Original Article| Volume 38, ISSUE 11, P2960-2968, November 2022

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Anterolateral Acromioplasty Does Not Change the Critical Shoulder Angle and Acromion Index in a Clinically Relevant Amount


      Assessment on whether radiographic parameters of the acromion measured in radiographs change significantly after anterolateral acromioplasty.


      This retrospective study included patients that underwent an arthroscopic anterolateral acromioplasty between January 2014 and September 2020. n = 435 subjects with high-quality preoperative and postoperative radiographs according to Suter-Henninger criteria were included in the final assessment. All measurements were independently performed by the first and second author in a blinded fashion using dicomPACS software: acromion index (AI), critical shoulder angle (CSA), lateral acromial angle (LAA), beta angle, acromio-humeral distance (AHD), Aoki angle, frontal supraspinatus outlet angle (FSOW), and acromion type, according to Bigliani. SPSS software was used for statistical analysis.


      The beta angle and the CSA did not significantly change after operation (alpha power 0.32 and 0.11, respectively). In a subgroup analysis of patients with a pathological CSA >35° (n = 194), the CSA changed from 38.62 (range: 35.08-47.52, SD 2.83) to 38.04 (range: 29.18-48.12, SD 3.77) postoperatively (P = .028) (Fig 8). All other parameters changed significantly after operation (AI, AHD, FSOW, and Aoki; P = .001, LAA; P = .039) (Fig. 9). The interobserver and intraobserver reliability was good to excellent in the majority of measured values. Mean patient age was 59.2 years (range: 18.1-87.1; SD 11.3), mean height was 1.73 meters (range: 1,50-1.98, SD 0.09), mean weight was 80.2 kg (range: 37.0-133.0, SD 16.68), and mean body mass index was 26.6 (range: 0.0-46.1, SD 4.73).


      Anterolateral acromioplasty producing a flat acromion undersurface did not result in a significant change of the CSA in the study population. Pathological preoperative CSA values of >35° were significantly reduced but not to normal values, but only by a small amount that puts the clinical relevance into question.

