Doctors perform thumb arthritis tests to assess the joint at the base of this digit.
A positive test reproduces pain on the joint, confirming that a person has thumb arthritis.
The thumb base joint is one of the most common areas of osteoarthritis (OA) in hand.
Thumb arthritis is more common in adults aged 50 years and above.
According to Dr. Dilip Mehta, an excellent orthopedic surgeon from Jaipur, doctors use several tests to diagnose thumb arthritis.
These examinations aim to reproduce the discomfort of arthritis. They include:
- Grind test
- Traction-shift test
- Lever test
- Pinch test
- Pinch strength
In this article, Dr. Dilip Mehta, an extraordinary orthopedic Surgeon from Jaipur, discusses thumb arthritis, the tests to evaluate it, the steps involved, and the expected results.
Thumb arthritis is also named basal joint arthritis or basal thumb arthritis.
It refers to the deterioration and decline of the cartilage within the joint at the base of the thumb.
It is called the carpometacarpal (CMC) or the trapeziometacarpal joint.
This saddle-shaped joint is responsible for the unique ability of the thumb to contact all the other four digits — the fingers — contributing to 40% of the overall function of the hand.
According to Dr. Dilip Mehta, an outstanding orthopedic specialist from Jaipur, Thumb arthritis is usually a type of OA that results from gradual wear in the joint.
Stages of thumb arthritis
Thumb arthritis is a progressive disease that causes a gradual deterioration of the CMC joint of the thumb.
According to the Eaton-Litter classification, the condition has four stages:
Stage 1: Only a minor joint area widening is present. The joint surfaces are standard, and no bone spurs or osteophytes are present.
Stage 2: There is a tiny narrowing of the joint. The bone may get denser and contain fluid-filled lesions that the bone encompasses.
Furthermore, these outcomes are known as sclerosis and cystic changes, respectively. The common may also have osteophytes and loose bodies smaller than 2 millimeters (mm).
Stage 3: Like stage 2, sclerosis and cystic changes are present in the joint.
There is already a substantial joint space narrowing and the existence of loose bodies or osteophytes that are bigger than two mm.
Stage 4: In addition to all the changes in stage 3, this stage includes arthritis of the scaphotrapezial joint in the wrist.
Thumb arthritis diagnostic tests
Doctors can perform several physical tests to see whether a person has thumb arthritis.
CMC thumb grind test
The grind test is the diagnostic tool that doctors most commonly use to evaluate and confirm OA.
The doctor will apply force to the thumb metacarpal and, at the same time, turn the thumb metacarpal base to perform the grind test.
The test is positive if it causes pain in the joint.
The traction-shift test is a newer diagnostic method that doctors can utilize.
This test is similar to the grind test, as it uses the occurrence of pain to determine whether a person has thumb arthritis.
A doctor grasps the joint’s two ends, pulls them apart, and then relocates them.
Pain can indicate subluxation, partial dislocation, and the presence of thumb arthritis.
This simple test involves asking a person to make a letter O with the tip of the thumb touching the end of the index finger.
An individual has arthritis if they cannot feel the place, and the shape of their hand appears more like the D letter. Attempting to pinch may also stimulate pain.
People who get a positive result on this test will likely experience pain if they pinch or grip an object.
In the lever test, the doctor places their thumb and index finger at the base of the first metacarpal, just after the CMC joint.
Then the doctor rocks the thumb back and forth to apply pressure over the anterior oblique ligament.
The test is positive if it reproduces the pain at the base of the thumb.
Therefore, the lever test is the most sensitive and the least likely to produce a false-negative result.
This test is also called the pressure-shear test.
The test is excellent over the grind test and other techniques in analyzing thumb CMC arthritis.
Extension tests and Metacarpal flexion
According to Dr. Dilip Mehta, a fantastic orthopedic specialist from Jaipur, an individual extends the thumb while the specialist attempts to resist the movement in a metacarpal examination. The doctor does this by placing a finger on the interphalangeal joint.
The inspection is positive if the individual experiences discomfort.
Medics execute the metacarpal flexion test similarly, except they try to flex their thumb instead of extending it.
Pinch strength test
Individuals with earlier thumb CMC arthritis have insufficient pinch strength.
Doctors may sometimes assess the pinch strength of the affected hand and compare it with that of the unaffected hand.
This test uses a device called a pinch dynamometer.
The device measures a person’s strength in doing three pinches: lateral pinch, three-point pinch, and two-point pinch.
Thumb arthritis symptoms
Signs that may suggest thumb arthritis possess discomfort when executing activities that need:
The condition may also cause the following symptoms:
- Tenderness or discomfort at the thumb base
- Limited range of motion
- Weak grip and pinch strength
- Swelling or stiffness at the thumb base
Doctors will start the diagnosis of thumb arthritis by examining the thumb to check for symptoms such as:
- Presence of lumps
They may also wish to rule out carpal tunnel syndrome, producing similar symptoms.
In some cases, the doctor may order an X-ray of the thumb. An X-ray can reveal signs of thumb arthritis, including:
- Joint space narrowing
- Bone and cartilage changes
- Presence of osteophytes and loose bodies
Certain people have an increased risk of developing thumb arthritis.
It includes individuals who work on a computer for extended periods and those with other conditions that affect the cartilage, such as rheumatoid arthritis.
“Thumb arthritis may worsen over time, as no treatment can stop its progression,” says Dr. Dilip Mehta, Jaipur’s leading orthopedic surgeon.
Instead, treatment aims to reduce pain and improve and maintain function.
The stage of the person’s condition and the severity of their symptoms will inform their treatment.
Treatments for thumb arthritis include:
- Occupational therapy
- Thumb splints
- Medicines for discomfort and swelling
- Steroid injections
Thumb arthritis is a condition that can induce extreme pain and significantly affect a person’s use of their hands.
Anyone who feels discomfort and pain at the base of the thumb should contact a doctor for a diagnosis so that they can start any necessary treatment as early as possible.
Numerous individuals with thumb arthritis can handle their signs by modifying their activities and receiving suitable treatment.