Squash Magazine Articles
by Michael Schumacher, DPM, FACFAS
Osteoarthritis of the big toe joint
A fairly common problem in the foot of athletes and non-athletes alike is something called hallux rigidus. In fact, it's the second most common problem of the 1st metatarsalphalangeal joint (1st MTP joint—or, big toe joint) next to hallux valgus (bunion). The interesting thing about the two conditions is that every day I see patients with hallux valgus without pain. I rarely see patients with hallux rigidus without pain.
To understand hallux rigidus (HR), a basic understanding of how the 1st MTP joint functions is in order. To greatly simplify human gait, let's break it into three sections: heel strike, foot flat on the ground and toe off. In patients with HR, toe off is where the problem strikes. Just prior to toe off, the 1st metatarsal (1st MT) bone wants to plantarflex, or move toward the ground, thus allowing the bones in the big toe (phalanges) to glide up and over the head of the metatarsal. This is called the windlass mechanism. This causes the plantar fascia—a broad wide ligament-like structure that originates at the heel and crosses the entire bottom of the foot and attaches to the ball of the foot at the MTP joints—to wrap around the head of the 1st MT. As a result, the plantar fascia tightens and raises the arch, thus creating a "rigid lever" for the foot to propel the body forward for the next step.
Hallux rigidus is Latin for "stiff great toe," but this is only part of the syndrome that comprises HR. HR is a progressive degenerative mechanical osteoarthritis of the 1st MTP joint (i.e., between the 1st MT and the phalanges). Symptoms can be mild to severe and affect a large age group of people, as young as teenagers to senior citizens.
Many of you might be asking, what causes HR? The answer to that question is, "No one really knows." Many different surgeons (myself included) have different opinions. In my practice, the two most common causes seem to be an elevated 1st MT or a long 1st MT. Both of these can cause the phalanges to "jam" against the head of the 1st MT bone. Other thoughts about the causes of HR include acute or repetitive micro trauma and overpronation.
The patient with HR usually comes to the office complaining of aching pain in the top of the big toe joint, usually on the "inside area." Activity where the patient is up on the ball of their foot usually produces pain. I have seen many sedentary patients in the office (for a separate complaint) with HR without pain in their foot. They often, when asked, complain of hip pain. The reason for this is that they have been avoiding bending their 1st MTP joint, so they walk by lifting their foot off the ground early, by lifting at their hip. I have "magically" solved chronic hip pain in this type of patient by addressing their HR.
Normal 1st MTP joint range of motion is between 60 and 70 degrees of upwards motion. Patients with HR often have between 15-35 degrees of upwards motion. Interestingly enough, the patients with the most arthritic joints often have the least pain. It is the arthritic, diseased motion that causes the pain. The end stage of HR often produces a joint that has completely fused. When there is no motion at all, there is often no pain, and this theory is applied to surgical correction. This same patient often says there is no pain in the foot at certain times. The reason for this is that if the patient is not making the 1st MTP joint bend, they can have almost no pain.
My treatment plan for the patient with HR is separated into surgical and non-surgical. Non-surgical treatment is aimed at identifying the biomechanical cause of the problem and addressing it. If the patient has an elevated 1st MT without advanced arthritic changes, a custom foot orthotic often can help the 1st MTP joint function more appropriately. If this doesn't work, attempts must be made to limit the motion of the 1st MTP joint. This can be accomplished through a different type of foot orthotic, or different types of shoe gear. Non-steroidal anti-inflammatory drugs and cortisone injections can often afford the patient significant symptomatic relief. When conservative therapy fails, surgical options are often used to treat the pain. Options can include simple procedures such as a cheilectomy (i.e., bone spur removal and "cleaning up the joint") or more complicated choices such as silastic implants (i.e., plastic joint replacement) or joint fusions. As always, if you think you have HR, make an appointment with our office so we can discuss your treatment options.