Ball of Foot Pain – Metatarsalgia
The area commonly referred to as the ball of the foot contains many different structures making diagnosis of pain in this area sometimes difficult. Some conditions can be diagnosed by a clinician directly, whilst X-rays or ultrasounds may be required to confirm the diagnosis for other conditions. Metatarsalgia is a general term used to refer to pain in the ball of the foot.
We will discuss some of the more common causes of metatarsalgia in this article, but first let's have a very brief overview of the area beneath the skin.
Anatomy of the ball of the foot
The ball of the foot is where the 5 metatarsal bones in your foot connect to the 5 toe bones (proximal phalangeal bones). When talking about the area, people may refer to the metatarsal heads (the rounded ends of the metatarsal bones), or the metatarso-phalangeal joints (MPJs – the joints where the ball of your foot bends). The big toe MPJ has two small round bones that sit beneath it called the sesamoids.
Each of the joints has a capsule that surrounds it containing synovial fluid which lubricates the joint. Tendons and ligaments attach to the metatarsal heads and phalangeal bones which are how they move, and also how they are stabilised so that they don't move too much.
Between each of the 5 metatarsal bones and joints run bundles of nerves, arteries and veins. Fluid filled sacs called bursa are positioned beside and beneath the metatarsals to cushion and protect the surrounding structures.
Morton's Neuroma
A Morton's neuroma occurs when one of the nerves that runs between the metatarsal bones becomes thickened. The symptoms can include numbness or burning in one or two toes, feeling like you are standing on a pebble under the ball of your foot, or pain in the ball of the foot. It most commonly occurs between the 2nd and 3rd, or 3rd and 4th metatarsals.
A Morton's neuroma can usually be diagnosed on examination of the foot, but sometimes ultrasound is used to confirm the diagnosis. Treatment varies depending on the severity of the condition and how well it responds to treatment. Conservative treatment may involve padding in the shoe, orthotic therapy or a change in the style of footwear worn. In more severe cases corticosteroid injections may be used, or the neuroma may be removed surgically.
Capsulitis
Capsulitis is inflammation of the capsule that surrounds the joint. Symptoms include pain around the joint, swelling, redness or a feeling that you are walking on a stone. It most commonly affects the 2nd MPJ, but can affect the other joints.
Capsulitis usually occurs in an MPJ which is taking an increased amount of pressure when walking. This may occur because of altered foot biomechanics such as having one toe significantly longer than the rest, bunion formation, a dropped metatarsal, or from wearing high heels or shoes that are too tight at the toes.
Treatment involves removing excessive pressure from the joint for a period of time. This may be achieved by changing footwear, or using padding or orthotics in the footwear to offload the joint. The toe may be taped to an adjacent toe to stop it from drifting. Icing the area may also help to reduce the inflammation. If left untreated it can cause the ligaments around the joint to weaken and the toe may become dislocated – it is important to treat this condition early.
Bursitis
A bursa is a small fluid filled sac. Their role is to create a cushion between two structures that would otherwise create friction on one another. Bursitis occurs when a bursa becomes inflamed, which can result from an acute injury or from repeated excessive pressure on the area caused by altered foot biomechanics, footwear that is too tight, or long periods of standing or running.
Symptoms include pain, swelling, and redness of the surrounding area as well as limitation in movement of the affected joint. Treatment involves reducing the amount of pressure being placed on the bursa – changing footwear, orthotics to control altered foot biomechanics, or reducing a particular activity for a period of time. More severe cases may require drainage of the bursa, steroid injections or removal of the bursa.
Sesamoiditis
The sesamoids are two small round bones that sit just below the big toe's metatarsal head within a tendon. Sesamoiditis occurs when the tendon surrounding the bones becomes inflamed, usually presenting as pain beneath the big toe joint which may begin gradually and then worsen. In severe cases the sesamoid bones can fracture.
Treatment involves removing as much pressure from the area as possible by means of rest, a change of footwear, padding in the shoe or orthotic insoles. The big toe may be taped to prevent too much movement, and icing can help reduce the inflammation.
Frieberg's Disease / Infraction
Frieberg's Disease is a condition in which the head of the metatarsal loses some of its blood supply, so the metatarsal head gradually reduces in size as the bone is reabsorbed. It mostly affects teenagers, usually at the time of a growth spurt, more commonly girls than boys, and the 2nd metatarsal head is usually affected.
Treatment involves offloading the joint by reducing weight-bearing activities and using supportive footwear or a CAM boot. Severe cases may require surgery.
Plantar Plate Rupture
The plantar plate is a thick ligament that runs beneath the base of all the MPJs, protecting the metatarsal heads and stopping the toes from spreading out too much. A rupture is a small tear, most commonly occurring around the 2nd MPJ, and most commonly affects middle aged women and people with flat feet.
Treatment involves strapping the toe to keep it in position and offloading the MPJ. Biomechanical anomalies which may have contributed to the condition need to be addressed with orthotics or a change of footwear. Severe cases may require surgery.
Arthritis
There are many different types of arthritis, the most common being osteoarthritis and rheumatoid arthritis. Both affect the joints of the body and can cause damage that makes them painful and reduces range of motion. Bunions are a common area for osteoarthritis due to the damage that has already occurred to the joint.
Arthritis often needs to be managed with medication as prescribed by your GP. However, arthritis of the foot can sometimes be helped by the use of orthotics to correct biomechanical misalignments, and by changing your footwear to accommodate your feet better.