Scientific Committee Report

CUnHTODPnOMB

fumcom

ofF

ISAKOS Upper Extremity Committee Consensus Statement onthe Need for Diversification of the Rockwood Classification for

Acromioclavicular Joint InjuriesKnut Beitzel, M.A., M.D., Augustus D. Mazzocca, M.S., M.D., Klaus Bak, M.D.,

Eiji Itoi, M.D., Ph.D., William B. Kibler, M.D., Raffy Mirzayan, M.D.,Andreas B. Imhoff, M.D., Emilio Calvo, M.D., Ph.D., Guillermo Arce, M.D.,

Kevin Shea, M.D., and the Upper Extremity Committee of ISAKOS

Optimal treatment for the unstable acromioclavicular (AC) joint remains a highly debated topic in the field of orthopaedicmedicine. In particular, no consensus exists regarding treatment of grade III injuries, which are classified according to theRockwood classification by disruption of both the coracoclavicular and AC ligaments. The ISAKOS Upper ExtremityCommittee has provided a more specific classification of shoulder pathologies to enhance the knowledge on and clinicalapproach to these injuries. We suggest the addition of grade IIIA and grade IIIB injuries to a modified Rockwood clas-sification. Grade IIIA injuries would be defined by a stable AC joint without overriding of the clavicle on the cross-bodyadduction view and without significant scapular dysfunction. The unstable grade IIIB injury would be further defined bytherapy-resistant scapular dysfunction and an overriding clavicle on the cross-body adduction view.

n the recent literature, injuries to the acromiocla-

Ivicular (AC) joint have been subject to extensivedevelopments regarding proper clinical diagnosis andtreatment. Despite these developments, controversy

From the Department of Trauma and Orthopaedic Surgery, BG Traumaenter (K.B.), Murnau, Germany; Department of Orthopaedic Surgery,niversity of Connecticut Health Center (A.D.M., K.S.), Farmington, Con-ecticut, U.S.A.; Department of Orthopaedic Surgery, University Hospitalerlev (K.B.), Copenhagen, Denmark; Department of Orthopaedic Surgery,ohoku University School of Medicine (E.I.), Sendai, Japan; Lexington ClinicrthopedicseSports Medicine Center (W.B.K.), Lexington, Kentucky, U.S.A.;epartment of Orthopaedic Surgery, Kaiser Permanente (R.M.), Baldwinark, California, U.S.A.; Department of Orthopaedic Sports Medicine, Tech-ical University of Munich (A.B.I.), Munich, Germany; Department ofrthopaedic Surgery, Fundacion Jimenez Diaz, Autónoma University (E.C.),adrid, Spain; and Instituto Argentino de Diagnostico y Tratamiento (G.A.),uenos Aires, Argentina.The authors report the following potential conflict of interest or source ofnding: A.D.M. is a consultant for Arthrex, and has received financial andaterial support from Arthrex and Donohugh Grant. G.A. is a speaker andnsultant for Mitek, Inc. A.B.I. is a consultant for Arthrex andediBayreuth.Received August 26, 2013; accepted November 7, 2013.Address correspondence to: Augustus D. Mazzocca, M.S., M.D., DepartmentOrthopaedic Surgery, University of Connecticut, 263 Farmington Ave,

armington, CT 06034, U.S.A. E-mail: mazzocca@uchc.edu� 2014 by the Arthroscopy Association of North America0749-8063/13619/$36.00http://dx.doi.org/10.1016/j.arthro.2013.11.005

Arthroscopy: The Journal of Arthroscopic and Related Su

still exists regarding indications for treatment of theunstable AC joint and, in particular, for grade IIIinjuries classified as AC separations with disruptionof both the coracoclavicular (CC) and AC ligaments.1

