radiographs recommended views AP, lateral, external obliques best seen with an external oblique view findings will see bony enlargement or accessory bone MRI indications evaluation for other pathology Treatment Nonoperative activity restriction, shoe modification, and non-narcotic analgesics indications first-line of treatment modalities the use of arch supports or pads over the bony prominence may be helpful a UCBL orthosis may invert the heel during walking and decrease symptoms orthotics must offload pressure from the accessory navicular or they will exacerbate symptoms outcomes most children and adolescents who have a symptomatic accessory tarsal navicular bone become asymptomatic when they reach skeletal maturity short period of cast immobilization indications pain is refractory to activity modification and shoe modifications Operative excision of accessory navicular indication recalcitrant cases that have failed extended nonoperative management Technique Excision of accessory navicular approach medial approach to the foot an incision is made from distal third of talus to medial cuneiform identify the posterior tibialis and then reflect the tendon (either plantar or dorsal) resection technique the synchondrosis between the accessory navicular and native navicular can typically be identified easily resect the accessory navicular (a 1/4" curved osteotome may facilitate the resection) through the synchondrosis trim down the body of the navicular (typically with osteotomes and rongeurs) to remove any medial prominence resection is typically in line with medial border of the medial cuneiform do NOT advance the posterior tibial tendon. The advancement does not enhance the result and increases downtime and morbidity flatfoot deformity correction this is not performed concomitantly with the procedure unless the flatfoot is the primary pathology Complications Persistent medial prominence and pain the most common complication is persistent medial prominence and pain when the body of the navicular is not trimmed sufficiently
QUESTIONS 1 of 5 1 2 3 4 5 Previous Next Sorry, this question is for PEAK Premium Subscribers only Upgrade to PEAK Sorry, this question is for PEAK Premium Subscribers only Upgrade to PEAK (OBQ08.160) An 18-year-old male complains of a painful prominence over his medial midfoot for the past 2 years; NSAIDs and orthotics have failed to provide relief. Physical exam demonstrates a firm, nonmobile, tender bump on the medial midfoot with no skin changes. A radiograph is provided in figure A. Which of the following is the best treatment option? QID: 546 FIGURES: A Type & Select Correct Answer 1 Total contact cast 3% (67/2627) 2 Steroid injection 1% (33/2627) 3 MRI of the foot and chest CT scan 1% (27/2627) 4 Open biopsy 1% (17/2627) 5 Surgical excision 94% (2475/2627) L 1 Question Complexity C Question Importance Select Answer to see Preferred Response SUBMIT RESPONSE 5 Review Tested Concept Review Full Topic (OBQ05.135) A 10-year-old boy presents with medial foot pain that is severe enough that it limits his daily activities such as walking to school. Physical exam shows tenderness in the medial forefoot 3 cm anterior and inferior to the medial malleolus. A radiograph is shown in Figure A. Nonoperative treatment including orthotics and cast immobilization was attempted for three months without success. What is the most appropriate next step in treatment? QID: 1021 FIGURES: A Type & Select Correct Answer 1 No treatment needed-return to class 1% (29/4529) 2 Continue serial casting 1% (34/4529) 3 Excision of the medial prominence of the navicular, including the synchondrosis 95% (4311/4529) 4 ORIF of the navicular non-union 3% (117/4529) 5 Bone stimulator for the navicular non-union 0% (14/4529) L 1 Question Complexity C Question Importance Select Answer to see Preferred Response SUBMIT RESPONSE 3 Review Tested Concept Review Full Topic Sorry, this question is for PEAK Premium Subscribers only Upgrade to PEAK
All Videos (3) Podcasts (1) Login to View Community Videos Login to View Community Videos Kidner's procedure for accessory navicular with flexible flat foot - Dr Karan Choudhry Derek W. Moore Pediatrics - Accessory Navicular C 11/27/2016 1464 views 3.8 (14) Login to View Community Videos Login to View Community Videos Anatomy of Navicular Bone Ujash Sheth General - Accessory Navicular C 2/8/2015 2111 views 4.4 (11) Login to View Community Videos Login to View Community Videos True Patellar "J Sign" Jonathan Cohen Pediatrics - Accessory Navicular B 1/15/2012 27425 views 4.7 (64) Pediatrics âȘAccessory Navicular Orthobullets Team Pediatrics - Accessory Navicular Listen Now 14:0 min 4/20/2020 333 plays 5.0 (1)