Stress fracture

A stress fracture is a small crack or area of injury in a bone caused by repeated force over time rather than a single injury. Bone is constantly breaking down and rebuilding; when activity increases faster than the bone can adapt, damage outpaces repair. They turn up most often in the lower leg and foot, which carry the body's weight, but the hip, pelvis, and lower back can be affected too.

• Pain that develops gradually, at first only during or after activity and easing with rest
• Pain that comes on sooner during activity and lasts longer afterward
• Tenderness at one specific spot on the bone
• Swelling over the painful area
• In more advanced cases, aching at rest or at night, or a limp

Continuing to train through the pain can turn a stress fracture into a complete break.

• A sudden increase in how often, how long, or how hard you train, such as a new sport, a new season, or a new program
• Running and jumping sports, dance, and military training
• Hard training surfaces and worn-out shoes
• Not eating enough to fuel training (low energy availability), and low vitamin D or calcium
• Conditions or medications that weaken bone, such as osteoporosis
• Weak or tired muscles, too little sleep or rest, and a previous stress fracture

The examination checks for pinpoint tenderness over the bone. X-rays are often the first test, but they may look normal early on. An MRI can show bone stress before a crack is visible, and a CT scan can show a fracture line in more detail. A bone density scan or blood tests may be recommended when there are risk factors for weak bones or the fracture happened with ordinary activity.

The main treatment is relief from the activity that caused the injury so the bone can heal. Low-impact exercise, such as swimming or cycling, can often maintain fitness if it is pain-free. If walking hurts, a stiff-soled shoe, a walking boot, or crutches reduce the load on the bone. Ice and pain relievers as advised by your clinician can ease discomfort, and nutrition, vitamin D, and bone health are addressed when needed.

Some stress fractures heal less reliably because of where they are or their blood supply, such as those in the hip (femoral neck), the front of the shinbone, the navicular bone in the midfoot, and the base of the fifth metatarsal on the outer edge of the foot. These may need a longer period without weight bearing or surgery to stabilize the bone with screws, pins, plates, or rods.

Healing usually takes weeks to months, depending on the bone and the severity of the injury. Return to activity is gradual: pain-free walking comes first, then a stepwise return to running or sport, sometimes alternating activity days with rest or cross-training days. Returning too quickly can delay healing or lead to a complete fracture.

• Increase training gradually and build in rest days
• Cross-train with lower-impact activities
• Wear supportive shoes and replace them when they wear out
• Eat enough to match your activity, with adequate calcium and vitamin D
• Get enough sleep and include strength training
• Stop and get checked if bone pain develops rather than training through it