Arthritis is a general term for joint inflammation. When it affects the thumb, it most often involves the carpometacarpal (CMC) joint, also called the basal joint. This joint connects the thumb’s metacarpal bone to a small wrist bone (the trapezium) at the fleshy base of the thumb near the wrist crease. The CMC joint allows for the thumb’s wide range of motion, which is necessary for pinching and grasping. When osteoarthritis develops here, the resulting pain and functional loss can significantly affect a person’s ability to use their hand.
The Specific Sensations of Thumb Arthritis
The pain is usually localized deep within the joint at the base of the thumb. It often begins as a dull ache or soreness that becomes noticeable after prolonged hand use. As the condition progresses, a more intense, throbbing pain can develop, particularly when pressure is applied to the joint.
A distinct mechanical sensation is a frequent complaint, often described as a grinding, grating, or gritty feeling within the joint. This sensation, known as crepitus, may also be audible as a clicking or popping sound when the thumb is moved. Stiffness is commonly felt, especially upon waking or after any period of rest. The joint may also exhibit visible swelling, warmth, and tenderness when pressed.
Activities That Trigger or Worsen Pain
The pain of thumb arthritis is aggravated by activities that require force, particularly pinching and gripping. Simple, everyday tasks relying on a strong pinch grip often become painful and difficult to perform. These tasks include turning a key in a lock, opening jars or bottles, or twisting a doorknob.
Any sustained or forceful grip can also trigger discomfort, such as holding a steering wheel or gripping a mug. Fine motor tasks, like buttoning clothes, writing, or using scissors, become challenging due to the strain placed on the joint. Even prolonged use of electronic devices, such as texting or scrolling, can lead to increased pain.
Why Arthritis Causes These Sensations
The cause of these sensations is the mechanical breakdown of the joint’s structure, predominantly due to osteoarthritis. The CMC joint is naturally lined with smooth cartilage, which acts as a cushion and allows the bones to glide easily. When arthritis sets in, this cartilage gradually wears down, becoming roughened and thinner over time.
This loss of cartilage causes the ends of the bones to rub together, which directly results in the grinding sensation and sharp pain during movement. The resulting friction and joint irritation lead to inflammation, manifesting as deep, persistent aching and throbbing pain. Over time, the body may attempt to repair the damage by growing new bone at the joint edges, forming bony spurs that limit smooth movement and contribute to stiffness.
When to Seek Professional Diagnosis and Management
Consult a healthcare professional if you experience persistent pain, swelling, or stiffness at the base of your thumb that does not resolve with rest. A medical evaluation is necessary if the pain interferes significantly with your ability to perform basic daily tasks, such as gripping or pinching objects. Doctors diagnose thumb arthritis through a physical examination and imaging techniques like X-rays, which reveal the extent of joint space narrowing and bone changes.
Initial management focuses on non-operative strategies aimed at reducing pain and improving function. These steps involve wearing a supportive thumb splint or brace to rest and stabilize the joint. Using ice or heat therapy and taking over-the-counter anti-inflammatory medications can help manage pain and swelling. Modifying daily activities by employing adaptive tools, such as jar openers, or using a relaxed grip can also reduce strain on the affected joint.