Multiple papers have described aspects of treatment of acromioclavicular (AC) joint injuries. Most have emphasized aspects of surgical treatment, and some papers have addressed non-operative treatment. Few papers have highlighted the specific pathoanatomy of an AC joint injury or have described methods of evaluating the 3-dimensional pathomechanics resulting from the pathoanatomical injury. This paper is based on 3 observations: (1) AC joint injuries exist and present on a spectrum of pathoanatomy; (2) The effect of the pathoanatomy on normal AC joint mechanics to produce pathomechanics is dependent on the extent of the pathoanatomy; and (3) Treatment protocols should be developed to address the specific pathoanatomy to optimize the mechanics. A comprehensive clinical approach emphasizing the evaluation of the extent of the anatomic injury and understanding its mechanical consequences regarding shoulder and arm function is a key in the development of guidelines for developing operative or non-operative treatment protocols and for establishing outcomes of the treatment protocols.
DebskiREParsonsLMIIIFenwickJ,et al.Ligament mechanics during three degree-of-freedom motion at the acromioclavicular joint. Ann Biomed Eng2000; 28: 612–618.
2.
BeitzelKObopilweEApostolakosJ, , et al.Rotational and translational stability of different methods for direct acromioclavicular ligament repair in anatomic acromioclavicular joint reconstruction. Am J Sports Med2014; 42: 2141–2148.
3.
OkiSMatsumuraNIwamotoW, , et al.Acromioclavicular joint ligamentous system contributing to clavicular strut function: a cadaveric study. J Shoulder Elbow Surg2013; 22: 1433–1439.
4.
OkiSMatsumuraNIwamotoW, , et al.The function of the acromioclavicular and coracoclavicular ligaments in shoulder motion: a whole-cadaver study. Am J Sports Med2012; 40: 2612–2626.
5.
SaharaWSugamotoKMuraiM,et al.Three-dimensional clavicular and acromioclavicular rotations during arm abduction using vertically open MRI. J Orthop Res2007; 25: 1243–1249.
6.
CopelandSKesselL. Disruption of the acromioclavicular joint: surgical anatomy and biological reconstruction. Injury1980; 11: 208–214.
7.
BeitzelKSablanNChowaniecDM, , et al.Sequential resection of the distal clavicle and its effects on horizontal acromioclavicular joint translation. Am J Sports Med2012; 40: 681–685.
8.
PhadnisJBainGIBakK. Pathoanatomy of acromioclavicular joint instability. In: BainGItoiEDi GiacomoGSugayaH (eds) Normal and pathological anatomy of the shoulder. Heidelberg: Springer, 2015, pp.171–184.
9.
ScheibelMDroschelSGerhardtC,et al.Arthroscopically assisted stabilization of acute high-grade acromioclavicular joint separations. Am J Sports Med2011; 39: 1507–1516.
10.
BaxterJAPhadnisJRobinsonPM,et al.Functional outcome of open acromioclavicular joint stabilization for instability following distal clavicle resection. J Orthop2018; 15: 761–764.
11.
RockwoodCAJr. Injuries to the acromioclavicular joint. In: RockwoodCAJrGreenDP (eds) Fractures in adults. 2nd ed. Philadelphia: Lippincott; 1984 pp.860–910.
12.
WilliamsGRNguyenVDRockwoodCAJr. Classification and radiographic analysis of acromioclavicular dislocation. Appl Radiol1989; 18: 29–34.
13.
NgCYSmithEKFunkL. Reliability of the traditional classification systems for acromioclavicular joint injuries by radiography. Shoulder Elbow2012; 4: 266–269.
14.
ChoCHHwangISeoJS, , et al.Reliability of the classification and treatment of dislocations of the acromioclavicular joint. J Shoulder Elbow Surg2014; 23: 665–670.
15.
BeitzelKMazzoccaADBakK, , et al.ISAKOS Upper extremity committee consensus statement on the need for diversification of the Rockwood classification for acromioclavicular joint injuries. Arthroscopy2014; 30: 271–278.
16.
