Study PI on this study is Dr. James Gregory, who is sitting here. Thank you so much for attending this presentation. All right, so let me figure out how it works. Athletes who engage in contact sports often experience an injury to their acromioculavicular joint. There's still much debate on the ideal treatment for high-grade ACJ injuries. Typically the decision to do the surgery depends on severity of the injury as determined by, for example, Rockwood classification. However, the effectiveness of modern anatomical non-rigid fixations in restoring normal shoulder mechanics and function remains unclear. Also it remains unclear if conservative treatments for grade III injuries can provide comparable shoulder stability and function, making surgical intervention unnecessary. Therefore the main objective of this study is to determine whether shoulder mechanics, strength and range of motion are restored after undergoing ACJ reconstruction surgery. And our hypothesis is that shoulder mechanics and function may not be fully restored two to three years post-surgery. We also had access to a few number of conservatively treated subjects who had grade III injuries. So we explored an additional study aim to better understand the mechanical and functional deficits between surgical and non-surgical treatments. And our hypothesis was that non-surgical group is doing even worse. We evaluated 11 surgically treated patients, two females who had surgery around two years prior. Seven received CC-only surgeries and four had combined AC and CC ligament reconstruction followed by standardized rehab. We also had three non-surgical participants who had similar demographics. The Rockwood grade for non-surgical group was 3A, so unstable grade III. And for surgical group were 3B, and eight of them had grade V. Participants underwent a biomotion test with biplane x-ray taken during abduction, escapation and forward flexion. Motion-specific bone models were created from CT and were frame-by-frame matched to the contours of these bones were matched frame-by-frame to the background x-ray video that we took from the joint from two different planes, which resulted in validated accuracy of half a millimeter and half a degrees or better in measuring the shoulder mechanics. Also subject range of motion and isometric strengths and patient-reported outcomes were collected. So these methods were performed. So rotational kinematics of the scapula with respect to clavicle was one of the first outcomes that we investigated during abduction, escapation and forward flexion. Now internal rotation direction, downward rotation and posterior tilting. Solid black lines represent contralateral healthy shoulders. Dashed blue lines, dotted blue lines are surgical and dashed red lines are non-operative. As you can see qualitatively and as tested by statistical analysis, there was no difference between surgically treated shoulders and contralateral shoulders. However, when we look at non-operative treatment, we can see that there is a considerable amount of increased internal rotation that may or may not increase the risk of impingement, which we cannot directly extract from the rotational kinematic data. Therefore we went ahead and then calculated subacromial space during functional activities. And what we have noticed was that uninjured group had the largest subacromial space, followed by surgical group, and the difference between surgical and uninjured shoulders did not reach a statistical significance. The p-value is reported here. And the smallest distance belonged to non-surgical group, which may indicate that this group might be at increased risk of impingement, rotational impingement and degeneration risk, and under increased risk of long-term shoulder pathologies. Also we looked at translational kinematics by digitizing the acromion and distal clavicle ends and looking at the displacement at the AC joint along its line of action during functional activities. Again, similar results, surgical and contralateral shoulders reported very similar patterns of movement during abduction, escapation and forward flexion. And that was not the case for the non-operative patients. In fact, when we extracted the range of contraction and distraction of range of movement of ACJ joint, in non-operative group, it was as large as twice as large as the healthy shoulders or surgically treated shoulders, at least for abduction and escapation. Lastly, we looked at range of motion isometric strengths and we detected no difference between surgical and contralateral shoulders. So in conclusion, no abnormalities were detected in ACJ biomechanics, range of motion, isometric strengths of the surgical group who received surgery using anatomical non-rigid fixation of ACJ joint. The outcomes of non-operative treatments were not very promising, although it should be acknowledged that the sample size were very small and studies with larger sample sizes needed, but this preliminary results on conservative treatment indicates or provides ample motivation to pursue this line of research and see for ourselves whether or not conservative treatment are as promising of a treatment as it was previously thought. Thank you so much for your attention.

Dr. James Gregory

high-grade acromioculavicular joint injuries

contact sports athletes

ACJ reconstruction surgery

surgical and non-surgical treatments