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 termed 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). This section will concentrate on these joints.
What causes capsulitis/synovitis?
This is generally due to overload from 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 destabilises 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 / joint
- Redness around the joint
- Swelling around the joint
- Deformity of the toe
- Difficulty in shoes
- Difficulty with walking
- Stiffness in the joint
- The swelling in the joint can irritate the nerve giving symptoms similar to a neuroma
How is it recognised?
Clinical examination and a detailed history allow diagnosis. X-rays help to evaluate the extent of the deformity and the degree of arthritis / damage within the joint. Injecting a dye which can be seen on x-ray (radio opaque) into the joint can help to identify damage to the capsule. This is known as an arthrogram. An ultrasound or MRI scan can help to diagnose soft tissue problems such as inflammation.
What can I do to reduce the pain?
There are several things that you can do to try and relieve your symptoms:
- Wear good fitting shoes
- Avoid high heels
- Wear a protective pad
- Hot or cold packs may help
- See a podiatrist
What will a podiatrist do?
If simple measures do not reduce your symptoms, there are other options:
- Advise appropriate shoes
- Advise exercises
- Advise on how you can strap/splint the toe into a corrected position
- Consider prescribing orthotics with deflective padding
- Refer for postural manipulation / control where appropriate
- Consider a cortisone injection
- Advise on surgery
The way in which your foot loads during walking can place increased stress on . Special shoe inserts (orthotics) can help to control foot movement. Whilst these are unlikely to resolve established deformity, orthoses with extra padding beneath the ball of the foot are often necessary for this condition.
A cortisone injection can relieve discomfort. However, if walking and trauma continues, this can result in rupture of the joint capsule causing a fixed toe deformity. The use of a period of immobilisation following the injection minimises this risk.
Some patients have reduced motion in the foot which can be related to their postural control of the whole leg. In these instances, physiotherapy / osteopathy / chiropractic input may be necessary
Will this cure the problem?
If there is an underlying deformity, this will not be cured. However, the contributing factors and therefore symptoms can be controlled.
What will happen if I leave this alone?
There is a window of opportunity to address the overload before the joint capsule ruptures. If this problem is not treated, it is common for the pain to get worse until rupture and toe deformity occurs.
If symptoms persist, or deformity results, surgery may be necessary.
How can I cure the deformity?
Surgery is generally required.
How does the operation correct the problem?
If there is a bunion or hammer toe deformity pre-disposing to overload of the joint, these will often require correction (see appropriate link).
If there is evidence that the metatarsal is too long, it can be shortened. However, this operation is not without risk. In addition to the risks and complications common to all foot surgery, reduction of load beneath the metatarsal can cause increased load beneath the adjacent metatarsals (transfer pain). Stiffness of the joint or a toe that sits up in the air (floating toe) can occur with this type of surgery.
If the metatarsal is too prominent, then an operation to raise it (dorsiflexion osteotomy) can be performed. This carries the same risks as shortening osteotomy.
If capsule rupture alone is the cause of the problem, a repair can be performed but this generally needs to be in the early stages before any associated toe deformity becomes fixed.
The implications / recovery for this type of surgery are covered under the related conditions.