GuminaSCarboneSPostacchiniF. Scapular dyskinesis and SICK scapula syndrome in patients with chronic type III acromioclavicular dislocation. Arthroscopy2009; 25: 40–45.
17.
TischerTSalzmannGMEl-AzabH,et al.Incidence of associated injuries with acute acromioclavicular joint dislocations types III through V. Am J Sports Med2009; 37: 136–139.
18.
SciasciaABoisAJKiblerWB. Nonoperative management of traumatic acromioclavicular joint injury: a clinical commentary with clinical practice considerations. Int J Sports Phys Ther2022; 17: 519–540.
19.
SciasciaADSpigelmanTKiblerWB,et al.Frequency of use of clinical shoulder examination tests by experienced shoulder surgeons. J Athl Train2012; 47: 457–466.
20.
O'BrienSJPagnaniMJFealyS,et al.The active compression test: a new and effective test for diagnosing labral tears and acromioclavicular joint abnormality. Am J Sports Med1998; 26: 610–613.
21.
McLaughlinHL. On the frozen shoulder. Bull Hosp Joint Dis1951; 12: 383–393.
22.
Evidence-based practice in the diagnostic process. In: Starkey C, Brown SD and Ryan J (eds) Examination of Orthopedic and Athletic Injuries. Vol 3. Philadelphia: F.A. David, 2010, pp. 45–56.
ChronopoulosEKimTKParkHB,et al.Diagnostic value of physical tests for isolated chronic acromioclavicular lesions. Am J Sports Med2004; 32: 655–661.
25.
CadoganAMcNairPLaslettM,et al.Diagnostic accuracy of clinical examination features for identifying large rotator cuff tears in primary health care. J Man Manip Ther2013; 21: 148–159.
26.
WaltonJMahajanSPaxinosA, , et al.Diagnostic values of tests for acromioclavicular joint pain. J Bone Joint Surg Am2004; 86A: 807–812.
27.
JiaXPetersonSAKhosraviAH,et al.Examination of the shoulder: the past, the present, and the future. J Bone Joint Surg (Am)2009; 91: 10–18.
28.
HawkinsRJKennedyJC. Impingement syndrome in athletes. Am J Sports Med1980; 8: 151–158.
29.
KiblerWBLudewigPMMcClurePW,et al.Clinical implications of scapular dyskinesis in shoulder injury: the 2013 consensus statement from the "scapula summit". Br J Sports Med2013; 47: 877–885.
30.
KiblerWB. The role of the scapula in athletic function. Am J Sports Med1998; 26: 325–337.
KiblerWBSciasciaADDomeDC,et al.Clinical utility of new and traditional exam tests for biceps and superior glenoid labral injuries. Am J Sports Med2009; 37: 1840–1847.
33.
Hegedus EJ, Goode AP, Cook CE, et al. Which physical examination tests provide clinicians with the most value when examining the shoulder? Update of a systematic review with meta-analysis of individual tests. Br J Sports Med 2012; 46: 964–978.
34.
JobeFWKvitneRSGiangarraCE. Shoulder pain in the overhand or throwing athlete the relationship of anterior instability and rotator cuff impingement. Orthop Rev1989; 18: 963–975.
35.
SciasciaAKiblerWB. Current views of scapular dyskinesis and its possible clinical relevance. Int J Sports Phys Ther2022; 17: 117–130.
36.
Canadian Orthopaedic Trauma Society. Multicenter randomized clinical trial of nonoperative versus operative treatment of acute acromio-clavicular joint dislocation. J Orthop Trauma2015; 29: 479–487.
37.
CisnerosLGNReirizJS. Acute high-grade acromioclavicular joint injuries: quality of life comparison between patients managed operatively with a hook plate versus patients managed non-operatively. Eur J Orthop Surg Traumatol2017; 27: 341–350.
38.
De CarliALanzettiRMCiompiA,et al.Acromioclavicular third degree dislocation: surgical treatment in acute cases. J Orthop Surg Res2015; 10: 13.
39.
