Impact of Reverse Shoulder Arthroplasty on Rotator Cuff Biomechanics
Author Information
Author(s): Herrmann Sebastian, König Christian, Heller Markus, Perka Carsten, Greiner Stefan
Primary Institution: Charité-Universitätsmedizin Berlin
Hypothesis
Reverse shoulder arthroplasty reduces the moment arms and the origin-to-insertion distance of subscapularis and teres minor.
Conclusion
Reduced rotational moment arms and decreased origin-to-insertion distances may explain the functional deficits observed after reverse shoulder arthroplasty.
Supporting Evidence
- Moment arms for humeral rotation are significantly smaller for cranial segments of SSC and all segments of TMIN in abduction angles of 30 degrees and above.
- Abduction moment arms were significantly decreased for all segments.
- OID was significantly smaller for all muscles at the 15 degree position.
Takeaway
This study looked at how a shoulder surgery changes the way certain muscles work, which might help explain why some movements are harder after the surgery.
Methodology
The study used 3D models from CT scans of seven cadaveric specimens to calculate muscle moment arms and origin-to-insertion distances.
Potential Biases
Potential bias due to the small sample size and the specific conditions of the cadaveric specimens.
Limitations
The accuracy of muscle origin and insertion identification was assumed to be low, and muscle wrapping was not included in the model.
Participant Demographics
Mean age of 77 years, with a range of 63-84 years; five right and two left shoulders.
Statistical Information
P-Value
p ≤ 0.0012
Statistical Significance
p ≤ 0.005
Digital Object Identifier (DOI)
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