      Level of Evidence

      IV, diagnostic study, case series
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        • Milgrom C.
        • Schaffler M.
        • Gilbert S.
        • van Holsbeeck M.
        Rotator-cuff changes in asymptomatic adults. The effect of age, hand dominance and gender.
        J Bone Joint Surg. 1995; 77-B: 296-298
        • Teunis T.
        • Lubberts B.
        • Reilly B.T.
        • Ring D.
        A systematic review and pooled analysis of the prevalence of rotator cuff disease with increasing age.
        J Shoulder Elbow Surg. 2014; 23: 1913-1921
        • Yamaguchi K.
        • Ditsios K.
        • Middleton W.D.
        • Hildebolt C.F.
        • Galatz L.M.
        • Teefey S.A.
        The demographic and morphological features of rotator cuff disease. A comparison of asymptomatic and symptomatic shoulders.
        J Bone Joint Surg Am. 2006; 88: 1699-1704
        • Keener J.D.
        • Skelley N.W.
        • Stobbs-Cucchi G.
        • et al.
        Shoulder activity level and progression of degenerative cuff disease.
        J Shoulder Elbow Surg. 2017; 26: 1500-1507
        • Yamamoto A.
        • Takagishi K.
        • Osawa T.
        • et al.
        Prevalence and risk factors of a rotator cuff tear in the general population.
        J Shoulder Elbow Surg. 2010; 19: 116-120
        • Ozaki J.
        • Fujimoto S.
        • Nakagawa Y.
        • Masuhara K.
        • Tamai S.
        Tears of the rotator cuff of the shoulder associated with pathological changes in the acromion. A study in cadavera.
        J Bone Joint Surg Am. 1988; 70: 1224-1230
        • Petersson C.J.
        • Gentz C.F.
        Ruptures of the supraspinatus tendon. The significance of distally pointing acromioclavicular osteophytes.
        Clin Orthop Relat Res. 1983; 174: 143-148
        • Bigliani L.U.
        • Morrison D.S.
        • April E.W.
        The morphology of the acromion and its relationship to rotator cuff tears.
        Orthop Trans. 1986; 10: 228
        • Gumina S.
        • Candela V.
        • Passaretti D.
        • et al.
        The association between body fat and rotator cuff tear: the influence on rotator cuff tear sizes.
        J Shoulder Elbow Surg. 2014; 23: 1669-1674
        • Tashjian R.Z.
        • Farnham J.M.
        • Albright F.S.
        • Teerlink C.C.
        • Cannon-Albright L.A.
        Evidence for an inherited predisposition contributing to the risk for rotator cuff disease.
        J Bone Joint Surg Am. 2009; 91: 1136-1142
        • Loew M.
        • Magosch P.
        • Lichtenberg S.
        • Habermeyer P.
        • Porschke F.
        How to discriminate between acute traumatic and chronic degenerative rotator cuff lesions: An analysis of specific criteria on radiography and magnetic resonance imaging.
        J Shoulder Elbow Surg. 2015; 24: 1685-1693
        • Nyffeler R.W.
        • Werner C.M.
        • Sukthankar A.
        • Schmid M.R.
        • Gerber C.
        Association of a large lateral extension of the acromion with rotator cuff tears.
        J Bone Joint Surg Am. 2006; 88: 800-805
        • Moor B.K.
        • Kuster R.
        • Osterhoff G.
        • et al.
        Inclination-dependent changes of the critical shoulder angle significantly influence superior glenohumeral joint stability.
        Clin Biomech (Bristol, Avon). 2016; 32: 268-273
        • Song J.G.
        • Yun S.J.
        • Song Y.W.
        • Lee S.H.
        High performance of critical shoulder angle for diagnosing rotator cuff tears on radiographs.
        Knee Surg Sports Traumatol Arthrosc. 2019; 27: 289-298
        • Zeng Y.M.
        • Xu C.
        • Zhang K.
        • Yu D.G.
        • Zhang J.
        Prediction of rotator cuff injury associated with acromial morphology: A three-dimensional measurement study.
        Orthop Surg. 2020; 12: 1394-1404
        • Tang Y.
        • Hou J.
        • Li Q.
        • et al.
        The effectiveness of using the critical shoulder angle and acromion index for predicting rotator cuff tears: Accurate diagnosis based on standard and nonstandard anteroposterior radiographs.
        Arthroscopy. 2019; 35: 2553-2561
        • Kim J.H.
        • Min Y.K.
        • Gwak H.C.
        • Kim C.W.
        • Lee C.R.
        • Lee S.J.
        Rotator cuff tear incidence association with critical shoulder angle and subacromial osteophytes.
        J Shoulder Elbow Surg. 2019; 28: 470-475
        • Moor B.K.
        • Wieser K.
        • Slankamenac K.
        • Gerber C.
        • Bouaicha S.
        Relationship of individual scapular anatomy and degenerative rotator cuff tears.
        J Shoulder Elbow Surg. 2014; 23: 536-541
        • İncesoy M.A.
        • Yıldız K.
        • Türk Ö.
        • et al.
        The critical shoulder angle, the acromial index, the glenoid version angle and the acromial angulation are associated with rotator cuff tears.
        Knee Surg Sports Traumatol Arthrosc. 2021; 29: 2257-2263
        • Docter S.
        • Khan M.
        • Ekhtiari S.
        • et al.
        The relationship between the critical shoulder angle and the incidence of chronic, full-thickness rotator cuff tears and outcomes after rotator cuff repair: A systematic review.
        Arthroscopy. 2019; 35: 3135-3143.e3134
        • Scheiderer B.
