What is the Navicular?
The navicular is bone in the middle side of the midfoot and is shaped like a boat!
It plays an important role in normal weight bearing activities such as walking.
The navicular serves as a keystone for the medial longitudinal arch which is essential for absorbing ground force reactions and bearing the impact of body weight during movement.
The lower extremity accounts for about 95% of stress fractures, and one third of all lower extremity stress fractures are within the navicular.
What are stress fractures?
Stress fractures can be caused when there is an imbalance within this process and the resorption rate outweighs the rate of new bone formation.
This imbalance can occur in cases where high levels of tension are being applied to the bone as tension stimulates osteoclastic resorption.
Periods of intense training and little recovery time contribute to the thinning of cortical or cancellous bone making the bone more susceptible to micro traumas and ultimately causing a stress fracture.
Navicular stress fractures are more common amongst athletes compared to the general population.
As imaging technology advances the overall incidence of navicular stress fractures appears to be increasing.
The importance of blood supply to the Navicular bone
It is important to consider the blood supply to the navicular. Why? Because blood supply is important for healing.
The navicular bone’s blood supply is provided by branches of the dorsalis pedis and posterior tibial arteries, which supply the medial and lateral areas of the bone well. However, the central portion of the bone has a poorer supply of blood, and this leads to slower healing and recovery rates to stress.
Once injured, the navicular bone maintains its strength through the remodeling process. This process involves resorption of bone by osteoclasts and formation of new bone by osteoblasts.
What does a stress fracture feel like?
Patients will complain of a dull aching pain that increases with activity and is still present when they are resting.
Bruising and swelling can also be present.
How is a Navicular stress fracture diagnosed?
Navicular stress fractures can be difficult or delayed in diagnosing.
This is often due to unclear descriptions of complaints and less signs of bruising or swelling due to a poorer blood supply and also a high occurrence of false-negative results given on radiographs.
When we are diagnosing a Navicular stress fracture, our team of podiatrists will start by discussing your history to see if this can give us an indication of what is happening.
This history taking is essential as it helps to identify both intrinsic (internal) and extrinsic (external) factors that have been implicated in the progression of navicular stress fractures.
These factors include:
Extrinsic factors that increase the risk of navicular stress fractures include:
- Inadequate footwear
- Poor nutritional status
- Excessive training routine resulting in overloading and chronic fatigue
- Activity type
However, there are more intrinsic factors, including the patient’s anatomy and underlying biological processes, that increase the risk of navicular stress factors. These include:
- Previous history of stress fracture
- Insufficient vascular supply
- Foot or ankle biomechanics
- Specific anatomic variants for example having a short first metatarsal and a long second metatarsal, limited ankle joint range of motion, high and flat arches
After thorough history taking, we will begin a physical examination of the foot. This includes palpating for pain, testing joint range of motion, muscle testing and gait analysis. We may also request a series of scans including x-ray, ultrasounds MRI.
Who is most at risk of developing a Navicular stress fracture?
Unfortunately, females are at a higher risk of developing a stress fracture of their navicular bone.
This is due to something called the “female triad”. This is an important aspect when evaluating risk factors. The triad includes decreased bone mineral density, irregular menses and eating disorders.
The presence of female triad-related risk factors increases female patient risk of bony stress injury.
The risk factor is increased in women who have low bone density and participate in more than 12 hours of exercise weekly.
However, young male athletes tend to have higher rates of navicular stress fracture!
What can we do to help with Navicular stress fractures?
Here at Watsonia Podiatry our podiatrists will work to create an individualised treatment plan that is tailored for your needs.
Our goal is to get you pain free and functioning at your best as soon as possible.
This treatment plan will encompass aspects to initially assist with bone healing, then focus on long term support and a strengthening program to get you back to activity as soon as possible. Some of the treatment options that may be included in a treatment plan include:
- The use of a moon boot/CAM walker.
- Orthotics to help redistribute pressure.
- Activity modifications
- Padding and strapping.
- Footwear modifications.
- A strengthening program to get you back to activity.
If you think you are suffering from a stress fracture, make an appointment with one of our podiatrists today by calling 9432 2689 or booking online here.