When is a Fair test (Flexion, Adduction, and Internal Rotation) positive and what are the physical exam signs of piriformis syndrome?

FAIR Test Positivity and Physical Exam Signs of Piriformis Syndrome

The FAIR test (Flexion, Adduction, and Internal Rotation) is positive when it reproduces the patient's buttock pain and/or sciatica symptoms, indicating potential piriformis syndrome, while physical exam findings include buttock tenderness from the sacrum to greater trochanter, piriformis tenderness on rectal examination, and pain with prolonged hip flexion, adduction, and internal rotation. 1, 2

FAIR Test Interpretation

• The FAIR test is performed by flexing, adducting, and internally rotating the hip, which stretches the piriformis muscle and may compress the sciatic nerve if piriformis syndrome is present 2
• A modified FAIR test, which combines the Lasègue sign and FAIR test, has been shown to be a reliable method for clinical diagnosis of piriformis syndrome with a prevalence of 17.2% among chronic low back pain patients 2
• A negative FAIR test helps rule out hip-related pain, although its clinical utility is limited due to poor specificity 3
• The test should be prolonged for several tens of seconds to successfully reproduce the buttock-centered and frequently associated sciatic symptoms 4

Key Physical Examination Findings in Piriformis Syndrome

• Buttock tenderness extending from the sacrum to the greater trochanter 5
• Piriformis tenderness on rectal or pelvic examination 5, 4
• Pain with prolonged hip flexion, adduction, and internal rotation 1, 4
• Normal neurological examination results and negative straight leg raising test results, which helps differentiate from true radiculopathy 1
• Pain on direct palpation of the piriformis muscle 1

Additional Diagnostic Tests

• Freiberg sign: Pain with passive internal rotation of the extended thigh 1, 4
• Pace sign: Pain with resisted abduction and external rotation of the thigh 1
• Beatty's maneuver: Pain with resisted contraction in lateral rotation 4
• HCLK (Heel Contra-Lateral Knee) maneuver: Stretching the piriformis by placing the heel of the affected side on the contralateral knee, which should be prolonged for several tens of seconds 4

Clinical Presentation

• Pain may be described as dull, aching, sharp, or electrical in character 6
• Symptoms may mimic those of L5-S1 disc lesions, but typically without the specific neurological deficits associated with true radiculopathy 6
• Unlike true radiculopathy, piriformis syndrome usually does not cause specific dermatomal sensory loss or myotomal weakness 6
• Symptoms may appear suddenly after activities involving back stretching or trauma 6
• Patients typically have sciatica, buttock pain, and worse pain with sitting 1
• In long-standing cases, patients may develop compensatory gait patterns 6

Differential Diagnosis Considerations

• Piriformis syndrome is often misdiagnosed due to symptom overlap with lumbar radiculopathy and other causes of sciatica 6, 1
• Hip-related pain requires a comprehensive clinical examination that includes screening for other conditions that might present with similar symptoms 7
• When hip pain coexists with low back pathology, MRI is the best next test after radiography to screen for significant pathology 7
• Diagnostic imaging and neurodiagnostic studies are typically normal in piriformis syndrome and are used primarily to rule out other etiologies for sciatica 1

Management Approach

• Conservative treatment, including medication and physiotherapy, is usually helpful for the majority of patients 1, 8
• Treatment protocols should emphasize exercises that promote strength, flexibility, and functional activities 8
• For recalcitrant cases, corticosteroid and botulinum toxin injections may be attempted 1, 5
• Piriformis tenotomy and decompression of the sciatic nerve can be considered for those who do not respond to conservative management 1