Dr. Brian Fullem practices at Elite Sports Podiatry in Clearwater, FL. He ran 14:25 for 5K while at Bucknell University. This is the continuation in a series of articles by Dr. Fullem, educating us about injury care, injury prevention & other health topics for athletes at all levels of performance. The following article is the first in a 3-part series of exerpts from Dr. Fullem’s recently published book, The Runner’s Guide to Healthy Feet and Ankles, which can be purchased here:
The Runner’s Guide to Healthy Feet and Ankles:
Simple Steps to Prevent Injury and Run Stronger
by Dr. Brian W. Fullem et al.
The treatment of stress fractures in athletes can be a challenging task. Runners that are competing in school, professionally or at the highest recreational levels often have a narrow time frame to train and compete in their desired sporting activities. Reducing healing time by every means possible is crucial to the success of these athletes. The goal of any sports medicine professional should always be to return the athlete back to activity as soon as is safely possible for the athlete.
When to Suspect a Stress Fracture
The most common site of a stress fracture in the lower body is the tibia or shin bone, followed by the metatarsals, the bones in the foot behind the toes. Most stress fractures develop gradually. A typical tibial stress fracture will initially be felt as “shin splints,” a catch-all term that refers to pain along the inside of the tibia. The pain usually starts out over a large area along the shin bone, and is mainly noticed after a hard training session or race, or the morning after a long or difficult workout.
Shin splints occur when the muscles pull away from their attachment site along the inside of the tibia. At this point it’s possible to prevent a stress fracture by responding to the developing problem: Stop running and see a sports medicine specialist. Left untreated, the muscles will continue to pull, and this may cause a crack to form in the bone. The pain will progress to the point where it is noticed more during the run, and become focused on a smaller area of the bone.
Do not be fooled into thinking that your injury is a stress fracture only if you are unable to run. Rich Kenah won bronze medals in both the indoor and outdoor World Track Championships in the 800 meters in 1997. Early in his buildup for the 1998 season Rich began experiencing pain in the middle of his foot that turned out to be a navicular stress fracture. Rich was able to continue to train despite the stress fracture and in the process of compensating for the pain he developed a second stress fracture in the fourth metatarsal of the same foot. Rich eventually healed both fractures and made the US Olympic team in 2000, competing in the Sydney Olympics. Athletes tend to have high levels of pain tolerance and while working out endorphins are released further masking the pain.
Not every stress fracture is the same. I learned the hard way that they don’t hand out medals for pain tolerance. Quite the contrary. I am absolutely convinced my career would have ended before I qualified for the Games were it not for Brian’s counsel on the navicular fracture that I was dealing with.
~ Rich Kenah
Stress fractures will commonly cause more pain as the run progresses and may actually be more painful after the run. With a metatarsal stress fracture one will often see an accompanying swelling over the area that may not be noticeable unless you compare it to the unaffected side.
Stress fractures were first described in 1855 as “march fractures” by the German military surgeon Breithaupt1, who made the clinical description of swelling and pain in the foot of a metatarsal stress fracture. The fractures were closely associated with the marching done by soldiers. In 1897 Stechow2 described the radiographic appearance in military recruits forced to go on long marches establishing the association between stress fractures and overuse. Most competitive athletes will straddle the fine line between optimal fitness and injury in order to achieve the best performance possible.
In a landmark paper, Matheson et al7 analyzed cases of 320 athletes with bone scan- positive stress fractures seen over 3.5 years and assessed the results of conservative management. The most common bone injured was the tibia (49.1 %), followed by the tarsals (25.3%), metatarsals (8.8%), femur (7.2%), fibula (6.6%), pelvis (1.6%), sesamoids (0.9%), and spine (0.6%). Stress fractures were bilateral in 16.6% of cases.
Much of the literature points to overuse as one of the main causes of a stress fracture. Overuse or training errors can account for the extrinsic factors in an injury but there are typically other more intrinsic factors such as poor bone density, low body weight, low Vitamin D levels, weakness of the core muscular and biomechanical abnormalities including limb length differences can all lead to a stress fracture. It is the duty of the physician to make the proper diagnosis and also to ascertain the possible cause to attempt to prevent future injuries.
