MRI versus radiography of acromioclavicular joint dislocation

Management of type III acromioclavicular joint dislocation: A Delphi consensus survey by Shoulder & Elbow Society, India (SESI)

PURPOSE

The study aimed to report the results of the Delphi survey conducted by the Shoulder, Elbow Society India (SESI), to achieve consensus on ambiguous topics in managing type III acromioclavicular joint (ACJ) dislocations.

METHODS

This study was based on responses from the Shoulder Elbow Society India (SESI) panel of peer-selected twenty senior surgeons practicing shoulder orthopedics. They participated in two rounds of the survey to obtain consensus on several topics pertaining to the management of type III ACJ dislocations. Consensus was achieved when at least 70 % of the panel members selected at least a 4-point on a 5-point Likert scale.

RESULTS

Our Delphi survey reached a consensus on seven topics of ambiguity. An anteroposterior and axillary view of the shoulder without any traction or weight in hand is sufficient in the setting of a suspected type III ACJ dislocation. Magnetic resonance imaging (MRI) is not routinely indicated in type III ACJ dislocation. Either cross-arm adduction X-rays or clinical examination may be used to distinguish between ISAKOS (International Society of Arthroscopy, Knee surgery and Orthopaedics Sports medicine) IIIA and B classification of ACJ to identify stable and unstable injuries. Conservative treatment can be offered to patients who have stable injuries and who are not high-demand individuals in acute type III ACJ dislocations. In conservative management of type III ACJ dislocation, a two-week sling suffices. Jones strapping has no clear advantage over a shoulder sling. Coracoclavicular reconstruction with an autograft is an acceptable way to treat symptomatic, chronic grade III ACJ dislocation.

CONCLUSION

The survey helped achieve consensus on several controversial issues related to type III ACJ dislocations. However, there remains ambiguity on the definition of chronicity of such dislocations, the necessity of bilateral Zanca views, and the duration of conservative trial before switching to a surgical line of management.

Presence of Additional Pathology in Low-Grade Acromioclavicular Joint Injuries

OBJECTIVE

To determine if additional pathology is present in low-grade acromioclavicular (AC) joint injuries.

DESIGN

Prospective case series.

SETTING

Patients were assessed by primary care sports medicine physicians at a single institution between 2019 and 2023.

PATIENTS

Patients aged 18 to 65 years diagnosed with a type I to III AC injury based on clinical and radiographic evaluation.

INTERVENTION

Consenting patients underwent magnetic resonance imaging (MRI) evaluation within 21 days of injury. All injuries were treated nonoperatively.

MAIN OUTCOME MEASURES

Additional pathologies identified on MRI were reported in a standardized fashion by fellowship-trained musculoskeletal radiologists.

RESULTS

Twenty-nine patients (26 men/3 women) were consented with a mean (±SD) age of 28.6 ± 9.5 years. The mean time from injury to MRI was 8.1 ± 5.9 days. Twenty-three injuries were sport related, and 6 were accidental traumas. Based on MRI, injury type was reclassified in 16 of 29 patients, and 13 remained unchanged. Additional pathologies identified included 14 muscle injuries, 5 rotator cuff tears, 5 labral tears, 1 nondisplaced fracture, and 1 intra-articular body.

CONCLUSION

MRI evidence suggests that most AC joint injuries are more severe than clinically diagnosed. Identifying additional pathology may alter diagnostic and treatment guidelines for type I to III AC joint injuries.

Acromioclavicular Joint Injury and Repair

The acromioclavicular (AC) joint is commonly injured in athletes participating in contact and overhead throwing sports. Injuries range from simple sprains to complete ligamentous disruption, and they are classified by the established Rockwood grading system. High-grade injuries are associated with fractures around the AC joint and disruption of the superior shoulder suspensory complex, a ring of osseous and ligamentous structures at the superior aspect of the shoulder. Radiographs are the mainstay of imaging of the AC joint, with magnetic resonance imaging reserved for high-grade injuries to aid classification and plan surgical management. Low-grade AC joint injuries tend to be managed conservatively, but a wide range of surgical procedures have been described for higher grade injuries and fractures around the AC joint. This review illustrates the anatomy of the AC joint and surrounding structures, the imaging features of AC joint injury, and the most commonly performed methods of reconstruction and their complications.

Anatomical variants of the acromioclavicular joint influence its visibility in the standard MRI protocol in patients aged 18-31 years

Purpose

Visualization of a structure in orthogonal planes is essential for correct radiological assessment. The aim was to assess the utility of the standard MRI protocol for the shoulder in the assessment of the acromioclavicular joint (ACJ).

Methods

A total of 204 MRI scans of the shoulder were re-reviewed. Visibility of the ACJ in orthogonal planes was assessed, and the type of acromion and the angle between the ACJ and the glenoid cavity were assessed by two observers.

Results

Agreement in the assessment of ACJ visibility was moderate to substantial. The ACJ was visible in the three anatomical views in 48% (confidence interval [CI] 95% = [41–54%]) of the examinations, and no significant difference regarding gender or age was noticed. The mean angle between the ACJ and the glenoid cavity was 41.12 deg. CI95% = (39.72, 42.53) in the axial plane, 33.39 deg. CI95% = (31.33, 35.45) in the coronal plane and 52.49 deg. CI95% = (50.10, 54.86) in the sagittal plane. When the ACJ was visible in the sagittal and axial planes, significant differences were noticed in the remaining planes (p < .05).

