The association between a low critical shoulder angle and SLAP lesions
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To evaluate the critical shoulder angle (CSA), acromion index (AI) and further acromion parameters in patients with isolated SLAP lesions compared with patients without SLAP lesions.
Between 2012 and 2016, the CSA, AI, lateral acromion angle (LAA) and acromion slope (AS) were radiologically examined in consecutive patients > 18 years having had a shoulder arthroscopy with isolated SLAP lesion types II–IV. These were compared to controls without SLAP lesions and without (control group I) or with (control group II) complete supraspinatus tendon (SSP) tears.
75/103 patients with isolated SLAP lesion types II–IV with a mean age of 46.5 years (± 13.0, 18.1–76.3) were analyzed, 61% of them being male. For control, n = 211 consecutive patients (47% male) with an intact SSP and SLAP complex and a mean age of 52.3 years (± 15.0, 18.6–88.4) and n = 115 patients (60% male) with an intact SLAP complex but complete SSP tears, mean age 66.6 years (± 9.3, 44.7–87.9) were examined. The CSA in SLAP patients was 29.6° (± 3.5, 21.0–38.0), 33.8° (± 3.7, 25.1–46.9) in no SLAP and no SSP (p < 0.001) and 36.7° (± 3.6, 29.1–46.6) in no SLAP but SSP (p < 0.001). The area under the curve (AUC) for CSA was 0.83 for SLAP lesions resulting in a probability of 83% for patients with SLAP lesion to be associated with a specific CSA.
Isolated SLAP lesion types II–IV are associated with a low CSA < 30°. The AI, the AS as well as the LAA showed no correlation with SLAP lesions.
Level of evidence
Retrospective comparative study, Level III.
KeywordsShoulder arthroscopy SLAP lesion Critical shoulder angle Acromion index Risk factor Overhead sports
Area under the curve
Critical shoulder angle
Exempli gratia; for example
Id est; that is to say
Institutional review board
Lateral acromion angle
Long head of biceps tendon
Receiving operating characteristic
Superior labrum from anterior to posterior
There is no funding source.
Compliance with ethical standards
Conflict of interest
The authors declare that they have no conflict of interest.
All procedures performed in studies involving human participants were in concordance with the ethical standards of the institutional research committee and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards.
- 2.Aoki M, Ishii S, Usui M (1986) The slope of the acromion and rotator cuff impingement. Orthop Trans 10:168–171Google Scholar
- 6.Burkhart SS, Lo IKY, Brady PC (2006) A cowboy’s guide to advanced shoulder arthroscopy. Lippincott Williams & Wilkins, Philadelphia, pp 65–66Google Scholar
- 18.Hothorn T, Hornik K, Zeileis A (2006) Unbiased recursive partitioning: a conditional inference framework. J Comput Graph Stat 15:651–674Google Scholar
- 25.Mihata T, McGarry MH, Tibone JE, Fitzpatrick MJ, Kinoshita M, Lee TQ (2008) Biomechanical assessment of Type II superior labral anterior-posterior (SLAP) lesions associated with anterior shoulder capsular laxity as seen in throwers: a cadaveric study. Am J Sports Med 36:1604–1610PubMedGoogle Scholar
- 26.Miswan MF, Saman MS, Hui TS, Al-Fayyadh MZ, Ali MR, Min NW (2017) Correlation between anatomy of the scapula and the incidence of rotator cuff tear and glenohumeral osteoarthritis via radiological study. J Orthop Surg (Hong Kong) 25:1–5Google Scholar
- 27.Mollon B, Mahure SA, Ensor KL, Zuckerman JD, Kwon YW, Rokito AS (2016) Subsequent shoulder surgery after isolated arthroscopic SLAP repair. Arthroscopy 32(1954–1962):e1951Google Scholar
- 28.Moor BK, Bouaicha S, Rothenfluh DA, Sukthankar A, Gerber C (2013) Is there an association between the individual anatomy of the scapula and the development of rotator cuff tears or osteoarthritis of the glenohumeral joint? A radiological study of the critical shoulder angle. Bone Joint J 95-B:935–941PubMedGoogle Scholar
- 34.Patzer T, Habermeyer P, Hurschler C, Bobrowitsch E, Paletta JR, Fuchs-Winkelmann S et al (2011) Increased glenohumeral translation and biceps load after SLAP lesions with potential influence on glenohumeral chondral lesions: a biomechanical study on human cadavers. Knee Surg Sports Traumatol Arthrosc 19:1780–1787PubMedGoogle Scholar
- 35.Patzer T, Habermeyer P, Hurschler C, Bobrowitsch E, Wellmann M, Kircher J et al (2012) The influence of superior labrum anterior to posterior (SLAP) repair on restoring baseline glenohumeral translation and increased biceps loading after simulated SLAP tear and the effectiveness of SLAP repair after long head of biceps tenotomy. J Shoulder Elbow Surg 21:1580–1587PubMedGoogle Scholar
- 43.Taylor SA, Degen RM, White AE, McCarthy MM, Gulotta LV, O’Brien SJ et al (2017) Risk factors for revision surgery after superior labral anterior-posterior repair. Am J Sports Med. https://doi.org/10.1177/0363546517691950363546517691950 CrossRefPubMedGoogle Scholar