Silk Screws To Repair Bones

Mar 10, 2014 By Radhika, Young Editor
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If you have had a major bone fracture, you know the pain of having a metal plate and screws inserted in your body. 

Surgical screws—used with surgical plates, rods, or bolts—can hold together bones to speed up the healing process. After the bone is healed, the screw is often removed.

While the screw helps with healing, it can also cause problems; over-tightening and increased risk of infection could necessitate a second surgery to remove the metallic implants. 

Researchers from Harvard Medical School and Tufts University have come up with silk screws that can dissolve in the body. Fascinated? Read On!

How Bones Heal

A bone may seem like a lifeless piece of your body; however, bone is made up of much more than the white exterior that you see. So when you break a bone, how does it go back to normal?

Without any medical help, a broken bone will heal itself in four steps:

  1. The blood clots and stabilizes the fractured bone, and tiny blood vessels grow into the clot to facilitate healing.
  2. The damaged area becomes stronger as tissue, collagen, and cartilage grow.
  3. Bone cells develop, creating a hard, protective shell.
  4. The bone is remodeled, circulation of blood through the bone improves, and nutrients like calcium and phosphorus strengthen the bone.

Based on the bone, this healing process can take from four weeks to three months. To keep the bone immobile while it is healing, doctors put patients in a cast in most cases. However, for complex fractures, our bones may need a little extra help. 

Benefits Of Silk Screws

Silk has many properties that makes it an attractive option for holding together bone. Being an organic substance, it is biocompatible and will be accepted by the body with few side effects. It has the added advantage that it will not be seen on X-ray images. Most importantly, it is biodegradable, so no future surgeries need to be done to remove the screw.

In order to make the screw, researchers dissolved silk in alcohol and baked them in implant molds. Preliminary tests in rodents have suggested that the new screw has no significant negative effect due to the biological similarity between silk and bone. While these early tests have been successful, we will have to wait before these screws become a common part of surgeries.

Courtesy BBC, Howstuffworks