OVERVIEW

What is a stress fracture?

A stress fracture is a special type of bone fracture. Its unique characteristic is that patients typically have no obvious history of trauma. Instead, the fracture is usually caused by repeated mechanical stress (e.g., in track and field athletes or ballet dancers).

Therefore, stress fractures commonly occur in areas subjected to concentrated mechanical loads, such as the femoral neck (thigh bone), the anterior tibia (shin bone), and the metatarsals in the foot.

Since the upper limbs bear less weight, stress fractures are relatively rare there, though they can still occur—for example, in the humerus.

The symptoms of stress fractures are similar to those of regular fractures, such as localized pain and tenderness. However, they also have distinct features, such as being more common in high-intensity athletes, occurring primarily in stress-concentrated areas, and exhibiting progressively worsening pain.

The general treatment principles for stress fractures are pain relief, preventing further progression, and promoting bone healing. Most patients respond well to non-surgical treatment, while a minority may require surgery.

With timely intervention, stress fractures usually heal completely, leaving no long-term complications or impact on daily life.

SYMPTOMS

What are the symptoms of a stress fracture?

A stress fracture occurs due to repeated external stress rather than sudden trauma, so it develops gradually. The pain also worsens progressively, and there will be tenderness at the fracture site.

What are the characteristics of stress fractures that differ from ordinary fractures?

Due to their unique cause, stress fractures have the following features:

• They commonly occur in high-intensity athletes, such as sports players, ballet dancers, or military personnel, though they can also occur in the general population, albeit less frequently.
• Since the lower limbs bear more weight, stress fractures are more likely to occur there, while they are rare in the upper limbs.
• The pain progresses gradually—starting with discomfort during intense activity, then worsening to pain during mild movement, and eventually becoming constant even at rest.
• Unlike traumatic fractures, stress fractures typically do not show obvious localized swelling, bruising, or deformity.
• In the early stages, the fracture may be incomplete, but without intervention, it can develop into a complete fracture.

CAUSES

What are the risk factors for stress fractures?

Stress fractures are overuse injuries caused by a combination of multiple factors, including extrinsic and intrinsic factors:

Extrinsic factors:

1. Sudden increases in training intensity, frequency, or duration;
2. Running, jumping, or training on hard surfaces;
3. Abrupt changes in footwear.

Intrinsic factors:

1. Previous history of stress fractures;
2. Lower limb misalignment or structural abnormalities, such as flat feet;
3. Women are more prone to stress fractures than men;
4. Nutritional deficiencies, including insufficient protein, calcium, or vitamin D in the diet.

Who is more likely to develop stress fractures?

Stress fractures are more common in the following groups:

• Individuals with a history of previous stress fractures.
• Those who suddenly increase their activity level or intensity.
• People with a low body mass index (BMI) or malnutrition. BMI = weight (kg) ÷ height² (m²). Current research suggests that individuals with a low BMI may have reduced muscle and fat mass. Low muscle mass can lead to poor posture during exercise, increasing stress on certain bones, while low fat mass may weaken the body's ability to absorb and distribute stress. Both factors increase the risk of stress fractures.
• Individuals with poor bone quality, such as osteoporosis.
• Long-term use of glucocorticoid medications, which can deteriorate bone quality.

DIAGNOSIS

How to Diagnose a Stress Fracture?

Since stress fractures occur gradually and often go unnoticed, delayed diagnosis can lead to severe consequences such as complete displaced fractures. Therefore, early diagnosis is crucial.

Doctors primarily rely on medical history, symptoms, physical examination, and imaging tests to determine the presence of a stress fracture.

• Medical History: The doctor will inquire about risk factors for stress fractures, such as the patient's occupation, recent changes in physical activity or exercise routines, and any history of bone development issues.
• Symptoms: The doctor will ask about the symptoms mentioned earlier that are associated with stress fractures.
• Physical Examination: The doctor may identify localized tenderness at the painful site, but significant swelling, bruising, or deformity is usually absent. In some long-standing cases, a palpable bony prominence may be present. A tuning fork test can elicit pain at the fracture site, which is a distinctive sign of stress fractures.
• Imaging Tests: These include X-rays, CT scans, and MRI, which can confirm the diagnosis. Other methods, such as bone scans, are less commonly used today.

