MCP Squeeze Test: Purpose, Procedure, and Interpretation

What is a MCP squeeze test?

The Metacarpophalangeal (MCP) squeeze test is a clinical examination maneuver used primarily to assess for inflammation within the metacarpophalangeal joints of the hand, often serving as an indicator for inflammatory arthropathies such as Rheumatoid Arthritis.

Introduction to the MCP Squeeze Test

The MCP squeeze test, sometimes referred to simply as the "hand squeeze test," is a quick and non-invasive physical assessment technique employed by healthcare professionals, including physicians, physical therapists, and occupational therapists, to evaluate the presence of synovitis (inflammation of the synovial membrane) in the joints of the hand. Its utility lies in its ability to broadly screen for joint inflammation, providing valuable clinical information that can guide further diagnostic investigations.

Anatomy of the Metacarpophalangeal (MCP) Joints

To understand the MCP squeeze test, it's essential to briefly review the anatomy involved. The metacarpophalangeal joints are the knuckles where the long bones of the hand (metacarpals) meet the bones of the fingers (phalanges). Specifically, these are the joints at the base of your fingers, just before the first knuckle you typically bend to make a fist. Each MCP joint is encased in a joint capsule lined with a synovial membrane, which produces synovial fluid to lubricate the joint. When this membrane becomes inflamed, a condition known as synovitis, it can lead to pain, swelling, and tenderness.

Purpose of the Test

The primary purpose of the MCP squeeze test is to detect synovitis in the metacarpophalangeal joints. It is frequently utilized in the diagnostic workup for:

• Inflammatory Arthropathies: Most notably, it is a common screening test for Rheumatoid Arthritis (RA), where symmetrical synovitis of the small joints of the hands and feet is a hallmark feature.
• Other Inflammatory Conditions: While less specific, it can also be positive in other inflammatory conditions affecting the joints of the hand.
• Monitoring Disease Activity: In individuals already diagnosed with an inflammatory condition, a positive MCP squeeze test can indicate active inflammation and help monitor disease progression or response to treatment.

How the Test is Performed

The MCP squeeze test is a straightforward maneuver performed by an examiner on the patient's hand.

1. Patient Positioning: The patient is typically seated comfortably, with their hand relaxed and open.
2. Examiner's Grip: The examiner grasps the patient's hand firmly across the knuckles (MCP joints). The examiner's fingers should be positioned over the dorsal (back) aspect of the patient's MCP joints, and the thumb on the palmar (front) aspect.
3. Application of Force: A compressive force is then applied, squeezing the MCP joints together. This force should be firm but not overly aggressive, aiming to compress the joint capsules and synovial membranes.
4. Observation and Elicitation: The examiner carefully observes the patient's reaction and asks about any pain experienced during the compression.

The test is usually performed on both hands for comparison and to assess for symmetry of symptoms, which is characteristic of certain inflammatory conditions like Rheumatoid Arthritis.

Interpreting the Results

The interpretation of the MCP squeeze test is based on the patient's subjective experience of pain:

• Positive Test: A positive MCP squeeze test is indicated by the elicitation of pain upon compression of the MCP joints. The severity and location of the pain are noted.
• Negative Test: A negative test means the patient experiences no pain upon compression.

It is crucial to understand that a positive test indicates the presence of inflammation or tenderness but does not specifically diagnose a particular condition on its own.

Clinical Significance and Limitations

While a valuable tool, the MCP squeeze test has specific clinical significance and inherent limitations:

• High Specificity for RA: When positive, especially with symmetrical involvement, it has a relatively high specificity for Rheumatoid Arthritis, meaning that if the test is positive, there's a good chance RA is present.
• Low Sensitivity for Early Disease: The test's sensitivity, however, is not as high, particularly in the early stages of inflammatory conditions. A negative test does not definitively rule out the presence of early or mild synovitis.
• Not a Standalone Diagnostic Tool: The MCP squeeze test is always used in conjunction with other clinical findings, such as patient history, other physical examination findings (e.g., joint swelling, warmth, limited range of motion), laboratory tests (e.g., ESR, CRP, rheumatoid factor, anti-CCP antibodies), and imaging studies (e.g., X-rays, ultrasound, MRI).
• Potential for False Positives: Pain during the squeeze test can also be caused by non-inflammatory conditions, such as recent trauma, osteoarthritis, or other localized hand issues, although these typically present differently than inflammatory synovitis.

When to Seek Professional Advice

If you experience persistent pain, swelling, stiffness, or tenderness in the joints of your hands or feet, especially if it's worse in the mornings or affects multiple joints symmetrically, it is important to seek prompt medical attention. A healthcare professional can perform a comprehensive evaluation, including the MCP squeeze test and other diagnostic procedures, to determine the underlying cause of your symptoms and recommend appropriate management. Early diagnosis and intervention are crucial for managing inflammatory conditions and preventing long-term joint damage.