Facet Joint Pain Does Not Cause Knee Pain
No, facet joint pain does not cause referred pain to the knee. The evidence clearly demonstrates that these are anatomically and clinically distinct entities with no established pain referral pattern between lumbar facet joints and the knee.
Anatomical Pain Patterns Are Site-Specific
The available evidence shows that osteoarthritis affects specific target joints with characteristic pain distributions that do not cross between spinal facet joints and peripheral joints like the knee:
- Hip OA produces groin pain that may radiate to the buttock or thigh, but not to the knee as a primary referral pattern 1
- Knee OA causes localized knee pain that is mechanical in nature and does not originate from spinal structures 2, 3
- Facet joint OA affects the spine with localized spinal symptoms, not peripheral joint pain 2
The Concept of Generalized OA Explains Multi-Joint Involvement
Your elderly patient with severe hand OA and knee pain likely has generalized osteoarthritis, not referred pain from facet joints:
- Patients with polyarticular hand OA are at significantly increased risk of developing knee OA and hip OA as part of a generalized OA pattern 4
- This represents a systemic predisposition to OA at multiple sites, not a pain referral phenomenon 4
- The hand, knee, hip, and spine are all common target sites for OA that can coexist independently 4, 2
Clinical Pitfall: Distinguishing Coexistent Conditions from Referred Pain
A critical error would be attributing knee pain to facet joint disease when the patient actually has:
- Independent knee OA that should be diagnosed based on knee-specific symptoms: mechanical pain, stiffness, crepitus, and joint-line tenderness 5
- Poor correlation between radiographic severity and symptoms means both conditions can exist with varying degrees of clinical manifestation 1
- The diagnosis of knee OA can be made clinically in at-risk patients (over 40 years) with typical symptoms without requiring imaging 1, 6
Practical Diagnostic Approach
For your patient, evaluate each joint independently:
- Assess the knee directly for signs of OA: joint-line tenderness, crepitus, effusion, bony enlargement, and reduced range of motion 5
- Examine for hand OA features: Heberden nodes, Bouchard nodes, and involvement of characteristic target joints (DIPJs, PIPJs, thumb base) 4
- Consider that generalized OA is the unifying diagnosis rather than a referred pain mechanism 4
Management Implications
Treat each affected joint site according to site-specific guidelines:
- For knee OA: strongly recommend exercise programs and weight loss if overweight 4
- For hand OA: provide joint protection techniques, assistive devices, and consider topical NSAIDs or capsaicin 4
- Recognize that functional impairment from hand OA can be as severe as rheumatoid arthritis and requires careful assessment 4
The presence of multiple joint involvement indicates a worse prognosis, as risk factors for OA progression include concurrent OA in multiple joints (generalized disease) 7.