Indications for surgical intervention vary based onevaluation of functional impairment and assessment ofthe patient’s concern regarding the cosmetic deformityof the injury. The basis of the surgical indication shouldideally rest on a thorough, validated, and precise clas-sification based on a clinical examination and diagnosticimaging. The most widely used classification is that ofRockwood2 published in 1984. He expanded the clas-sification presented by Tossy et al.3 in 1963 to a total of6 injury types by describing 3 additional injuries. TheRockwood classification is a purely radiographic classi-fication system that allows the clinician to furtherevaluate the patient and to consider treatment options.However, a wide number of factors seem to influencethe final result after treatment, including the timing ofsurgery, degree of dislocation, and ability to restorescapular kinematics after the initial injury.4

Treatment of the highly debated type III dislocationsbased on the current Rockwood classification system isespecially problematic for clinicians.1,4,5 Literatureshows that nonoperative treatment is able to restorefunction even in the elite-level, overhead-throwingcontact athlete.5 There is a lack of information,

rgery, Vol 30, No 2 (February), 2014: pp 271-278 271

Fig 1. The 4 suggested projections forradiologic imaging of a right shouldershowing a chronic type IIIB instabilityof the AC joint: (A) true AP projection,(B) Zanca, (C) axillary projection, and(D) cross-body adduction view (Basa-mania/Alexander).

272 K. BEITZEL ET AL.

however, describing which factors are used to identifypatients who are more suitable for surgical interven-tion, in addition to the factors that influence outcomes.The ISAKOS (International Society of Arthroscopy,Knee Surgery & Orthopaedic Sports Medicine) UpperExtremity Committee provided a more specific classi-fication of shoulder pathologies to enhance theknowledge on and clinical approach to these injuries.The purpose of this article is to evaluate the scientificbasis of optimal clinical decision making with specialemphasis on the highly debated grade III AC disloca-tion. Furthermore, a modification of the Rockwoodclassification is suggested.

Radiologic Evaluation of AC Joint injuries(Rockwood Classification and Its

Extension)The Rockwood classification is the most widely used

classification for AC joint dislocation but has the disad-vantage of being a purely radiographic classificationsystem.3 This classification is based on the increasingseverity of subsequent injury to the stabilizing structuresof the AC joint complex and was described by Rock-wood2 in a very detailed anatomic fashion. However,clinical decisionmaking is often a process based solely on2-dimensional and static anteroposterior (AP) radio-graphic views without specific guidelines relating toradiographic technique.

Current classification of the Rockwood system isgenerally described as follows: In a type I injury, there isa sprain of the AC ligament with no radiographicabnormality. In type II injuries, the AC ligaments andjoint capsule are disruptedwhereas the CC ligaments aresprained but intact in addition to a 50% verticalsubluxation of the distal clavicle. In type III injuries, theAC ligaments and joint capsule, as well as the CC liga-ments, are disrupted (100% superior displacement ofthe distal clavicle). In type IV injuries, there is posteriorsubluxation of the clavicle into the trapezius. Currently,this is thought to be best seen on axillary radiographs.This technique, however, does not safely allow for 3-dimensional and functional evaluation of this lesion. Atype V injury is an exaggeration of a type III injury with100% to 300% superior displacement of the clavicle. Inthe rare type VI injury, there is subacromial or sub-coracoid displacement of the clavicle and a reversed CCinterspace.Radiographic evaluation should include a bilateral

Zanca view, which visualizes the ipsilateral and contra-lateral AC joints on a single x-ray cassette while main-taining the same orientation of the x-ray beam (Fig 1).6

The view is obtained by tilting the x-ray beam 10� to 15�

toward the cephalic direction and using only 50% of thestandard shoulder AP penetration strength. By visual-izing both AC joints on the same cassette, the CCdistance can be compared from side to side, also allowingfor future comparison of preoperative and postoperativeexamination findings. Varying configurations of the AC

Table 1. Important Steps in Clinical Evaluation of Injured ACJoint

Joint Clinical Testing*

AC joint � Examine patient while standing or sitting(weight of arm pulling downward)

� Check for direct pain, swelling, and pointtenderness of AC joint

� Check for AP and superoinferior translation� Perform cross-arm adduction test� Perform active compression test (O’Brien)� Perform resisted extension test� Check for combined injuries to glenohumeral

joint� Check for neural, vascular, or additional

injuries to adjoining jointsScapulothoracic joint � Assess patient in resting scapular position

(from behind with arms at side)� Assess scapular motion in upward/downward

flexion� Assess scapula position aftermanual reduction

of AC joint� Perform scapular assistance test� Perform scapular retraction test

*Note the importance of combined clinical testing to improve thetests’ specificity.

