The thumb joints are what help us pinch and grasp. Osteoarthritis (OA) in the joints of the thumb can be debilitating. OA of the thumb joints is fairly common. Still, doctors don’t understand exactly how the cartilage of the thumb joints wears down over time. Knowing cartilage wear patterns could help doctors more effectively diagnose and treat OA in the thumb.
These authors used cadavers (human bodies preserved for research) to study the way thumb cartilage wears down with age. The authors looked at the thumb joints in 100 cadavers. The joints were rated for stage of OA using visual exams and X-rays. Then the cartilage thickness was measured on the surface of the carpometacarpal (CMC) and trapezium joints.
Both joints showed more wear in the areas that bear the most force, as the authors expected. Cartilage in the CMC wore away primarily in the center of the joint. The trapezium joint showed wear along one edge. The authors say that this information could be used to develop exercises and therapy to shift the forces on the joints.
The authors also note that visual ratings of the stage of OA were generally higher than ratings done by X-ray. The authors say this means that X-rays may not be helpful in diagnosing OA in its early stages.