Bad Thumb Arthritis – What Does It Look Like?

The video below shows a patient’s thumb moving back and forth. As you’ll see, most of the range of motion is at the MP (metacarpophalangeal) joint. This is abnormal – in a normal thumb, the majority of the motion is through the CMC (carpometacarpal joint, at the base of the thumb).

When the CMC joint stiffens up from arthritis, the next joint toward the tip of the thumb gets hyperflexible to compensate.