ACROMIOCLAVICULAR JOINT INJURY CLASSIFICATION 273

joint can be found on AP radiographs. For example,Zanca6 reported a normal AC joint width of 1 to 3 mm.Stress views are believed to be helpful in distinguishingbetween type II and III injuries by allowing inspection ofthe integrity of the CC ligaments. However, the differ-ence in type II and III injuries is rarely significant, and inour opinion, the classical stress views with distal tractiontypically are not necessary for diagnosis.An axillary view is particularly helpful in visualizing

a type IV AC joint injury that results in an anteromedialdisplacement of the scapula because radiographicanalysis will allow for visualization of a posteriorlydisplaced distal clavicle in relation to the acromion.However, one has to be careful in diagnosing posteriortranslation of the distal clavicle based on this viewbecause recent studies have shown the difficulties inidentifying a posteriorly translated clavicle on an axil-lary radiograph.7 The Stryker notch view is useful fordetermining a coracoid fracture in a complete ACdislocation with normal CC interspace. Coracoidprocess fracture should be suspected when radiographsshow AC dislocations with a normal CC distance.According to our recommendations, additional radio-

graphs should be taken to allow for differentiationbetween clinically relevant stable and unstable AC jointinjuries. Because these findings are more associatedwith functional problems, the diagnostic imagingshould take these into account and try to objectivelyevaluate the function of the AC joint. Although thereare no published studies, Barnes et al.8 have reportedon a cross-body adduction radiograph (so-called Basa-mania view) to differentiate between a stable andunstable AC joint. In this imaging technique, a cross-body adduction AP view of the AC joint is used toassess the degree to which the clavicle overlaps theacromion because of the anteromedial translation of thescapula. In 1949 Alexander9 described a similar radio-graphic imaging technique for AC joint instability. If theclavicle overrides the acromion on the cross-bodyadduction view, it indicates instability of the CC liga-ments in addition to the AC joint disruption.

Clinical Evaluation of AC Joint InjuriesAC joint dislocations are injuries to a complex osseous

ligamentous structure requiring thorough clinicalevaluation for correct diagnosis and determination ofoptimal treatment. Whenever possible, patients shouldbe examined standing or sitting so that the weight ofthe arm pulling downward stresses the AC joint andwill make any deformity more apparent (Table 1).Traumatic pathology of the AC joint is identified bypain, swelling, and point tenderness at the AC joint. Ifa patient has more pain than expected for a simple ACjoint injury, a coracoid fracture or a type IV injury withdisplacement of the clavicle through the trapezial fasciashould be suspected. It has also been shown that in high

degrees of dislocation of the AC joint, associatedinjuries of the glenohumeral joint are very commonand should be searched for.10

In type III injuries, both the AC and CC ligaments aretorn, with no significant disruption of the deltoid ortrapezial fascia. The upper extremity is held in anadducted position with the acromion depressed. Theclavicle appears “high riding”; however, in reality theacromion and upper extremity are displaced inferior tothe horizontal plane of the lateral clavicle. This is the“third translation,” or an extra gliding motion of thescapula. Severe pain persists with motions even 1 to 3weeks after injury. Patients should be evaluated 3 to 6weeks after injury to allow for a thorough examination,which is not possible in the acute phase because of thepatient’s significant pain. Therefore the patient shouldbe referred to a physiotherapist to improve range ofmotion and re-establish scapular kinematics after initialexamination.An examination for neural, vascular, or additional

injuries of the adjoining joints should always becompleted. Point tenderness at the joint will beincreased with the cross-arm adduction test (armelevated to 90� and then adducted across the chest withthe elbow bent at 90�). Injection of anesthetic agentmay relieve the pain, which implicates the AC joint asthe source of pain. The examination should be per-formed before and after injection to determine whetherchanges in symptoms occurred.Several physical tests have been described as clinical

tools to detect lesions of the AC joint. Previous studiesreported a sensitivity of 77% for the cross-bodyabduction test, 72% for the AC resistance test, and

