Avulsion Fracture treatment at the Physio Clinic Naas & Newbridge

Avulsion Fracture. Ross Allen is a former Ireland rugby International & County Football Player

Contact Naas Physio Clinic on: (045) 874 682 

Avulsion Fracture 

An Avulsion fracture takes place in cases where a small bone fragment is pulled away (avulsed) from the main body of the bone. Both ligaments & tendons attach to bones at certain landmarks & for this reason avulsion fractures are particularly commonplace in certain areas of the body such as the outside of the foot (at the head of the 5th metatarsal). A severe hamstring injury may also give rise to an avulsion fracture of the bone & this requires a lengthy rehabilitation process.

The fracture may be a result of a violent contraction of a muscle, which pulls on the tendon. The pull causes the piece of bone attached to the tendon to break away. A sudden twisting movement at the joint may cause an avulsion fracture which can accompany a ligament sprain such as occurs at the ankle.

Avulsion fractures can be due to an overuse injury as well. Repeated forceful movements over time may cause weakness at the tendon-bone or ligament–bone attachment. Avulsion injuries are more noted in the lower limbs as compared to upper limbs or spine.


Young athletes and avulsion fractures

Avulsion fractures are one of the rarer sporting injuries. They are seen more in the adolescent athletes aged between 11-17 years. With increased participation of youths in sports like soccer, running and tennis, the number of avulsion injuries has increased. Literature reports these injuries to be more common in boys than girls.

The skeleton of a teenager is quite different from an adult. There are two types of growth plates- epiphysis and apophysis, in a growing child. The epiphysis are plates found at the ends of long bones. They help the bones to grow in length. Whereas the apophysis are offshoots of the bones where the tendons and ligaments attach.

During the growing years these end plates (epiphysis) are structurally weak and liable to injury. More so in young athletes participating in sprinting, hurdle racing, football, tennis and skiing etc. These sports involve explosive and repeated actions that put excessive loads on the tendons and their attachment.

In young athletes the muscles and tendons are stronger than the surface of the bones where they attach. Thus, when these athletes perform a strong brisk muscle contraction the loads are passed through the tendon to the bone. The tendon can snap taking along a fragment of the apophysis with it causing an avulsion fracture.

Once these growth plates ossify and fuse with the rest of the bone, they are stronger than the musculotendinous unit attaching to it. Thus, avulsion fractures are less common in adults.

Interestingly the avulsion fractures are more common in the pelvis and hip as these growth plates fuse much later than the rest of the body.

Inflammation of the apophysis in young players (e.g. Osgood Schlatter’s disease) is often present prior to an avulsion fractures.

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Risk factors for avulsion fractures


  • More and more kids participating in explosive sports
  • Training not modified for younger athletes
  • Strong repeated eccentric contraction (lengthening and contracting at the same time)
  • Reduced muscle flexibility
  • Prior inflammation of the tendon insertion on bone (apophysitis). For example with Osgood-schlatter’s disease of the knee
  • Prior surgeries in elderly athletes
  • Specific sports such as football, running, and tennis


Avulsion fractures at the pelvis:

Avulsion fractures at the pelvis can occur at two locations- at the attachment of rectus femoris and sartorius in the front and at the attachment of hamstrings muscle to the ischial tuberosity behind.

The ilium (top part of pelvic bone) has two bony protuberances where the quadriceps muscles attach – the anterior superior iliac spine (ASIS) where the sartorius muscle inserts and anterior inferior iliac spine (AIIS). The rectus femoris originates from the AIIS. It is an important muscle in the front of the thigh. Along with three other muscles, it forms the quadriceps.

Avulsion fractures of the pelvis, are seen in adolescents in the age group of 14 to 17 years. The injury is associated with sports having violent “kick in air” action. The contraction of these muscles as they elongate over the hip and knee while running or kicking forcefully is the main cause.

In case of rectus femoris or sartorius involvement, there is pain in the groin. Resisted hip flexion elicits muscle weakness. The athlete puts less weight on the affected side while walking.

In case of hamstrings involvement, there is pain and tenderness in buttock, especially on sitting. There is weakness in the hamstring muscle and the athlete finds it difficult to walk or run.

Kids playing soccer are more prone to hamstring avulsion injury as compared to quadriceps avulsion injury. The incidence of pubic symphysis avulsion due to rectus abdominis contraction is even rarer.

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treatment of arthritis at Naas Physio Clinic

Avulsion fractures at the knee:

Segond fracture is the most well known avulsion fracture at the knee. It is the fracture of the upper part of shin bone (tibia) just below the tibial plateaus. The implicating movement is an outward movement of the knee with the leg fixed in internal rotation. This action exerts a pull on the anterolateral ligament of the knee resulting in the avulsion fracture. In over 90% of the cases it is associated with injuries to the anterior cruciate ligament and the medial meniscus. It is also associated with avulsion fracture of the proximal fibula. The fibula is the slender bone present laterally to the shin bone in the leg where the hamstring inserts. Pain and tenderness is usually present on the outer side of the knee alongside a decreased range of motion. The patient might limp while walking.


