Tibial Rotation and the Screw-Home Mechanism 🦵 . In this video, the patient is working on tibial rotation — gently rotating the shin bone in and out while stretching the soleus muscle (the deep calf muscle). . Tibial rotation is a small but critical movement that happens every time you bend or straighten your knee. When the knee straightens, the tibia externally rotates (turns outward slightly). When the knee bends, it internally rotates to unlock the joint. . This process is known as the screw