Navicular Stress Fracture

Navicular fractures are relatively rare but are clinically significant due to their potential for delayed healing and chronic pain if missed. Although traditionally underdiagnosed, they now account for up to 35% of stress fractures in the foot and ankle, especially in elite athletes. Pain over the medial foot or midfoot in a high-impact athlete should raise clinical suspicion.

Importance of Early Diagnosis

Failure to detect and treat these fractures promptly can result in:

• Non-union or delayed union
• Chronic midfoot pain
• Loss of function
• Delayed return to sport

 

Anatomy of the Navicular Bone

The navicular is a small boat-shaped bone located on the medial aspect of the midfoot, wedged between the talar head proximally and the three cuneiforms distally.

Articulations:

• Posterior: Talar head
• Anterior: 3 cuneiforms
• Occasionally: Cuboid (lateral articulation)

Attachments:

• Tibialis posterior tendon inserts on the navicular tuberosity (medial)
• Spring ligament (plantar calcaneonavicular) attaches on the plantar side

Vascular Supply:

• Dorsalis pedis artery - supplies dorsal surface
• Posterior tibial artery - supplies plantar and medial aspects
• Central third of the navicular is often described as avascular - a zone of concern in stress injury. However, cadaveric studies by McKeon et al. suggest that vascularity may be more robust than previously believed.

 

Biomechanics & Pathophysiology

Why is the Navicular at Risk?

The navicular bone is subjected to repetitive compressive and shear forces, especially during:

• Running
• Jumping
• Cutting maneuvers in sports

During midstance in gait or sprinting:

• Medial compression is shared between the talar head and navicular
• Lateral compression is largely borne by the navicular alone
• Tibialis posterior activation increases medial tension

These biomechanical forces lead to maximal stress at the central third, coinciding with the suspected avascular region, thus increasing susceptibility to injury and delayed healing.

 

Epidemiology

• First formally described in 1970 by Towne et al.
• Increased incidence in recent decades due to better imaging (MRI/CT) and clinical awareness
• Up to 59% of cases in athletes occur in track and field
• Can also present in non-athletes with medial midfoot pain and activity-related tenderness

 

Risk Factors

Athletic & Activity-Based:

• Running, basketball, track and field
• Sudden increase in training intensity
• Inadequate rest or recovery

Anatomical & Individual:

• Gender, mostly female
• Hindfoot valgus
• Decreased plantarflexion
• Forefoot abduction

 

Diagnosing Navicular Stress Fractures

Imaging Evaluation

Plain Radiographs (X-rays)

• Three standard weight-bearing views are obtained.
• Frequently normal in early stages.
• Fracture line may appear after 3 weeks due to bone resorption.
• Helpful to rule out other foot pathologies.

Bone Scan (Triple-Phase)

• 100% sensitivity, high positive predictive value.
• Shows increased uptake in all three phases.
• Limitation - poor anatomical resolution, non-specific findings.

CT Scan

• More accurate than MRI for fracture identification.
• Typically shows incomplete fracture through the central third.
• Orientation - dorsolateral → plantar medial.
•  Useful for fracture classification (e.g., Saxena).
•  Persistent dorsal notching may remain visible years later.

MRI

• High sensitivity.
• Best for detecting medullary extension and bone marrow edema.
• Less accurate than CT in defining the exact fracture line.

Differential Diagnoses

1. Tibialis anterior tendinopathy

2. Tibialis posterior tendinopathy

3. Midfoot osteoarthritis

4. Lisfranc injury

5. Accessory navicular syndrome

6. Tarsal coalition

7. Medial plantar nerve entrapment

8. Dorsal ganglion cyst

9. Plantar fasciitis (medial extension)

10. Bone tumor (e.g., osteoid osteoma)

11. Extensor hallucis longus tendinopathy

12. Complex regional pain syndrome (CRPS)

Physiotherapy Management of Navicular Stress Fractures

Physiotherapy plays a crucial role in restoring function, preventing recurrence, and optimizing return to sport following navicular stress fractures. Management strategies depend on the treatment pathway - nonoperative (cast immobilization) or surgical fixation - but both require structured rehab to ensure successful recovery.

A. During Immobilization Phase (Weeks 0–6)

Goals

1. Protect healing fracture (non-weight bearing)
2. Maintain cardiovascular and muscular conditioning
3. Prevent complications of immobilization (e.g., joint stiffness, muscle atrophy)

Precautions

1. Strict non-weight bearing on the affected limb
2. Avoid activities that increase foot pressure or vibration

Interventions

• Crutch/walker training for NWB gait
• Core strengthening and upper body exercises
• Contralateral leg strengthening
• Isometric contractions of thigh/glute muscles
• Circulatory exercises (ankle pumps, toe curls) if permitted
• Pool exercises (upper body only) if incision or cast allows (post-op only)

 

B. Early Rehabilitation Phase (Weeks 6–8)

Begins once the patient is transitioned to a CAM boot walker and allowed partial weight bearing (PWB).

Goals

1. Initiate foot and ankle mobility
2. Begin progressive weight bearing
3. Restore neuromuscular control and proprioception

Precautions

1. Limit impact activities
2. Monitor for pain or swelling
3. Respect bone healing timelines - avoid aggressive mobilization

Interventions

• Ankle and foot ROM exercises (DF, PF, inversion, eversion)
• Toe curls, towel scrunches
• Ankle alphabet for mobility
• Seated balance training (e.g., ball under foot)
• Progressive weight-bearing drills in boot (per surgeon/PT clearance)
• Isometric strengthening - ankle, foot intrinsics

 

C. Progressive Strengthening Phase (Weeks 8–12)

At this stage, the patient is full weight bearing in a supportive shoe and cleared for increased activity.

Goals

1. Improve strength and endurance of lower limb muscles
2. Restore full ankle/foot ROM
3. Improve gait mechanics and proprioception
4. Begin low-impact functional activities

Precautions

1. Avoid barefoot walking on hard surfaces
2. Stop any exercise if it reproduces pain at navicular site

Interventions

• Gait training - emphasize heel-toe transition and symmetry
• Progressive resistance exercises (e.g., TheraBands, foot doming)
• Calf raises, progressing from bilateral → unilateral
• Closed kinetic chain exercises - mini-squats, step-ups
• Single-leg balance - on firm surface → foam → wobble board
• Tibialis posterior strengthening - resisted inversion, heel raises with slight supination
• Foot core strengthening - short foot exercises, toe spreading

 

D. Functional Rehabilitation Phase (Weeks 12–16+)

After imaging confirms healing (CT), and the patient meets functional criteria, pain-free ROM, strength, and ability to perform heel raises.

Goals

1. Restore dynamic balance and agility
2. Prepare for sport-specific demands
3. Prevent recurrence

Interventions

• Plyometrics - low-level jumping (e.g., line hops, hop-to-balance)
• Agility drills - lateral shuffles, zig-zags
• Sport-specific retraining (based on return-to-play protocol)
• Running progression - walk–jog intervals → short runs → sprinting
• Functional testing -Y-Balance Test, hop tests, heel raise endurance

 

Return to Sport Criteria

Before full return to competitive sports:

1. CT scan confirms healing
2. Full, pain-free ROM and strength
3. Can perform 10+ single-leg heel raises without discomfort
4. Completes sport-specific drills without symptoms
5. Demonstrates good neuromuscular control and endurance

 

Red Flags During Rehab

• Return or worsening of midfoot pain
• Swelling or limp with walking or exercise
• Tenderness at central navicular
• Delayed progression in strength or ROM
• If these appear, pause loading and reassess with imaging.