A broken navicular bone poses a serious threat to the foot’s structure. The navicular is a small, boat-shaped bone situated on the inner side of the midfoot, and a fracture immediately compromises the foot’s mechanical stability. This injury requires prompt medical attention and a period of strict non-weight bearing to prevent severe long-term complications.
The Navicular Bone’s Central Role in the Foot
The navicular bone is one of the seven tarsal bones, located between the talus (ankle bone) and the three cuneiform bones. Its position is integral to the structure and function of the entire foot, linking the hindfoot and the forefoot. The bone’s unique shape makes it the “keystone” of the medial longitudinal arch, the foot’s primary load-bearing structure.
The arch distributes weight, absorbs shock during movement, and provides the stability needed for gait. When the navicular bone is fractured, this system is disrupted, making the foot unable to manage walking forces. Furthermore, the navicular is susceptible to healing difficulties due to a limited blood supply, particularly in its central third.
This region of compromised blood flow means the fracture cannot easily receive the nutrients and oxygen needed for repair, increasing the risk of bone tissue dying. The tibialis posterior tendon, a major dynamic stabilizer of the arch, attaches directly to the navicular. Any fracture involving this bone is considered a high-risk injury because of the difficulty in achieving complete healing.
Why Walking is Difficult and Dangerous
Walking with a broken navicular bone is not advised and poses significant danger to the foot’s long-term health. A fracture in this keystone structure causes immediate and severe pain in the midfoot, particularly when attempting to bear weight. Symptoms include localized swelling, tenderness over the arch, and difficulty putting weight on the affected foot.
Attempting to walk on a fractured navicular bone risks displacing the fragments, even if the fracture was initially stable. The force exerted during walking transfers the body’s weight through the arch and can cause the bone pieces to shift. This displacement can damage surrounding cartilage and ligaments, potentially leading to chronic instability and midfoot arthritis.
The most severe danger is the risk of Avascular Necrosis (AVN), also known as osteonecrosis. Since the central part of the navicular already has a poor blood supply, the trauma of the fracture and continued pressure from walking can completely cut off remaining blood flow. If AVN occurs, the bone tissue dies, causing the navicular to collapse, resulting in permanent deformity and joint destruction.
Confirming the Diagnosis and Initial Care
The initial step in managing a suspected navicular fracture is a prompt medical evaluation, typically beginning with standard X-rays of the foot. Due to the bone’s complex shape and location, a fracture (especially a stress fracture) is often not visible on initial radiographs. A negative X-ray result should not rule out the diagnosis if clinical suspicion remains high.
Advanced imaging is frequently required to accurately determine the extent and pattern of the injury. A Computed Tomography (CT) scan provides detailed cross-sectional images, superior for visualizing the fracture line, displacement, and joint involvement. Magnetic Resonance Imaging (MRI) is also used, particularly for stress fractures, as it is highly sensitive in detecting bone marrow edema, which indicates an early stress injury.
Once a navicular fracture is confirmed, initial care focuses on protecting the bone and ensuring a non-weight bearing period. For non-displaced fractures, treatment involves placing the foot in a non-weight bearing cast or specialized boot for a minimum of six to eight weeks. Patients must strictly use crutches to avoid putting any force on the foot, which is the most important factor for non-surgical healing.
Displaced fractures, where the bone fragments have shifted out of alignment, often necessitate surgical intervention. This procedure, known as open reduction and internal fixation, involves realigning the fragments and securing them with screws or plates. Surgery restores the proper anatomy of the arch and prevents long-term joint instability.
Long-Term Complications and Recovery Timeline
The prognosis for a navicular fracture depends on the type of injury and strict adherence to the treatment plan, especially the non-weight bearing period. The primary long-term risk is Avascular Necrosis (AVN), where bone tissue dies due to insufficient blood flow, leading to bone collapse and severe arthritis. A delayed diagnosis, especially of stress fractures, increases the chances of this complication.
Another potential complication is non-union, which occurs when the fracture fails to heal completely, necessitating further interventions like bone grafting. Even after healing, post-traumatic arthritis can develop in the midfoot joints due to cartilage damage or minor residual anatomical changes.
The recovery process is lengthy, reflecting the bone’s poor healing capacity. Following the initial six to eight weeks of non-weight bearing immobilization, a gradual return to walking and physical therapy is initiated to restore strength and mobility. Full return to strenuous activities, such as running or sports, typically takes four to six months, or up to a year in complex cases.