What do Stress Fractures feel like?
We’re going to start out like we normally do with the case study to get his thinking about stress fractures and the people will often come to the clinic with them. My patient today is a 47-year-old female who has had six weeks of pain on the top of her arch. She did not notice any change in her activities when the pain started. She is a single mother of 2 teenage children who recently took a job at a local department store. She began to notice swelling on the top of her foot which has gotten worse with activity. She had initially assumed that the swelling was from tendinitis. She notes the pain to be especially bad after she has been seated for short period of time or in the morning when she gets up and begins walking to the bathroom.
Her health is good. She has regular periods. She had originally seen her primary care doctor who obtained x-rays which were normal. And she was sent because no further explanation could be determined for her pain.
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Stress Fractures: What else could it be?
So what could this be? It could be a developing hammertoe. I myself have had one of these. Often when they first begin, there is swelling around the joints in the ball of the foot. This is because a ligament has torn in these joints, which makes them inflamed. Usually, the swelling resolves, but the deformity of the hammertoe with the prominence of the first joint or proximal interphalangeal joint of the toe will remain forever.
It could be a Morton’s neuroma. A Morton’s neuroma is a condition that involves irritation of the nerve that gives sensation to the web of the toe. This nerve goes under a ligament in the ball of the foot and can become scarred and enlarged as it passes under the ligament and into the toe web. This can cause a peculiar clicking, swelling, and pain which radiates into the toes along with numbness occasionally. Usually, this pain is located in between the third and fourth toes although on occasion it can be between the second and third toes.
It could be arthritis in the middle part of the foot. There are several small joints in the arch. Breakdown of the cartilage in these joints is quite common in middle age. Often the pain is associated with a bump on the top of the foot near what people call the instep.
Tendinitis, as was suspected by our patient, is very uncommon. A tendon is a connective tissue that joins a muscle to the bone that it pulls on. The tendons on the top of the foot very rarely become inflamed or overused.
Finally, we come to the diagnosis of stress fracture. That is what this patient had and we’ll discuss what that means.
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Why Do Stress Fractures Occur?
Well, I would have to say in our patient that no obvious cause is immediately identified. The general explanation for why you might develop a stress fracture is that small bits of damage accumulated with daily use and overwhelm your body’s ability to heal itself. I compare this to a bank account. Hopefully if we opened and bank account, we will begin with a certain amount of money, let’s say $1000. This is the capacity of your bone to withstand damage. We’ll also hope that you have a job that brings in $1000 a month. This is your bone’s ability to heal itself. Now every day from this account you have to withdraw money, to take care of living expenses etc. Now if the amount of money that we withdraw every day is on the average less than $30, you’re okay, because we are withdrawing less than you’re putting in. But let’s say we go to Las Vegas, and suddenly your withdrawing $100 a day. This would be the equivalent to our bones of starting a new workout program, engaging in activity that overwhelms our body’s ability to heal itself.
It’s easy to see that we would to run out of money in our bank account. When your bone runs out of its reserve, it begins to break.
The Sequence: Micro fracture to Macro fracture.
When the bone starts to break through stress, it begins as an area of localized micro-damage. While this amount of damage may be painful, we will not be able to see it on x-ray because the bone does not have a crack in it. However, it can swell. Soon after this, the swelling becomes worse and may involve the entire bone. Still, we may not be able to see anything on x-ray. A small crack may begin to propagate through the bone, usually on the tension side of the bone. In the case of the foot, this would be on the bottom, in the arch itself. As the damage continues, the crack we’ll continue to extend through the bone and may even complete itself with bleeding into the tissue becoming a fracture that is obvious on x-ray.
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So, like we discussed with our bank account example above, changes in the way that we use our bones cause damage to the bones that may overwhelm our body’s ability to heal itself and are one very common way to develop a stress fracture. A new workout regimen, moving into a house, a new job may require more activity than you’re accustomed to and can initiate a stress fracture. An injury that was not quite severe enough to cause a fracture may initiate enough damage to start you along this path.