Conclusion

Anatomical variations of the ACJ influence its visibility in the standard MRI protocol for examining the shoulder, making this protocol insufficient for ACJ assessment in the examined population.

Acromioclavicular joint instability on cross-body adduction view: the biomechanical effect of acromioclavicular and coracoclavicular ligaments sectioning

BACKGROUND

The acromioclavicular (AC) and coracoclavicular (CC) ligaments are important stabilizers of the AC joint. We hypothesized that AC and trapezoid ligament injuries induce AC joint instability and that the clavicle can override the acromion on cross-body adduction view even in the absence of conoid ligament injury. Accordingly, we investigated how sectioning the AC and CC ligaments contribute to AC joint instability in the cross-body adduction position.

METHODS

Six fresh-frozen cadaveric shoulders were used in this study, comprising five male and one female specimen, with a mean age of 68.7 (range, 51-87) years. The left side of the trunk and upper limb, and the cervical and thoracic vertebrae and sternum were firmly fixed with an external fixator. The displacement of the distal end of the clavicle relative to the acromion was measured using an electromagnetic tracking device. We simulated AC joint dislocation by the sequential resection of the AC ligament, AC joint capsule, and CC ligaments in the following order of stages. Stage 0: Intact AC and CC ligaments and acromioclavicular joint capsule; stage 1: Completely sectioned AC ligament, capsule and joint disc; stage 2: Sectioned trapezoid ligament; and stage 3: Sectioned conoid ligament. The superior clavicle displacement related to the acromion was measured in the horizontal adduction position, and clavicle overriding on the acromion was assessed radiologically at each stage. Data were analyzed using a one-way analysis of variance and post-hoc tests.

RESULTS

Superior displacement was 0.3 mm at stage 1, 6.5 mm at stage 2, and 10.7 mm at stage 3. On the cross-body adduction view, there was no distal clavicle overriding at stages 0 and 1, and distal clavicle overriding was observed in five cases (5/6: 83%) at stage 2 and in six cases (6/6: 100%) at stage 3.

CONCLUSION

We found that AC and trapezoid ligament sectioning induced AC joint instability and that the clavicle could override the acromion on cross-body adduction view regardless of conoid ligament sectioning. The traumatic sections of the AC and trapezoid ligament may lead to high grade AC joint instability, and the distal clavicle may subsequently override the acromion.

Usefulness of the acromioclavicular joint cross-sectional area as a diagnostic image parameter of acromioclavicular osteoarthritis

BACKGROUND

Acromioclavicular joint (ACJ) space narrowing has been considered to be an important diagnostic image parameter of ACJ osteoarthritis (ACJO). However, the morphology of the ACJ space is irregular because of osteophyte formation, subchondral irregularity, capsular distention, sclerosis, and erosion. Therefore, we created the ACJ cross-sectional area (ACJCSA) as a new diagnostic image parameter to assess the irregular morphologic changes of the ACJ.

AIM

To hypothesize that the ACJCSA is a new diagnostic image parameter for ACJO.

METHODS

ACJ samples were obtained from 35 patients with ACJO and 30 healthy individuals who underwent shoulder magnetic resonance (S-MR) imaging that revealed no evidence of ACJO. Oblique coronal, T2-weighted, fat-suppressed S-MR images were acquired at the ACJ level from the two groups. We measured the ACJCSA and the ACJ space width (ACJSW) at the ACJ on the S-MR images using our imaging analysis program. The ACJCSA was measured as the cross-sectional area of the ACJ. The ACJSW was measured as the narrowest point between the acromion and the clavicle.

RESULTS

The average ACJCSA was 39.88 ± 10.60 mm² in the normal group and 18.80 ± 5.13 mm² in the ACJO group. The mean ACJSW was 3.51 ± 0.58 mm in the normal group and 2.02 ± 0.48 mm in the ACJO group. ACJO individuals had significantly lower ACJCSA and ACJSW than the healthy individuals. Receiver operating characteristic curve analyses demonstrated that the most suitable ACJCSA cutoff score was 26.14 mm², with 91.4% sensitivity and 90.0% specificity.

CONCLUSION

The optimal ACJSW cutoff score was 2.37 mm, with 88.6% sensitivity and 96.7% specificity. Even though both the ACJCSA and ACJSW were significantly associated with ACJO, the ACJCSA was a more sensitive diagnostic image parameter.

Evaluation of the Circles Measurement and the ABC Classification of Acromioclavicular Joint Injuries

BACKGROUND

Acromioclavicular joint (ACJ) injuries are common. Despite this, it remains unclear how best to assess, classify, and manage these cases. A simple, reliable, valid, and accurate radiographic parameter to measure ACJ displacement would allow improved consistency of diagnosis and subsequent treatment pathways.

PURPOSE

To evaluate "the circles measurement" and associated "ABC classification" as a tool for assessing ACJ displacement and injury classification.

STUDY DESIGN

Descriptive laboratory study.

