Facet Joint Syndrome
This is one of the possible diagnoses in people with low back pain.
It is often not possible to pin down the exact contribution of these joints to a person’s pain but they are known to be an important pain source.
The facet joints
The facet joints (technically called the zygapophysial joints) are located at the back (posterior) of the spine. They perform an important locking mechanism between adjoining lumbar bones. They prevent rotation and forward sliding of one lumbar vertebra on another. Preventing rotation is designed to protect the discs from excessive rotation. Preventing forward slide stops the bones moving forward under the weight of the body.
There are two facet joints at each level, and they combine with the disc space joint to create a three-joint complex. The facet joint is made up of two relatively flat bony surfaces lined with articular cartilage, surrounded and supported by a fibrous capsule which produces small amounts of synovial fluid.
The articular cartilage and synovial fluid allow the joints to move with little friction, and they can resist the forces on the spine comfortably. However, changes can occur in these joints with time and injury, leading in some cases to pain.
Facet joint pain
Research studies have used diagnostic injections into these joints to see if they are sources of pain. If the painkilling injection into the joint reduces or abolishes the pain which the patient is complaining of, the joint can be considered at least partly to be responsible for the pain.
Facet joint pain is present in 40% of the elderly population, and 10-15% of younger workers who are injured. Even this smaller figure adds up to a large number of individuals.
Injury changes in the facet joints
No particular changes in the facet joints has been directly linked to pain, but there are clues to what the underlying causes might be.
Forced extension (backward bending) of the spine seems to one of the damaging processes. This causes the lower half of the joint to rotate markedly, pulling away some of the attachment of the capsule at the edges of the joint. Injuries involving rotation can cause small factures from impact of one side of the joint against the other, or pull away the capsule again. These kind of changes have been observed in people with know injuries, and are not found if there is no history of trauma.
Facet joint osteoarthritis
Osteoarthritis (degenerative arthritis) can cause breakdown of the cartilage which lines the facet joints. This lack of the cartilage could cause pain as well as loss of motion and stiffness. This kind of pain is often worst in the morning, loosening up as movement lubricates and eases the joints. As the joint is loaded longer as the day goes on, the pain may again increase.
Treatments for facet joint arthritis
There are no reliably effective treatments for this problem, but conservative treatments concentrating on keeping ranges of motion in the back may be helpful in relieving the pain.
Stretching exercises for the hamstring muscles, the back and hip joints, may be useful over the longer term. Manipulative treatment may also be helpful but the evidence for this is not good.
Hydrotherapy may be helpful since the joints have much of the load removed in the water and and can move further without generating pain. However, this is seldom useful in isolation, and the person will need to keep up swimming and water exercises, or perform similar movements regularly in the air.
Other treatments include painkillers and anti-inflammatory drugs, and modification of activities. This last idea can be very useful, as avoiding activities which significantly aggravate pain can allow more control over the syndrome. Surgery is recognized not to be helpful
Facet joint injections
This technique can be used for treatment and for diagnosis. See Injections for back and leg pain for more information.