A nonaugmented prosthetic ligament for permanently replacing a natural ligament spanning first and second body members, such as the femur and tibia includes a load bearing member formed from a plurality of biocompatible polyolefin fibers positioned at angles of from 0.degree. to 55.degree. relative to the longitudinal axis of the load bearing member. Each fiber is less than 100 microns in diameter and has a tensile strength greater than or equal to about 50,000 psi. The load bearing member may be used alone or may be formed into a hollow braid having a core disposed within the hollow portion of the braid to provide shape for the load bearing member. A sheath may be friction fit or molded onto the exterior of the load bearing member to prevent abrasion of the fibers.