During the last years inline-skating became one of the most familiar kind of sports with more than 12 million inline-skaters. The danger of injuring is often underestimated. Protectors and technique are important for an effective prophylaxis of injury. The upper extremity is mainly endangered. But despite effective protectors there is still the danger of injury. In particular protectors of the hand can shift the force when falling and result in a fracture of the Os pisiforme. This fracture can be missed in standard x-rays and only be diagnosed with special x-rays.