        • Imhoff F.B.
        • Johnson J.D.
        • et al.
        Higher critical shoulder angle and acromion index are associated with increased retear risk after isolated supraspinatus tendon repair at short-term follow up.
        Arthroscopy. 2018; 34: 2748-2754
        • Sheean A.J.
        • Sa D.
        • Woolnough T.
        • Cognetti D.J.
        • Kay J.
        • Burkhart S.S.
        Does an increased critical shoulder angle affect re-tear rates and clinical outcomes following primary rotator cuff repair? A systematic review.
        Arthroscopy. 2019; 35: 2938-2947.e2931
        • Li H.
        • Chen Y.
        • Chen J.
        • Hua Y.
        • Chen S.
        Large critical shoulder angle has higher risk of tendon retear after arthroscopic rotator cuff repair.
        Am J Sports Med. 2018; 46: 1892-1900
        • Chalmers P.N.
        • Salazar D.
        • Steger-May K.
        • Chamberlain A.M.
        • Yamaguchi K.
        • Keener J.D.
        Does the critical shoulder angle correlate with rotator cuff tear progression?.
        Clin Orthop Relat Res. 2017; 475: 1608-1617
        • Opsomer G.J.
        • Verstuyft L.
        • Muermans S.
        Long-term follow-up of patients with a high critical shoulder angle and acromion index: Is there an increased retear risk after arthroscopic supraspinatus tendon repair?.
        JSES Int. 2020; 4: 882-887
        • Garcia G.H.
        • Liu J.N.
        • Degen R.M.
        • et al.
        Higher critical shoulder angle increases the risk of retear after rotator cuff repair.
        J Shoulder Elbow Surg. 2017; 26: 241-245
        • Misir A.
        • Uzun E.
        • Kizkapan T.B.
        • Ozcamdalli M.
        • Sekban H.
        • Guney A.
        Factors associated with the development of early- to mid-term cuff-tear arthropathy following arthroscopic rotator cuff repair.
        J Shoulder Elbow Surg. 2021; 30: 1572-1580
        • Harada N.
        • Gotoh M.
        • Ishitani E.
        • et al.
        Combination of risk factors affecting retear after arthroscopic rotator cuff repair: A decision tree analysis.
        J Shoulder Elbow Surg. 2021; 30: 9-15
        • Jung W.
        • Lee S.
        • Hoon Kim S.
        The natural course of and risk factors for tear progression in conservatively treated full-thickness rotator cuff tears.
        J Shoulder Elbow Surg. 2020; 29: 1168-1176
        • MacLean I.S.
        • Gowd A.K.
        • Waterman B.R.
        • et al.
        The effect of acromioplasty on the critical shoulder angle and acromial index.
        Arthrosc Sports Med Rehabil. 2020; 2: e623-e628
        • Billaud A.
        • Cruz-Ferreira E.
        • Pesquer L.
        • Abadie P.
        • Carlier Y.
        • Flurin P.H.
        Does the critical shoulder angle decrease after anterior acromioplasty?.
        Arch Orthop Trauma Surg. 2019; 139: 1125-1132
        • Girard M.
        • Colombi R.
        • Azoulay V.
        • et al.
        Does anterior acromioplasty reduce critical shoulder angle?.
        Orthop Traumatol Surg Res. 2020; 106: 1101-1106
        • Suter T.
        • Gerber Popp A.
        • et al.
        The influence of radiographic viewing perspective and demographics on the critical shoulder angle.
        J Shoulder Elbow Surg. 2015; 24: e149-e158
        • Henninger H.B.
        • Suter T.
        • Chalmers P.N.
        Editorial commentary: Is your critical shoulder angle accurate? Only if you can verify that you have the correct images.
        Arthroscopy. 2021; 37: 447-449
        • Kim J.H.
        • Gwak H.C.
        • Kim C.W.
        • Lee C.R.
        • Kwon Y.U.
        • Seo H.W.
        Difference of critical shoulder angle (CSA) according to minimal rotation: Can minimal rotation of the scapula be allowed in the evaluation of CSA?.
        Clin Orthop Surg. 2019; 11: 309-315
        • Ellman H.
        Arthroscopic subacromial decompression: analysis of one- to three-year results.
        Arthroscopy. 1987; 3: 173-181
        • Caspari R.B.
        • Thal R.
        A technique for arthroscopic subacromial decompression.
        Arthroscopy. 1992; 8: 23-30
        • Suter T.
        • Krähenbühl N.
        • Howell C.K.
        • Zhang Y.
        • Henninger H.B.
        Viewing perspective malrotation influences angular measurements on lateral radiographs of the scapula.
        J Shoulder Elbow Surg. 2020; 29: 1030-1039
        • Moor B.K.
        • Bouaicha S.
        • Rothenfluh D.A.
        • Sukthankar A.
        • Gerber C.
        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. 2013; 95-b: 935-941
        • Banas M.P.
        • Miller R.J.
        • Totterman S.
        Relationship between the lateral acromion angle and rotator cuff disease.
        J Shoulder Elbow Surg. 1995; 4: 454-461
        • Maurer A.
        • Fucentese S.F.
        • Pfirrmann C.W.
        • et al.
        Assessment of glenoid inclination on routine clinical radiographs and computed tomography examinations of the shoulder.
        J Shoulder Elbow Surg. 2012; 21: 1096-1103
      1. Schleberger YR. Die Morphologie des Rotatorenmanschettendefektes im Zusammenhang mit der Radiobiometrie der Schulter [Dissertation]. Ruhr-Universität Bochum, Universitätsbibliothek: Medizinische Fakultät, Ruhr-Universität Bochum, Medizinische Fakultät; 2019.

