Facet Arthropathy: Stages, Symptoms & Treatment

Facet arthropathy is arthritis of the facet joints, the small paired joints at the back of the spine that link each vertebra to the next. As the smooth cartilage in these joints wears down, the joint space narrows, the bone thickens, and bone spurs (osteophytes) form around the edges. This can cause low back or neck pain and stiffness. When the enlarged joints narrow the space for the nerves, it can also cause leg or arm pain. It is most common in the lower back at L4-L5 and L5-S1. The illustration above shows normal facet joints beside arthritic ones.

The anatomy

Each vertebra has two small joints at the back, one on each side, called facet joints or zygapophyseal joints. In each one, the inferior articular process of the vertebra above meets the superior articular process of the vertebra below. Like a knee or a hip, each facet joint is lined with smooth cartilage and enclosed in a joint capsule with fluid inside. The facet joints guide movement and stop the vertebrae from slipping and twisting too far. Each joint has its own small nerves, the medial branches, which carry pain signals from it. For the full anatomy, see lumbar spine anatomy.

Grades

Radiologists often grade facet arthropathy on CT or MRI:

Grade	Joint space	Spurs and enlargement
0 (normal)	Normal, 2 to 4 mm	None
1 (mild)	Mildly narrowed	Small spurs, mild enlargement
2 (moderate)	Narrowed	Moderate spurs and enlargement, small erosions
3 (severe)	Very narrow or gone	Large spurs, marked enlargement, cysts

The severity on a scan often does not match the amount of pain.

Causes

• Age-related wear: most adults over 60 have some facet arthritis on imaging
• Disc degeneration: when a disc loses height, more weight shifts onto the facet joints behind it
• Repetitive strain: years of heavy lifting, twisting or back arching
• Excess body weight, which adds load to the joints
• Injury: a facet joint sprain or fracture from a fall or crash, which can speed up wear
• Spinal alignment: scoliosis, or a vertebra that has slipped
• Inflammatory arthritis, such as rheumatoid arthritis or ankylosing spondylitis (less common)

Symptoms

• Dull, aching low back pain, often on one or both sides of the spine
• Pain spreading into the buttock or back of the thigh, usually not below the knee
• Pain that is worse leaning backward, twisting or standing for a long time
• Relief when bending forward or sitting
• Stiffness, especially in the morning or after rest
• In the neck: neck pain spreading to the shoulder blade or the back of the head
• Leg or arm pain, numbness or tingling when enlarged joints and spurs pinch a nerve root

Diagnosis

The doctor checks posture and movement, and presses over the joints to find tender spots. Pain when leaning back and twisting suggests the facet joints. X-rays show joint narrowing and spurs. CT shows the bone changes best. MRI shows fluid in the joint, cysts, inflammation and any pinched nerves. Because many people have facet arthritis on a scan without pain, the most reliable test is a diagnostic block. A numbing medicine is injected into the joint or onto its medial branch nerves. If the pain goes away for a few hours, the facet joint is the likely source.

Treatment

• Activity changes: staying active while avoiding movements that trigger pain
• Physical therapy: core strength, hip and hamstring flexibility, posture and flexion-based exercises
• Weight control to reduce load on the joints
• Medicines: anti-inflammatory drugs and short courses of other pain medicine
• Facet joint injection: a steroid placed into the joint for short-term relief
• Radiofrequency ablation: heat is used to turn off the medial branch nerves that carry pain from the joint. Relief often lasts about 6 to 12 months or longer and can be repeated.
• Surgery: rarely needed for facet pain alone. When enlarged joints narrow the nerve openings, a foraminotomy or laminectomy can free the nerves. Fusion is considered for instability, such as a degenerative spondylolisthesis.

Recovery

A flare of facet joint pain often settles within a few weeks with activity changes, medicine and therapy. Because the arthritis is long-term, flares can return. A regular exercise program is the best way to reduce them. After radiofrequency ablation, most people return to normal activity within a day or two, and relief builds over 2 to 3 weeks.

Complications

• Chronic low back or neck pain
• Foraminal stenosis, when spurs and enlarged joints narrow the nerve opening
• Central spinal stenosis, together with a thickened ligament and a bulging disc
• Facet joint cysts (synovial cysts) that can press on a nerve root
• Degenerative slipping of one vertebra on another (anterolisthesis)

How facet arthropathy is shown in a personal injury case

Facet arthropathy appears in many spine imaging reports after car crashes and falls. Because it develops over years, the defense often argues that a plaintiff's pain comes from this pre-existing arthritis rather than the injury. The plaintiff's side may argue that the injury made a joint painful that caused no problems before, an aggravation of a pre-existing condition. Earlier imaging, medical records from before the incident, and diagnostic blocks that confirm the pain source all matter. A side-by-side illustration like the one above helps a jury see the difference between a normal joint and an arthritic one. For how these images are used at trial, see demonstrative evidence and medical legal illustration.