Overview
An ankle avulsion fracture occurs when a small fragment of bone is pulled away from the main bone by a ligament or tendon during a sudden twist, pull, or impact. Unlike typical ankle sprains, where ligaments stretch or tear, an avulsion fracture involves both soft-tissue damage and a small bone fracture. It often happens at the ends of the tibia, fibula, or talus, most commonly near ligament attachments on the outer ankle. While usually less severe than major ankle fractures, prompt diagnosis and proper treatment are crucial to ensure full healing and prevent chronic instability.
Commonly Associated With
- Severe ankle sprains or inversion injuries
- Sudden twisting or rolling of the ankle during sports
- Direct trauma, falls, or landing awkwardly from a jump
- High-impact activities such as soccer, basketball, or gymnastics
- Weakened bones (osteoporosis) increasing fracture risk
Causes Of Ankle Avulsion Fracture
An ankle avulsion fracture is caused by forceful traction of a ligament or tendon on its bony attachment site, pulling off a small bone fragment. Typical scenarios include:
- A rapid twist or roll of the foot, causing the ligament to pull part of the bone away.
- Sudden directional changes during running or jumping.
- Direct trauma to the ankle joint.
- Improper landing from a jump or fall, causing excessive ligament tension.
Symptoms Of Ankle Avulsion Fracture
- Sudden, sharp pain at the site of injury
- Rapid swelling and bruising around the ankle
- Tenderness over the bone rather than just soft tissue
- Difficulty bearing weight or walking
- Reduced ankle motion and stiffness
- Possible deformity or visible bump in more severe cases
Note: Because symptoms can resemble a severe ankle sprain, imaging is often necessary for diagnosis.
Exams & Tests
- Physical Examination: Checks for tenderness directly over the bone, swelling, bruising, and joint stability.
- X-ray: The primary diagnostic tool to detect a bone fragment near the ligament attachment site.
- MRI or Ultrasound: May be ordered to assess associated ligament or tendon damage.
- CT Scan: Rarely needed but may be used to evaluate complex fractures or pre-surgical planning.
Treatment Of Ankle Avulsion Fracture
Treatment depends on the size and displacement of the bone fragment and overall joint stability:
- R.I.C.E. Protocol: Rest, Ice, Compression, Elevation in the acute phase to control swelling and pain.
- Immobilization: Most cases require a walking boot, cast, or splint for 4–6 weeks to allow bone healing.
- Weight-Bearing: Gradual return to weight-bearing as tolerated, often guided by pain and X-ray results.
- Physical Therapy: Essential after immobilization to restore strength, balance, and range of motion.
- Surgery: Rare but indicated if the bone fragment is large, significantly displaced, or if the joint is unstable. Surgical fixation reattaches the fragment and stabilizes the ankle.
Source
- American Academy of Orthopaedic Surgeons (AAOS)
- Mayo Clinic – “Ankle Fractures”
- National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS)