What Are the Pros and Cons of X-rays, CT, and MRI for Diagnosing Stress Fractures?

• X-rays: The advantage is their high "confirmatory ability"—if a fracture is visible on an X-ray, it is almost certain. However, their "exclusion ability" is poor; a negative X-ray does not rule out a stress fracture. X-rays are inexpensive and widely available in most hospitals.
• CT Scans: CT can be considered an advanced version of X-rays, providing more comprehensive and clearer images of bones, but with higher radiation exposure.
• MRI: MRI has higher sensitivity and can detect soft tissue swelling or bone bruising. It involves no radiation but is more expensive.

Here’s a simple analogy: An X-ray is like a 2D photo, offering limited visibility of the bone. A CT scan is more like a 3D model, providing a fuller view. MRI goes further, revealing not only the bone but also internal conditions.

Generally, doctors recommend the following testing sequence: Start with an X-ray or CT scan. If the diagnosis remains unclear but suspicion is high, proceed with an MRI.

TREATMENT

Which department should I see for a stress fracture?

Orthopedics.

How to treat a stress fracture in the acute phase?

The acute phase refers to the period when the lower leg is painful, swollen, warm to the touch, and walking is affected. The primary treatment goal is to reduce swelling and relieve pain. The following measures are recommended for the acute phase:

1. Rest is essential during the acute phase. Stop all activities and avoid running, climbing stairs, jumping, etc. In severe cases, use crutches to limit weight-bearing and prevent further damage.
2. Apply ice to the painful area. Place an ice pack (or a plastic bag filled with ice and water) on the affected area, with a thin cloth between the ice and skin to prevent frostbite. Ice for 15–20 minutes at a time, every 2 hours, 4–5 times a day.
3. Elevate the affected leg by placing 1–2 pillows under the thigh, keeping it above heart level to promote blood circulation.
4. For severe pain, nonsteroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen may be used under a doctor's guidance.

How is a stress fracture treated?

The general principle is to relieve pain, prevent further progression, and promote fracture healing.

Treatment methods include conservative therapy (e.g., non-weight-bearing, bed rest, cast immobilization) and surgical treatment (primarily internal fixation).

The specific treatment plan is determined based on the patient's expectations, age, fracture location, severity, and other factors affecting healing. Most patients respond well to conservative treatment, while a few may require surgery.

How is the treatment plan selected based on the risk level of the fracture site?

The risk level varies depending on the fracture location.

• Low-risk fracture sites include: the 2nd and 3rd metatarsal shafts, posteromedial tibial shaft, fibula, proximal humerus or humeral shaft, ribs, sacrum, and pubic rami.
• High-risk fracture sites include: lumbar pars interarticularis, femoral head, femoral neck, patella, anterior tibial cortex, medial malleolus, talus, navicular bone, proximal 4th metatarsal near the lateral plantar aspect, proximal 5th metatarsal shaft, and base of the 2nd metatarsal.

Low-risk fractures usually heal with conservative treatment. High-risk fractures may initially be treated conservatively, but surgery is required if conservative measures fail.

What are the specific measures for conservative treatment of stress fractures?

• Protection of the fracture site: For mild stress fractures, avoid weight-bearing and use crutches. More severe cases may require cast or brace immobilization.
• Pain relief: NSAIDs such as etoricoxib, celecoxib, ibuprofen, loxoprofen, flurbiprofen, or diclofenac are the first choice.
• Avoid strenuous activity: Since intense activity often triggers stress fractures, avoiding it aids recovery.
• Bone-forming medications: Osteoporosis or reduced bone density weakens bones, increasing fracture risk. Calcium, vitamin D, and bisphosphonates can treat osteoporosis. Elderly patients should note that bisphosphonates may increase the risk of atypical femoral fractures (a type of stress fracture).