METHODS

The circles measurement is taken from a lateral Alexander radiograph of the shoulder. The measurement is the center-to-center distance between 2 circles drawn to define the lateral extent of the clavicle and the anteromedial extent of the acromion; it is independent of the displacement plane, judging total ACJ displacement in any direction rather than trying to quantify vertical and/or horizontal displacement. When utilized clinically, the circles measurement is a single measurement calculated as the difference between values recorded for the injured and uninjured sides. Validation of the circles measurement was performed using lateral Alexander radiographs (including ±20° projection error in all planes) and computed tomography of standardized ACJ injury simulations. We assessed inter- and intrarater reliability, convergent validity, and discriminant validity of the circles measurement and subsequently generated a classification of ACJ injury based on displacement.

RESULTS

Reliability and validity of the circles measurement was excellent throughout. Interrater reliability (ICC [intraclass correlation coefficient] [2,1], 95% CI; n = 78; 4 observers) was 0.976 (0.964-0.985). Intrarater reliability (ICC [2,1]; 95% CI; n = 78; 2 measures) was 0.998 (0.996-0.998). Convergent validity (Pearson correlation coefficient, r) was 0.970 for ideal radiographs and 0.889 with ±20° projection error in all planes. Discriminant validity, with 1-way analysis of variance, showed a P value of <.0001 and effect size (η²) of 0.960, with the ability to distinguish between the previously defined stable (Rockwood IIIA) and unstable (Rockwood IIIB) injuries. The results permitted objective, statistically sound parameters for the proposed ABC classification system.

CONCLUSION

The circles measurement is a simple, reliable, valid, accurate, and resilient parameter for assessing ACJ displacement and can be used in conjunction with the proposed ABC classification to define ACJ injuries more accurately and objectively than previously described.

CLINICAL RELEVANCE

This novel parameter has the potential to standardize the initial assessment and possibly the subsequent clinical management of ACJ injuries, in addition to providing a standardized measure for future research.

The ligamentous injury pattern in acute acromioclavicular dislocations and its impact on clinical and radiographic parameters

BACKGROUND

Acromioclavicular (AC) joint dislocations are classified according to the Rockwood (RW) classification, which is based on radiographic findings. Several authors have suggested magnetic resonance imaging (MRI) for visualization of the capsuloligamentous structures stabilizing the AC joint. The aim of this study was to describe the ligamentous injury pattern in acute AC joint dislocations by MRI and investigate associations with clinical and radiographic parameters.

METHODS

This prospective study included 45 consecutive patients (5 women and 40 men; mean age, 33.6 years [range, 19-65 years]) with an acute AC joint separation (RW type I in 5, RW type II in 8, RW type III in 18, and RW type V in 14). All patients underwent physical examination of both shoulders, and clinical scores (Subjective Shoulder Value, Constant score, Taft score, and Acromioclavicular Joint Instability Score) were used to evaluate the AC joint clinically as well as radiographically. Post-traumatic radiography included bilateral anteroposterior stress views and bilateral Alexander views to evaluate vertical instability and dynamic posterior translation. MRI was performed for assessment of the AC and coracoclavicular (CC) ligaments and the delto-trapezoidal fascia.

RESULTS

Radiographic and MRI classifications were concordant in 23 of 45 patients (51%), whereas 22 injuries (49%) were misjudged; of these, 6 (13%) were reclassified to a more severe type and 16 (36%), to a less severe type. The integrity of the CC ligaments was found to have a clinical impact on vertical as well as horizontal translation determined by radiographs and on clinical parameters. Among patients with an MRI-confirmed complete disruption of the CC ligaments, 68% showed a radiographic CC difference > 30% and 75% showed complete dynamic posterior translation. Inferior clinical parameters were noted in these patients as compared with patients with intact CC ligaments or partial disruption of the CC ligaments (Constant score of 67 points vs. 49 points [P < .05] and Acromioclavicular Joint Instability Score of 51 points vs. 23 points [P < .05]). The inter-rater and intra-rater reliability for assessment of the ligamentous injury pattern by MRI was fair to substantial (r = 0.37-0.66).

CONCLUSION

The integrity of the CC and AC ligaments found on MRI has an impact on clinical and radiographic parameters.

Acromioclavicular Joint Injuries in Professional Ice Hockey Players: Epidemiologic and MRI Findings and Association With Return to Play

Background:

Acromioclavicular joint (ACJ) injuries are common in ice hockey players and are traditionally evaluated with conventional radiography, which has recognized limitations in the accurate characterization of the spectrum of soft tissue injuries and severity/grade of injury sustained.

Purpose:

To evaluate the epidemiologic, clinical, and magnetic resonance imaging (MRI) findings in professional ice hockey players who have sustained acute ACJ injuries.

Study Design:

Case series; Level of evidence, 4.

Methods:

A retrospective review was performed of professional National Hockey League (NHL) players referred for MRI evaluation of acute ACJ injuries. All MRI scans were assessed for status of the ACJ, ligamentous stabilizers, and surrounding musculature. MRI-based overall grade of ACJ injury (modified Rockwood grade 1-6) was assigned to each case. Data regarding mechanism of injury, player handedness, clinical features, and return to play were evaluated.