Fig 2. Patient showing scapular dyskinesis of left shoulderafter type V AC joint dislocation (note the prominence of themedial scapula border).

274 K. BEITZEL ET AL.

41% for the active compression test; however, thecombination of all 3 tests showed a high specificity of95%.11

Clinical Evaluation of Scapula in AC JointInjuries

Injury to the AC joint not only affects glenohumeralfunction but may also have a negative effect on scap-ulothoracic function and scapulohumeral rhythm. Theclavicle is the anterior strut supporting the scapula, andproper function of the AC and CC ligaments greatlycontributes to the physiological motion of thescapula.12-14 Shortening of the clavicle or instability ofthe AC joint may position the scapula in a protractedand internally rotated position. We know from previousstudies that scapular dyskinesis may lead to gleno-humeral and lateral shoulder pain as well as motiondeficits.15

Clinical evaluation of the scapula can determine thepresence or absence of alterations in scapular positionor motion, collectively called “scapular dyskinesis,”and can help guide effective treatment of any func-tional deficits. A reliable examination can be per-formed within 10 days after acute injury, when theimmediate symptoms have decreased. To assess theresting scapular position with visual access to bothscapulae, an evaluation should be performed frombehind with both arms at the side. During observation,the clinician should check for asymmetry of themedial scapular border because any prominenceindicates excessive scapular internal rotation and/oranterior tilt. This prominence can result when the

scapular strut is lost from injury either to the ACligaments by themselves (type II) or to both AC andCC ligaments (type III and higher), and it suggests thatfunctional deficits due to scapular dyskinesis may bepresent and treatment to stabilize the joint is indicated(Fig 2).15

In type III and higher injuries, the anterior/posteriordrawer test of the AC joint will show positive results, aswill the inferior/superior motion test. It is occasionallypossible to reduce the AC separation by manuallyreversing the third translation of the scapula, pushing itlaterally and then superiorly. If this can be accom-plished, the medial scapular border prominence willoften be diminished or eliminated, indicating howimportant the AC joint is to proper scapular position. Ifthis is restored, rotator cuff strength and arm motion inflexion and abduction will also be improved. Moreoften, the AC joint cannot be completely reducedbecause of interposed tissue. In these cases scapularcorrective maneuvers involved in the scapular assis-tance and scapular retraction tests can be used to placethe scapula in a more anatomic position to improvearm and shoulder function.16 These manipulations willfrequently place the scapula in a position with moreposterior tilt and external rotation, thereby improvingapparent rotator cuff strength and symptoms ofexternal impingement, as well as enhancing the abilityto achieve shoulder abduction and external rotation.These tests, when the findings are positive, indicate thelevel of contribution that scapular dyskinesis has inshoulder problems, and they give objective evidence tohelp guide operative or nonoperative treatment deci-sions. Any AC joint separation that results in scapulardyskinesis will potentially create the physiological andbiomechanical deficits that can affect maximalshoulder function. Patients who demonstrate theseproblems on physical examination should be consid-ered for repair or reconstruction of both the AC and CCligaments.

