Sage Journals: Discover world-class research

Abstract

Background:

Posterior shoulder instability has been associated with abnormal acromial and glenoid morphology. However, the role of coracoid morphology in posterior instability remains unclear.

Hypothesis:

Patients undergoing surgery for posterior shoulder instability will have more inferiorly oriented and lateralized coracoids compared to patients with anterior instability or a noninstability comparison group.

Study Design:

Cohort study; Level of evidence, 3.

Methods:

Magnetic resonance imaging measurements were collected for 3 surgical cohorts: posterior instability (n = 41), anterior instability (n = 39), and a comparison group undergoing arthroscopy for snapping scapula (n = 38). Coracoid morphology metrics included: lateral coracoid offset, sagittal coracoid angle, coronal coracoid angle (CCA), transverse coracoid length, coracoacromial length (CAL), coracohumeral distance, and inferior coracoid coverage (ICC). Glenoid version and bone loss were also measured. One-way analysis of variance with Tukey post hoc testing or Kruskal-Wallis with Dunn testing was used as appropriate to compare groups. The P value was set a priori at <.05 to represent statistical significance. Analyses were performed using SPSS Version 30.0 and R Version 4.5.0.

Results:

The posterior instability group demonstrated a significantly higher CCA (69.4° ± 23.5°) than the anterior (52.8° ± 23.8°; P = .002) and comparison (56.9° ± 17.7°; P = .015) groups. The CAL and ICC were also significantly different in the posterior group (both P < .001). No significant differences in coracoid morphology were found between the anterior and comparison groups. Patients with posterior instability had significantly increased glenoid retroversion (–8.1° ± 3.7°) versus the anterior (–3.1° ± 5.3°) and comparison (–4.2° ± 4.3°) groups (both P < .001).

Conclusion:

Coracoid morphology differs significantly in patients undergoing posterior shoulder stabilization when compared to patients undergoing surgery for anterior instability or a comparison cohort. Increased CCA, increased CAL, and greater ICC are associated with patients undergoing posterior stabilization surgery. These findings suggest that a lower coracoid with increased inferior coverage of the humeral head may contribute to the pathogenesis of posterior instability.

Keywords

posterior shoulder instability coracoid morphology scapula dysplasia risk factors

Get full access to this article

View all access options for this article.

References

Antosh

Tokish

Owens

. Posterior shoulder instability. Sports Health. 2016;8(6):520-526. doi:10.1177/1941738116672446

Arciero

Mazzocca

. Posterior acromial bone block augmentation for the treatment of posterior glenoid bone loss associated with recurrent posterior shoulder instability. Tech Shoulder Elb Surg. 2006;7(4):210. doi:10.1097/01.bte.0000235403.44352.6e

Arner

Nolte

Ruzbarsky

, et al. Correlation of acromial morphology with risk and direction of shoulder instability: an MRI study. Am J Sports Med. 2023;51(12):3211-3216. doi:10.1177/03635465231197661

Arner

Ruzbarsky

Midtgaard

Peebles

Bradley

Provencher

. Defining critical glenoid bone loss in posterior shoulder capsulolabral repair. Am J Sports Med. 2021;49(8):2013-2019. doi:10.1177/03635465211016804

Bokshan

Kotchman

DeFroda

Cameron

Owens

. Incidence of posterior shoulder instability in the United States military: demographic considerations from a high-risk population. Am J Sports Med. 2021;49(2):340-345. doi:10.1177/0363546520976143

Bradley

McClincy

Arner

Tejwani

. Arthroscopic capsulolabral reconstruction for posterior instability of the shoulder: a prospective study of 200 shoulders. Am J Sports Med. 2013;41(9):2005-2014. doi:10.1177/0363546513493599

Eichinger

Galvin

Grassbaugh

Parada

. Glenoid dysplasia: pathophysiology, diagnosis, and management. J Bone Joint Surg Am. 2016;98(11):958-968. doi:10.2106/JBJS.15.00916

Friedman

Hawthorne

Genez

. The use of computerized tomography in the measurement of glenoid version. J Bone Joint Surg Am. 1992;74(7):1032-1037.

Gerber

Terrier

Ganz

. The role of the coracoid process in the chronic impingement syndrome. J Bone Joint Surg Br. 1985;67(5):703-708. doi:10.1302/0301-620X.67B5.4055864

10.

Gottschalk

Ghasem

Todd

Daruwalla

Xerogeanes

Karas

. Posterior shoulder instability: does glenoid retroversion predict recurrence and contralateral instability? Arthroscopy. 2015;31(3):488-493. doi:10.1016/j.arthro.2014.10.009

11.

Hachem

Molina-Creixell

Rius

, et al. Comprehensive management of posterior shoulder instability: diagnosis, indications, and technique for arthroscopic bone block augmentation. EFORT Open Rev. 2022;7(8):576-586. doi:10.1530/EOR-22-0009

12.

