The anterior interosseous syndrome is an entrapment neuropathy which can be caused by several different etiologies. It is also clinically known that it weakens flexor pollicis longus, flexor digitorum profundus to the index and long fingers without loss of finger sensory. We have experienced anterior interosseous syndrome which found to be rare to ordinary conservative treatment, i.e. application of Kenny-Howard brace, given to a patient with acromioclavicular separation type III. We also review related articles.