EsenEOzturkAMDogramaciY,et al.Comparison of surgical treatment and conservative approach for type III acromioclavicular dislocations. Turkiye Klinikleri J Med Sci2011; 31: 109–114.
40.
GalpinRDHawkinsRJGraingerRW. A comparative analysis of operative versus nonoperative treatment of grade III acromioclavicular separations. Clin Orthop Rel Res1985; 193: 150–155.
41.
JoukainenAKrogerHNiemitukiaL,et al.Results of operative and nonoperative treatment of rockwood types III and V acromioclavicular joint dislocation: a prospective, randomized trial with an 18– to 20-year follow-up. Orthop J Sports Med2014; 2: 1–9.
42.
LarsenEBjerg-NielsenAChristensenP. Conservative or surgical treatment of acromioclavicular dislocation: a prospective, controlled, randomized study. J Bone Joint Surg Am1986; 68: 552–555.
43.
LarsenEHedeA. Treatment of acute acromioclavicular dislocation: three different methods of treatment prospectively studied. Acta Orthop Belg1987; 53: 480–484.
44.
MahJM. General health Status after nonoperative versus operative treatment for acute, complete acromioclavicular joint dislocation: results of a multicenter randomized clinical trial. J Orthop Trauma2017; 31: 485–490.
45.
MurrayIRRobinsonPGGoudieEB,et al.Open reduction and tunneled suspensory device fixation compared with nonoperative treatment for type-III and type-IV acromioclavicular joint dislocations: the ACORN prospective, randomized controlled trial. J Bone Joint Surg Am2018; 100: 1912–1918.
46.
PetriMWarthRJGreenspoonJA, , et al.Clinical results after conservative management for grade III acromioclavicular joint injuries: does eventual surgery affect overall outcomes?Arthroscopy2016; 32: 740–746.
47.
GstettnerCTauberMHitzlW,et al.Rockwood type III acromioclavicular dislocation: surgical versus conservative treatment. J Shoulder Elbow Surg2008; 17: 220–225.
48.
TaftTNWilsonFCOglesbyJW. Dislocation of the acromioclavicular joint: an end-result study. J Bone Joint Surg Am1987; 69: 1045–1051.
49.
BannisterGCWallaceWAStableforthPG,et al.The management of acute acromioclavicular dislocation: a randomized prospective controlled trial. J Bone Joint Surg Br1989; 71: 848–850.
50.
CardoneDBrownJNRobertsSNJ,et al.Grade III acromioclavicular joint injury in Australian rules football. J Sci Med Sport2002; 5: 143–148.
51.
PressJZuckermanJDGallagherM,et al.Treatment of grade III acromioclavicular separations. Bull Hosp Joint Dis1997; 56: 77–83.
52.
RosenornMPedersenEB. A comparison between conservative and operative treatment of acute acromioclavicular dislocation. Acta Orthop Scand1984; 45: 50–59.
53.
McMullenJUhlTL. A kinetic chain approach for shoulder rehabilitation. J Ath Train2000; 35: 329–337.
54.
KiblerWBSciasciaAWilkesT. Scapular dyskinesis and its relation to shoulder injury. J Am Acad Orthop Surg2012; 20: 364–372.
MacDonaldPBAlexanderMJFrejukJ,et al.Comprehensive functional analysis of shoulders following complete acromioclavicular separation. Am J Sports Med1988; 16: 475–480.
57.
WalshWMPetersonDASheltonG,et al.Shoulder strength following acromioclavicular injury. Am J Sports Med1985; 13: 153–158.
58.
BakalimGWilppulaE. Surgical or conservative treatment of total dislocation of the acromioclavicular joint. Acta Chir Scand1975; 141: 43–47.
59.
CalvoELopez-FrancoMArribasIM. Clinical and radiologic outcomes of surgical and conservative treatment of type III acromioclavicular joint injury. J Shoulder Elbow Surg2006; 15: 300–305.
60.
YounisFAjwaniSBibiA,et al.Operative versus non-operative treatment of grade III acromioclavicular joint dislocations and the use of SurgiLig: a retrospective review. Orthop Traumatol Rehabil2017; 6: 523–530.
