Does the Walch type B shoulder have a transverse force couple imbalance? A volumetric analysis of segmented rotator cuff muscles in osteoarthritic shoulders

Arenas-Miquelez, Antonio; Liu, Victor K.; Cavanagh, Joseph; Ferreira, Louis M.; Bokor, Desmond J.; Athwal, George S.; Raniga, Sumit

doi:10.1016/j.jse.2021.02.005

Cited by 11 publications

(6 citation statements)

References 30 publications

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“…Patients with eccentric deformities demonstrated no relative external to internal rotation weakness compared with patients with concentric deformities, but they exhibited greater variability in strength measured with 3D methods. More intramuscular fat was found in the posterior RC in patients with eccentric compared with concentric deformities, as reported previously [4, 12, 20, 42]. The size of the posterior relative to the anterior RC, after adjusting for intramuscular fat, did not differ between deformity groups.…”

Section: Discussionsupporting

confidence: 85%

“…More intramuscular fat was found in the posterior RC in patients with eccentric compared with concentric deformities, as reported previously [4,12,20,42]. The size of the posterior relative to the anterior RC, after adjusting for intramuscular fat, did not differ between deformity groups.…”

Section: Discussionsupporting

confidence: 85%

“…Our results show the posterior-to-anterior RC fat% ratio was higher in patients with eccentric deformities than in patients with concentric deformities, which is in agreement with prior studies showing greater posterior RC intramuscular fat in patients with eccentric deformities [4,12,20,42]. Our quantitative methods show that the median fat% in the posterior RC in patients with eccentric deformities (10.2%) fell within the range identified for Goutallier Grade 2 fatty degeneration (6.44% to 14.86%), whereas that in patients with concentric deformities (4.83%) fell within the range for Goutallier Grade 1 (1.1% to 9.70%) [31].…”

Section: Resting and Torque-dependent Painsupporting

confidence: 93%

“…With regard to our secondary study goals, MRIs were only collected in a subset of patients, limiting the information we have on RC fat infiltration to this subset. Despite the small sample size, the differences observed between deformity groups in the amount of fat in the posterior relative to the anterior RC agree with existing evidence [4, 12, 20, 42]. Additionally, we examined all primary and secondary study outcome metrics in the subsets of patients with and without MRIs in each deformity group and confirmed the subsets were representative samples.…”

Section: Discussionsupporting

confidence: 81%

“…Our quantitative methods show that the median fat% in the posterior RC in patients with eccentric deformities (10.2%) fell within the range identified for Goutallier Grade 2 fatty degeneration (6.44% to 14.86%), whereas that in patients with concentric deformities (4.83%) fell within the range for Goutallier Grade 1 (1.1% to 9.70%) [31]. Our results also agree with prior work showing no difference in the volume ratio (nonfat-adjusted) of the posterior-to-anterior RC between patients with eccentric deformities and those with concentric deformities [4]. Although not previously reported, we found that the relative remaining muscle, represented by the posterior-to-anterior RC fat-adjusted cross-sectional area ratio, did not differ between groups.…”

Section: Resting and Torque-dependent Painsupporting

confidence: 90%

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No Strength Differences Despite Greater Posterior Rotator Cuff Intramuscular Fat in Patients With Eccentric Glenohumeral Osteoarthritis

Coats-Thomas

Baillargeon

Ludvig

et al. 2022

Clin Orthop Relat Res

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BackgroundWhen nonoperative measures do not alleviate the symptoms of glenohumeral osteoarthritis (OA), patients with advanced OA primarily are treated with anatomic total shoulder arthroplasty (TSA). It is unknown why TSAs performed in patients with eccentric (asymmetric glenoid wear) compared with concentric (symmetric glenoid wear) deformities exhibit higher failure rates, despite surgical advances. Persistent disruption of the posterior-to-anterior rotator cuff (RC) force couple resulting from posterior RC intramuscular degeneration in patients with eccentric deformities could impair external rotation strength and may contribute to eventual TSA failure. Pain and intramuscular fat within the RC muscles may impact external rotation strength measures and are important to consider.Questions/purposes(1) Is there relative shoulder external rotation weakness in patients with eccentric compared with concentric deformities? (2) Is there higher resting or torque-dependent pain in patients with eccentric compared with concentric deformities? (3) Do patients with eccentric deformities have higher posterior-to-anterior RC intramuscular fat percent ratios than patients with concentric deformities?MethodsFrom February 2020 to November 2021, 65% (52 of 80) of patients with OA met study eligibility criteria. Of these, 63% (33 of 52) of patients enrolled and provided informed consent. From a convenience sample of 21 older adults with no history of shoulder pain, 20 met eligibility criteria as control participants. Of the convenience sample, 18 patients enrolled and provided informed consent. In total for this prospective, cross-sectional study, across patients with OA and control participants, 50% (51 of 101) of participants were enrolled and allocated into the eccentric (n = 16), concentric (n = 17), and control groups (n = 18). A 3-degree-of-freedom load cell was used to sensitively quantify strength in all three dimensions surrounding the shoulder. Participants performed maximal isometric contractions in 26 1-, 2-, and 3-degree-of-freedom direction combinations involving adduction/abduction, internal/external rotation, and/or flexion/extension. To test for relative external rotation weakness, we quantified relative strength in opposing directions (three-dimensional [3D] strength balance) along the X (+adduction/-abduction), Y (+internal/-external rotation), and Z (+flexion/-extension) axes and compared across the three groups. Patients with OA rated their shoulder pain (numerical rating 0-10) before testing at rest (resting pain; response to “How bad is your pain today?”) and with each maximal contraction (torque-dependent pain; numerical rating 0-10). Resting and torque-dependent pain were compared between patients with eccentric and concentric deformities to determine if pain was higher in the eccentric group. The RC cross-sectional areas and intramuscular fat percentages were quantified on Dixon-sequence MRIs by a single observer who performed manual segmentation using previously validated methods. Ratios of poste...

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Section: Discussionsupporting

confidence: 85%