Severity of ulnar deficiency and its relationship with lower extremity deficiencies.

To assess the characteristics of ulnar deficiency (UD) and their relationship to lower extremity deficiencies, we retrospectively classified 82 limbs with UD in 62 patients, 55% of whom had femoral, fibular, or combined deficiencies. In general, UD severity classification at one level (elbow, ulna, fingers, thumb/first web space) statistically correlated with similar severity at another. Ours is the first study to show that presence of a lower limb deficiency is associated with less severe UD on the basis of elbow, ulnar, and thumb/first web parameters. This is consistent with the embryological timing of proximal upper extremities developing before the lower extremities.