Definition
Axial low back pain arising from the lumbar zygapophyseal joints, usually from degeneration.
Anatomy
- Each joint is supplied by the medial branches of the dorsal rami at the same level and the level above
- The L4 to L5 facet is supplied by the L3 and L4 medial branches
Clinical Features
- Axial back pain, worse on extension and rotation, eased by flexion
- Referred pain to the buttock and thigh, rarely below the knee
- Paraspinal tenderness and no neurological deficit
Investigations
- Imaging correlates poorly with pain
- Diagnosis by controlled medial branch blocks. Dual comparative blocks reduce false positives
- MRI to exclude other causes
Management
- Conservative care. Physiotherapy, analgesia and activity modification
- Intra-articular steroid injection. Limited evidence
- Medial branch radiofrequency ablation. For patients with a positive block. Relief lasts months and may be repeated
Reviewed by Professor Phong Tran, Head of Orthopaedic Surgery, Western Health. Last updated 21 October 2026.