Elbow injuries continue to be on the rise in baseball players, especially pitchers, yet little is known about the actual variables that influence these injuries.
While elbow varus torque is already linked to ulnar collateral ligament (UCL) injuries, the connection between certain pitching movements and elbow varus torque is unknown.
A study from Hospital for Special Surgery set out to find the relationship between elbow varus torque and the following variables: arm slot, arm speed and shoulder rotation. The prospective cohort study looked at 81 professional pitchers (either in the Major or Minor Leagues) who took 81,999 throws while wearing a Motus baseball sleeve. The study was presented at the American Academy of Orthopaedic Surgeons Annual Meeting on March 14 in San Diego.
These were a combination of throws that were evaluated in real settings, such as structured long tosses and live game play, as opposed to in a laboratory, like previous studies. This was the largest analysis of throwing biomechanics to date.
"Obtaining this comprehensive, individualized analysis of on-field throwing activity was made possible by technological advancements that give us the ability to accurately measure body motions outside the lab," said Joshua Dines, MD, sports medicine surgeon at HSS and primary investigator. "Capturing data during the pitchers' normal activities provided us with robust, baseline biomechanical performance metrics."
The study found that arm slot, arm speed and shoulder rotation all have a significant relationship with elbow varus torque. There was a 1-nm increase in elbow varus torque associated with a 13 degree decrease in arm slot, 116% increase in arm speed and 8 degree increase in shoulder rotation.
Increased arm speed and shoulder rotation were found to be associated with increased elbow stress as well as decreased arm slot. Height and weight were also positively correlated with elbow varus torque.
"Now that we know these modifiable risk factors, we have a foundation to develop evidence-based rehabilitation programs. Additionally, these findings can be utilized to prevent injury and help to identify potential pitchers at risk," said David Altchek, MD, sports medicine surgeon at HSS.
HSS Clinical fellow Christopher Camp, MD, also was an author on the study.
About Hospital for Special Surgery
Hospital for Special Surgery (HSS) is the world's largest academic medical center focused on musculoskeletal health. HSS is nationally ranked No. 1 in orthopedics and No. 2 in rheumatology by U.S. News & World Report (2016-2017), and is the first hospital in New York State to receive Magnet Recognition for Excellence in Nursing Service from the American Nurses Credentialing Center four consecutive times. HSS has one of the lowest infection rates in the country. HSS is an affiliate of Weill Cornell Medical College and as such all Hospital for Special Surgery medical staff are faculty of Weill Cornell. The hospital's research division is internationally recognized as a leader in the investigation of musculoskeletal and autoimmune diseases. Hospital for Special Surgery is located in New York City and online at https:/