Written by Dr. Jeffrey Peng, MD — Board-Certified Sports Medicine Physician Published: March 2, 2026 | Last Updated: March 2, 2026 Thumb arthritis at the carpometacarpal (CMC) joint is one of the most common and debilitating forms of hand osteoarthritis. This small but critical joint at the base of the thumb enables grasping, pinching, and fine motor tasks — and when arthritis sets in, it can significantly diminish quality of life. Many patients find that traditional treatme