Management of Accessory Navicular Syndrome
Initial management should consist of conservative treatment including immobilization, activity restriction, and orthotic devices for at least 3-8 months, with surgical intervention (modified Kidner procedure) reserved for patients who fail conservative therapy.
Initial Conservative Management
Conservative treatment is the mandatory first-line approach for all patients with accessory navicular syndrome 1, 2, 3. The evidence demonstrates that approximately 28% of patients achieve complete pain relief with nonoperative management, while an additional 41% experience partial relief sufficient to avoid surgery 2.
Conservative measures include:
- Rest and immobilization (casting or walking boot)
- Activity restriction from sports and high-impact activities
- Orthotic insoles with medial arch support
- Average treatment duration of 8 months for those achieving complete relief 2
For athletes specifically, customized orthoses demonstrate superior outcomes compared to conventional insoles, with significant improvements in arch angle, arch height, reduction in heel eversion angle, and decreased plantar pressure at the medial arch 4. These custom orthotics provide faster and more significant pain relief than standard insoles 4.
When Conservative Treatment Fails
Approximately 30% of patients will require surgical intervention after failed conservative management 2. The modified Kidner procedure is the recommended surgical technique, involving resection of the accessory navicular with reattachment of the posterior tibial tendon to the navicular 5, 6.
Key surgical considerations:
- The Kidner procedure demonstrates excellent clinical and radiological outcomes with an 11% complication rate 5
- Simple excision alone (without PTT reattachment) shows similar subjective outcomes but may not address the underlying biomechanical issues 5
- Alternative procedures like arthrodesis (25% complication rate, 3% failure rate) and percutaneous drilling (42% nonunion rate) have concerning complication profiles and are not recommended 5
Special Population Considerations
Athletes: Both single-sport and multisport athletes achieve comparable postoperative outcomes with the modified Kidner procedure, though single-sport athletes may present with more severe preoperative symptoms 6. Athletes experience similar improvement to nonathletes in FAAM ADL and VAS scores postoperatively 6.
Diagnostic Imaging Algorithm
When radiographs are negative or equivocal with clinical concern for symptomatic accessory navicular 7:
- MRI is the preferred advanced imaging to assess bone marrow edema, soft tissue pathology, and confirm symptomatic accessory navicular
- CT can confirm ossicle presence and characterize the synchondrosis but is limited for soft tissue assessment 7
- Bone scintigraphy shows increased uptake at the synchondrosis but lacks specificity; a negative scan can exclude symptomatic accessory ossicle 7
Common Pitfalls
- Premature surgical intervention: Ensure adequate conservative trial (minimum 3 months, ideally 8 months) before considering surgery 2
- Using inferior surgical techniques: Avoid arthrodesis, arthroeresis, or percutaneous drilling as primary procedures due to high nonunion and complication rates 5
- Generic orthotics in athletes: Standard insoles are insufficient; customized orthoses provide significantly better outcomes 4
Emerging Treatment Option
For patients refractory to conservative management who wish to avoid surgery, transarterial microembolization (TAME) shows promise as an intermediate option. A 2026 study demonstrated favorable safety with no major complications and significant pain reduction (NRS from 6.9 to 1.4) at mean 31-month follow-up 8. However, this remains investigational and should be considered only in specialized centers.