Capsulitis of the MTP joint

What is capsulitis of the MTP joint, and how common is it?

Capsulitis of the MTP joint (the metatarsophalangeal joint, at the base of a toe) is inflammation of the capsule, the covering around that joint¹. It most often affects the second toe²¹. Small repeated knocks or damage can make the joint produce extra fluid, so it swells and hurts when you put weight on it³. Underneath, the plantar plate (a deep ligament) forms the floor of the capsule³. It's a fairly common complaint, more so in athletes¹.

What causes it, and who gets it?

Capsulitis is thought to come partly from overload: running, jumping or long walks². A sudden increase in activity is the most common cause of ball-of-foot pain⁴, and athletes get capsulitis more often¹. Overload can also wear down or tear the plantar plate⁵.

Other contributors:

• a bunion, which shifts pressure onto the second toe joint¹; hammer toes³;
• narrow, thin-soled or high-heeled shoes²³;
• higher body weight²;
• inflammatory arthritis³;
• a fat pad that thins with age, more so with diabetes³.

Mention a bunion, hammer toes or inflammatory arthritis at your assessment.

What does it feel like, and how is it diagnosed?

Capsulitis often feels like pain at the base of a toe, like walking on a pebble or marble²¹. The area can be stiff, swollen or red²¹. It's worse when you stand, walk or run, and often builds over weeks⁶.

Morton's neuroma and a stress fracture can also feel like walking on a pebble⁷¹. Assessment covers when it started, what aggravates it and a hands-on exam of the toe. Plantar plate tears are often missed at first⁸. MRI looks more accurate than ultrasound for tears⁹. MRI cannot be used in some conditions, such as with implanted cardiac pacemakers or automatic defibrillators⁹. Note which toe hurts and when it started.

What helps first?

Self-care comes first. Cut back on running, jumping and long walks that bring on the pain, and keep moving with low-impact exercise such as swimming².

Choose supportive shoes with a deep, wide toe box and a lower heel⁶. Cushioning pads or insoles from a pharmacy can ease pressure on the ball of the foot³.

A podiatrist or physiotherapist can add toe taping, a stretching and exercise plan, and offloading pads¹⁰².

Anti-inflammatory pain relief isn't suitable for everyone; a pharmacist or GP can advise.

Rest with your foot up³. An ice pack wrapped in a towel can be applied for up to 20 minutes at a time, every two to three hours²³.

What helps if that isn't enough?

A podiatrist or your GP can review the diagnosis and plan. In lesser MTP joint instability, anti-inflammatory medicines, steroid injections into the joint, orthoses (shoe inserts) and shoe modifications generally give only temporary relief and in most cases do not stop deformity from progressing¹¹. Surgery to repair the plantar plate is an option, though it isn't yet clear how well it works¹². Before agreeing to an injection or surgery, ask what the options are, how likely each is to help, and the risks, and decide with your treating clinician⁷¹².

How long does it take, and how can I stop it coming back?

Improvement is usually gradual³. There's no quick fix, and symptoms won't settle overnight³. If capsulitis is left, the toe can drift, cross over its neighbour or become a hammer toe². Delayed diagnosis can let pain and deformity progress¹⁰.

What can make it serious?

• You have new numbness, tingling, pins and needles or weakness in your foot that has come on gradually.
• Your pain is getting worse, or doesn't settle with rest, less activity or pain relief.
• You have a foot wound, ulcer or infection, or a red, hot, swollen foot, and also have a fever, chills, a fast heartbeat or feel unwell.
• You can't put weight on your foot or take four steps after an injury.
• You think you may have broken a bone in your foot or ankle in an injury, for example you heard a crack, or it swelled or bruised badly within minutes.