Results:

Overall, 24 MRI examinations of acute ACJ injuries (23 patients; mean age, 24 years) were reviewed. We found that 50% of injuries were sustained during the first period of play, and in 75% of cases, injuries involved the same side as player shooting handedness. Analysis of MRI scans revealed 29% (7/24) grade 1 ACJ injuries, 46% (11/24) grade 2 injuries, 21% (5/24) grade 3 injuries, and 4% (1/24) grade 5 injuries. Trapezius muscle strains were seen in 79% and deltoid muscle strain in 50% of cases. Nonoperative management was used for 23 injuries; 1 patient (grade 5 injury) underwent acute reconstructive surgery. All players successfully returned to professional NHL competition. Excluding cases with additional injuries or surgery (n = 3) or convalescence extending into the offseason (n = 3), we found that the mean return to play was 21.4 days (7.2 games missed). No statistically significant difference was observed in return to play between nonoperatively treated grade 3 injuries (mean, 28.3 days) and grade 1 or 2 injuries (mean, 20.1 days). However, grade 3 injuries were associated with a greater number of NHL scheduled games missed (mean, 12.7) compared with lower grade injuries (mean, 6.1) (P = .027).

Conclusion:

The spectrum of pathology and grading of acute ACJ injuries sustained in professional ice hockey can be accurately assessed with MRI; the majority of injuries observed in this study were low grade (grades 1 and 2). Although grade 3 injuries were associated with a greater number of games missed, similar return-to-play results were observed between nonoperatively treated grade 3 and grade 1 or 2 ACJ injuries.

Ultrasound Evaluation of Anterior Acromioclavicular Relationship in the Horizontal Plane on 40 Healthy Subjects. A New Possibility for Differential Diagnosis of Acromioclavicular Disjunctions Rockwood Stage 3 and 4? A Pilot Study

OBJECTIVE

To evaluate the repeatability and reproducibility of an ultrasound examination of the acromioclavicular joint (ACJ) performed by an orthopaedic surgeon to analyze anterior ACJ relationship in the horizontal plane.

DESIGN

Prospective observational study on healthy subjects.

SETTING

The study was conducted in 2017 in a university department of orthopaedic surgery and traumatology.

LEVEL OF EVIDENCE

III.

PATIENTS (OR PARTICIPANTS)

Forty consecutive volunteers aged 18 to 40 years were involved. INTERVENTIONS (OR ASSESSMENT OF RISK FACTORS OR INDEPENDENT VARIABLES):: The ultrasound examination was performed by 2 orthopaedic surgeons with a SonoSite M-Turbo portable ultrasound machine (Fujifilm, Japan). Distance measurement between the anterior edge of the clavicle (AECL) and the anterior edge of the acromion (AEAC) was done on the right side, then on the left one and repeated by the same examiner.

MAIN OUTCOME MEASURES

The intra- and interexaminer reproducibility of measurements was analyzed as primary outcome. Concordance of distance measurements between the right and left sides on the same subject was evaluated, as well as the "typical morphology" of the ACJ in the horizontal plane.

RESULTS

The intra- and interexaminer reproducibility for AECL-AEAC distance measurements was, respectively, 0.95 (0.93-0.97) and 0.87 (0.84-0.90). The correlation between the right and left sides was significant (P < 0.001), with a reproducibility of 0.86 (0.83-0.89). Twenty-seven (67.5%) volunteers were considered to have a "perfect alignment" of the AECL and AEAC.

CONCLUSIONS

This study confirms that it is possible to evaluate with good reproducibility the anterior AC relationship in the horizontal plane and that both sides are similar on the same subject.

Magnetic resonance imaging of the shoulder

The aim of this article is to review the use of magnetic resonance imaging (MRI) for the evaluation of shoulder pain, which is a common clinical complaint of the musculoskeletal system. MRI is an essential auxiliary tool to evaluate these patients because of its high resolution and high sensitivity in depicting the soft tissues. This article will review the imaging technique, normal imaging anatomy, and most common imaging findings of disorders of tendons, labrum, and ligaments of the shoulder. It will also discuss common systemic diseases that manifest in the shoulder as well as disorders of the acromioclavicular joint and bursae. New advances and research in MRI have provided additional potential uses for evaluating shoulder derangements.

Acromioclavicular joint injuries: Imaging and management

Acromioclavicular joint injuries are commonly encountered in the setting of shoulder trauma. Knowledge of the anatomy and biomechanics of the joint, grading of joint injuries, and understanding the capabilities and limitations of different radiological modalities will help in selecting the best management option and outcomes for affected patients.

Imaging of the Acromioclavicular Joint: Anatomy, Function, Pathologic Features, and Treatment

The acromioclavicular joint is an important component of the shoulder girdle; it links the axial skeleton with the upper limb. This joint, a planar diarthrodial articulation between the clavicle and the acromion, contains a meniscus-like fibrous disk that is prone to degeneration. The acromioclavicular capsule and ligaments stabilize the joint in the horizontal direction, while the coracoclavicular ligament complex provides vertical stability. Dynamic stability is afforded by the deltoid and trapezius muscles during clavicular and scapular motion. The acromioclavicular joint is susceptible to a broad spectrum of pathologic entities, traumatic and degenerative disorders being the most common. Acromioclavicular joint injury typically affects young adult males and can be categorized by using the Rockwood classification system as one of six types on the basis of the direction and degree of osseous displacement seen on conventional radiographs. MRI enables the radiologist to more accurately assess the regional soft-tissue structures in the setting of high-grade acromioclavicular separation, helping to guide the surgeon's selection of the appropriate management. Involvement of the acromioclavicular joint and its stabilizing ligaments is also important for understanding and classifying distal clavicle fractures. Other pathologic processes encountered at this joint include degenerative disorders; overuse syndromes; and, less commonly, inflammatory arthritides, infection, metabolic disorders, and developmental malformations. Treatment options for acromioclavicular dysfunction include conservative measures, resection arthroplasty for recalcitrant symptoms, and surgical reconstruction techniques for stabilization after major trauma.