Fredericson4 found that athletes that played ball sports such as basketball or soccer during childhood had a decreased incidence of stress fractures as adults. A correlation can be made that these athletes have developed better core musculature such as their hip abductors leading to fewer injuries. Fredericson5,6 has proven that improving hip abductor strength is the key component for treatment of Ilio-Tibial Band syndrome and is also useful in prevention and treatment of other lower extremity injuries such as Achilles tendonitis and medial tibial stress syndrome.
Athletes are often searching for ways to improve performance and adding a core strengthening program is arguably the best way to help prevent injury leading to improved performance.
Injured athletes should always be questioned about their dietary habits, in particular their ingestion of dietary calcium and Vitamin D. A prospective study by Tendford et al in 2010 showed a decrease in stress fractures in runners when there was an increase of their dietary calcium and Vitamin D intake.
A referral to an Endocrinologist is appropriate when an athlete presents with any signs of an eating disorder or multiple stress fractures in a short span of time. It is imperative to check the blood levels of Vitamin D. The normal lab values for Vitamin D may show a level of 30. The blood test checks serum 25–hydroxy-Vitamin D (25(OH)D), many labs will list a “normal” range of 30-70 ng/ml. Low vitamin D increases bone turnover, which increases the risk for a bone injury, like a stress fracture.
A study examining male Finnish military recruits found vitamin D status to be a significant determinant of maximal peak bone mass and also discovered that 25(OH)D levels below 30 ng/mL significantly increased the risk of stress fractures in this subject group. Many experts recommend a minimum level of 75-90 nm/ml.
In November of 2010, the Institute of Medicine (IOM) released new recommendations for dietary intake of vitamin D, 400–600 IU/day for children & adults (0–70 years), 800 IU/day for older adults (>70 years). These values are only slightly higher than past recommendations. The Endocrine Society recommends 400–1000 IU/day for infants, 600–1000 IU/day in children (1–18 years) and 1500–2000 IU/day in adults, in addition to sensible sun exposure.
Based on the research presented on recovery, force and power production, 4000- 5000 IU/day of vitamin D3 in conjunction with a mixture of 50 mcg/day to 1000 mcg/day of vitamin K1 and K2 seems to be a safe dose and has the potential to aid athletic performance.
Make sure to use this dose of vitamin D only if your levels have been checked and noted to be low. Blood levels of vitamin D need to be monitored if you are supplementing at this level because it’s a fat-soluble vitamin and toxicity can occur if the levels become too high.
The main consequence of vitamin D over dosage is hypercalcemia, a build-up of calcium in your blood that can lead to a decreased appetite, weakness, nausea, and, in severe cases, kidney problems.
Women can have a harder time maintaining and improving bone health. The older terminology that addressed female athletes and bone health was known as Female Athlete Triad Syndrome. Relative Energy Deficiency in Sport (RED-S) is the new term, which includes male athletes as well.
For women, the three components of the triad were amenorrhea, anorexia and osteoporosis. We have come to understand that this issue is much more complex.
An editorial in the British Journal of Sports Medicine summarized the terminology change and the reasons for it:
“The syndrome of RED-S refers to impaired physiological function including, but not limited to, metabolic rate, menstrual function, bone health, immunity, protein synthesis, cardiovascular health caused by relative energy deficiency. The cause of this syndrome is energy deficiency relative to the balance between dietary energy intake and energy expenditure required for health and activities of daily living, growth and sporting activities. Psychological consequences can either precede RED-S or be the result of RED-S. The clinical phenomenon is not a ‘triad’ of the three entities of energy availability, menstrual function and bone health, but rather a syndrome that affects many aspects of physiological function, health and athletic performance. This Consensus Statement also recommends practical clinical models for the management of affected athletes. The ‘Sport Risk Assessment and Return to Play Model’ categorizes the syndrome into three groups and translates these classifications into clinical recommendations.”
Part 2 and Part 3 of the series will be about the diagnosis and treatment of stress fractures.