Normal bone is always responding to the stress applied to the bone mostly during activity. Bone responds to inactivity by resorping calcium and making the bone weaker. Bone responds to increased activity by increasing the bone strength. Weight bearing activity helps bones become stronger. However increased impact activity can cause microstresses to the bone. When these stresses accumulate through too much impact such as running or marching or jumping, they overwhelm the body’s ability to repair these microstresses. As the activity continues, the bone undergoes a stress response by increasing blood flow and bone healing. If the impacts continue a stress fracture will begin to occur at an area of weakness in the bone. As the impact further continues the stress fracture can complete itself to a fracture also known as a broken bone.
Any bone can sustain a stress fracture. A stress fracture occurs when the balance of microdamage to micro healing is unbalanced towards the microdamage. Any time we do any sort of impact activity, whether it’s running or weight-bearing activity, the bone responds by resporping areas of bone and building up other areas of bone. This is a balance of bone metabolism. In its response to growing new bone, the mounts of microdamage that can occur from repetitive impact activity, such as running, lifting, or jumping, can cause this balance to become unbalanced. When this occurs, a stress response can occur. Taking steps to maintain adequate bone density and training correctly, and avoiding overuse injuries to the bone can help prevent stress injuries. In the hip, the most common location for a stress injury is at the femoral neck. This is a very significant problem because if this progresses from a stress response to a stress fracture to a whole hip fracture, this can cause the need for surgery to fix this broken bone.
Symptoms associated with hip stress response or fracture are severe pain in the hip and groin. It can cause difficulty to walk. Stress fractures are often caused by repetitive injury, rather than a specific fall, but a trauma can cause a stress fracture. Pain causing you to limp or pain moving your hip around can also be symptoms of a stress fracture.
The most common cause is from overuse, but other medical causes such as thyroid disorders, other hormonal disorders, and eating disorders can put you at risk for stress fractures. Other risk fractures include:
- Age: As we age, the ability to keep our bone density decreases, which increases the risk of injury.
- Sex: Hip stress fractures occur more frequently in woman than men. In particular, after menopause, bone becomes weaker and is more susceptible to stress fractures and injuries.
- Osteoporosis: If you have this condition, which is weakened bone, you are at risk for increased stress fractures.
- Other medical conditions: Hyperthyroidism, vitamin D deficiency.
- Other medications: Prednisone can weaken your bone.
- Nutritional problems: Lack of calcium and vitamin D are critical parts of bone metabolism. It is important to keep an adequate amount of these. However, overusing these does not improve your bone metabolism.
- Tobacco and Alcohol Use: Both of these interfere with the normal process of bone metabolism.
Dr. Faucett will examine you and your hip. He will monitor the way you walk and evaluate your gait if you are limping, this would be one sign. He will also be examining your hip by doing a physical examination of your hip. X-rays are very helpful to determine whether or not there is an increase in the amount of bone, or sometimes can even see a small fracture line. Often in the early stages of stress fractures/stress response, an MRI is needed to look at the bone metabolism. In some cases, a bone scan can help look at bone activity, as well as a CT scan that can help look at the structure of the bone and can determine whether there is a fracture. In some cases, a repeat MRI will be needed afterwards to evaluate healing.
Laboratory tests to evaluate your hormonal balance can be helpful to rule out the above medical conditions and make sure you have adequate calcium and vitamin D in your blood.
Most stress fractures in an earlier stage can be treated with nonsurgical treatment of protective weight bearing using crutches and limiting any impact activity. Other non weight bearing activities such as swimming, or even an anti gravity elliptical can be initiated after the initial pain has been resolved. In many cases, 6 weeks of crutch use is necessary to manage the pain, but if you continue to have pain, you may need to have crutches. Repeat X-rays and MRIs will also be obtained to monitor healing of the stress fracture. In some cases, in severe stress fractures are areas where there is a line or a rare case that the fracture completes to a full fracture, emergent surgical treatment is needed to place screws across the fracture to stabilize the hip from further fracture or displacement and allow adequate healing.
In some cases, if the stress fracture does not heal or there occurs to be a fracture, surgery may be needed. If even then, the fracture does not heal, in some cases a hip replacement is needed.
The best way to prevent stress fractures is to maintain a healthy balanced diet of protein, calcium, and vitamin D and to monitor your training program to avoid repetitive injuries and repetitive processes to limit the amount of microdamage that occurs at the bone.