Acromioclavicular Joint: What to Look for

Acromioclavicular joint (ACJ) pathology is a common source of shoulder girdle pain, frequently coexisting with and sharing overlapping clinical features of rotator cuff and glenohumeral articular lesions. ACJ trauma and osteoarthritis dominate clinical presentation; however, an array of pathologies can affect the joint. MR imaging of the ACJ is a powerful secondary diagnostic tool in early diagnosis of ACJ pathology and in accurate assessment of ACJ injuries, helping to resolve clinically challenging cases and allowing for individualized treatment planning. Knowledge of ACJ anatomy, biomechanics, and pathology is fundamental to interpreting and providing a clinically relevant ACJ MR imaging report.

Horizontal Instability of the Acromioclavicular Joint: A Systematic Review

BACKGROUND

Injuries to the acromioclavicular (AC) joint are common and should be suspected in patients who have shoulder pain in the region of the acromion and clavicle. Injuries to the AC ligament can cause horizontal instability and are often neglected or underdiagnosed, which can lead to poor patient outcomes.

PURPOSE

To perform a systematic review of the literature on the diagnosis and treatment of horizontal instability of the AC joint.

STUDY DESIGN

Systematic review.

METHODS

The authors performed a systematic review using the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. PubMed and EMBASE were searched for studies that investigated diagnosis, treatment, and failure of operative management of acute and chronic AC separations. Studies that did not specifically evaluate AC joint injuries, were not written in English, or were specific only to vertical instability of the AC joint were excluded.

RESULTS

Overall, 23 articles met the inclusion criteria and were therefore included in this systematic review. Diagnosing horizontal AC instability is difficult using plain radiographs; dynamic views were shown in some cases to better detect horizontal instability than with static views. More than 60 procedures for treating AC joint injuries have been published, but many focus on vertical rather than horizontal instability. Modifications to current surgical procedures to incorporate reconstruction of the horizontal component showed improved patient outcomes. Such modifications included additional AC joint suture cord cerclage, combined AC and coracoclavicular ligament reconstruction, and the Twin Tail TightRope triple button technique. Failure after surgical stabilization of AC joint separation has been reported to occur in 15% to 80% of cases.

CONCLUSION

No consensus is available regarding the best practices for diagnosis, evaluation, and treatment of acute or chronic horizontal instability of the AC joint. Moreover, horizontal instability injuries are often neglected or poorly understood, making diagnosis difficult, which may lead to high complication rates and failure after surgical stabilization.

Normal development imaging pitfalls and injuries in the pediatric shoulder

The skeletal maturation of the shoulder has been well documented on radiographic and cadaveric studies. Recent increased use of MRI has provided increased understanding of the soft-tissue and osseous changes that occur during development. Thus recognizing normal maturation, imaging manifestations and pitfalls is crucial when evaluating the pediatric shoulder joint. At birth, the humeral diaphysis, midportion of the clavicle, and the body of the scapula are ossified, while the remainder of the bones of the shoulder are composed of non-ossified cartilaginous precursors. During growth, cartilaginous apophyses and epiphyses of the shoulder develop numerous secondary ossification centers, which fuse with the primary ossification centers to form the complete bony components of the shoulder. Additionally changes in the morphology of the growth plates as well as marrow signal occur in an organized manner. This paper affords the reader with an understanding of the normal development of three major components of skeletal maturation in the shoulder: ossification centers, growth plates and marrow signal. These topics are further subdivided into the glenoid, proximal humerus and acromioclavicular joint. We also provide a focus on distinguishing normal anatomy from imaging pitfalls related to skeletal maturation.

Radiographic/MR Imaging Correlation of the Shoulder

This article discusses the typical findings seen on conventional radiography in 3 common shoulder pathologies, namely glenohumeral instability, rotator cuff pathology, and acromioclavicular joint dislocation. Correlative MR images are used to explain and illustrate the significance of radiographic findings that suggest the presence of underlying shoulder pathology.

The Rockwood classification in acute acromioclavicular joint injury does not correlate with symptoms

PURPOSE

Rockwood classified acromioclavicular (AC) joint injuries by displacement of the joint on radiographs. This classification has driven the management dogma of acute AC dislocation. The correlation between Rockwood grade and symptoms has not been described in acute injury. This study assesses that relationship.

METHODS

This series included 77 patients with acute AC joint injury (<6 weeks), treated between 2006 and 2015. Objective and patient-reported measures enabled correlation between clinical measures and Rockwood grade.

RESULTS

The mean age was 32 years (±11.86; range 17-59 years); 88% were male. Forty-four per cent were professional athletes and 43% suffered injury during rugby. The mean time from injury to presentation was 2 weeks (±1.64; range 0-5 weeks). There was poor correlation between Rockwood classification and pain (visual analogue scale) ( r_s = 0.05; p = 0.752). Poor correlation was noted between Rockwood grade and functional deficit (elevation ( r_s = 0.18; p = 0.275), abduction ( r_s = 0.19; p = 0.246) and strength ( r_s = 0.09; p = 0.579) vs. contralateral side). Oxford and Constant scores did not correlate with Rockwood grade ( r_s = 0.13; p = 0.972 and 0.01; p = 0.448, respectively).

