What is Finkelstein's test?

Finkelstein's Test

Finkelstein's test is a clinical examination maneuver used to diagnose de Quervain's tenosynovitis, characterized by stenosing tenosynovitis of the abductor pollicis longus (APL) and extensor pollicis brevis (EPB) tendons in the first dorsal compartment of the wrist.

Correct Technique

The proper Finkelstein's test involves:

1. The examiner grasps the patient's thumb and passively deviates the wrist in the ulnar direction
2. Pain over the radial styloid process indicates a positive test, suggesting de Quervain's tenosynovitis

It's important to note that the original Finkelstein's test is often confused with Eichhoff's test, which is commonly but incorrectly referred to as Finkelstein's test in clinical practice 1.

Biomechanical Basis

The test works through specific biomechanical principles:

• During ulnar deviation of the wrist (approximately 30 degrees), the EPB tendon moves significantly more distally compared to other wrist positions 2
• This position creates a measurable "bulk effect" (increased muscle mass within the retinaculum) and "tethering effect" (stretching of synovial tissue) within the first dorsal compartment 2
• The EPB tendon experiences significantly greater resistance in this position, which explains why the test provokes pain in patients with de Quervain's tenosynovitis 2

Diagnostic Accuracy

• Finkelstein's test has superior specificity compared to Eichhoff's test (99% vs 74%) 3, 1
• While its sensitivity (91%) is slightly lower than Eichhoff's test (97%), the higher specificity makes it more valuable for accurate diagnosis 3
• Finkelstein's test produces significantly fewer false-positive results and causes less discomfort to patients 1

Common Errors in Technique

The most common error is performing Eichhoff's test while calling it Finkelstein's test:

• Eichhoff's test: The patient makes a fist with the thumb tucked inside and then deviates the wrist ulnarly
• This maneuver can produce pain in asymptomatic individuals, leading to false positives 1

Clinical Application

When evaluating a patient with radial-sided wrist pain:

1. Perform the correct Finkelstein's test (examiner-guided passive ulnar deviation)
2. Look for localized tenderness over the first dorsal compartment
3. Consider using the Radial Synergy Test as an adjunct (isometric contraction of first dorsal compartment with resisted abduction of the small finger) for its high specificity (99%) 3
4. A positive test, combined with clinical history of pain with thumb and wrist movement, strongly suggests de Quervain's tenosynovitis
5. Response to corticosteroid injection can confirm the diagnosis (98.75% of patients become symptom-free by 12 weeks after injection) 4

Finkelstein's test primarily reflects abnormalities of the EPB tendon rather than the APL tendon, as demonstrated by biomechanical studies showing greater bulk and tethering effects on the EPB in the test position 2.