Treatment Algorithm Based on Clinical andRadiologic Evaluation

The main goals of treatment, whether surgical ornonsurgical, are to achieve a pain-free shoulder withfull range of motion, normal strength, and no limita-tions in activities. The demands on the shoulder willdiffer from patient to patient, and these demandsshould be taken into account during the initial evalu-ation. Commonly known contraindications for electivesurgical procedures (non-tolerable anesthesia risk,increased risk of intraoperative bleeding, increased riskof infection, and so on) may prohibit or delay surgicaltreatment for all types of AC joint dislocations.Minimal evidence exists on treatment strategies for

AC joint lesions, and treatment for type III lesions

Fig 3. Algorithm showing decisionprocess for early evaluation of ACjoint instabilities. The asterisk indicatesan individual decision, if the patientdoes not want to possibly undergodelayed surgery and demands promptsurgical intervention.

ACROMIOCLAVICULAR JOINT INJURY CLASSIFICATION 275

remains especially controversial.1,4 This may be becausethese type III injuries present a variety of lesions,ranging from non-symptomatic stable to symptomaticnon-stable lesions. Therefore the key for optimaltreatment may be seen in a correct diagnosis of theunderlying pathology. The findings of the ISAKOSTerminology Project resulted in a new suggestion forthe Rockwood classification by further subdividing thetype III AC joint injuries into type IIIA (stable) and typeIIIB (unstable). The basis for the subclassification isprimarily functional rather than anatomic, but specialradiographic views (i.e., cross-body stress view) mayprovide the necessary objective information. Unstabletype III lesions (type IIIB) will continue to cause pain(usually on the anterior acromion, rotator cuff, andmedial scapular area), weakness during rotator cufftesting, decreased flexion and abduction range ofmotion, and demonstrable scapular dyskinesis onobservation.In type I injuries, the AC ligaments are sprained but

the AC and CC ligaments are intact with no palpabledisplacement of the distal clavicle. Clinically, the patientpresents with swelling and joint tenderness, althoughthere is no widening, separation, or deformity at the ACjoint seen radiographically. An examination for neural,vascular, or additional injuries to the adjacent jointsshould always be completed if a lesion of the AC joint issuggested. In type II injuries, the CC ligaments areintact but the AC ligaments are torn. The patient has

moderate to severe pain at the AC joint, a slightlysuperior position, and increased horizontal mobility ofthe distal clavicle. On radiographic examination, thelateral end of the clavicle may be elevated. Type I and IIlesions are generally treated conservatively with a sling,ice, and a brief period of immobilization, typicallylasting 3 to 7 days. The patient is encouraged to initiaterange-of-motion activities within the first week afterinjury to reduce pain and inflammation in an effort todecrease associated morbidity.17 We use the 4-partphysical therapy protocol suggested by Gladstoneet al.18: Phase 1 focuses on the elimination of pain andprotection of the AC joint through sling immobilization(3 to 10 days), along with the prevention of muscularatrophy. We prefer to start with closed-chain scapularactivities that are easily tolerated early in the post-injury period, allowing the patient to work onscapular strength and motion without provokingundesirable increases in symptoms. These exercisesunload the weight of the upper extremity, allowing thepatient to focus on isolating scapular motion.17 Phase 2consists of range-of-motion exercises to restore fullmobility and a gradual progression of strengtheningwith the addition of isotonic exercise. Phase 3 involvesadvanced strengthening to enhance the dynamicstability of the AC joint, whereas phase 4 incorporatessport-specific training to prepare for a full return toprior level of activity. Full rehabilitation should beachieved within 6 to 12 weeks.

Fig 4. Algorithm showing decisionprocess for second evaluation oftype III instabilities. The distinctionbetween type IIIA and type IIIB lesionsis based on function, pain, clinicalevaluation of scapular motion, and thecross-body adduction view.

