The term "hallux" refers to the big toe. As the name implies, hallux limitus sometimes also known as hallux rigidus refers to lack of motion of the big toe relative to the metatarsal bone. This articulation is known as the first metatarsal phalangeal joint and because it is such an important part of the gait cycle, limitation of motion in this joint can be a very painful proposition.
Look at the first diagram where you will notice the big toe is bent upward (dorsiflexed) to about 45 degrees relative to the first metatarsal bone. This is an ideal amount of motion. Although the big toe should also be able to bend downwards (plantarflexed), the amount of plantarflexion that an average person exhibits does not even come close to 45 degrees for the simple reason that amount of motion is unneccessary when ambulating.
It should also be pointed out that many people can have far less than 45 degrees of dorsiflexion and still walk and run without any pain.
In our normal gait as we move forward with one foot, the other foot, which is planted on the ground starts to lift up. In the propulsion part of gait where we get ready to push that foot off the ground, it is usually from a thrust occurring at the big toe joint. So, any problem with that particular joint will cause pain in the joint and more than likely adversely affect our ability to wak or run in a normal fashion.
The major cause of pain in the first metatarsal-phalangeal joint is generally a result of arthritic degeneration which occurs in the joint over time. We are talking about osteoarthritis, the normal "wear and tear" arthritis that occurs over time in most of the joints in our bodies. This type of arthritis is also known as repetitive stress arthritis where the same motion over time, causes the joint to wear out. Notice the worn out joint on the right. This big toe can no longer bend upwards without some degree of pain.
From a strictly anatomical standpoint, there are two structural issues that can accelerate the formation of hallux limitus. The first is the length of the first metatarsal. In an ideal foot structure, the first metatarsal should be slightly shorter than the second metatarsal bone. In the gait cycle this allows the foot to roll over the second metatarsal on to the first metatarsal head from which the foot can "push off".
Some people exhibit a longer than normal first metatarsal bone. Notice the blue line on the diagram to the left. This is the ideal relationship of metatarsal bone length of all five metatarsals. When there is a longer first metatarsal bone, there ensues a jamming effect at the level of the joint and over time the repeated jamming causes the joint to become arthritic and thus painful.
The second anatomical deviation is one where the first metatarsal bone is elevated or dorsiflexed relative to the toe. Looking at the side view of the foot, the metatarsal is higher up than the great toe. This makes it very difficult for the big toe to bend upwards and once again, over time, the joint will wear out.
These anatomical variations along with other factors such as trauma to the joint or metabolic disorders like gout will eventually cause this particular joint to wear out and result in pain. The amount of pain is generally proportional to the activity level of the patient. No discussion of hallux limitus would be complete without mentioning the effect high heels can have on the excaberation of this problem. Simply wearing a high heel creates an abnormal relationship between the big toe and the first metatarsal bone.
For a younger athletic person hallux limitus can end up being a real problem for obvious reasons. Their active lifestyle puts tremendous demands on the first metatarsal-phalangeal joint and once the joint has worn out, in most cases there is nothing but ongoing pain. For the older, more sedentary individual a hallux rigidus is not as big an issue if he or she is careful about shoe selection and limits their activity. Of course, in our modern day society, many older individuals remain exceptionally active and so once again hallux limitus may be a serious issue.
At this point I have to give my disclaimer, and that is I do not consider orthotic therapy a primary treatment for hallux rigidus. In most cases of very painful hallux limitus (rigidus) that has not responded to conservative therapies, surgery is usually the treatment of choice. Once the joint is worn out, it is worn out, and doing a surgical procedure to improve whatever motion one can get out of the arthritic joint ends up being the only treatment that will allow most people to return to an active lifestyle.
Having said that, it is possible to get some degree of relief from using an orthotic and perhaps I am stating the obvious, but those with less severe cases of hallux limitus generally do better with orthotics than those with more advanced cases.
how does an orthotic help hallux limitus?
An orthotic can help with hallux limitus in a couple of ways. The first way is to re-balance the foot meaning cutting down on excess pronation (if that is part of the problem). By doing so you have removed some of the stresses on the first metatarsal-phalangeal joint which creates a better alignment at the level of the joint. When you have the best alignment possible, you tend to maximize the amount of motion you are able to get out of the joint. Maximum motion in an otherwise arthritic joint may very well cut down on the amount of pain one will experience.
The second and perhaps more important way an orthotic can help hallux limitus is by stabilizing the first ray which makes up the first metatarsal bone and great toe. This is accomplished through the use of what is knwn as a Morton's extension. As you can see by the picture here, the extension is essentially padding that goes under the first metatarsal and big toe thus reducing the demands placed on the great toe joint when one is ambulating.
There are variations on the Morton's extension based on the architecture of the particular foot that is being treated. Sometimes for example, if the problem is a dorsiflexed first metatarsal, the padding of this extension will lie more at the level of the toe in an effort to elevate the toe to better line up with the metatarsal bone and thus increase motion.
It is also worth pointing out that in most instances the Morton's extension is built into the orthotic so unlike the one pictured here, you can feel it in your shoe, but it is not visible when looking at the orthotic.
So, there are two instances where an orthotic may be helpful in hallux limitus. As previously stated, in mild cases of hallux limitus, orthotic therapy may be of great benefit expecially if combined with other conservative therapies. The second instance would be in those individuals who have undergone surgical correction particularly for one of the two structural deformities that were discussed earlier. If you have had successful surgery, keeping the alignment of the big toe even with the first metatarsal bone through the use of an orthotic is not a bad idea.ORTHOTIC RATING:
store bought arch support this is a condition where something purchased in a drug store or supermarket will probably be of little value
medical grade off the shelf orthotic would be indicated for this problem assuming your doctor is able to add a Morton's extension to the device
prescription orthotic very effective simply because the Morton's extension can be built into the orthotic, properly placed and modified as needed