Osteoarthritis at the base of the thumb joint, especially common in elderly and female patients, is one of the leading causes of pain in this area. This affected joint plays a crucial role in thumb mobility and grip strength. Over time, the cartilage in this joint wears down, causing the bones to rub against each other.
This leads to pain, swelling, stiffness, and limited movement in the base of the thumb joint. The condition tends to progress over the years. In the early stages, treatments like splinting and corticosteroid injections under ultrasound guidance are used, while advanced cases may require surgical intervention.
What is Thumb Osteoarthritis?
One of the most commonly affected joints by osteoarthritis in the hand is the first carpometacarpal (CMC) joint, also known as the base of the thumb joint. The CMC joint connects the trapezium bone of the wrist to the metacarpal bone of the thumb. Anatomically, this joint resembles a saddle, allowing the thumb to move up, down, sideways, and perform a pinching motion, providing a wide range of movements.
Who is Affected by Thumb Osteoarthritis?
Osteoarthritis at the base of the thumb is more common in women over 40. Although the exact cause is unclear, factors such as genetics, previous injuries like fractures or dislocations, and generalized joint laxity can predispose individuals to this type of osteoarthritis.
Symptoms of Thumb Osteoarthritis
Pain: The most common symptom is pain at the base of the thumb, particularly during tasks that require pinching, like opening jars, turning door handles or keys, and holding a pen to write. Over time, this pain can intensify, even occurring at rest or waking patients up at night.
Deformity: In advanced cases, the joint may become misaligned, leading to subluxation (partial dislocation) and deformity. This can reduce the range of motion and weaken the thumb's grip function. To compensate for the reduced movement in the arthritic joint, the thumb's other joint (the metacarpophalangeal joint) may hyperextend.
Diagnosis of Thumb Osteoarthritis
Diagnosis is typically based on a thorough medical history and physical examination. Pain is often felt when pressure is applied to the base of the thumb, and patients may even wince during a handshake. A grating sensation may also be present. X-rays are taken to confirm the diagnosis.
Treatment of Thumb Osteoarthritis
In the early stages, most patients respond well to non-surgical treatments. Pain relief can be achieved with anti-inflammatory medications, splinting, and corticosteroid injections under ultrasound guidance.
Corticosteroid Injection for Thumb Osteoarthritis
Corticosteroid injections are a highly effective treatment for patients with mild to moderate osteoarthritis. The use of ultrasound during the injection enhances the treatment’s accuracy and effectiveness.
When is Surgery Necessary for Thumb Osteoarthritis?
Surgery is considered for patients with advanced disease or those who have not responded to non-surgical treatments.
Thumb Osteoarthritis Surgery
Surgery involves accessing the base of the thumb joint, where the damaged trapezium bone is removed. To stabilize the joint and prevent further dislocation, a tendon from the nearby area is transferred to fill the gap left by the removed bone.
This procedure helps relieve pain and allows the thumb to regain function, such as writing and grasping objects without discomfort.
Post-Surgical Recovery for Thumb Osteoarthritis
After surgery, a splint is worn for one week, followed by a removable splint for ease of use. Early movement is encouraged, and most patients return to normal activities within eight weeks.
