====== Facet Joint Arthropathy ======

[[Facet joint]] [[arthropathy]] is a degenerative condition affecting the zygapophyseal (facet) joints of the spine, often contributing to chronic axial pain, especially in the cervical and lumbar regions.

===== Pathophysiology =====

Facet joints are synovial joints prone to wear and tear due to repetitive mechanical stress and age-related degeneration. Arthropathy involves:
  * Cartilage degeneration
  * Subchondral bone sclerosis
  * Osteophyte formation
  * Joint space narrowing
  * Synovial inflammation

These changes lead to **nociceptive pain** from the richly innervated joint capsule and surrounding structures.

===== Clinical Presentation =====

  * Axial pain (neck or low back)
  * Worse with **extension**, **rotation**, **prolonged standing**
  * May mimic radiculopathy but without dermatomal distribution
  * Pain often improves with flexion or sitting

===== Diagnosis =====

=== Clinical Exam ===
  * Localized paraspinal tenderness
  * Pain reproduced with extension/rotation

=== Imaging ===
^ Modality ^ Findings ^
| **MRI** | Joint effusion, osteoarthritis signs, adjacent edema |
| **CT** | Bone detail: osteophytes, sclerosis, hypertrophy |
| **SPECT/CT** | Identifies metabolically active (painful) joints |

=== Diagnostic Injections ===
  * **Medial branch block** (MBB) – anesthetic near the medial branch nerves
  * **Intra-articular injection** – direct steroid/anesthetic into the facet joint
  * Positive response supports diagnosis

===== Management =====

=== Conservative ===
  * NSAIDs
  * Physical therapy (core strengthening, posture)
  * Activity modification

=== Interventional ===
  * **MBB** (diagnostic and therapeutic)
  * **Intra-articular steroid injection**
  * **Radiofrequency ablation (RFA)** – long-lasting denervation of medial branches

=== Surgical ===
  * Rarely needed
  * Consider **facet resection** or **spinal fusion** in unstable or refractory cases

===== Key Points =====

  * Common source of axial spinal pain in adults
  * Often underdiagnosed; imaging alone may be insufficient
  * SPECT/CT can identify active facet joint involvement
  * RFA provides long-term relief in selected patients