In the treatment of this deformity in a newborn infant, the priority is given to physical therapy with additional orthopaedic treatment, such as adduction splints. In our opinion the treatment of such a defect should start as soon as possible, i.e., immediately after birth. This kind of treatment is usually long and persistent. By this treatment muscular atrophy, muscular corrective contractures wich cause serious invalidism in these young patients, should be prevented. In fact, inadequately treated children remain invalids for their whole life because a deformed arm will never be in complete function. Furthermore, from the aesthetic point of view, such an arm provokes a negative feeling in other persons. Therefore, we insist on the early appropriate treatment which is the only guarantee for good results.