Mechanical Engineering graduate student Zhijun Wu studies bone screws

The Fastening and Joining Research Institute (FAJRI), led by Professor Sayed Nassar and housed in the Department of Mechanical Engineering, is a unique academic research facility dedicated to the fastening and joining of materials. An article in the Fall 2010 issue of OU Research stated that

“Founded in 2003, FAJRI has been playing an important role in boosting the safety and reliability of products in both the military and civilian sectors of the American economy. At FAJRI, a team of about 20 faculty, post-doctoral students, and graduate researchers at the Ph.D. and master’s levels is fully engaged in fundamental and applied research. In 2008, it was designated a National Center of Excellence, which enables it to receive core research funding from the U.S. Army.

From small businesses to the automotive and nuclear power industries, the institute aims to ensure the safety, quality, and reliability of many mechanical and structural systems, machinery and equipment.”

Recently, FAJFI researchers have ventured into biomedical research. Nassar and his team published Pullout Performance of Self-Tapping Medical Screws in the November issue of the Journal of Biomechanical Engineering—Transactions of the ASME (Volume 133, Article Number 111002). The introduction of the paper begins

“Since the concept of placing a screw in the lateral masses of the cervical spine for stabilization purposes was presented by Roy-Camille in 1963, self-tapping screws have been widely used in orthopedic joints after surgery and during the healing process. This type of threaded fastener is primarily screwed into the bone without any tension in the screw or clamping force in the bone. Applications include neck and spine injuries, as well as hip and knee replacements. The strength of the screw connection is one of the main concerns in the post-surgery recovery and the long term mobility of the patient. Hence, it is important that a high reliability level is ensured for those self-tapping screws used in medical devices.”

The lead author on the article is Mechanical Engineering graduate student Zhijun Wu, who is one of Nassar's PhD students at FAJRI. Associate researcher Xianjie Yang is also a coauthor. Wu recently returned from China where he spent two months validating his spine screw model on male and female cadavers, in collaboration with neurological and orthopedic surgeons at the Shanghai Jiaotong Medical School (Bone Research Institute).  The cadaver test data is being processed for journal publication.