I'd like to thank my good friend and colleague, Dr. Golan, for the opportunity to be here to present for their group at Mammamities and Alterations of Colonial Humeral Force Distribution Following Rotator Cuff Injury and Repair. The group and myself have no particular disclosures. Larger rotator cuff tears are often challenging, and there's a classic teaching to cover their head or restore the footprint with tissue. The subjective intraoperative evaluations of how we're doing is whether we cover the head and whether we restore cuffs to the articular margin, and repair tension is always a question mark in how much tension is too much. Repair tension is often not considered intraoperatively. There's no good way to do it. Clinical data demonstrating high-tension repairs tend to have more or worse outcomes. The ability of high-tension repair to restore native glenohumeral force is unknown, and the effect of a high-tension repair on the glenohumeral force is unknown. The group had the hypothesis that re-approximation of larger rotator cuff tear lesions will result in increased loading about the glenohumeral joint when compared to baseline values. Such increases will occur even in the setting of an anatomic rotator cuff repair where the footprint is covered. The group had 10 fresh-frozen cadaveric shoulders. Transduction mapping was done via a text scan sensor. It was implanted through the rotator interval. Tears were created through a separate deltoid-splitting approach. They're able to measure contact force and contact area, and then calculate contact pressure through the text scan. This was done with 60-second collection time per phase and four frames per second. This is a picture of the deltoid-splitting approach to the rotator cuff. The text scan sensor is in the top picture, and you can see the ribbon that leads into the rotator interval. And there's a picture of the glenohumeral joint with a text scan sensor implanted. The humeral head is off to the left. Testing conditions included an intact baseline, a one-centimeter tear. After repair with two mattress sutures of that one-centimeter tear, then after the sutures were removed, a similar protocol was used at a bigger two-centimeter tear. New baseline force values were calculated following each testing condition. This is a picture after the creation of the tear. A crescent-shaped model was used and laid over the cuff tendon, and then tissue was excised to create the tear. This is the larger two-centimeter tear with sutures passed for the repair through bone tunnels prior to tensioning. The group found that with a one-centimeter lesion, for that, there was no statistically significant change from baseline following both injury and repair. With a two-centimeter lesion, the creation of the tear resulted in a decrease in overall contact area. With a four-suture repair of the two-centimeter lesion, this resulted in significant increases from the uninjured baseline. Glenohumeral force increased 116%. There was a 73.3% change in contact pressure. The largest change in contact area was noted with removal of the four-suture repair. Contact area changed by 37%, similarly, 155% decrease in contact force and an 86.9% decrease in glenohumeral pressure. These are TechScan force tracings. Before injury is the top left, the native resting position. We skipped over the one-centimeter tear mapping because there's no significant change. The two-centimeter tear is the top right. There's a significant force spike in a particular area of the mapping with a two-centimeter tear when it was repaired in the lower left. And then the bottom right, the two-centimeter repair was taken down, and we see forces more close to the before injury state. So in conclusion, repair of a larger size rotator cuff lesion resulted in increased glenohumeral loads. Changes in peak contact forces, contact area, and pressures were seen. Studies data now suggest that high tension repair may result in overtensioning from baseline. So practitioners should be mindful and consider assessing repair tension in addition to the more classic factors such as getting tissue over that footprint and covering the head during intraoperative assessment of a rotator cuff repair.

rotator cuff injury

humeral force distribution

cadaveric shoulders

contact force measurement

rotator cuff repair