        • Petersson C.J.
        • Redlund-Johnell I.
        The subacromial space in normal shoulder radiographs.
        Acta Orthop Scand. 1984; 55: 57-58
        • Aoki M.
        • Ishii S.
        • Usui M.
        The slope of the acromion and rotator cuff impingement.
        Orthop Trans. 1986; 10: 228
        • Koo T.K.
        • Li M.Y.
        A guideline of selecting and reporting intraclass correlation coefficients for reliability research.
        J Chiropr Med. 2016; 15: 155-163
        • Cicchetti C.
        Guidelines, criteria, and rules of thumb for evaluating normed and standardized assessment instruments in psychology.
        Psychol Assess. 1994; 6: 284-290
        • Bjarnison A.O.
        • Sørensen T.J.
        • Kallemose T.
        • Barfod K.W.
        The critical shoulder angle is associated with osteoarthritis in the shoulder but not rotator cuff tears: A retrospective case-control study.
        J Shoulder Elbow Surg. 2017; 26: 2097-2102
        • Chalmers P.N.
        • Beck L.
        • Miller M.
        • et al.
        Acromial morphology is not associated with rotator cuff tearing or repair healing.
        J Shoulder Elbow Surg. 2020; 29: 2229-2239
        • Lädermann A.
        The law of use and disuse: Critical shoulder angle and rotator cuff tears—Association does not imply causation.
        Arthroscopy. 2020; 36: 2342-2343
        • Maalouly J.
        • Tawk A.
        • Aouad D.
        • et al.
        Association of acromial morphological parameters and rotator cuff tears, and evaluation of the influence of age and gender on the parameters and impact on cuff tears: A study on a Middle Eastern population.
        Asia Pac J Sports Med Arthrosc Rehabil Technol. 2020; 20: 17-23
        • Mantell M.T.
        • Nelson R.
        • Lowe J.T.
        • Endrizzi D.P.
        • Jawa A.
        Critical shoulder angle is associated with full-thickness rotator cuff tears in patients with glenohumeral osteoarthritis.
        J Shoulder Elbow Surg. 2017; 26: e376-e381
        • Smith G.C.S.
        • Liu V.
        • Lam P.H.
        The critical shoulder angle shows a reciprocal change in magnitude when evaluating symptomatic full-thickness rotator cuff tears versus primary glenohumeral osteoarthritis as compared with control subjects: A systematic review and meta-analysis.
        Arthroscopy. 2020; 36: 566-575
        • Altintas B.
        • Kaab M.
        • Greiner S.
        Arthroscopic lateral acromion resection (ALAR) optimizes rotator cuff tear relevant scapula parameters.
        Arch Orthop Trauma Surg. 2016; 136: 799-804
        • Katthagen J.C.
        • Marchetti D.C.
        • Tahal D.S.
        • Turnbull T.L.
        • Millett P.J.
        The effects of arthroscopic lateral acromioplasty on the critical shoulder angle and the anterolateral deltoid origin: An anatomic cadaveric study.
        Arthroscopy. 2016; 32: 569-575
        • Marchetti D.C.
        • Katthagen J.C.
        • Mikula J.D.
        • et al.
        Impact of arthroscopic lateral acromioplasty on the mechanical and structural integrity of the lateral deltoid origin: A cadaveric study.
        Arthroscopy. 2017; 33: 511-517
        • Gerber C.
        • Catanzaro S.
        • Betz M.
        • Ernstbrunner L.
        Arthroscopic correction of the critical shoulder angle through lateral acromioplasty: A safe adjunct to rotator cuff repair.
        Arthroscopy. 2018; 34: 771-780
        • Tauber M.
        • Habermeyer P.
        • Zumbansen N.
        • Martetschläger F.
        Lateral acromioplasty for correction of the critical shoulder angle.
        Obere Extremität. 2020;
        • Franceschetti E.
        • Giovannetti de Sanctis E.
        • Palumbo A.
        • et al.
        Lateral Acromioplasty has a positive impact on rotator cuff repair in patients with a critical shoulder angle greater than 35 degrees.
        J Clin Med. 2020; 9: 3950
        • Karns M.R.
        • Jacxsens M.
        • Uffmann W.J.
        • Todd D.C.
        • Henninger H.B.
        • Burks R.T.
        The critical acromial point: the Anatomic location of the lateral acromion in the critical shoulder angle.
        J Shoulder Elbow Surg. 2018; 27: 151-159
        • Olmos M.I.
        • Boutsiadis A.
        • Swan J.
        • et al.
        Lateral acromioplasty cannot sufficiently reduce the critical shoulder angle if preoperatively measured over 40°.
        Knee Surg Sports Traumatol Arthrosc. 2021; 29: 240-249