Monday, August 22, 2011

Stress Fracture Season Is Upon Us!!

I've been seeing a significant increase in the number of stress fractures of the legs in the running population.  Unfortunately, this goes hand in hand with marathon training season and the beginning of cross country season.  Keep reading for tips to avoid these injuries.

A stress fracture is an incomplete fracture or crack within a bone, occurring when too much repetitive stress is applied to the bone.  In runners and other athletes, they most commonly affect the metatarsal bones of the feet, the calcaneus (heel), the tibia (shin), the fibula (outside of the lower leg), and the femoral neck (hip).  They occur more often in females than males.

When a bone in the lower extremity is loaded and stressed during exercise, it responds by increasing bone turnover. This involves the removal of old, damaged areas of bone and the production of new bone to replace it.  This happens in all weight-bearing bones in all of us, even with walking.  However, it is supercharged in those who aggressively exercise.  If bone formation cannot keep up with bone removal, an area of weakness develops.  This area can develop into a stress fracture if the bone continues to be loaded over time.  Think of this like bending a paper clip.  If you continue to repetitively bend a portion of a paper clip in the same location, it develops a weak spot.  When the stress is continued, it eventually breaks apart.

Any number of training errors can cause this imbalance of bone turnover.  A common occurrence is the commencement of a new exercise activity or a sudden increase in training.  This may include increasing the frequency, duration, or intensity of your workouts.  Inappropriate footwear for an individual’s foot type and the unforgiving nature of one’s training surface are also other notable factors that may lead to stress injury.  Individual biomechanical abnormalities in one’s running gait may contribute, as may muscle fatigue during long bouts of exercise that lead to compensation changes in the gait.

A stress fracture is characterized by increasing pain at the affected bone over a period of weeks.  It is usually well-localized and made worse by exercise.  Initially, the pain is only present after exercise, but with continued loading it becomes evident during the activity.  Eventually, the area may become sore with regular walking.  If the injury is allowed to progress, it may even cause pain at rest or even at night.  The area will be painful when touched.  There is typically minimal swelling, if any is present at all.

If you are concerned you have a stress fracture, you should come in to the office.  We can assist by confirming the diagnosis using X-ray, bone scan, or MRI, and help to determine the extent of damage to the bone.  Early stress fractures often are not evident on regular X-rays, necessitating further imaging. 

Once a stress fracture is diagnosed, activity modification is essential.  Rest and occasionally the use of crutches will help the bone begin to heal.  Fortunately, a complete discontinuation of activity is rarely necessary.  Low impact cross training and progressive strengthening is important to maintain muscle function and aerobic capacity and to not lose too much ground in training.  Such activities include swimming, deep water running, and cycling.  I will also help determine what errors may have contributed to the stress fracture and how to correct them. Also, I will help guide your safe and successful return to full activity.

Using appropriate footwear, varying your training surface, and alternating a cross training activity with running are all ways to help prevent stress fractures.  Most important is a gradual, progressive increase in running over several weeks as your training begins.  A good core strengthening program and working to correct muscle imbalances may also help avoid problems.

If you experience a new, acute onset of pain over a bone with activity that tends to worsen with continuation of the activity, you may be on your way to developing a stress fracture.  A short period of rest with low load cross training may allow the bone’s remodeling to catch up and may only result in a few days or weeks of lost time.  If you’ve rested and continue to note pain or the pain is worsening, it is probably time to get it checked out.  You should not attempt to run through this pain!  This may lead to a complete fracture and more time lost from training.  If caught early, some of my patients with stress fractures are healed and back on course in a matter of four to six weeks.  If more severe, the recovery can take months.  The majority of stress fractures heal with time, and with the help a good sports medicine specialist, training errors will be corrected and you will be back on the road in no time.