Hip Instability is NOT Caused by Lumbar Facet Joints or Herniated Discs
No, hip instability cannot be caused by low back facet joint arthritis or herniated discs—these are distinct anatomical conditions with separate pathophysiologies. Hip instability arises from intra-articular hip pathology (capsular laxity, labral tears, ligamentum teres pathology, acetabular dysplasia, or femoroacetabular impingement), not from spinal structures 1.
Why This Distinction Matters
The 2020 International Hip-Related Pain Research Network consensus guidelines explicitly recommend that clinicians perform comprehensive screening of the spine and pelvis when evaluating hip-related pain precisely because these are separate conditions that can coexist or be confused 1. The guidelines emphasize that diagnosis should never rely on imaging alone but must integrate symptoms and clinical signs—this is critical because:
- Hip instability presents with hip-specific symptoms (pain with rotation, feeling of giving way, apprehension with certain movements)
- Lumbar pathology presents with back pain, radicular symptoms, or referred pain patterns
The Evidence on Spinal-Hip Relationships
While lumbar pathology does NOT cause hip instability, there are important biomechanical relationships to understand:
Lumbar Stiffness Affects Hip Mechanics (Not Instability)
Research shows that multilevel lumbar degenerative disc disease creates lumbar stiffness (reduced lordosis change <20°), which forces greater hip motion to compensate during functional movements 2. This increases hip dependence and raises the risk of total hip arthroplasty instability post-operatively—but this is about surgical complications, not primary hip instability.
Chronic Radiculopathy May Correlate with Hip OA
One study found that prolonged lumbar disc herniation symptoms (>24 months with motor deficit) correlated with higher rates of ipsilateral hip osteoarthritis 3. However, this represents secondary joint degeneration from altered biomechanics and gait patterns, not hip instability. The mechanism involves:
- Altered weight-bearing patterns from radicular pain
- Muscle weakness affecting gait
- Chronic compensatory movement strategies
Facet Joint Pathology Indicates Spinal Instability
Facet joint dilatation is a radiological marker of vertebral segmental microinstability—a spinal condition associated with Modic changes and disc degeneration 4. This has no direct causative relationship with hip instability.
Clinical Approach to Avoid Diagnostic Confusion
When evaluating a patient with hip symptoms and known lumbar pathology:
Use the FADIR test: A negative flexion-adduction-internal rotation test helps rule out hip disease 1
Obtain appropriate imaging:
- AP pelvis and lateral femoral head-neck radiographs for hip morphology
- MRI/MRA if intra-articular pathology suspected (labrum, cartilage, ligamentum teres)
- Never diagnose based on imaging alone 1
Look for true hip instability features 5, 6:
- Capsular laxity on examination
- History of subluxation or apprehension
- Generalized ligamentous laxity
- Positive traction views showing excessive joint distraction
Recognize FAI as a cause of instability: 74% of patients with documented hip instability have cam morphology, and 64% have pincer morphology 7. FAI can lever the femoral head posteriorly, causing subluxation.
Common Pitfall to Avoid
Do not attribute hip symptoms to "referred pain" from the spine without proper hip evaluation. The guidelines specifically warn that hip-related pain requires dedicated hip assessment, including screening for acetabular dysplasia, FAI syndrome, and soft-tissue pathology 1. Conversely, don't assume hip pathology explains all symptoms when clear radicular patterns exist.
The relationship between spine and hip is biomechanical and compensatory, not causative for instability. Treat each condition based on its own diagnostic criteria.