PRORehab Library

Tibial Stress Fractures in Athletics

One of the most common complaints among athletes who participate in repetitive motion activities such as running, soccer, basketball, and football is lower leg and shin pain. Shin pain generally has a gradual onset with increased activity levels and if it is not given the appropriate attention and care, it can become a debilitating condition and may become a stress fracture. The purpose of this article is to provide information on the causes of, symptoms of, and diagnosis and treatment of tibial stress fractures. Additionally tips for prevention of shin pain and stress fractures will be presented.

A stress fracture is one or a series of microfractures that occur secondary to an increase in repetitive loading and excessive shock being applied to a bone. In athletic activity bones are in a constant process of remodeling along the lines of stress. Remodeling is the process by which bone cells die, are destroyed, and are replaced with new bone cells. The two types of bone cells involved in the remodeling process are osteoclasts (bone destroyer cells) and osteoblasts (bone builder cells). These builder and destroyer cells usually exist in a 1:1 ratio in a normal bone. As one cell dies, a new cell is created to take its place. An increase in the amount of stress applied to a bone leads to an increase in remodeling activity. Eventually the bone destroying activity will exceed the bone building process and the bone may be weakened along the stress lines and may microfracture. The resulting microfractures are called stress fractures. If given time to rest, the remodeling process will eventually normalize and the fractures will heal.
When looking at shin pain, the relevant anatomy should be considered. The low leg consists of two large, long bones that make up the shin region. The tibia is the larger of the two bones and is located on the large toe side of the leg. The fibula is smaller in size and can be found on the small toe side of the leg. The tibia is a large dense bone that bears most of the weight of the body. The muscles that attach to the tibia assist in shock absorption. The fibula bears very little body weight and exists primarily for a base of attachment for muscles that control the ankle joint and extend the toes. Since the tibia bears more body weight than the fibula, the tibia is much more prone to stress fractures.

Causes of Stress Fractures
Generally the most common cause of stress fractures is an error in training. More often than not, that error is over training, or performing more than your body is ready to handle and not allowing proper rest periods between training sessions. Stress fractures are common following significant increases in distance running and changing from running on a softer surface to a harder one, such as going from track running to road running. Running in old broken down shoes or in new shoes that have yet to be properly broken in can lead to shin pain and stress fractures.
Foot structure and arch height can play a role in the onset of stress fractures. People with very high, rigid arches are prone to stress fractures because high rigid arches do not allow the foot to absorb shock like it should. Conversely, people who have low arches or flat feet are prone to stress fractures because of increased pronation (running on the inside of the feet). Increased pronation places the stress on the muscles on the inside of the low leg that cannot handle the stress, which transfers that stress to the bone.
Some factors that relate to bone mineral density can cause stress fractures to occur. Inadequate calcium intake may lead to decreased bone mineral density, which can weaken bones and make them prone to stress fractures. Research has shown that women are more prone to stress fractures than men and that estrogen levels correlate to bone mineral density. If estrogen levels are insufficient, it can affect the bone builder/destroyer ratio and disrupt the bone remodeling process just as much as an increase in activity level can.

Signs and Symptoms of Stress Fractures
The symptoms of stress fractures include shin pain on the front or inside of the shin that is debilitating in nature and can prevent aggressive athletic activity and may even interfere with activities of daily living. This shin pain usually onsets at the beginning of athletic activity and does not relent until potentially up to several hours following activity. Shin pain that decreases immediately following activity is more than likely not a stress fracture. There may be mild swelling present in the painful region. These areas will be point tender, or tender to the touch in a specific small area. Stress fractures generally do not cause pain that runs the entire length of the shin. If one would run the back of their hand down the shaft of the shin bones, similar to checking for a fever, the painful region may feel warmer than the rest of the shin. This heat on the bone is a sign of excessive metabolic activity within the bone, meaning that the remodeling process is working overtime. These warm spots are known as “hot spots” and are a sure sign of a stress fracture. Any athlete with painful hot spots on the shin should stop athletic activity and follow up with a physician for examination.

Clinical Diagnosis of Stress Fractures
Clinical examination is the best tool to determine the presence of a stress fracture. A patient will present with the above listed symptoms, and if further diagnostic testing is required, the physician may utilize a radiographic imaging technique to diagnose the stress fracture.
There are two radiographic imaging techniques that are useful in the diagnosis of stress fractures. These images are the X-ray and bone scan. X-rays are very specific in diagnosing stress fractures, but they are not the most sensitive test. Most initial X-rays will be negative for stress fractures because they reveal the bony calluses and thickening on the bony edges, which are common with fracture healing. It may take 2-3 months following initial onset of shin pain to get a positive X-ray for a stress fracture. The bone scan can show a stress fracture in as few as 2-8 days following the onset of symptoms. It is a very sensitive test and measures “hot spots” on the bone. It is very useful for differentiating between stress fractures and other soft tissue injury which may be present. Bone scans are expensive tests but they are considered the most accurate in diagnosing stress fractures. If a bone scan is negative for a stress fracture, a CT scan can be performed to determine if a stress fracture is present. A CT scan may detect the presence of a stress fracture but is not useful for determining when the fracture is healed. MRI scans are useful for diagnosing soft tissue injuries but are generally not used to diagnose stress fractures.



Treatment of Stress Fractures
The standard treatment for stress fractures is to reduce the patient’s activity level to a level that does not provoke the shin pain symptoms. This may be accomplished with complete rest, immobilization in a walking boot, crutches with partial or no weight bearing, or the use of orthotics. The duration of decreased activity varies, but usually lasts 4-6 weeks. The patient may continue cardiovascular training by performing activities that do not provoke shin pain, and low impact activities such as swimming, stationary cycling, and even an elliptical trainer. They may also continue weight training as long as they are not using heavy weights that may produce pain. Conservative treatment also includes stretching of the lower leg muscles and the use of ice massage, which is rubbing ice directly on the skin in a massaging motion for ten minutes. Over the counter anti-inflammatory medications such as ibuprofen, Advil, and Motrin, are also effective in decreasing pain and inflammation. This course of conservative treatment usually lasts from 3-8 weeks. Once radiographic imaging techniques are negative for stress fractures, the athlete may begin gradual return to athletic activity.

Tips for Preventing Stress Fractures
1) Gradually increase your training level by 5-10% over the course of three or four training sessions. Be sure to allow proper recovery time, such as one to two days rest between training sessions.
2) Calcium supplementaion/intake in excess of 800 mg. per day can help prevent stress fractures.
3) Arch supports for flat feet will help prevent stress fractures by limiting excessive pronation.
4) Soft inserts will benefit athletes with high rigid arches by helping them absorb shock and dissipate it over a larger area.
5) Be sure to stretch your calves and the muscles on the front of your shins before, during, and after activity.
6) Icing the shins for 20 minutes following activity can help to reduce pain and inflammation.
7) Do not neglect your shoes. Running shoes may break down every 4-5 months and need to be replaced. The shoes may wear out long before the shoe uppers wear out.

The purpose of this article is to provide the reader with information regarding stress fractures that they may find useful. If you experience shin pain following the cessation of athletic activity, you should follow up with your physician for examination.

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