CONCLUSION

The Rockwood grade does not correlate with clinical symptoms in acute AC joint injury. Previous evidence demonstrates the Rockwood classification's limitations in predicting the structures injured. Therefore, the reliability of using the Rockwood grade as a decision-making tool in the management of acute AC joint dislocation is unclear.

ACR Appropriateness Criteria® Shoulder Pain-Traumatic

Traumatic shoulder pain is pain directly attributed to a traumatic event, either acute or chronic. This pain may be the result of either fracture (the clavicle, scapula, or proximal humerus) or soft-tissue injury (most commonly of the rotator cuff, acromioclavicular ligaments, or labroligamentous complex). Imaging assessment of traumatic shoulder pain begins with conventional radiography and, depending on physical examination findings, will require MRI or MR arthrography for assessment of soft-tissue injuries and CT for delineation of fracture planes. Ultrasound excels in assessment of rotator cuff injuries but has limited usefulness for assessment of the deep soft-tissues. CT angiography and conventional arteriography are helpful for assessment of vascular injury, and bone scintigraphy can be used in assessment of complex regional pain syndrome after traumatic shoulder injury. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

Interobserver and intraobserver reliability of radiographic classification of acromioclavicular joint dislocations

HYPOTHESIS AND BACKGROUND

The classification and treatment of acromioclavicular (AC) joint dislocations remain controversial. The purpose of this study was to determine the interobserver and intraobserver reliability of the Rockwood classification system. We hypothesized poor interobserver and intraobserver reliability, limiting the role of the Rockwood classification system in determining severity of AC joint dislocations and accurately guiding treatment decisions.

METHODS

We identified 200 patients with AC joint injuries using the International Classification of Diseases, Ninth Revision code 831.04. Fifty patients met inclusion criteria. Deidentified radiographs were compiled and presented to 6 fellowship-trained upper extremity orthopedic surgeons. The surgeons classified each patient into 1 of the 6 classification types described by Rockwood. A second review was performed several months later by 2 surgeons. A κ value was calculated to determine the interobserver and intraobserver reliability.

RESULTS

The interobserver and intraobserver κ values were fair (κ = 0.278) and moderate (κ = 0.468), respectively. Interobserver results showed that 4 of the 50 radiographic images had a unanimous classification. Intraobserver results for the 2 surgeons showed that 18 of the 50 images were rated the same on second review by the first surgeon and 38 of the 50 images were rated the same on second review by the second surgeon.

CONCLUSION

We found that the Rockwood classification system has limited interobserver and intraobserver reliability. We believe that unreliable classification may account for some of the inconsistent treatment outcomes among patients with similarly classified injuries. We suggest that a better classification system is needed to use radiographic imaging for diagnosis and treatment of AC joint dislocations.

Stress radiographs for evaluating acromioclavicular joint separations in an active-duty patient population: What have we learned?

Introduction

Acromioclavicular (AC) joint separation is a common entity in athletic patient populations. The surgical treatment of these injuries varies based upon extent of injury, with numerous imaging modalities recommended to differentiate injury severity and treatment options. The use of weighted stress radiographs is controversial in the diagnostic evaluation of AC separation with previous consensus recommending against their use. No study to date has investigated the clinical utilization of diagnostic studies in the evaluation of AC joint separations in a military surgeon population.

Methods

Thirty-eight shoulder or sports medicine sub-specialty certified orthopaedic surgeons on active service in the Army, Air Force, and Navy were surveyed on their evaluation and treatment protocols for AC joint injuries. Specifically analyzed were imaging choice including the use of weighted stress radiographs as well as treatment recommendations based upon Rockwood grade. Responses were recorded in addition to surgeon descriptive data. Responses were analyzed with descriptive statistics.

Results

Thirty-seven of the identified thirty eight surgeons responded to the survey, for a 97% response rate. Of the group, 70% of surgeons were within 10 years of completing fellowship with an estimated average of 15 AC joint separations treated annually. Plain radiographic examination was relied upon by 48% of surgeons for treatment of AC joint separation with 13% using weighted stress radiographs. Overall, 10% of surgeon stated that their treatment plan would vary based upon results from a weighted stress view. 51% of surgeons included magnetic resonance imaging in their diagnostic approach of these injuries. Treatment recommendation varied according to injury severity with 78% preferring nonoperative treatment for acute Grade III injuries with 86% waiting a minimum of 3 months before proceeding with operative treatment. For Grade V injuries, 81% of surgeon preferred operative treatment, with 59% incorporating a soft-tissue graft in their repair or reconstructive procedure.

Discussion

This study identified substantial practice variation amongst military surgeons treating a relatively homogenous population with AC joint separations, reflective of a lack of definitive evidence to guide diagnosis and treatment. Overall, nonoperative management is the preferred initial approach for Type III injuries and operative treatment is the preferred initial approach for Type V injuries. The diagnostic evaluation varied across the surgeon cohort, but 87% elected against the use of weighted stress radiographs for the evaluation of AC joint separations, with only 10% relying upon them to dictate their recommended treatment. Future research identifying optimal diagnosis and treatment of AC joint separations is needed.