Changes in your body’s health can also cause this. If your bone has become weakened through osteoporosis or other such diseases, it may become weakened to the point that normal activity may continue the injury. Finally, certain health problems may decrease your body’s ability to heal. Inflammatory conditions or conditions that affect your immune system can commonly do this.
The Body’s Protective Mechanisms
Let’s talk about the mechanisms that your body already has in place to prevent overuse and stress in the bones. It is fascinating the way that the body has engineered itself to resist the injury of normal everyday activity. First of all, like wood or steel or any of the other materials that we are familiar with on and today basis, bone is very capable of withstanding compression or weight. It is only when the bone begins to bend or twist that it becomes susceptible to damage. It has little tolerance for bending, which is also known as shearing, stress. So the body has created ingenious methods of converting shearing stresses into compression.
The first is the bony arch itself. This has been compared to a stone archway which he might see in a bridge or in a castle. But the arch itself is not stable without linking the bases of the arch together. This is the plantar fascia. It is a tough ligament that links the toes to the heel. The best way to illustrate the importance of the plantar fascia is to compare it to a radio tower. A radio tower is a thin delicate structure. If the wind blew against it, it would twist and collapse. However, guidewires support the top and apply compressive stress across both sides of the tower. As long as this compressive stress is greater in the shearing of the wind, the tower remains intact. The plantar fascia does this in a very similar way.
The intrinsic muscles and ligaments are also supporters of the arch. The action of these muscles protects the plantar fascia. However, the use of shoes has caused them to the weaken during our development as a child. Therefore they’re not as effective as they could be. This predisposes us to injuries such as stress fractures. Finally, the posterior tibial tendon supports the arch. It does this by pulling on the inside of the middle portion of the foot. This strong tendon is attached to the navicular bone and draws the foot towards the midline of the body. It adjusts the foot to keep it centered over the body’s weight. If the arch is lost, the stresses within the foot change and this can easily overload the foot and cause an injury.
So, key to the body’s ability to withstand stress, is its resilience. This depends on the history of activity of the bone. An minor traumatic injury may begin a stress injury by damaging it if it is not allowed to rest and recover properly. A bone that is under new increased stress will break easier than a bone that has been tempered by significant activity. So, the bones of a marathon runner will have a different resistance to breaking that someone who sits at a desk every day and rarely does anything physical. This principle was developed by Julius Wolff, the first orthopedic professor in Berlin, Germany. He studied heel and hip bones and determined that the body reinforces itself depending on the stresses that it sees. However, the body has a limited capacity to heal and, if this is overwhelmed, it will progress to fracture. Rapid changes in activity are not well tolerated and can lead to injury.
The foot can also change. So that a gradual loss of alignment, such as when someone develops a “fallen arch”, can change the stresses within the foot so that it can break. Damage to the nerves, such as occurs in diabetes, can blunt our ability to tell when we are damaging ourselves so that the stress fractures can become quite serious. Finally, metabolic problems such as vitamin D deficiency or abnormalities to the hyperparathyroid gland or even age related thinning of the bones or osteoporosis can lead to stress injuries.
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How do I get better?
As a stress fracture is caused by excessive stress, the stategy for treatment of a stress fracture is reducing this stress. This may depend on the degree of damage.
Activities that place a great deal of stress on the metatarsalgia such as jogging and sports may need to be temporarily curtailed and replaced by other activities such as bicycling and swimming.
When the swelling is severe and the pain is present with even light activities, the foot should be protected in a cast or a cast-boot. A short period of restricted weight-bearing may even be necessary.
When the pain is less acute, curtailing strenuous activities may be all that is necessary. Rocker-soled shoes or shoes that are stiff and disperse pressure on the bottom of the foot may be helpful. Inexpensive over-the-counter arch supports may also improve support of the fracture and pain. Custom inserts are not necessary.
Non-steroidal anti-inflammatory medications such as ibuprofen and naprosyn are effective pain medications, but do little to cure metatarsal stress fracture. There is some evidence that these medications may delay bone healing..
Postural training and rehabilitation is the effective long-term solution. Changing the forces on the front of the foot means improving flexibility, toning the muscles of the abdomen, hip, and back. It also means learning a different way of walking and standing.
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