Metatarsalgia – forefoot pain: A guide for patients

Introduction

Metatarsalgia is an umbrella term that covers different conditions affecting the forefoot but excludes problems with the big toe joint or the toes themselves.

Metatarsalgia can be extremely debilitating and have an impact on a person’s daily living activities and quality of life.

Causes of metatarsalgia include:

• corn or callus formation – this can be secondary to prominent metatarsals (the long bones of the forefoot) on the sole of the foot or due to tightness of the calf muscle
• neuroma – a benign enlargement of a nerve between the metatarsals
• Freiberg’s disease or avascular necrosis – a condition where the blood supply to the bone is interrupted
• stress fracture
• tailor’s bunion
• osteoarthritis
• capsultits – inflammation of the joint capsule
• arthropathies – such as rheumatoid or psoriatic
• crystal arthropathies – such as gout.

Capsulitis (inflammation of a joint capsule)

Capsulitis is inflammation of the capsule around a joint. This is a relatively common complaint with a greater incidence in athletes. The most common joint affected is the second metatarsophalangeal joint, but other joints can be affected. Sometimes, all of the ball joints can be involved.

Sometimes, patients can recall a specific episode of trauma, but often the complaint happens more gradually and there is no specific cause.

With this condition, the joint capsule and the fluid inside become inflamed. This produces pain. Patients often liken the pain to walking on a pebble or marble. The problem can also be associated with redness and swelling of the area. As the condition progresses, it can produce a hammer toe deformity.

There are many different causes of capsulitis. It can happen in isolation, for example, it can affect one joint or it can affect multiple joints. When it affects multiple joints it can often be related to an underlying inflammatory disease, such as rheumatoid arthritis. Often, when there is no underlying disease and there is inflammation of all the joint capsules, this can be secondary to tightness of the calf muscle. If this is the case, a strict regime of calf stretching is implemented.

Capsulitis of the second toe joint can happen in combination with a bunion deformity. As the bunion deformity worsens, pressure that is normally distributed to the big toe and first metatarsal moves over to the second metatarsal. The soft tissue structures around the second metatarsal and toe are more delicate and susceptible to injury. Often, a diagnosis can be made through the history and examination. However, further investigation, such as X-ray can determine whether there is a problem with the length or angulation of the bones. An ultrasound scan or an MRI is sometimes required.

Treatment involves altering footwear; wearing a rigid soled shoe, such as a walking trainer can protect the area, rest, calf stretching, analgesics and steroid injection. Surgery for capsulitis is a last resort and is done with caution, as shortening of a metatarsal carries the risk of transferring the problem to the next joint.

Freiberg’s disease 

Freiberg’s disease is a term specifically related to the second metatarsal. If any other metatarsal is affected, it is called an osteochondrosis (children) or an avascular necrosis (adults). As mentioned, Frieberg’s disease and osteochondrosis affect an immature bone; where the bone is still growing and the growth plates are still present (children aged up to 14 to 16-years-old). In an adult, the condition is termed avascular necrosis.

Freiberg’s disease affects the bone and the growth plate. Symptoms include pain, swelling, redness and loss of the joint’s function. It is five times more common in females between the ages of 12 and 15. The primary cause is repetitive trauma. This leads to the blood supply to the metatarsal head and growth plate being disrupted.

Investigations include X-ray and MRI.

Treatment involves off loading and protecting the area, such as a below knee cast or walker boot and insoles. This type of protection is required while the bone heals itself.

In some cases, the metatarsal head can collapse and this can often lead to discomfort that is secondary to osteoarthritic changes. If this is the case, surgical management may be required.

Neuroma

A neuroma is a benign condition which affects nerve tissue. In the foot, the most common place to develop a neuroma is between the third and fourth metatarsals, commonly termed Morton’s neuroma. This produces symptoms in the third and fourth toes. The neuroma can affect other inter metatarsal spaces and it is not uncommon to develop multiple neuromas. There are many different theories about why a neuroma may develop; to include anatomical factors, such as friction between the nerve and the neighbouring metatarsals, footwear like high-heeled shoes and certain inflammatory diseases, such as rheumatoid arthritis. The nerve becomes irritated and this allows scar tissue to form. The scar tissue disrupts the nerve’s normal electrical pathway. It produces pain and altered sensation. A patient’s history is often symptoms of burning, tingling and numbness in the toes, as well as the sensation that their sock is rucked up under their toes. The symptoms are often made worse by wearing closed in footwear.

