Increased Glenohumeral Joint Load Can Be Reversed

Rotator cuff repair can be used to reverse increased glenohumeral joint load, according to a new study.

In “Increased Glenohumeral Joint Loads Due to a Supraspinatus Tear Can Be Reversed with Rotator Cuff Repair,” published online on November 18, 2021 in the journal Arthroscopy, the researchers evaluated the effect of an isolated full-thickness supraspinatus tear on glenohumeral kinematics and contact mechanics. They also wanted to assess improvement following rotator cuff repair.

To do this, they tested ten fresh-frozen cadaveric shoulders with a dynamic shoulder simulator. The pressure mapping sensor was placed between the humeral head and glenoid. Three different conditions were analyzed: native, isolated full-thickness supraspinatus tear, and rotator cuff repair.

They measured maximum abduction angle and superior humeral head migration using 3D motion tracking software. They also assessed cumulative deltoid force and glenohumeral contact mechanics, including contact area and contact pressure at resting position and 15°, 30°, 45°, and 60° of glenohumeral abduction.

Overall, the supraspinatus tear resulted in a significant decrease in maximum abduction angle (Δ-8.3°; p < .001) along with a superior humeral migration of 6.4 ± 3.8mm, while significantly increasing cumulative deltoid force (Δ20.5N; p = .008), glenohumeral contact mechanics (Δ63.1kPa; p < .001), and peak glenohumeral contact pressure (Δ278.6kPa; p < .001) as well as decreasing glenohumeral contact area (Δ-45.8mm ² ; p < .001) at each degree of abduction.

Rotator cuff repair reduced superior humeral head migration to 1.2 ± 2.5mm, while restoring native maximum abduction angle, cumulative deltoid force (Δ1.8N), glenohumeral contact area (Δ4.5mm²), glenohumeral contact pressure (Δ-4.5kPa) and peak glenohumeral contact pressure (Δ19.9kPa) at each degree of abduction (p > .999, respectively).

“In a dynamic biomechanical cadaveric model, increased glenohumeral joint loads due to a full-thickness supraspinatus tear can be reversed with rotator cuff repair. More specifically, rotator cuff repair restored native glenohumeral contact area and contact pressure, while preventing superior humeral head migration and decreasing compensatory deltoid forces,” the researchers wrote.

“These time-zero observations indicate that undergoing rotator cuff repair may prevent the development of degenerative changes by significantly reducing glenohumeral joint loads and ensuring sufficiently stable joint kinematics.”

The study authors included Lukas N. Muench, M.D. of Technical University of Munich, Germany, Daniel P. Berthold, M.D. of Technical University of Munich, Germany, Alexander Otto of Technical University of Munich, Germany, M.D., Felix Dyrna, M.D. of University of Münster, Germany, Ryan Bell of University of Connecticut, Elifho Obopilwe of University of Connecticut, Mark P. Cote of University of Connecticut, Andreas B. Imhoff, M.D. of Technical University of Munich, Augustus D. Mazzocca, M.D. of University of Connecticut, and Knut Beitzel, M.D. of Technical University of Munich.