What is a stress fracture?
A stress fracture is an overuse injury to a bone. An overuse injury is a type of injury that develops gradually over a period of time rather than at one specific time. Some other types of overuse injuries are tendinitis, bursitis, epicondylitis. When a bone is exposed to repetitive stress, there is a breakdown of the bone. Normally, bones respond to stress by producing more bone cells which help to repair the bone. If too much stress is applied, the normal repair process cannot keep up with the breakdown and a fracture occurs.
Risk Factors
There are multiple factors that increase the risk of a stress fracture:
- Intrinsic factors, which are characteristics of the individual, include weakness of the bones and muscles, abnormal alignment of the legs and feet, hormonal or menstrual irregularities, and dietary deficiencies of Vitamin D , calcium, or calories.
- Extrinsic factors, which are outside the individual and may include training errors such as too much activity, too hard or uneven surfaces, and improper footwear.
Lower Extremity Fractures
The majority of stress fractures occur in the lower extremities. The person usually has a history of gradual onset of pain after an increase in running activity such as at the beginning of a sports season. Symptoms develop gradually over a few weeks. In the early stages the pain occurs at the end of a long run and goes away when the activity ceases. If training continues, the pain occurs with shorter runs and persists for a while after the run is completed. If the offending activity continues, the pain may continue during the night and with normal daily activities. The pain may go away after resting for a few days, but when running resumes, the pain returns.
Types of Stress Fractures
Stress fractures can be classified as either low risk / faster healing type or high risk / slower healing type. Low risk stress fractures usually heal well by avoiding high impact activity for 4-8 weeks. High risk fractures do not heal well due to poor blood supply to the bone around the fracture or the amount of stress placed on the bone during normal daily activities. These high risk fractures are treated with non-weight bearing and possible surgical fixation.
A stress fracture in the upper femur or thigh bone is a femoral neck stress fracture. Symptoms include hip or groin pain that is worsened by bearing weight. Diagnosis is confirmed with x-ray or MRI. Treatment is keeping all weight off that leg and possible surgery to place a pin in the bone.
In a stress fracture of the tibia, there is point tenderness directly over the shin bone. Treatment of most tibial stress fractures is by avoidance of high impact activity for 4-6 weeks. However, there is one type, an anterior tibial stress fracture, that is considered a high risk fracture. Radiographs show a “dreaded black line’ on the bone. Treatment is with non-weightbearing immobilization for 6-8 weeks. Surgery may be needed if healing does not occur.
Another high risk stress fracture that occurs in the inner side of the midfoot is a navicular stress fracture. Diagnosis is usually with a CT or MRI scan. Treatment is at least 6 weeks in a non-weightbearing cast, followed by rehabilitation. Displacement or delayed healing usually requires surgery.
Stress Fractures in the Feet
The metatarsals are bones in the foot that are proximal to the toes. A metatarsal stress fracture usually occurs in the distal end or middle part of the bone and most commonly in the 2nd or 3rd metatarsal. There is usually swelling and tenderness on top of the foot. Diagnosis is with x-ray or MRI. These usually heal with rest from running for 6-8 weeks and wearing a firm- soled shoe or a walker boot . A high risk stress fracture in a metatarsal is a 5th metatarsal proximal shaft fracture which causes pain and swelling on the outside of the foot. This fracture also requires non-weightbearing and possible surgical fixation to heal.
In summary, stress fractures are a common injury, especially in runners. They are often difficult to diagnose because they develop slowly and are often not visible with x-rays. Proper diagnosis and treatment is important to prevent complications or long term damage.
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About NGPG Sports Medicine
NGPG’s Sports Medicine Team consists of board-certified physicians offering more than 20 years of sports medicine experience treating patients of all ages. Specialized in treating sports-related injuries, our team is dedicated to helping athletes return to the big game and the active lifestyle they know and love.