Facet arthropathy is a common condition affecting the small joints along the back of the spine, essentially representing a form of spinal arthritis. This progressive, degenerative disorder involves the wearing down of joint structures, often developing over many years. It is a frequent source of chronic back or neck pain. The condition’s prevalence increases significantly with age, making it one of the most common causes of chronic spinal discomfort.
The Anatomy and Function of Facet Joints
The spine is composed of stacked bones called vertebrae, and the facet joints connect these bones at each level. These joints, also known as zygapophyseal joints, are positioned on the posterior side of the vertebral column. Each spinal segment has two facet joints, forming a three-joint complex with the large disc in the front.
Facet joints are synovial joints, surrounded by a capsule that produces lubricating synovial fluid and coated with smooth cartilage. This structure allows the vertebrae to glide over one another, enabling the spine to bend, twist, and extend. The joints provide stability to the spine and prevent excessive motion, particularly limiting hyperextension and hyperflexion.
Understanding Facet Arthropathy: Degeneration and Causes
Facet arthropathy occurs when the specialized joint structure begins to break down, leading to painful inflammation and irritation. This degenerative process is similar to osteoarthritis in other joints. The protective cartilage that cushions the ends of the bones wears away over time, causing the bones to rub against each other.
This friction triggers an inflammatory response and often leads to the formation of osteophytes, commonly known as bone spurs. The joint capsule may also become thickened and inflamed, restricting smooth movement. Aging is the primary factor contributing to this wear and tear, as lubricating fluid thins and cartilage naturally degenerates.
Repetitive stress, spinal trauma, or injuries can accelerate the arthritic process. Underlying conditions like degenerative disc disease also play a significant role, as a loss of disc height shifts stress onto the facet joints. Other contributing factors include obesity, poor posture, and a family history of degenerative arthritis.
Recognising the Signs: Symptoms and Pain Patterns
The symptoms of facet arthropathy are typically localized to the affected joint, presenting as a dull ache or stiffness in the neck or back. The pain is often worse in the morning or after periods of inactivity. A distinguishing feature is that the pain tends to worsen with movements that compress the joints, specifically bending backward (extension) or twisting sideways toward the affected side.
Conversely, activities that take weight off the joints, such as sitting or bending slightly forward, often provide relief. The discomfort can be highly localized, with tenderness directly over the inflamed joint. While the primary pain is in the spine, it can be referred to other areas.
For facet arthropathy in the lower back (lumbar spine), pain commonly radiates into the buttocks, groin, hips, or the back of the thighs, but it typically does not extend below the knee. In the neck (cervical spine), the pain may spread to the back of the head, ear, or shoulder. This pattern of pain referral helps distinguish facet joint problems from nerve root compression, such as sciatica.
Diagnosis and Management Options
Diagnosis begins with a physical examination and a detailed medical history, focusing on the specific characteristics of the pain. Imaging tests (X-rays, CT scans, and MRI scans) can show physical changes consistent with arthritis, such as joint narrowing and bone spur formation. However, imaging alone is not always conclusive, as many people without symptoms may show signs of arthropathy on a scan.
The most definitive diagnostic tool is a diagnostic injection, specifically a medial branch block. This procedure involves injecting a local anesthetic near the medial branch nerves that transmit pain signals from the facet joint. If the patient experiences significant, temporary pain relief, it confirms the facet joint as the source.
Management typically starts with conservative, non-surgical approaches aimed at reducing pain and improving function. Anti-inflammatory medications (NSAIDs) help reduce inflammation, and physical therapy focuses on strengthening core muscles and improving posture.
When conservative methods prove insufficient, interventional pain procedures are used. Facet joint injections deliver a corticosteroid directly into the joint for longer-lasting relief. If the diagnostic nerve block was successful, radiofrequency ablation (RFA) may be performed, which uses radio waves to temporarily disable the medial branch nerves, preventing pain signals for an extended period.