Orthopedic Bone Screws
Orthopedic bone screws are stainless steel or titanium screws used for the surgical treatment of broken bones. They are the most commonly used devices for surgical internal fixation of bones. The material of the screws is highly non-reactive does not cause any allergic or corrosive reactions inside the body. It can safely remain in our body for an entire lifetime without causing any complications.
Materials used for Orthopedic Screws?
Titanium screws are quite expensive but are preferred because of their durability and non-magnetic property, which makes them for all kinds of magnetic imaging, like MRI. A stainless steel bone screw is cheap and easily available in several types, but is not safe for medical imaging and its presence has to be clearly mentioned before any kind of medical imaging.
Why use Orthopedic Bone Screws?
Injury to the bones in the form of fractures causes the broken ends to move away from each other due to the muscular forces, e.g. knee injuries. A bone screw helps to keep the broken ends of the bone together, so that the bone fracture healing can proceed normally. A wide variety of metal plates (strips of metal with holes for screws) can be used along with screws for this purpose. Strong support by the bone screws help to ensure healing of the bones without any misalignment due to the muscular forces. This is very critical for 4-6 weeks during which the broken bones regain their full strength. The bone screws can be removed after a period of around 1-2 years.
Why Remove a Bone Screw?
Bone screws are treated as a foreign body by the human tissues. Hence, they are more likely to get infected from micro-organisms through the blood flow. An infected bone screw transmits the infection to the underlying bone. Bone infections are the most dreaded orthopedic complication and are highly difficult to treat. Hence, removal of a bone screw within 2 years is advisable. Beyond a period of 2 years, a layer of bone is formed over the screw, which makes removal of the screw complicated.
Types of Orthopedic Bone Screws
Depending on the consistency of bone tissue and the type of fracture, various types of orthopedic screws are in use. Some of the commonly used types are
- Cortical Screw used for hard bone tissue, like shaft of long bones.
- Cancellous Screw used for spongy bone present at the ends.
- Cannulated Screw used for passing a guide wire through it for accurate screw placement
- Herbert Screw is a headless screw for lag screw fixation of fractures involving the joint cartilage, so that even after placement of screw the joint movements are not obstructed by a screw head.
- Malleolar Screw used for ankle fractures.
- Pedicle Screw used for spine fractures or fusion.
A proper use of orthopedic bone screws is vital to surgical treatment of complicated orthopedic injuries. However, improper use can also lead to non union of the broken bones, infection, and damage to body tissues.