| 摘要 |
PURPOSE: To assure the fixing power necessary for treatment and to enable early rehabilitation by forming a lock screw for rebuilding the tendon and ligament of a poly-L lactic acid subjected to a stretching treatment, forming the shape of thread ridges to an asymmetrical saw tooth thread shape and making the peaks of the thread ridges flat. CONSTITUTION: This lock screw for rebuilding the tendon and ligament is formed of the poly-L lactic acid subjected to the stretching treatment. The thread ridges 4, 4' are formed to the asymmetrical saw tooth thread shape and the peaks of the thread ridges 4, 4' are made flat. The radius R1 reaching a thread groove 5 from the thread ridge 4 is specified to a range of 0.30 to 0.45 and the radius R2 reaching the next thread ridge 4' from the thread groove 5 to 0.80 to 0.95. The outside diameter of a screw head 2 and the max. diameter of the thread ridge 4 are made nearly the same. The screw head 2 is provided with cruciform slits 3 for screwing and the inside surface part where such cruciform slits intersect is provided with a notch. Further, the screw breaking torque value is adjusted to a range of 8 to 12kgfcm by the stretching treatment. |
