Sesamoid bones are small, independent bones often found embedded within tendons, with two prominent ones located beneath the big toe joint in the foot. Pain in the sesamoid bones of the foot is a frequent complaint. Understanding the causes of this pain is key to finding relief.
Understanding Sesamoid Bones
Sesamoid bones are small bones encased within a tendon, not directly connected to other bones at a joint. They function similarly to a pulley system, providing a smooth surface for the tendon to glide over and enhancing muscle leverage.
The most recognized sesamoid bones are two located on the underside of the forefoot, beneath the head of the first metatarsal bone (the long bone leading to the big toe). These sesamoids assist with propulsion during walking and running. They also help absorb impact and protect the tendon that flexes the big toe.
Common Reasons for Pain
Pain originating from the sesamoid bones stems from various conditions. Sesamoiditis, an inflammation of the sesamoid bones and surrounding tendons, is a common issue. This condition often develops from repetitive stress or a sudden increase in activities that pressure the ball of the foot, such as running, dancing, or wearing high heels. Individuals often experience a dull ache under the big toe joint, which may be accompanied by mild swelling and difficulty bending the big toe.
Another cause of pain can be a fracture of one of the sesamoid bones. Acute fractures result from a sudden, direct impact or forceful landing, leading to immediate and sharp pain. Stress fractures can develop gradually over time due to repetitive micro-trauma, often seen in athletes. Pain from a fracture usually intensifies with activity and may persist even during rest, making walking difficult.
A more serious, though less common, condition is avascular necrosis (AVN) of the sesamoid bone. This occurs when the blood supply to the bone is disrupted, leading to the death of bone tissue. AVN typically causes persistent, deep pain that may worsen over time, and it can eventually lead to the collapse of the bone. Other factors like osteoarthritis within the big toe joint or soft tissue injuries such as “turf toe” can also contribute to pain.
Diagnosis and Management
A professional medical evaluation is key to accurately diagnosing sesamoid bone pain. The diagnostic process begins with a thorough physical examination, where a healthcare provider will palpate the area under the big toe to pinpoint tenderness and range of motion. They may also observe your gait to understand how weight is distributed on your foot.
Imaging studies confirm a diagnosis. X-rays can reveal fractures or signs of avascular necrosis, showing changes in bone density or shape. For subtle issues like stress fractures not immediately visible on X-rays, or for assessing soft tissue damage like tendon inflammation, a magnetic resonance imaging (MRI) scan may be performed. These techniques help differentiate between various causes of pain.
Management approaches for sesamoid pain begin with conservative treatments. Rest, applying ice to the affected area, and elevating the foot (RICE protocol) reduce inflammation and pain. Non-steroidal anti-inflammatory drugs (NSAIDs) may be recommended for discomfort.
Specialized padding, taping techniques, supportive footwear, and custom orthotics offload pressure from the sesamoid bones. Physical therapy exercises improve foot strength and flexibility. In severe cases, such as non-healing fractures or advanced avascular necrosis, surgical intervention may be considered as a last resort to remove or repair the damaged bone.
Preventing Recurrence and Long-Term Care
Preventing the recurrence of sesamoid pain involves proactive forefoot protection. Choosing appropriate footwear with adequate cushioning and arch support distributes pressure evenly. For individuals engaging in high-stress activities like running or dancing, gradually increasing activity levels helps sesamoid bones adapt without excessive strain. Regular stretching and strengthening exercises enhance foot and ankle stability and resilience.
Long-term care for sesamoid conditions emphasizes early pain management. Consistent use of custom orthotics or other supportive measures provides ongoing protection. For chronic conditions, maintaining regular follow-up appointments with a healthcare provider ensures continuous management and treatment adjustments. Adhering to these strategies reduces future pain episodes.