A momentum free bearing assembly for use in orthotic and prosthetic devices and a prosthetic knee incorporating the same are disclosed. The bearing assembly includes an engaging ring having a swivel portion received within the engaging ring. The engaging ring is received within a bore in a mount. Retainer rings may be placed on either side of the engaging ring within the bore to retain the engaging ring within the mount. Seals having sealing members may be provided on either side of the engaging ring to seal the engaging ring within the mount. A cylindrical rod engages the swivel portion and the seal through bores provided in each of the seal and the swivel portion. The ends of the cylindrical rod can be press-fit within bores on a mount and a frame of a prosthetic knee.