Undergoing rotator cuff repair may prevent degenerative changes by reducing glenohumeral joint loads and stabilizing joint kinematics, according to a new study.
The study, “Increased Glenohumeral Joint Loads Due to a Supraspinatus Tear Can Be Reversed With Rotator Cuff Repair: A Biomechanical Investigation,” is published in the May 1, 2022 issue of the journal Arthroscopy.
For this study, a German and U.S. research team evaluated the effect of an isolated full-thickness supraspinatus tear on glenohumeral kinematics and contact mechanics. Using a cadaveric model, the team also calculated motion change following rotator cuff repair.
The team employed a dynamic shoulder simulator to test ten fresh-frozen cadaveric shoulders (mean age: 63.1 ± 4.6 years). They also used a pressure-mapping sensor that they placed between the humeral head and the glenoid.
Each of the shoulders was tested under three conditions: native, isolated full-thickness supraspinatus tear and rotator cuff repair. The team then used 3D motion tracking software to measure maximum abduction angle and superior humeral head migration.
They also determined cumulative deltoid force and glenohumeral contact mechanics, including contact area and contact pressure at resting position and as well as at 15°, 30°, 45°, and 60° of glenohumeral abduction.
Compared to native, the supraspinatus tear resulted in a significant decrease in maximum abduction angle (Δ−8.3°; p < .001) along with a superior humeral head migration of 6.4 ± 3.8 mm, while significantly increasing cumulative deltoid force (Δ20.5 N; p = .008), contact pressure (Δ63.1 kPa p < .001), and peak contact pressure (Δ278.6 kPa; p < .001), as well as decreasing contact area (Δ−45.8 mm2; p < .001) at each degree of abduction. Rotator cuff repair reduced superior humeral head migration to 1.2 ± 2.5 mm, while restoring native maximum abduction angle, cumulative deltoid force (Δ1.8 N), contact area (Δ4.5 mm2), contact pressure (Δ−4.5 kPa) and peak contact pressure (Δ19.9 kPa) 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 0 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 were Lukas N. Muench, M.D., of Technical University of Munich, Germany, Daniel P. Berthold, M.D., of Technical University of Munich, Germany Alexander Otto, M.D., of Technical University of Munich, Germany, Felix Dyrna, M.D., of University of Münster, Münster, Germany, Ryan Bell, B.S, of University of Connecticut, Elifho Obopilwe, M.S., of University of Connecticut, Mark P. Cote, M.S., D.P.T., of the University of Connecticut, Andreas B. Imhoff, M.D., of Technical University of Munich, Augustus D. Mazzocca, M.S., M.D., of the University of Connecticut and Knut Beitzel, M.D., of Technical University of Munich.
