Advancements in Bone Screws

A few years back the American Academy of Orthopedic Surgeons listed internal fixation as one of the most important advances in treatment during the 20th century.  The most common of all surgical implants for internal fixation is the bone screw.  Bone screws come in many varieties and these varieties are all designed to work in different applications.  In truth, bone screws have evolved pretty dramatically in recent years providing orthopedic surgeons more flexibility in treating their patients.

Dr. Arthur Valadie is an orthopedic surgeon at Coastal Orthopedics.  He says, “The new technology in bone screws is the most exciting thing about what they (orthopedic surgeons) do and something new is coming out nearly every week. The technology definitely improves how they work.”

Andy Kant, MD says that newer designs are less likely to cause additional surgeries from hardware failure.  According to Kant, “The most significant advancement has been in screw/thread design to prevent pull out or dislodgement and the strength of materials to prevent breakage.”

Dr. David Ott, an orthopedic surgeon and the head of Arizona Orthopaedic Associates in Phoenix points out four major advancements – Variable pitch screws, locked screws, cannulation and lower profile screws. 

He points out the benefits of each of these advancements:

•          Variable pitch screws have different pitch on each end which allows compression of bone fragments as the screw goes in.
•          Locked screws are ones which have a dual thread and are used to attach metal plates to the bone when stabilizing fractures.  The majority of the screw has a tread pitch which goes into the bone, but the end has a machine thread which locks into the plate.  This allows a much stronger construct especially for bone which is more osteoporotic.
•          Cannulation is a hollow screw which allows the surgeon to place a guide pin in the bone and then place the screw over it.  This allow more accurate placement of the screw.
•          Lower profile screws have a smaller head which attaches more closely to the bone or plate making the screw less noticeable under the skin or less intrusive to the adjacent tissues (muscles & tendons).

As for the future of bone screws, Dr. Ott elaborates, “The area I see developing is bio-absorbable screws which can be places in the joint and will dissolve over time as well as through a plate which will weaken over time and decrease the stress shielding which occurs, changes in metallurgy will also likely make stronger screws which are smaller and lower profile.”

While it’s interesting to speculate on what the next big advancement in bone screws will be, it’s clear to see that the technology has already come a long way.  As internal fixation continues to advance, orthopedic professionals and their patients will likely see continuously improving outcomes.