What surgical treatments are available for stress fractures?

The primary surgical option is internal fixation, similar to standard fracture treatment.

How is rehabilitation conducted for stress fractures?

Rehabilitation includes activity modification, physical therapy, and training. Activity modification is the primary measure to treat and prevent progression. Adequate rest and reduced stress allow bone healing. Physical therapy alleviates pain and speeds recovery, while rehabilitation training helps patients return to activity.

1. Activity modification: Stop high-impact activities like running and jumping. Switch to low-impact cross-training (e.g., swimming, elliptical machine, cycling) that doesn’t provoke symptoms. Avoid complete bed rest.
2. Physical therapy: Cold therapy (ice packs for 15–20 minutes) during the acute phase reduces pain. After the acute phase, heat therapy (warm towels or heating pads) eases swelling and stiffness. Ultrasound or shockwave therapy at rehabilitation centers may accelerate healing.
3. Rehabilitation training: Stretch and relax tight muscles (e.g., soleus, tibialis posterior) and strengthen weak ones (e.g., calf, glutes). Tailor exercises based on assessment. Maintain normal training for unaffected areas (arms, core, healthy leg) to preserve fitness. Gradual running can resume once pain and tenderness fully resolve.

What physical therapies can be used for stress fractures?

1. Ultrasound: Effective for complete fractures. Low-intensity pulsed ultrasound stimulates bone healing and shortens recovery, while high-intensity pulses may hinder collagen synthesis.
2. Shockwave therapy: Effective for nonunion or delayed healing, typically used after 6 weeks of failed conservative treatment. Shockwaves create "micro-fractures" to activate growth factors and vascularization, but early use is avoided as it initially damages the fracture site.

DIET & LIFESTYLE

What should patients with stress fractures pay attention to in their diet?

• Maintain a balanced diet of meat and vegetables. If vegetarian, focus on consuming soy products to supplement protein.
• If possible, drink 300 mL of milk daily to avoid calcium deficiency.
• Eat plenty of fruits and vegetables.
• Avoid alcohol as much as possible.

Can patients with stress fractures still run?

Yes.

Patients with stress fractures can return to running, but three conditions must be met: first, wait until the acute phase (after pain and swelling subside); second, combine it with rehabilitation training and physical therapy; and third, follow a progressive running plan.

A progressive running plan refers to "walk to run," transitioning from walking to running while gradually increasing running time and distance. In the early stages of recovery, start by walking on a treadmill, then progress to brisk walking, and eventually slow jogging. Begin with 15 minutes of slow jogging every other day, increasing by 5 minutes per week, and then gradually increase the duration. Once you can comfortably and painlessly jog for 40 minutes, you can start increasing long-distance running by 10% weekly.

Any increase in running time or distance must be symptom-free. If pain or swelling occurs the next day, it indicates that the current intensity is too high. Rest for a few days, reduce the running volume, and gradually increase again after adaptation.

Does smoking affect the healing of stress fractures?

Yes ^[4].
Studies show that nicotine directly inhibits bone cell proliferation, reducing the maturity of fracture callus. Smokers have a 2–6 times higher risk of fractures than non-smokers, and smoking patients take 62% longer to heal compared to non-smokers.

PREVENTION

Can Stress Fractures Be Prevented?

Stress fractures can be prevented in daily life. Key preventive measures include:

• Individuals engaging in intense physical activity should master proper techniques and maintain correct posture. Wear appropriate gear, such as cushioned running shoes with soft silicone pads.
• Patients on long-term oral corticosteroid therapy should take osteoporosis-preventive medication and undergo regular bone density tests.
• Those with low bone mass or osteoporosis should consistently supplement with calcium and vitamin D, and follow doctor-recommended anti-osteoporosis treatments.
• Underweight individuals should moderately increase body weight to maintain a normal BMI level.