Accessory Navicular Syndrome – When an Extra Bone Causes Pain
Accessory navicular syndrome causes pain from an extra bone on the inside of your foot. Learn about symptoms, diagnosis, and why conservative treatment is highly effective.
By Dr. Carli Hoover, DPM
Accessory Navicular Syndrome – When an Extra Bone Causes Pain
Do you have a small bump on the inside of your foot that's become increasingly painful? You might have an accessory navicular bone—an extra bone that some people are born with. When this bone causes pain and inflammation, it's called accessory navicular syndrome. At Central Florida Foot & Ankle Institute, we help patients with this condition find relief and return to their normal activities. Let's explore what you need to know about this common anatomical variation.
Understanding the Accessory Navicular
The accessory navicular is a small extra bone located on the inner side of the midfoot, near the main navicular bone. Approximately 10-14% of the population has this anatomical variation, but most people never experience symptoms. When the accessory navicular does cause pain—typically from inflammation or irritation—it's diagnosed as accessory navicular syndrome.
The condition becomes symptomatic when repetitive stress or trauma irritates the bone and the surrounding soft tissues, particularly where the posterior tibialis tendon attaches to it.
Who Develops Accessory Navicular Syndrome?
Anatomical Predisposition
Having an accessory navicular bone is a hereditary trait, meaning it often runs in families. If your parents have an accessory navicular, you're more likely to have one as well. However, having the bone doesn't guarantee you'll develop symptoms.
Age and Activity Level
Accessory navicular syndrome most commonly appears in adolescents and young adults, typically between ages 10-30. It often emerges during growth spurts when bones and tendons are changing rapidly. Athletes and very active individuals are at higher risk because increased foot stress can irritate the bone and tendon.
Biomechanical Risk Factors
Certain foot types and movement patterns increase symptom risk:
- Flat feet or overpronation – places excessive stress on the posterior tibialis tendon
- High-arched feet – can put pressure on the accessory navicular
- Tight Achilles tendon – increases stress throughout the foot
- Ankle instability – causes compensatory stress patterns
- Poor foot mechanics – such as intoeing or outtoeing
Recognizing the Symptoms
The Classic Presentation
Patients typically report a painful bump on the inner side of the foot, just below the ankle. This bump is the accessory navicular bone, which becomes tender and inflamed when irritated.
Pain Patterns
You might experience:
- Pain that's worse with activity and improves with rest
- Swelling and redness over the bump
- Pain when wearing certain shoes, especially tight or supportive ones
- Difficulty with activities that involve pushing off the inner foot
- Tenderness to direct pressure on the bump
- Pain that worsens with prolonged walking or running
Impact on Daily Life
As the condition progresses, the pain can affect your ability to:
- Participate in sports and exercise
- Wear favorite shoes comfortably
- Walk for extended periods
- Stand for long periods at work
- Perform activities that require lateral movements
How We Diagnose Accessory Navicular Syndrome
Clinical Assessment
When you visit Central Florida Foot & Ankle Institute, our podiatrists will examine the inside of your foot, looking for the characteristic bump. We'll ask about when the pain started, which activities make it worse, and whether you've had any injuries. We'll also assess your foot structure, arch shape, and walking pattern to identify biomechanical factors contributing to your symptoms.
Imaging Studies
X-rays clearly show the accessory navicular bone and help us confirm the diagnosis. X-rays also reveal any arthritis or bone changes that might be developing.
Ultrasound allows us to visualize the posterior tibialis tendon and assess inflammation around the bone, helping us understand the degree of soft tissue involvement.
MRI may be recommended if we need detailed images of the tendons and soft tissues or if we're considering surgical intervention.
Treatment Options for Pain Relief
Conservative Care Works for Most Patients
Approximately 90% of people with accessory navicular syndrome improve with conservative treatment. Our goal is to reduce inflammation and stress on the bone and tendon.
Rest and Activity Modification
Temporarily reducing high-impact activities gives the irritated tissues time to heal:
- Switch from high-impact to low-impact exercise (running to swimming or cycling)
- Take frequent rest breaks during activity
- Avoid activities that directly stress the accessory navicular
- Use ice after activities to reduce inflammation
Custom Orthotics
Custom shoe inserts are often the most effective conservative treatment. We design orthotics that:
- Support your arch and reduce overpronation
- Offload stress from the accessory navicular
- Improve overall foot mechanics
- Reduce stress on the posterior tibialis tendon
- Provide cushioning and protection
Many patients experience immediate pain relief with proper orthotics and can return to full activity within weeks.
Footwear Modifications
We recommend:
- Shoes with good arch support
- Shoes with stiff soles that limit excessive foot motion
- Avoiding tight or rigid shoes that press on the bump
- Breaking in new shoes gradually
- Using open-toed or sandal options when possible during symptomatic periods
Ice and Anti-Inflammatory Measures
Regular icing for 15-20 minutes after activity reduces inflammation. Some patients benefit from taking over-the-counter anti-inflammatory medications during acute phases.
Immobilization
For more painful cases, a walking boot or cast for 2-4 weeks can significantly reduce symptoms by protecting the bone while inflammation resolves. This approach is particularly helpful when initial conservative measures haven't provided sufficient relief.
Physical Therapy
A focused physical therapy program addresses underlying biomechanical issues:
- Posterior tibialis strengthening – strengthens the muscle-tendon unit
- Calf stretching – reduces tension on the foot
- Arch strengthening – improves foot stability
- Ankle stability exercises – prevents compensatory stress patterns
- Gait training – optimizes your walking mechanics
Surgical Options
If conservative treatment doesn't resolve symptoms after 6-12 months, or if the accessory navicular significantly interferes with your quality of life, surgery may be recommended. Surgical options include:
Excision of the accessory bone – removing the accessory navicular while preserving the posterior tibialis tendon attachment
Tendon transfer – repositioning the posterior tibialis tendon attachment to improve mechanics
Combined procedures – addressing both the bone and any underlying biomechanical issues
Surgery is successful in approximately 90% of cases, with most patients returning to full activity within 8-12 weeks of recovery.
Prevention and Long-Term Management
Once you've recovered, these strategies help prevent symptom recurrence:
- Continue wearing custom orthotics
- Maintain regular stretching and strengthening exercises
- Gradually increase activity intensity
- Wear supportive footwear
- Listen to your body and take rest days when needed
- Stay aware of foot mechanics and posture
When to See a Podiatrist
If you have a painful bump on the inside of your foot, especially if it's affecting your activities, schedule an appointment with Central Florida Foot & Ankle Institute. Early treatment prevents progression and helps you avoid surgery.
Bring your concerns to us if you have:
- A painful bump on the inner side of your foot
- Pain that worsens with activity
- Difficulty finding comfortable shoes
- Swelling on the inside of your foot
- Pain that doesn't improve with rest
Find Relief from Accessory Navicular Pain
While accessory navicular syndrome can be frustrating, it's highly treatable. With proper diagnosis and conservative management, most patients achieve complete pain relief without surgery. Our team at Central Florida Foot & Ankle Institute has extensive experience treating this condition and is committed to helping you get back to the activities you love.
Call (407) 307-0006 or book at https://floridafai.intakeq.com/booking today. With locations throughout Central Florida—Lake Mary (Waymont and MedPlex) and Downtown Orlando / SODO—we're ready to provide expert care and help you find lasting relief. People also drive in from Sanford, Altamonte, and Longwood — we do not have offices in those towns.