New quantitative radiographic parameters for vertical and horizontal instability in acromioclavicular joint dislocations

PURPOSE

The aim of this study was to identify the most accurate and reliable quantitative radiographic parameters for assessing vertical and horizontal instability in different Rockwood grades of acromioclavicular joint (ACJ) separations. Furthermore, the effect of projectional variation on these parameters was investigated in obtaining lateral Alexander view radiographs.

METHODS

A Sawbone model of a scapula with clavicle was mounted on a holding device, and acromioclavicular dislocations as per the Rockwood classification system were simulated with the addition of horizontal posterior displacement. Projectional variations for each injury type were performed by tilting/rotating the Sawbone construct in the coronal, sagittal or axial plane. Radiographic imaging in the form of an anterior-posterior Zanca view and a lateral Alexander view were taken for each injury type and each projectional variation. Five newly defined radiographic parameters for assessing horizontal and vertical displacement as well as commonly used coracoclavicular distance view were measured. Reliability, validity and the effect of projectional variation were investigated for these radiographic measurements.

RESULTS

All radiographic parameters showed excellent intra- and interobserver reliability. The validity was excellent for the acromial centre line to dorsal clavicle (AC-DC) in vertical displacement and for the glenoid centre line to posterior clavicle (GC-PC) in horizontal displacement, whilst the remaining measurements showed moderate validity. For AC-DC and GC-PC, convergent validity expressed strong correlation to the effective distance and discriminant validity demonstrated its ability to differentiate between various grades of ACJ dislocations. The effect of projectional variation increased with the degree of deviation and was maximal (3 mm) for AC-DC in 20° anteverted malpositioning and for GC-PC in 20° retroverted malpositioning.

CONCLUSIONS

AC-DC and the GC-PC are two novel quantitative radiographic parameters of vertical and horizontal instability in ACJ dislocations that demonstrate excellent reliability and validity with reasonable inertness to malpositioning. The use of AC-DC for assessing vertical displacement and GC-PC for assessing horizontal displacement in a single Alexander view is recommended to guide the appropriate management of ACJ dislocations. A better appreciation of the degree of horizontal instability, especially in lower Rockwood grades (II, III) of ACJ dislocations, may improve management of these controversial injuries.

The acutely injured acromioclavicular joint - which imaging modalities should be used for accurate diagnosis? A systematic review

Background

The management of acute acromioclavicular (AC) joint injuries depends on the degree of injury diagnosed by the Rockwood classification. Inadequate imaging and not selecting the most helpful imaging protocols can often lead to incorrect diagnosis of the injury. A consensus on a diagnostic imaging protocol for acute AC joint injuries does not currently exist. Therefore we conducted a systematic review of the literature considering three diagnostic parameters for patients with acromioclavicular (AC) joint injuries: 1) Assessment of vertical instability; 2) Assessment of horizontal instability; 3) Benefit of weighted panoramic views.

Methods

Internet databases were searched in March 2016 using the terms (“AC joint” OR “acromioclavicular joint”) AND (MRI OR MR OR radiograph OR X-ray OR Xray OR ultrasound OR “computer tomography” OR “computed tomography” OR CT). Diagnostic, prospective, retrospective, cohort and cross- sectional studies were included to compare their use of different radiological methods. Case reports, cadaveric studies, and studies concerning chronic AC injuries and clinical outcomes were excluded.

Results

This search returned 1359 citations of which 1151 were excluded based on title, 116 based on abstract and 75 based on manuscript. 17 studies were included for review and were analyzed for their contributions to the three parameters of interest mentioned above. The inter- and intra-observer reliability for diagnosing vertical instabilities of the clavicle using x-ray alone show a high level of reproducibility while for horizontal instabilities the values were much more variable. In general, digitally measured parameters seem to be more precise and reliable between investigators than visual classification alone. Currently, evidence for the value of weighted views and other additional diagnostic imaging to supplement standard x-rays is controversial.

Conclusion

To date there is no consensus on a gold standard for diagnostic measures needed to classify acute AC joint injuries. The inter- and intra-observer reliability for diagnosing vertical instabilities of the clavicle using bilateral projections show a high level of reproducibility while for horizontal instabilities the results are much more inconsistent. There is currently no clear consensus on a protocol for image-based diagnosis and classification of acute AC joint injuries, leading to a lack of confidence in reproducibility and reliability.

Concomitant glenohumeral pathologies associated with acute and chronic grade III and grade V acromioclavicular joint injuries

PURPOSE

The purpose of this study was to identify the risk of concomitant glenohumeral pathologies with acromioclavicular joint injuries grade III and V.

METHODS

Patients who underwent arthroscopically-assisted stabilization of acromioclavicular joint injuries grade III or grade V between 01/2007 and 12/2015 were identified in the patient databases of two surgical centres. Gender, age at index surgery, grade of acromioclavicular joint injury (Rockwood III or Rockwood V), and duration between injury and index surgery (classified as acute or chronic) were of interest. Concomitant glenohumeral pathologies were noted and their treatment was classified as debridement or reconstructive procedure.

