Functional Hallux Limitus
What is Functional Hallux Limitus?
Hallux Limitus is a restriction in movement of the big toe joint (metatarsophalangeal joint). Functional hallux limitus (FHL) is a condition where there is reduced up and down movement of the main big toe joint under. This is particularly noticeable during walking and when weight is being put through the toe. However, the movement may seem normal when not putting weight through the toe.
We use the term ‘functional’ because the limitation is during activity, rather than due to true stiffness. It is different from hallux rigidus, where movement is limited even when not loading the joint. Functional limitus may progress to hallux rigidus over time.
If you would like to see a video summary of the what happens in this condition then please click here.
Who gets functional hallux limitus?
Whilst it can be present at any age, most people may not ever know they have it, until it starts to cause pain later in life, or starts to get stiffer. Some patients may not realise they have it until it causes arthritis. However, studies have found this condition in school-age children and have also found that as many as 1 in 40 adults over the age of 50 may have it. In my practice I often see active people (such as runners) in their 30s with this condition.
Why does it happen?
There are many possible causes and no one knows for sure why people get this problem. However, some possible reasons include:
- Abnormal positions or strength of muscles (flexor hallucis longus) which may pull the tip of the big toe down
- Abnormal rotation of the joint which may limit its movement
- Tightness of the plantar fascia – tightens the joint during walking
- Hypermobility of other joints (tarsometatarsal joint) may allow the long bone of the big toe (metatarsal) to rise up too high when walking, which causes the joint to misalign and lock.
- Previous trauma causing scarring / disruption of the joints.
What is the end result?
When we walk, as we push off the ground our weight comes to lie over the big toe joint – this puts a lot of force on the ‘ball’ of the big toe joint (metatarsal head). Normally, the rest of the toe can bend upwards, to allow us to ‘roll’ off the front of our foot. However, if the joint is tight, this cannot happen, which can change the way we walk and jam the joint together, causing pain. Over time this can lead to extra bone being formed around the toe (osteophytes, or dorsal bunions). It can also disrupt the entire gait cycle and lead to hip and knee disorders.
What do patients complain of?
Common symptoms include:
- Pain in the big toe joint, especially during push-off during gait.
- Reduced range of motion during walking or weight-bearing activities.
- Compensatory pain in other areas of the foot or lower limb due to changes in gait.
- Swelling of the big toe joint
- Change in shape / a bump on top of the big toe joint
How do we diagnose it?
The main way to tell if a patient has functional hallux limitus is by clinical examination. Patients may have more than 50 degrees of upward movement without load, but this reduces to about 10 to 15 degrees during weight-bearing activities.
A specialist will ‘look’ at your toe, ‘feel’ your toe, and ‘move’ your toe. As part of a ‘special test’, they will assess ‘passive movement’ – this means that they will move your toe for you. This is usually done with the foot relaxed and pointing slightly downward, and then again with pressure under the ball of the big toe, pushing it upward. They may also assess the range of movement with you standing.
Investigations
Other investigations might be used to supplement clinical examination and rule out other conditions. These may include:
- Weight-bearing radiographs (XRs), which can be used to see if there are any extra pieces of bone, or any wear and tear / arthritis in the joint.
- Magnetic resonance imaging (MRI) can be used to assess the cartilage and other soft tissues in the joint.
- Pressure studies and gait analysis can be useful if the diagnosis is still unclear, or when designing custom insoles, but are not routinely needed.
What treatments are there (other than surgery)?
Particularly if picked up early, most patients can be managed with appropriate advice and lifestyle / footwear modifications.
Activity modification is often required in the short term to allow symptoms to settle. However it should be coupled with other treatments to help the mechanics of the foot to allow a successful return to activity
Physiotherapy plays an important role, and will include gait optimisation and stretching the muscles, tendons and ligaments which are tight to try and allow a better range of movement.
Footwear and insoles are however a key component of treatment and this goes hand in hand with physiotherapy to help alter the forces from the ground up. This includes shoes with a rocker at the bottom, to allow the foot to ‘roll’ off during toe-off, rather than bend. Many trainers from reputable companies producing running shoes are suitable in this regard (I personally find that Asics and Hoka work well).
Where trainers cannot be worn, orthotics / insoles are helpful and can take many forms. In general they aim to reduce the upward force on the ball of the big toe by incorporating a cut out. This can reduce the tightness in the joint. Other types of insoles are also available.
Other options include injections of steroids and simultaneous manipulation of the joint, which has a role in some select cases.
Who needs surgery?
Although the condition is common, most patients have mild symptoms, and are managed successfully with non-operative measures. If you do not respond to non-operative treatment, or have already developed signs of arthritis, then you may require surgery.
What if I require surgery?
Sometimes, if non-operative management has not been successful, then operative management is considered. Although in an ideal world one could simply reduce the tight soft tissues, this is not reliable as they can scar back up, and it runs the risk of creating an unstable joint, Therefore most of the options involve addressing the problems through the bones.
A cheilectomy is a procedure to remove bone from the top of the foot where it has created a bump. This can help with pain, but seldom improves movement on its own.
An osteotomy is often my preferred option for earlier disease (I prefer a Youngswick osteotomy). This is where we shorten the bone (metatarsal) slightly and lower it. This creates more room for the joint and changes the way the bones can roll over one another, increasing the movement during walking and reducing pain. This also has a shorter recovery time, with patients able to go home the same day, weighbear straight away, and it takes about 6 weeks for the bone to heal.
A joint replacement is an option where there is still some movement and the joint is well aligned, yet has established arthritis. Here we can cut out the worn out bits of the bone and insert a piece of silastic in between. This allows movement straight away but is not suitable for everyone. They do wear out over time so they are often reserved for slightly older patients who are less active and where there is no deformity.
A joint fusion / arthrodesis is the final option, but is only really required for severe deformity and arthritis. It is however a good option, and famously Lleyton Hewitt, the Australian tennis player has his big toe joint fused, and continued to compete, playing at Wimbledon 5 months after this fusion!
Conclusion
Functional hallux limitus is a dynamic condition where the big toe joint does not bend upwards well during weight-bearing, despite a normal range of motion when not walking / standing. It can lead to pain in the big toe joint and altered gait. Diagnosis is mostly on clinical examination, and non-operative treatment with insoles, footwear modifications, and physiotherapy is the first line of treatment, with promising outcomes. Where these measures are not successful, surgery may be required, and there are a number of joint preserving options available.
If you feel that you may have functional hallux limitus, it is advisable to seek a specialist opinion as early intervention can go a long way.