Thumb osteoarthritis (OA) is associated with pain, reduced grip strength, loss of range of motion (ROM), and joint stiffness leading to impaired hand function and difficulty with daily activities.

 

Etiology:

Osteoarthritis is a disorder of the entire synovial joint organ and involves more structures than articular cartilage. Current evidence states that the subchondral bone may be the primary etiologic agent in osteoarthritis and joint cartilage is simply the final target of the process. Periarticular bone changes occur very early in the development of OA and these changes can be segregated into distinct patterns based on the anatomic location and pathogenic mechanisms. There is a progressive increase in subchondral plate thickness, alterations in the architecture of subchondral trabecular bone, formation of new bone at joint margins (osteophytes), and development of sub chondral bone cysts. Once the pathology reaches the articular cartilage, the cartilage thins and the joint space narrows. This causes sclerosis of the subchondral bone due to the new mechanical load placed on the affected joint.

 

Clinical Presentation:

The primary complaint is radial sided wrist pain that radiates up the forearm with grasping or extension of the thumb. The pain has been described as a “constant aching, burning, pulling sensation." Pain is often aggravated by repetitive lifting, gripping, or twisting motions of the hand. Swelling in the anatomical snuff box, tenderness at the radial styloid process, decreased CMC abduction ROM of the 1st digit, palpable thickening of the extensor sheaths of the 1st dorsal compartment and crepitus of the tendons moving from the extensor sheath may be found upon examination. Other possible findings include weakness and paresthesia in the hand. Finkelstein’s diagnostic test will present positive provoking the patient’s symptoms.