Treatment of this condition involves alteration of footwear; a shoe with a larger toe box, orthotics and steroid injections. If conservative treatment fails, surgery is often required. The surgery locates the nerve and the neuroma and removes it from between the metatarsals. This alleviates the pain and discomfort but does produce some residual numbness on the base of the toes affected. This numbness does not affect a person’s walking ability nor does it prevent you from feeling pain if you tread on a sharp or uncomfortable object.

Stress fracture

A stress fracture develops when there are increased forces directed to the bone. The bone reacts by producing more bone (remodelling), however the repetitive stresses continue and the bone is unable to meet its demands – the forces outpace the bony remodelling. When this occurs a stress fracture develops. Often people experience a stress fracture following an increase in their activity levels e.g. running, gym classes or from going to standing, more active job.

Often with a stress fracture there is no bruising or swelling and often the patients only complaint is that of pain which is increased with activity.

Initial X-rays (up to three weeks) can be normal, so a high index of suspicion is required. Other investigations such as MRI can be more sensitive in diagnosing a stress fracture.

Treatment consists of:

• rest
• analgesics (avoiding non-steroidal anti-inflammatory drugs - NSAIDs)
• immobilisation in a below knee cast or air cast boot.

Surgery isn't generally used for this condition.

Corn or callus formation

Corn and callus formation can be secondary to prominent metatarsal bones, either long or more prominent on the sole of the foot, digital deformities such as a clawed toe can make the metatarsal more prominent leading to it becoming more prominent on the sole of the foot.

Sometimes there is no obvious bony prominence and a corn formation can be due to a patients’ skin type, these types of corns are far more difficult to treat and often recur.

Sometimes callus formation can be across the whole of the forefoot this can be related to tightness of the calf muscle or due to a high arched foot. A high arched foot makes the forefoot more prominent and this area therefore takes more pressure.

Non-surgical treatment includes:

• calf stretching
• clinical podiatry – corn and callus debridement
• insoles
• footwear alteration.

Surgical treatment can vary and is dependent on the underlying causes:

• surgical excision of the corn
• shortening or elevating the metatarsals
• lengthening the calf muscle
• addressing the digital deformities
• correcting the cavoid foot type.

Osteoarthritis

Osteoarthritis can be either primary, occurs without any specific cause or secondary, occurs in relation to a disease process such as rheumatoid arthritis or post Freiberg’s disease.

In osteoarthritis the cartilage (the shiny material at the end of bones) becomes damaged leading to exposure of the underlying bone. When the bony surfaces start rubbing against one another pain develops. The bone also reacts by creating more bone and the nice concave/convex appearance of the joint disappears.

The pain and discomfort can often occur with swelling. The pain is increased with standing and activity and relieved by rest and analgesics.

Non-surgical treatment includes:

• footwear alteration – rigid soled running trainer, this prevents the foot from bending so much and reduces the motion required form the joint
• insoles
• analgesics
• steroid injections.

Surgical treatment includes:

• joint debridement
• metatarsal osteotomies (cutting and repositioning of the bone) to shorten or elevate the bone
• joint replacement – medical grade silicone joint replacement.

Tailor’s bunion

A tailor’s bunion is a reverse bunion, for instance, a bunion occurring on the outside aspect of the foot.

This prominence can be due to:

• enlargement of the head of the metatarsal
• movement of the fifth metatarsal away from the fourth
• bowing of the fifth metatarsal.

A tailor’s bunion can lead to corn or callus formation over the outside aspect of the joint or produce pain from within the joint itself, often it is associated with a fifth toe deformity. The most common problems experienced are due to footwear rubbing.

Non-surgical treatment includes:

• Joint padding and protective shields
• Gel or silicone wedges between the toes
• Avoid high heels
• Surgical footwear
• Insoles (orthoses).

Surgical treatment includes:

• Metatarsal osteotomy (cutting and repositioning of the bone) followed by the placement of screws to hold the bone together while it heals.