What is Facet Joint Arthropathy?
Facet joint arthropathy is osteoarthritis of the facet joints—the only true synovial joints between adjacent vertebral levels in the spine—which is widely prevalent in older adults and represents a common cause of chronic back and neck pain. 1
Anatomical and Pathophysiological Features
Facet joints are located in the posterior aspect of the vertebral column and function as true synovial joints with cartilage, synovial fluid, and a joint capsule. 1
The condition represents a failure of the whole joint structure, not simply cartilage degeneration, consistent with modern concepts of osteoarthritis as a disease affecting all joint components. 1
Facet joint arthropathy encompasses various inflammatory and degenerative features including joint effusion, bone marrow edema, soft tissue edema, cartilage loss, and osteophyte formation. 2, 3
Clinical Prevalence and Significance
Facet-mediated pain accounts for approximately 31% of chronic lumbar pain syndromes, 42% of thoracic pain syndromes, and 55% of cervical pain syndromes. 2
Among patients with degenerative lumbar disease, facet-mediated low back pain is the cause of chronic pain in 9-42% of cases. 4, 5
The prevalence of facet-mediated pain increases with age, suggesting facet joint arthropathy plays a particularly important role in older adults with spinal pain. 1
Pain Referral Patterns
Lower lumbar facet joints (L4-5, L5-S1) can refer pain to the groin and deep posterior thigh. 4
Upper lumbar facet joints can produce pain in the flank, hip, and upper lateral thigh. 4
Pain referred below the knee is highly questionable and should prompt consideration of alternative diagnoses. 4
No physical examination findings or radiographic features consistently correlate with facet-mediated pain, making clinical diagnosis challenging without diagnostic blocks. 4, 5
Common Facet Joint Disorders
Degenerative disorders include osteoarthritis, hypertrophied superior articular process, and facet joint cysts. 2
Inflammatory conditions such as septic arthritis, ankylosing spondylitis, and gout can affect facet joints. 4, 2
Traumatic dislocations and whiplash injuries may involve facet joints. 2
A critical caveat: high degrees of morphological change on imaging do not always correlate with pain, emphasizing the disconnect between radiographic findings and clinical symptoms. 2
Diagnostic Challenges
Facet joint arthropathy frequently overlaps clinically with other spinal pathology, particularly degenerative disc disease and radiculopathy, making accurate diagnosis crucial for appropriate management. 6
Inflammatory features such as facet joint effusion, bone marrow edema, and soft tissue edema are commonly present on MRI but are underreported in routine radiology reports, with sensitivity ranging from only 6-22%. 3
The diagnosis of facet-mediated pain relies on appropriately performed diagnostic facet blocks using the double-block technique with 80% pain relief threshold, as this is the most reliable diagnostic method. 4, 5