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 diagnoses 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.
Now that we know a little bit about the underlying anatomy of the ball of the foot, lets have a look at some of the most common causes for pain in this area.
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 dependant 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 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 or all 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 this condition is 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.
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. Bursae occur normally beneath the metatarsal heads and between the metatarsal bones.
Bursitis occurs when a bursa becomes inflammed. This 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 of bursitis include pain, swelling, and redness of the surrounding area as well as limitation in movement of the affected joint. Certain activities or footwear may exacerbate the pain.
Treatment for bursitis involves reducing the amount of pressure being placed on the bursa. This may involve changing footwear, orthotics to control altered foot biomechanics or reducing a particular activity for a period of time. Icing the area may help reduce the inflammation. More severe cases may require drainage of the bursa, steroid injections or removal of the bursa.
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 inflammed. It usually presents as pain beneath the big toe joint which may begin gradually and then worsen. In severe cases the sesamoid bones can fracture.
Sesamoiditis may occur after doing activities which involve putting a lot of pressure on the ball of the foot such as dancing, running up hills, sprinting or wearing high heels. People with high arches can also be predisposed to this condition.
Treatment for sesamoiditis involves removing as much pressure from the area 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. Icing can help to reduce the inflammation.
Frieberg’s Disease / Infraction
Frieberg’s Disease is a condition in which the head of the metatarsal loses some of it’s blood supply and thus the metatarsal head gradually reduces in size as the bone is reabsorbed. The cause of the condition is still not confirmed. It mostly affects teenagers usually at the time of a growth spurt, more commonly girls than boys. The 2nd metatarsal head is usually affected.
Symptoms include pain on top of and below the metatarsophalangeal joint. There may be mild swelling and some reduced motion at the joint.
Treatment involves offloading the joint by reducing weight-bearing activities and using supportive footwear or a CAM boot to completely offload the joint. Severe cases may require surgery. If left untreated arthritic changes may occur in the joint.
Plantar Plate Rupture
The Plantar Plate is a thick ligament that runs beneath the base of all the MPJs. It protects the metatarsal heads and stops the toes from ‘sticking up’ or spreading out too much. A rupture in the plantar plate is a small tear, most commonly occurring around the 2nd MPJ. It most commonly affects middle aged women and people with flat feet.
Symptoms include pain and swelling in the area. The affected toe may drift or begin to claw (stick up). 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 the use of orthotics or changing footwear. Severe cases my require surgery.
There are may different types of arthritis, the most common being Osteoarthritis and Rheumatoid Arthritis. Both have different mechanisms of action, but they both affect the joints of the body. They can cause damage to the joints which makes them painful and reduces the range of motion in them.
Bunions are a common area for osteoarthritis due to the damage that has already occurred to the joint when it became a bunion. Osteoarthritis can occur in any of the joints in the foot, but especially in joints where there has been previous damage.
Arthritis often needs to be managed by means of 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.