Tibial tuberosity avulsion fracturesoccurs as a result of strong eccentric contraction of the quadriceps muscle. The tibial tuberosity is the apophysis present in the proximal part of the shin bone (tibia). It is a bony protrusion felt just below the kneecap. The quadriceps tendon inserts on it. When a young athlete, lands after jumping or skiing, he bends his knees to cushion the impact. The abrupt jump landing causes quadriceps to contract eccentrically, creating a tension on its tendon. There is pain, swelling and tenderness below the kneecap. Resisted extension of the knee is painful. The athlete is unable to bear weight on the affected side.

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Avulsion fracture at the ankle

Tillaux avulsion fractureis a rare avulsion fracture at the ankle. It is the avulsion fracture of the bony protuberance (tubercle) present at the lower end of tibia (shin bone) due to the pull of the ligament running between the two shin bones (the anteroinferior tibiofibular ligament). Forced external rotation of the foot or inward rotation of the leg on the fixed foot severely stretches this ligament. Since the fracture is near the weight-bearing surface, degenerative arthritis is a major complication. Also, as the growth plate is involved, growth disturbances may occur.


How to diagnose an avulsion fracture?

An avulsion fracture must be suspected when a young athlete comes with a sporting injury in the lower limb. The mechanism of injury, an audible pop, localised pain and tenderness accompanied by swelling should prompt one to think along the lines of an avulsion fracture. Muscle weakness and difficulty in weight bearing are other telltale signs.

Usually plain x-rays are able to pick up avulsion fractures around the pelvis and knee. They will show a small fragment of bone detached from the main bone. For knee or ankle injuries, special views like oblique or axial projections may be needed. Avulsion fractures are easily confused with an unfused apophysis or epiphysis. An image of the contralateral joint helps to differentiate. This may be needed if the fracture is undisplaced. CT, MRI or ultrasound help to diagnose undisplaced avulsion fractures. Ultrasound is especially useful in determining if the union is bony or fibro-osseous. Sciatic nerve entrapment is common with the healing of avulsion fractures of the ischial tuberosity. This is usually picked up on an MRI or ultrasound.

Complications of avulsion fractures

  • Early arthritic changes
  • Growth plate disturbances
  • Malunion or delayed union
  • Nerve entrapment

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How are avulsion fractures treated?

Undisplaced fractures are treated by keeping the affected leg immobilised for 2-3 weeks in a plaster cast. If the avulsed segment is displaced by more than 2mm, reduction with screws and nails is the treatment. Return to sports is possible within 6-12 weeks of injury in both cases.


Physiotherapy after avulsion injuries

Physiotherapy is extremely important for early weight bearing and return to play following avulsion injuries. The initial goal following an avulsion fracture is to minimise pain & swelling. This requires the application of ice, compression & sufficient rest to allow bone healing. If weight-bearing exercise is initiated too early in the process then this can delay healing significantly & delay return to activity.

During the immobilisation phase isometrics muscle setting exercises are encouraged to maintain and improve muscle strength. Once the cast is removed active range of motion exercises are introduced. Once the fracture site has healed, then your physio will introduce a graded exercise programme. The first goal will be to restore normal range of motion as soon as possible. Stretching and flexibility exercises help to restore normal joint range and muscle length. Then the next goal is to increase strength & ensure that the strength is restored to pre-injury levels so as to prevent further injury to the area involved. Progressive resisted exercises for the entire lower limb muscles are incorporated. Gradual progression to full weight-bearing while walking is also started simultaneously.

Eccentric strengthening exercises and balance training are vital elements of rehabilitation. Eccentric strengthening helps to improve power and flexibility in young athletes. Prior to the phase of skeletal maturity, the young athlete undergoes rapid neural proliferation and heightened CNS maturation. Introducing moderate amounts of resistance training, especially the eccentric variety gives the ideal stimulus to the ongoing neural proliferation.

Proprioceptive training on unstable surfaces like the wobble board are also particularly useful for balance training. They can be made challenging by reducing the base of support and closing your eyes. Both of these exercises place positive stimulus on the growing nervous system, which improves power and reaction time.

Moderate intensity plyometric drills improve the speed, strength and power of a muscle. They also help to increase tendon & bone density and decrease the risk of future fractures. These must  begin after adequate strength and flexibility is achieved in the muscles. Sports specific drills like running and agility training begin on the field in the final stages of rehabilitation.

With more and more children and adolescents becoming involved in intense exercise and competitive sports it is extremely important to match the exercise intensity to the child’s age. Attention towards training and conditioning to optimise performance is vital. As the bones are still growing exercise which is too intense can damage the growth plates. At the same time training should encourage athletic development and be as consistent as possible to avoid sudden overload, which tends to create an environment where injuries such as avulsion fractures may occur.

Most avulsion fractures respond very well to physiotherapy treatment & only severe cases require surgical intervention.

To find out more, contact Naas Physio Clinic on:
(045) 874 682

or email us at info@physioclinic.ie

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