276 K. BEITZEL ET AL.

Recovering full range of motion in the absence ofpain and comprehensive functionality with the abilityof self-protection enable a return to competitive sports.If full function is achieved and only pain remains,a local anesthetic injection could be considered toallow a return to professional sports.Initial nonsurgical treatment is presently favored

in type III dislocations in most cases.1 The new classi-fication of type IIIA and type IIIB lesions helps todifferentiate and better identify patients who wouldbenefit from surgical intervention. In light of thecontroversy and clear lack of evidence supportingacute surgical management of grade III AC separations,we recommend that all patients presenting with typeIII instability initially undergo treatment with 3 to 4weeks of nonsurgical management.1,4,5 Some of theseconservatively treated patients will have persistent

pain and an inability to return to their sport or job.Subsequent surgical stabilization, albeit delayed, willstill allow eventual return to sport or work in suchcases.In type IV injuries, the AC ligaments, the CC liga-

ments, and the deltoid fascia are ruptured. The distalclavicle is displaced posteriorly into the trapeziusmuscle and may tent the posterior skin, which isusually associated with increased pain. Type V injuriesrepresent a greater degree of soft-tissue damage: boththe AC and CC ligaments are ruptured, and the delto-trapezial fascia is stripped off the acromion and theclavicle. A plethora of surgical procedures for thetreatment of lesions greater than type IV exist. Nonehas proved to be the gold standard, and it would bebeyond the scope of this article to define 1 surgicalprocedure to be superior to any others. However, we

ACROMIOCLAVICULAR JOINT INJURY CLASSIFICATION 277

believe that specific criteria should be used whentreating AC joint dislocations surgically: (1) Biologicaugmentation (e.g., tendon graft) should be used in thechronic situation (>3 weeks after injury), and (2)anatomic techniques for surgical reconstruction shouldbe favored.4

DiscussionThere is increasing evidence that AC joint lesions

might be incorrectly diagnosed, resulting in poor clin-ical decisions regarding diagnosis and treatmentoutcomes. The new subdivision of grade III injuriessuggested by the ISAKOS Terminology Project mayimprove our options for distinguishing stable andunstable AC joints. At present, this distinction is notpossible in the acute setting in which patients are inpain and provocative tests are inconclusive. On thebasis of these assumptions and our experience, wesuggest the following algorithm for clinical and radio-logic evaluation of dislocated AC joints.During the first clinical evaluation, the surgeon should

complete a detailed physical examination including alltests for AC stability (e.g., pain, translation, and cross-body test) and evaluate the scapula motion (Fig 3). Athorough evaluation for additional lesions within theglenohumeral joint should be performed to excludeadditional injuries.10 Skin lesions as a consequence ofclavicle dislocation or direct trauma should be ruled out.Self-evidently, neurologic insufficiencies and injuries toblood vesselsmust be excluded. Radiographic evaluationshould include AP, lateral, and axillary views of theshoulder. A bilateral Zanca viewmight be added to betterjudge the increase in CC distance. Clinical evaluation atthis stage might be difficult based on the degree of thepatient’s pain in the AC joint. After clinical evaluation,patients should be seen as early as possible by a physio-therapist to regain as much movement and scapularcontrol as possible. This is especially important for thosepresenting with type III lesions.We suggest a second evaluation for type III lesions at

3 to 6 weeks after the injury (Fig 4). This secondevaluation should always be completed within 3months. It has been reported that, at this time, around80% of patients have regained full function. Patientspresenting with persisting pain and loss of functioninterfering with return to previous activity (or sports)performance level are thoroughly re-evaluated clini-cally and radiographically. If the patient presents withcontinued abnormal scapular movement and radio-graphic images in the Basamania (Alexander) viewshow an overriding clavicle on the acromion, wesuggest operative treatment. We therefore recommendthat grade IIIA and grade IIIB injuries be added asa modification to the Rockwood classification todistinguish between stable type III injuries, defined asthose without overriding of the clavicle on the

acromion on the Basamania (Alexander) view andwithout significant scapular dysfunction, and unstablegrade III injuries, with therapy-resistant scapulardysfunction and overriding of the clavicle on theBasamania (Alexander) view.In the future, clinical studies will need to evaluate the

type IIIA and type IIIB modification of type III injuriesand the effect of nonoperative treatment addressingscapular dysfunction over regular nonoperative treat-ment. In particular, we need to improve our knowledgeof conservative treatment outcomes for type III injuriesin overhead athletes.

