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Stress Fractures of the Foot

Tony C. Nguyen, DPM

During this time of the year, one of the most common problems I see in my practice is stress fractures of the foot. A stress fracture is an incomplete fracture in the bone caused by repetitive stress or overuse. It typically occurs in weightbearing bones like the tibia metatarsals, or calcaneus (heel bone). Most patients are often confused when they hear this term. Their assumption is that the bone is completely broken and split into two pieces. They often wonder how it happened, especially when there is no history of injury or trauma. The term "stress fracture" is a misnomer. A fracture line is not typically seen in the majority of diagnosed "stress fractures", but is usually only demonstrated in severe cases. The more appropriate term is "stress reaction" or "stress injury" of bone, in essence the bruising or inflammation of the bone.

When you run, the pressure on your feet can oftentimes exceed four times your body weight. Bones constantly remodel and repair themselves, especially during a sport where extraordinary stress is applied to the bone. Over time, if enough stress is placed on the bone exceeding the capacity of the bone to remodel, a weakened site or "stress fracture" on the bone may appear. The fracture does not appear suddenly. It occurs from repeated trauma, none of which is sufficient to cause a sudden break, but the summation of events overwhelm the cells that remodel the bone.

Stress fractures typically present with a generalized area of pain and tenderness that worsen with weight bearing. Usually when running, a stress fracture causes severe pain in the beginning of the run, moderate pain in the middle of the run, and severe pain at the end and after the run. A stress fracture is diagnosed based on clinical symptoms and findings. X-rays usually do not show any evidence of stress fractures. A CT scan, MRI, or bone scan may be more effective in unclear cases. The most important treatment for a stress fracture is rest. In general, a fracture requires four to eight weeks for healing. I usually recommend two weeks of complete rest from the activity that caused the fracture. Icing and the use of anti-inflammatories are helpful. No high impact activities for one month. Gradual increase in activity level can be started if there are no pain symptoms.

Muscle fatigue plays an important role in the occurrence of stress fractures. Muscles are important for shock absorption. There is about 110 tons of force that must be absorbed by the leg for every mile a runner runs. When muscles in the lower leg become fatigued, all the forces are transferred to the bones. Bones are not made to withstand this much energy on their own.

Stress injury to bone can be prevented. Strengthening exercises to increase leg muscle strength is vital to absorb the pounding of running. Bones and muscles need time to adapt and strengthen. One rule of thumb is to increase the volume of training by no more than 10% per week. Runners should replace their shoes every 350-550miles to allow adequate mid-sole cushioning. Women and highly active individuals are at a higher risk. But children may also be at risk because their bones have yet to reach full density and strength. A recent study released by Creighton University in the Journal of Bone and Mineral Research has shown 2000mg Calcium and 800 IU Vitamin D supplementation can significantly reduce stress fractures in female military recruits.

Dr. Nguyen is board certified in Reconstructive Foot and Ankle Surgery and also specializes in Sports Medicine. He has a practice in Santa Rosa, California.

Dr. Tony Nguyen