A ball and socket joint prosthesis for use in arthroplasty is provided. The prosthesis includes a body for implantation at least partially within the medullary canal of a long bone. The long bone defines trabeculae in the proximal cancellous bone and lamellae in the cortical bone. The body includes a proximal portion thereof and a distal portion. The proximal portion has a medial periphery and includes surface features on a substantial portion of its proximal portion. The surface features are positioned to optimally transfer load from the prosthesis to the long bone.