The facet joints are the joints between the bones (the 'vertebrae') in the spine. The role of these joints is to allow the back to bend and twist, but at the same time to limit this movement within certain parameters. The two (left and right) facet joints are towards the back of the vertebrae with a vertebral disc towards the front of the joint.
Facet joint syndrome occurs where there is some degeneration in the facet joints. Degeneration of these joints is a normal part of ageing and so the condition is especially common in people 40-70 years old (men and women equally), although people with arthritis or who have had a spinal injury are more prone to the condition.
Depending on the joints affected, facet joint syndrome is described as 'cervical' where it affects the neck, 'thoracic' where it affects the middle of the back and 'lumbar' where it affects the lower back.
Facet joint syndrome is sometimes also referred to as 'facet joint pain', 'facet joint arthropathy' or 'facet joint sprain'. It is also occasionally referred to as 'zygapophyseal joint syndrome' or 'apophyseal joint syndrome' or simply 'Z-joint syndrome' as these are other medical terms for the facet joints.
It is estimated that facet joint syndrome is implicated in 15-50% of patients with chronic lower back pain.
The primary cause of facet joint syndrome is the ageing process – as we get older cartilage in all of the joints of the body thins and is worn away and this is only exacerbated by injury (either individual trauma or repetitive movement), bad posture and being overweight (which places greater strain on the joints).
Other conditions affecting the spine can also accelerate the development of facet joint syndrome, such as spondylolisthesis, spondylolysis and degenerative disc disease.
When facet joint syndrome develops, it can be due either to stiffening of the joint ('hypomobility') or loosening ('hypermobility'). The direct causes of these are, for hypomobility…
- Arthritis in the joint.
- Bone spur/s ('osteophytes').
- Damage to the joint capsule.
- Onset of muscle spasms.
- Locking of joint.
For hypermobility, the causes are generally…
- Joint conditions such as rheumatoid arthritis.
- Ligament injury causing overstretching of ligaments.
- Trauma to the joint, for example fracture or dislocation.
Although facet joint syndrome may be present without any symptoms, the primary symptom is pain in the area of the affected joint/s i.e.…
Cervical facet joint syndrome
- Pain in the neck (sometimes accompanied by pain in the shoulder/s, upper arm/s).
- Torticollis - a 'wry' neck where the neck is twisted or tilted to one side.
- Decreased movement of the neck, stiffness (due to a 'locked' facet joint).
- Tenderness of the area to touch.
Lumbar facet joint syndrome
- Dull ache in lower back (which may spread to the buttocks, hips and thighs and sometimes knees).
- Tenderness of the area to touch.
- Decreased movement of the lower back, stiffness.
- Difficulty with some movements e.g. getting out of a chair, standing upright.
- Pain when standing or sitting for long periods.
- Pain that is generally worse in the morning, improving through the day.
- Grinding or grating sensation in the joints when moving ('crepitus').
Tests / Diagnosis
Diagnosis of possible facet joint syndrome begins with a review of medical history and symptoms and an evaluation of body posture and 'palpating' (touching) the affected area to check for tenderness and muscle reflexes (this is to check that the nerves are functioning correctly) and range of motion tests.
Generally, imaging is not of much use in the diagnosis of facet pain. Rather, diagnostic medial branch blocks are considered most useful.
In some case an MRI scan may be recommended.