Hodax

Shah

Campbell

Cameron

Owens

. Measurement of the coracohumeral distance on magnetic resonance imaging in a large patient cohort. J Shoulder Elbow Surg. 2021;30(2):408-412. doi:10.1016/j.jse.2020.05.032

13.

Jacxsens

Elhabian

Brady

Chalmers

Tashjian

Henninger

. Coracoacromial morphology: a contributor to recurrent traumatic anterior glenohumeral instability? J Shoulder Elbow Surg. 2019;28(7):1316-1325.e1. doi:10.1016/j.jse.2019.01.009

14.

Katthagen

Tahal

Montgomery

Horan

Millett

. Association of traumatic and atraumatic posterior shoulder instability with glenoid retroversion and outcomes after arthroscopic capsulolabral repair. Arthroscopy. 2017;33(2):284-290. doi:10.1016/j.arthro.2016.07.020

15.

Kim

Noh

Park

Ryu

. Loss of chondrolabral containment of the glenohumeral joint in atraumatic posteroinferior multidirectional instability. J Bone Joint Surg Am. 2005;87(1):92-98. doi:10.2106/JBJS.C.01448

16.

Landis

Koch

. The measurement of observer agreement for categorical data. Biometrics. 1977;33(1):159-174.

17.

Levins

Badida

Garcia-Lopez

, et al. The influence of glenoid retroversion on posterior shoulder instability: a cadaveric study (214). Orthop J Sports Med. 2021;9(10 suppl 5):2325967121S00322. doi:10.1177/2325967121S00322

18.

Goetti

Sandman

Rouleau

. Influence of coracoid anatomy on the location of glenoid rim defects in anterior shoulder instability: 3D CT-scan evaluation of 51 patients. Surg Radiol Anat. 2020;42(8):895-901. doi:10.1007/s00276-020-02492-w

19.

Livesey

Bedrin

Baird

, et al. Acromion morphology is associated with glenoid bone loss in posterior glenohumeral instability. J Shoulder Elbow Surg. 2023;32(9):1850-1856. doi:10.1016/j.jse.2023.03.005

20.

Lopez

Ding

Bixby

, et al. Association between shoulder coracoacromial arch morphology and anterior instability of the shoulder. JSES Int. 2020;4(4):772-779. doi:10.1016/j.jseint.2020.07.013

21.

Makovicka

Moore

Pollock

, et al. Magnetic resonance imaging analysis demonstrates improved reliability in measuring shoulder glenoid bone loss using a two-thirds glenoid height technique compared to the “best-fit circle.” Arthroscopy. 2024;40(3):666-671. doi:10.1016/j.arthro.2023.06.048

22.

Meuffels

Schuit

Biezen

Reijman

Verhaar

JAN

. The posterior bone block procedure in posterior shoulder instability: a long-term follow-up study. J Bone Joint Surg Br. 2010;92(5):651-655. doi:10.1302/0301-620X.92B5.23529

23.

Meyer

Ernstbrunner

Boyce

Imam

El Nashar

Gerber

. Posterior acromial morphology is significantly associated with posterior shoulder instability. J Bone Joint Surg Am. 2019;101(14):1253-1260. doi:10.2106/JBJS.18.00541

24.

Nacca

Gil

Badida

Crisco

Owens

. Critical glenoid bone loss in posterior shoulder instability. Am J Sports Med. 2018;46(5):1058-1063. doi:10.1177/0363546518758015

25.

Owens

Campbell

Cameron

. Risk factors for anterior glenohumeral instability. Am J Sports Med. 2014;42(11):2591-2596. doi:10.1177/0363546514551149

26.

Testa

Katz

Zhang

, et al. Rotator cuff tears to shoulder instability: the relationship between acromial morphology and shoulder pathology. JBJS Rev. 2024;12(1):e23.00188. doi:10.2106/JBJS.RVW.23.00188

27.

Testa

van der List

Waterman

Caldwell

Parada

Owens

. Management of bone loss in posterior glenohumeral shoulder instability: current concepts. JBJS Rev. 2024;12(4):e23.00243. doi:10.2106/JBJS.RVW.23.00243

28.

Unal

. Defining an optimal cut-point value in ROC analysis: an alternative approach. Comput Math Methods Med. 2017;2017:3762651. doi:10.1155/2017/3762651

29.

Wolfe

Elsenbeck

Nappo

, et al. Effect of posterior glenoid bone loss and retroversion on arthroscopic posterior glenohumeral stabilization. Am J Sports Med. 2020;48(11):2621-2627. doi:10.1177/0363546520946101

30.

Woodmass

Lee

, et al. Incidence of posterior shoulder instability and trends in surgical reconstruction: a 22-year population-based study. J Shoulder Elbow Surg. 2019;28(4):611-616. doi:10.1016/j.jse.2018.08.046

Coracoid Morphology and the Risk of Posterior Shoulder Instability: A Magnetic Resonance Imaging Study

Abstract

Background:

Hypothesis:

Study Design:

Methods:

Results:

Conclusion:

Keywords

Get full access to this article

References