What is a Sesamoid?
The sesamoid bones are 2 solitary bones that are situated underneath the 1st metatarsal (1st long bone) just behind the big toe (hallux). There is a joint between each sesamoid bone and the 1st metatarsal above it. The bones are wrapped inside and held in place by the tendon that functions to pull the toe downward during gait (flexor hallucis longus). Some people are born with one or both of the sesamoids in 2 or more pieces. The sesamoids are named the: tibial (or medial) sesamoid and the fibular (or lateral) sesamoid. The bones take help to absorb the significant pressures that are produced when bearing weight through the foot. These bones do not have a significant blood supply. One or both of these bones can become damaged with injury.
What is Sesamoiditis?
When there is direct injury or repetitive micro injury to a sesamoid, it can become inflamed, bruised, and irritated. This is then called sesamoiditis (-itis = inflammation). This is a painful condition because of the continued pressure placed upon the injured bone when walking.
Sesamoids that are naturally in 2 or more pieces (bipartite) have a slight boney or soft tissue connection between the pieces. Injury to the sesamoid can tear this connection and cause inflammation and pain.
Just like any bone, a sesamoid bone can fracture from an impact or injury, or repetitive injury.
What are the Symptoms of Sesamoiditis?
Most patients will complain of a deep ache and sharp pain with most steps in the ball of the foot just behind the big toe. There can also be pain in the big toe joint. There is usually no pain at rest. Some days may be more painful than others depending on the amount of activity on a given day causing more inflammation and bruising to the bone. Numbness to the ball of the boot can develop with constant friction of the skin and nerve over the area. Over time, if arthritis develops in the joint of the sesamoid, there will be pain within the joint when walking. Some shoes may be more painful than others. Most patients will complain of pain when walking barefoot.
What Causes Sesamoiditis?
Damage to the sesamoids is primarily caused by an injury. This may be a direct, one time incident that the patient will attribute to the pain; e.g. a basketball player jumps up for a layup and lands hard directly onto the ball of the foot. The damage could also be sustained from multiple small injuries that accumulate over time; e.g. a runner constantly running on the ball of the foot. Patients with a high arched foot (pes cavus, supination) may also produce undo pressure onto the ball of the foot due to the biomechanics of the high arch. Those with a bunion deformity (hallux abducto valgus) have a malposition of their sesamoids that may cause improper pressure to the bones. Long-term use of high heel shoes can cause extra pressure to the sesamoids.
How is Sesamoiditis Diagnosed?
Diagnosis is simply achieved by the clinical examination and x-rays of the patient. Dr. Soomekh will listen to the patient’s complaints, symptoms, and goals. The examination involves a hands-on analysis of the patient’s foot and evaluating their gait. Digital radiographs (x-rays) of the feet will be obtained and reviewed with the patient. An x-ray of the good foot may be taken for comparison if a bipartite sesamoid is suspected. The positions of the bones and joints evaluated on the x-rays help to determine the severity of the deformity and any associated deformities. In some cases an MRI or in office CT scan is needed to examine if the sesamoid bone has lost its blood supply (avascular necrosis, AVN)
How is Sesamoiditis Treated?
Dr. Soomekh educates that early diagnosis and treatment of a sesamoid injury are the keys to successful treatment, faster recovery and painless lifestyle.
Sesamoids have difficulty healing for two main reasons. One: Each step when walking places a great amount of pressure onto the damaged bone. Two: Sesamoids have a lack of good blood supply, making it difficult for the healing cells to get to the bone. Conservative treatments attempt to heal the sesamoid bone by removing the injuring force, and reducing the inflammatory process. The key is taking pressure off the sesamoids. If simple rest and cushioned shoes do not resolve the problem, then this may be achieved by wearing a special walking boot for 3 to 6 weeks. In rare cases, crutches may be needed. In order to reduce the bruising to the bone, a period of rest, ice therapy and use of anti-inflammatories (NSAIDS’s) may be recommended. Physical therapy maybe prescribed. Custom molded orthotics can be made as an important tool to slow the progression the sesamoid and prevent future injury to the area. The use of steroid injections are of limited value in this area.
Dr. Soomekh will always recommend and attempt conservative treatment when appropriate. However, when a sesamoiditis becomes chronically painful and has failed conservative treatments surgical repair may be indicated.
Considering surgery can be intimidating. Foot surgery including sesamoid surgery is not supposed to be painful during recovery. When the skin and the soft tissues are handled with care and focus, most patients experience little to no pain immediately after surgery and throughout the recovery period. Dr. Soomekh takes great care and focus to minimize the chance of postoperative pain. The goal of sesamoid surgery is to remove the problematic bone, alleviate pain, allow a return to normal shoes, and allow a return to all activities. Most procedures allow for immediate walking and a return to work while wearing a special walking boot. Dr. Soomekh performs the procedures in an outpatient setting at state of the art facilities.
Sesamoid surgery centers on removing part or all of the sesamoid that is injured. It is the responsibility of the surgeon to investigate each specific aspect of the bunion for each individual patient in order to formulate the proper procedure for repair. Dr. Soomekh will use the information gained from the patient’s symptoms, age, activity level, lifestyle goals, the severity of the deformity, the clinical examination, the patient’s gait, and the imaging, to make a recommendation on the proper procedure.
Removing the Sesamoid:
A small incision is made on the side of the big toe joint for the medial sesamoid, and at the bottom of the big toe joint for the lateral sesamoid. The sesamoid is carefully released from its attachments to the tendon and ligaments. The tendon and ligaments are repaired as needed. In some cases Dr. Soomekh will recommend the application of a specialized regenerative human umbilical cord graft (Amniox®) to reduce scar tissue. Dr. Soomekh will then close the skin using plastic surgery techniques.
In some cases, when appropriate, an effort is made to only the smaller of the fractured pieces of bone. When there is a bipartite sesamoid, often just one of the pieces would need to be removed.
Dr. Soomekh has perfected and reinvented these surgical procedures and techniques and is recognized by his peers as one of the top sesamoid specialists the in Los Angeles area.