The bipolar femoral head prosthesis is used for the treatment of femoral neck fractures in patients older than 75 years of age. It has the advantages of short operation time and the ability to leave the bed and move around early after surgery. Since the small head of the artificial femoral head rotates in the large head, while the large head in contact with the patient’s acetabular cartilage basically does not rotate, this design can reduce the wear and tear of the artificial femoral head on the acetabular cartilage and prolong the service life of the prosthesis. Animation link: http://photo.blog.sina.com.cn/category/u/1725050757/s/421881