My husband is 35 years old and works on road construction crews. He was recently diagnosed with Kienböck’s disease. What causes this?

Kienböck’s disease is most common in men who are manual laborers. It occurs between ages 30 and 40. The exact cause is still unclear. In all cases, there is a loss of blood supply to a bone in the wrist called the lunate.

At first, doctors thought this was the result of a sprained wrist. The blood vessels to the lunate go through the ligament. Damage to the ligament disrupts the blood supply. Later, doctors noticed that most of the patients with Kienböck’s also had one bone (ulna) in the forearm shorter than the other.

The lunate is in the center of the wrist. In this position, it gets a lot of force and stress with everyday activities. The forearm has two bones that connect to the lunate: the ulna and the radius. If the ulna is shorter than the radius, then even more force is placed on the lunate. This increases the risk of fracture and loss of blood supply.

More recently, this change in the ulna has been seen as a risk factor, not the cause. It increases the chances of Kienböck’s disease, but it doesn’t cause it. It’s more likely that a fracture in the area of the lunate cuts off the blood supply. As medical technology improves, researchers will probably find the exact cause.