References1. Tamaoki MJ, Belloti JC, Lenza M, et al. Surgical versus

conservative interventions for treating acromioclaviculardislocation of the shoulder in adults. Cochrane Database SystRev 2010;(8):CD007429.

2. Rockwood CA Jr. Injuries to the acromioclavicular joint:Subluxations and dislocations about the shoulder. In:Rockwood CA Jr, Green DP, eds. Fractures in adults. Phil-adelphia: JB Lippincott, 1984;860-910.

3. Tossy JD, Mead NC, Sigmond HM. Acromioclavicularseparations: Useful and practical classification for treat-ment. Clin Orthop Relat Res 1963;28:111-119.

4. Beitzel K, Cote MP, Apostolakos J, et al. Current conceptsin the treatment of acromioclavicular joint dislocations.Arthroscopy 2013;29:387-397.

5. Trainer G, Arciero RA, Mazzocca AD. Practical manage-ment of grade III acromioclavicular separations. Clin JSport Med 2008;18:162-166.

6. Zanca P. Shoulder pain: Involvement of the acromiocla-vicular joint. (Analysis of 1,000 cases.) Am J RoentgenolRadium Ther Nucl Med 1971;112:493-506.

7. Rahm S, Wieser K, Spross C, Vich M, Gerber C,Meyer DC. Standard axillary radiographs of the shouldermay mimic posterior subluxation of the lateral end of theclavicle. J Orthop Trauma 2013;27:622-626.

8. Barnes CJ, Higgins LD, Major NM, Basamania CJ.Magnetic resonance imaging of the coracoclavicular liga-ments: Its role in defining pathoanatomy at the acro-mioclavicular joint. J Surg Orthop Adv 2004;13:69-75.

9. Alexander OM. Dislocation of the acromioclavicular joint.Radiography 1949;15:260, illust.

10. Tischer T, Salzmann GM, El-Azab H, Vogt S, Imhoff AB.Incidence of associated injuries with acute acromiocla-vicular joint dislocations types III through V. Am J SportsMed 2009;37:136-139.

11. Chronopoulos E, Kim TK, Park HB, Ashenbrenner D,McFarland EG. Diagnostic value of physical tests for iso-lated chronic acromioclavicular lesions. Am J Sports Med2004;32:655-661.

12. Seo YJ, Yoo YS, Noh KC, et al. Dynamic function of cor-acoclavicular ligament at different shoulder abductionangles: A study using a 3-dimensional finite elementmodel. Arthroscopy 2012;28:778-787.

13. Izadpanah K, Weitzel E, Honal M, et al. In vivo analysis ofcoracoclavicular ligament kinematics during shoulderabduction. Am J Sports Med 2012;40:185-192.

278 K. BEITZEL ET AL.

14. Ludewig PM, Phadke V, Braman JP, Hassett DR,Cieminski CJ, LaPrade RF. Motion of the shouldercomplex during multiplanar humeral elevation. J BoneJoint Surg Am 2009;91:378-389.

15. Kibler WB, Sciascia A. Current concepts: Scapular dyski-nesis. Br J Sports Med 2010;44:300-305.

16. Kibler WB, Ludewig PM, McClure PW, Michener LA,Bak K, Sciascia AD. Clinical implications of scapular dys-kinesis in shoulder injury: The 2013 consensus statement

ARTHROSCOPY

Have you been to www.artlately? Check it out; we n

tech notes

from the ’Scapular Summit.’ Br J Sports Med 2013;47:877-885.

17. Cote MP, Wojcik KE, Gomlinski G, Mazzocca AD. Reha-bilitation of acromioclavicular joint separations: Operativeand nonoperative considerations. Clin Sports Med 2010;29:213-228, vii.

18. Gladstone JN, Wilk KE, Andrews JR. Nonoperativetreatment of acromioclavicular joint injuries. Oper TechSports Med 1997;5:78-87.

TECHNIQUES

hroscopytechniques.orgow publish three videoa week!