Spine
Lumbo-Sacral Spine
Evidence: confirmed
Prone Knee Flexion Test Special Test
Orthopedic Physical Examination & Clinical Assessment Guide
What is it used for?
- Differentiating between Lumbar, SI Joint, and Femoral Nerve pathology.
How to Perform
- Position: Patient lies prone (on stomach).
- Action: Examiner passively flexes the patient's knee, bringing the heel toward the buttock.
Interpretation of Results
- Anterior Thigh Pain: Suggests Femoral Nerve tension (L2-L3).
- Low Back Pain: Suggests Lumbar Disc lesion (L3-L4).
- Buttock/Sacral Pain: Suggests SI Joint lesion.
Clinical Context & Limitations
The Prone Knee Flexion Test should be considered as one component of a comprehensive musculoskeletal assessment. No single special test has perfect diagnostic accuracy; thus, clinical decision-making should integrate test results with patient-reported symptoms, mechanism of injury, functional impairment, and relevant imaging.
Clinicians should be aware of potential false-positive results in patients with pain sensitisation, muscle guarding, or poor relaxation. For the Spine region, combining the Prone Knee Flexion Test with complementary examination tests significantly improves overall diagnostic confidence.
References
- Clinical Tests for the Musculoskeletal 3rd Ed. Book
