Ball of Foot Pain
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A sesamoid is a floating bone that sits within a tendon, and the most well-known sesamoid is the knee cap (patella). The function of these sesamoid bones is to act as a lever for the tendons to pull on, allowing them to apply more force through the area than an isolated tendon. In the foot, the two sesamoids sit in the tendon of the Flexor Hallucis Brevis. The medial sesamoid, which sits towards the inside of the foot, bears more weight and is more commonly injured, while the tibial sesamoid sits on the outer aspect. When one or both sesamoids become inflamed, it is known as sesamoiditis.
Sesamoiditis can cause swelling on the underside of the big toe joint, although in severe cases, it is not unusual for the entire big toe joint to become swollen. Patients describe burning pain under their big toe when weight bearing, especially with impact activities such as walking and running. It is less common to see visible bruising and is more commonly associated with a fracture.
Moderate to severe symptoms of sesamoiditis can make it too painful to walk, or people subconsciously begin to walk on the outside of their foot to offload the sesamoids. In a non-weight-bearing position, it can be painful to bend or straighten your big toe.
A sudden change in activity levels can be sufficient to cause sesamoiditis. Examples of this include increasing your step count dramatically which we commonly see in people returning from city breaks or increasing impact such as running and jumping.
A change in footwear can cause sesamoiditis, especially in the summer when people transition from cushioned winter shoes to flip-flops. While high heels are one of the primary causes of sesamoiditis due to the direct impact being placed on them.
Other causes of sesamoiditis include flat feet, hypermobility, climbing, gymnastics, ballet and dancing.
A Physical examination by a Physical Therapist or a Sports Physician can be sufficient to diagnose Sesamoiditis. A Physical examination involves a clinical interview and palpation of the sesamoids for tenderness. If the clinician suspects a fracture or another cause of your pain, they may refer you for imaging.
An x-ray is a valuable tool to rule out a stress fracture of the sesamoid bones. At the same time, an MRI or Ultrasound are more effective for diagnosing Sesamoiditis as they can detect swelling and inflammation of the soft tissues around the bone and the sesamoid itself.
The quicker you can identify the symptoms of Sesamoiditis and begin some form of treatment, the better, as this can be difficult to settle due to the fact you are weight-bearing throughout the day.
Treatment for Sesamoiditis is best placed under the care of a Physical Therapist or a Podiatrist. Early stage treatment will be similar to our recommended home treatment. They are likely to tape the big toe into a slightly bent (plantarflexed) or neutral position, reducing the use of the big toe and, in turn, the sesamoid.
Gel pads or padding with felt are another effective treatment to offload the sesamoids. The clinician identifies tightness and balance issues in your assessment, which usually commences with a stretching regime, especially in the calf muscles. As symptoms improve, patients progress onto strengthening exercises of the ankle and foot muscles alongside balance and stability exercises.
A conversation with your clinician about the appropriate footwear is essential as you may need supportive or cushioned footwear. In some cases, a custom insole is required to improve the mechanics of the foot if this is a cause of your Sesamoiditis.
In very irritable cases, patients can be referred for an ultrasound-guided cortico-steroid injection into the sesamoids to reduce inflammation levels in the area. Some Sports Physicians recommend 1-2 weeks in a walker boot after the injection to allow the injection to take maximum effect. Following this, rehabilitation recommences.
If all of these treatment methods are unsuccessful, a minority of cases may require surgery. Surgery for Sesamoiditis involves the removal of the affected sesamoid.