Shriners, UDel Measure Intricacies of Shoulder Movement

Going boldly into uncharted areas, physician-researchers from Shriners Hospital for Children in Philadelphia and biomechanical researchers from the University of Delaware are isolating the moment-to-moment movements of the scapula and glenohumeral joint (a.k.a. shoulder blade and shoulder joint) using 3-D motion analysis. This project has required 10 years of dedication to learn how to measure these movements.

Scott H. Kozin, M.D. is chief of staff for Shriners Hospital for Children-Philadelphia. Dr. Kozin told OTW, “There are many orthopaedic ailments and injuries that would benefit from these detailed measurements. In children that have brachial plexus injuries, the effect on shoulder movement has been poorly understood and controversial. The injured nerves negatively affect shoulder movement and scapula winging (where the child’s shoulder blade pulls away from the ribcage) is endemic and a frequent cause of concern. Prior to this research we have not been able to give parents and patients a definitive answer as to why or how the scapula wings. Now, we can explain to them in detail the how and why. The parents and patients can be shown the altered movement patterns using the reflective 3-D markers. State-of-the-art motion capture technology captures the three-dimensional movement of reflective stickers that are placed on the patient’s skin overlying important boney structures underneath.”

“Part of the complexity is that the scapula moves in three planes and is connected to the glenohumeral joint (shoulder joint or ball and socket joint), which also moves in all three planes. In brachial plexus injuries, we have found that it is primarily the shoulder joint or ball and socket joint that is negatively affected and the scapula moves excessively to compensate for the limited movement of the shoulder joint. This finding explains the preponderance of scapular winging in children with brachial plexus injuries.”

“This research and technology is paramount for other problems and can divide shoulder motion into its two components—glenohumeral shoulder joint and scapular movement. Shoulder arthroplasty (joint replacement) doctors and sports medicine physicians that repair rotator cuffs are interested in these measurements to assess outcome.”

Stephanie Russo, M.D., Ph.D. told OTW, “Our early work focused on better understanding the function of the shoulder in kids with brachial plexus birth palsy. Much of our current work is aimed at understanding changes in shoulder function after different surgeries. We are also working on a new method of measuring dynamic motion of the shoulder blade.”