Capsulitis/Synovitis

Joints are held in place and supported by ligaments and an outer covering known as the joint capsule. The inner layer of the joint capsule is called the synovial membrane and this produces the oily liquid (synovial fluid) that lubricates the joint. Inflammation of the joint capsule can be referred to as capsulitis or synovitis. Synovitis is generally accompanied by an increased production of synovial fluid causing some swelling of the joint.

Whilst this can occur at any joint it often occurs at the joint at the base of the second or third toes and the ball of your foot (metatarsophalangeal joints).

What causes capsulitis/synovitis?

Capsulitis/Synovitis is generally caused by an associated deformity, poor foot function or inappropriate footwear (e .g. high heels). However, certain medical conditions (e .g. rheumatoid arthritis, osteoarthritis) can predispose to inflammation within the joints.

The second and third metatarsals (the long bones that form the joints with the toes of the ball of the foot) are the most stable in the foot. As we walk, the other metatarsals are mobile to allow the foot to adapt to uneven surfaces. If these metatarsals are not loading properly or the second and third metatarsals are either long or prominent, then overload and inflammation of the joint can occur.

Are women more likely to get the problem?

It is more common in women as they tend to wear tighter, narrower shoes with increased heel height. These shoes place a lot of pressure onto the joints and predispose to deformity. It is common for patients to wear shoes that are too small and this can aggravate the problem. In a study we have performed, 95% of patients were in the wrong size shoes, most of which were too small.

Will it get worse?

It is extremely common for people to develop discomfort at these joints and ignore it in the hope that it will settle. What commonly happens is that the pain slowly gets worse and the toes start to bend and become prominent.
Eventually, the pain settles but the toe sits up in the air causing a problem in shoes. This is because the long-term inflammation and damage to the joint capsule results in a rupture. This destabilizes the toe and it becomes deformed and prominent. Whilst the pain settles, the toe will cause discomfort in shoes, which is much harder to treat.

What are the common symptoms?

• Pain under the central ball of the foot directly under the bone I joint
• Redness around the joint
• Swelling around the joint
• Deformity of the toe
• Difficulty in shoes
• Difficulty with walking
• Stiffness in the joint