A prosthesis comprising: an inner layer formed from a polyaryletherketone; a first outer layer adjacent to said inner layer formed from a porous polyaryletherketone, at least some of said pores having located therein material to promote osteointegration having a crystallinity of from about 60% to about 90%; and a second outer layer adjacent to said first outer layer formed from a porous polyaryletherketone, at least a portion of said pores having located therein material to promote osteointegration having a crystallinity of less than about 50%. The invention also relates to a method of manufacture of the prosthesis.