Share

Stress Fracture of the Pars Interarticularis

What is a stress fracture?

A stress fracture is a bony defect through the back of the vertebrae in the area where the vertebrae adjoins the adjacent vertebrae. This area is known as the ‘pars’.

Why does it happen?

Most stress fractures occur due to either a single incident of extension injury (arching) or repetitious extension especially  combined  with  rotation  e.g.  fast  bowlers  or  landing  poorly  from  a  height.  The  incident  results  in excessive, unusual or asymmetrical loading onto the pars that fractures the bone and creates a defect in the pars. Pars defects may be classified as a ‘fresh’ injury or ‘old’ injury.

So if it’s a fracture should I be immobilized in plaster like if I break my arm?

The role of bracing is controversial for these injuries, even the specialists can’t agree on this one. It will depend on how recent your injury is. If there is some chance of bony healing then this may be the preferred option. However, sometimes immobilisation does not heal the fracture.

So how do I get better?

If the pars defect is fresh, then you must rest from the sport or activity to allow a chance for bony union to occur at the pars. Fresh and old pars defects need a program of lumbar stabilisation, core strength and stability exercises. Technique correction should be addressed in particular for fast bowlers who have a ‘mixed technique’.

Will I need surgery for my pars injury?

No. Active rehabilitation to retrain you muscular system to support the spine is the management of choice.

Once I have fractured my pars will it always be a  problem?

Not necessarily. The fracture may or may not heal completely. If bony healing does not occur initially then it never will, however, this does not mean that you will always have symptoms related to that fracture. However, once you have had a first attack of low back pain, your body changes the way it supports the spine. Subsequent back pain can then occur more easily (but not necessarily the pars region). This is due to the fact that your body has lost its protective mechanisms for the spine. Physioal therapists can train you to rehabilitate your muscular system to protect your spine.

Do I need to get a scan to show my pars injury?

X-rays, bone scans and CT Scans are all useful in assessing the degree of damage. They may also assist in grading the ‘age’ of the fracture in order to make management decisions.

So should I sit-ups to strengthen my back again?

No. Sit-ups can make the problem worse. During sit-up activity the hip flexors are maximally loaded which can result in more stress being placed on the mid lumbar facet joints and also the pars. Abdominal muscles support the back but sit-ups are not the way to work them. It is best to get a physical therapist to guide you through exercises appropriate to your problem.

When will I be better?

This can be variable and depends on the type and stage of the fracture. Whilst the acute pain may settle fairly quickly, prevention of re-injury may take much longer.

Subscribe to our mailing list