Avulsion Fractures: Causes, Symptoms, Treatment & Physiotherapy

Reviewed by the Physiotherapy Team at Waterloo Sports Medicine Centre  

An avulsion fracture occurs when a tendon or ligament pulls hard enough to break off a small piece of bone. Learn about avulsion fracture symptoms, causes, diagnosis, treatment, healing time, and how physiotherapy can help you safely return to sport and everyday activities. 

What Is an Avulsion Fracture? 

An avulsion fracture occurs when a tendon or ligament attached to a bone is subjected to a sudden, forceful pull, causing a small piece of bone to break away from the main bone. 

Unlike a typical fracture caused by a direct blow, an avulsion fracture is caused by the force transmitted through a tendon or ligament attachment. 

These injuries can occur anywhere in the body, but they are particularly common around the hip and pelvis in young athletes.

Common locations include the: 

• Ischial tuberosity, where the hamstrings attach  

• Anterior inferior iliac spine (AIIS), where the rectus femoris attaches  

• Anterior superior iliac spine (ASIS), where the sartorius attaches  

• Lesser trochanter, where the iliopsoas attaches  

Pelvic avulsion fractures are particularly associated with adolescent athletes because the growth plates at tendon and muscle attachment sites can be vulnerable to sudden, powerful forces.  

What Causes an Avulsion Fracture? 

Avulsion fractures commonly occur during sudden, explosive movements that create a powerful muscle contraction. 

Common causes include: 

• Sprinting  

• Jumping  

• Kicking  

• Sudden changes in direction  

• Explosive acceleration  

• Forceful stretching  

• Contact sports  

• Falls or other traumatic injuries  

Sports such as soccer, hockey, basketball, football, track and field, and gymnastics can place significant stress on muscle-tendon attachments. 

Why Are Young Athletes at Risk? 

In adolescents, bones are still developing and certain areas where tendons attach to bone contain growth plates (apophyses). During periods of rapid growth, these areas may be more vulnerable to force than the surrounding muscle-tendon unit. 

As a result, a powerful muscle contraction can sometimes pull a piece of bone away rather than simply causing a muscle or tendon injury. 

What Are the Symptoms of an Avulsion Fracture? 

• Sudden pain at the site of injury  

• A popping or snapping sensation  

• Swelling  

• Bruising  

• Localized tenderness  

• Pain with muscle contraction  

• Pain with stretching  

• Weakness  

• Difficulty walking or running  

• Difficulty participating in sports  

  
  

How Is an Avulsion Fracture Diagnosed? 

Diagnosis begins with a detailed history and physical examination. 

Your healthcare provider or physiotherapist may ask: 

• How the injury occurred  

• What movement caused the pain  

• Whether you felt a pop  

• Where the pain is located  

• Whether you can walk or bear weight  

• Whether certain movements reproduce your symptoms  

  
  

X-rays 

X-rays are commonly used to identify the avulsed piece of bone and determine its position. 

They can help determine: 

• The location of the fracture  

• The size of the bone fragment  

• How far the fragment has moved  

• Whether there are other fractures  

Additional imaging, such as an MRI or CT scan, may be considered when the diagnosis is unclear or when more information about the surrounding muscles, tendons, or fracture is required. 

Conservative Treatment 

An avulsion fracture does not always need surgery. Non-surgical treatment may include: 

• Relative rest  

• Temporary activity modification  

• Protected weight-bearing  

• Crutches when necessary  

• Pain management  

• Gradual rehabilitation  

When Might Surgery Be Considered? 

Surgery may be considered when: 

• The bone fragment is significantly displaced  

• The fracture is unstable  

• The fracture involves an important joint surface  

• Symptoms persist despite appropriate conservative treatment  

• A symptomatic non-union develops  

• The patient's sport or functional demands require consideration of surgical repair  

How Can Physiotherapy Help? 

Physiotherapy is an important part of recovery after an avulsion fracture, whether the injury is treated conservatively or surgically.  Your physiotherapist will work within the restrictions provided by your physician or orthopedic surgeon. 

1. Protecting the Injury 

Early rehabilitation focuses on protecting the healing bone while maintaining as much safe movement as possible. 

Your physiotherapist may help you determine: 

• How much weight you can put through the affected limb  

• Which movements should temporarily be avoided  

• When to use crutches  

• How to modify daily activities  

• When it is safe to progress exercise  

2. Restoring Mobility 

Once the injury is sufficiently stable, your physiotherapist can gradually restore: 

• Joint range of motion  

• Muscle flexibility  

• Normal movement patterns  

• Functional mobility  

The timing is individualized because aggressive stretching or strengthening too early can place excessive stress on the healing attachment. 

3. Rebuilding Strength 

Muscles surrounding the injured area may become weaker during recovery. 

Rehabilitation can progressively target: 

• The injured muscle group  

• Hip and core strength  

• Lower-limb strength  

• Balance and coordination  

• Sport-specific muscle capacity  

Exercise intensity is gradually increased as the bone and surrounding tissues become more tolerant of load. 

4. Returning to Running and Sport 

For athletes, rehabilitation eventually progresses from basic strengthening to more demanding activities. 

Depending on the injury, this may include: 

Strength → jogging → running → sprinting → jumping → cutting → sport-specific drills → full participation 

How Long Does an Avulsion Fracture Take to Heal? 

Healing time varies considerably depending on the location, size, displacement, age of the patient, and treatment approach. 

Many uncomplicated avulsion fractures can heal with conservative treatment over several weeks to a few months, but return to sport usually takes longer than basic bone healing. For adolescent pelvic avulsion fractures, return to sports may require several months of progressive rehabilitation. More significant injuries, surgical repairs, or fractures with delayed healing may take longer. 

It is important to remember: 

Bone healing and full functional recovery are not necessarily the same thing. 

Even after the fracture has healed, you may still need rehabilitation to restore strength, flexibility, power, and confidence. 

Can You Prevent an Avulsion Fracture? 

Not every avulsion fracture can be prevented, but athletes can reduce their risk by preparing their bodies for the demands of their sport. Helpful strategies include: 

• Gradually increasing training volume  

• Avoiding sudden increases in sprinting or jumping  

• Maintaining adequate strength  

• Including appropriate warm-ups  

• Allowing sufficient recovery between intense sessions  

• Avoiding training through significant pain  

• Maintaining overall physical conditioning  

This is particularly important for adolescent athletes involved in year-round or high-volume sports training. 

Looking for Avulsion Fracture Rehabilitation in Waterloo? 

At Waterloo Sports Medicine Centre, our physiotherapists can help guide your rehabilitation following an avulsion fracture, working alongside your physician or orthopedic team when appropriate.