RESULTS

A total of 376 patients (336 male, 40 female) were included. Mean age at time of arthroscopic acromioclavicular joint reconstruction surgery was 42.1 ± 14.0 years. Overall, 201 patients (53%) had one or more concomitant glenohumeral pathologies. Lesions of the biceps tendon complex and rotator cuff were the most common. Forty-five patients (12.0%) had concomitant glenohumeral pathologies that required an additional repair. The remaining 156 patients (41.5%) received a debridement of their concomitant pathologies. Rockwood grade V compared to Rockwood grade III (p = 0.013; odds ratio 1.7), and chronic compared to acute injury were significantly associated with having a concomitant glenohumeral pathology (p = 0.019; odds ratio 1.7). The probability of having a concomitant glenohumeral pathology was also significantly associated with increasing age (p < 0.0001).

CONCLUSIONS

Concomitant glenohumeral pathologies were observed in 53% of surgically treated patients with an acute or chronic acromioclavicular joint injury of either grade III or V. Twenty-two percent of these patients with concomitant glenohumeral pathologies received an additional dedicated repair procedure. Although a significant difference in occurrence of concomitant glenohumeral pathologies was seen between Rockwood grades III and V, and between acute and chronic lesions, increasing age was identified as the most dominant predictor.

LEVEL OF EVIDENCE

Level IV, case series.

Image interpolation improves the zonal analysis of cartilage T2 relaxation in MRI

BACKGROUND

This project aimed to investigate the improvement in the detection of osteoarthritis (OA) in cartilage by the interpolation of T2 images, in the situation when the native MRI resolution is insufficient to resolve the depth-dependent T2 characteristics in articular cartilage (AC).

METHODS

Eighteen intact canine knee joints that were healthy or had mild (contralateral) or severe OA were T2-imaged in a 7T/20 cm MRI system at 200 µm/pixel resolution (macro-MRI). Two image analysis methods were used to interpolate the images to 100 µm/pixel, i.e., by Fourier-transforming the time-domain FID (Free Induction Decay) signal using the Varian NMR software and by interpolating the 2D T2 image using the ImageJ software.

RESULTS

The T2 profiles from 30 individual ROI of each healthy [6], mild [6] and OA [6] cartilage at 200 µm and the interpolated 100 µm resolutions were subdivided into two equal-thickness regions and three-equal thickness regions based on clinical MRI protocols. A new method divided the T2 profiles into three-unequal thickness zones according to the T2 profiles at 17.6 µm/pixel from the same cartilage imaged in a 7 Tesla/9 cm µMRI system. Both interpolation methods improved the depth-dependent T2 images/profiles in macro-MRI. The unequal zone division in T2 had better OA sensitivity than the equal zone division. The three-equal zone division of T2 profiles had better OA sensitivity than the two-equal zone division. The statistical significant difference between the healthy and mild OA cartilage is detected (P=0.0018) only by the unequal zone division method at 100 µm resolution.

CONCLUSIONS

Data interpolation improves the T2 sensitivity in MRI of cartilage OA. Unequal division of tissue thickness enables better early stage of OA detection than the equal division.

Reliability of the Traditional Classification Systems for Acromioclavicular Joint Injuries by Radiography

Background

The present study aimed to examine the reliability of the radiographic classification systems for acromioclavicular (AC) joint injuries.

Methods

We initially polled 47 orthopaedic surgeons regarding what common technique they used for applying the Rockwood and the Tossy and Allman classification systems. All used a single standard AC joint view (Zanca view). We then presented 24 Zanca view radiographs of patients who had sustained AC joint injuries to 19 specialist shoulder surgeons and asked each of them to classify the injuries using the Rockwood and the Tossy and Allman classification systems. We then altered the order of radiographs and repeated the survey with the same group of surgeons 1 month later.

Results

The mean inter-observer agreement and the corresponding weighted kappa for the Rockwood and the Tossy and Allman classification system were 64.6% and 0.258; and 68.1% and 0.309, respectively. The mean intra-observer agreement and the corresponding weighted kappa for the systems were 59.4% and 0.150; and 67.4% and 0.113, respectively.

Conclusions

We conclude that the classification of AC joint injuries using a radiograph alone has limited reliability and consistency in clinical practice.

Shoulder acromioclavicular joint reconstruction options and outcomes

Acromioclavicular joint separations are a common cause of shoulder pain in the young athletic population. In high-grade injuries, acromioclavicular joint reconstruction procedures may be indicated for functional improvement. There is currently no gold standard for the surgical management of these injuries. Multiple reconstructive options exist, including coracoclavicular screws, hook plates, endobutton coracoclavicular fixations, and anatomic ligament reconstructions with tendon grafts. This article aims to review pertinent acromioclavicular joint anatomy and biomechanics, radiographic evaluation, classification system, as well as reconstruction options, outcomes, and complications.

Injury patterns of the acromioclavicular ligament complex in acute acromioclavicular joint dislocations: a cross-sectional, fundamental study

BACKGROUND

Horizontal instability impairs clinical outcome following acute acromioclavicular joint (ACJ) reconstruction and may be caused by insufficient healing of the superior acromioclavicular ligament complex (ACLC). However, characteristics of acute ACLC injuries are poorly understood so far. Purposes of this study were to identify different ACLC tear types, assess type-specific prevalence and determine influencing cofactors.

METHODS

This prospective, cross-sectional study comprised 65 patients with acute-traumatic Rockwood-5 (n = 57) and Rockwood-4 (n = 8) injuries treated operatively by means of mini-open ACJ reduction and hook plate stabilization. Mean age at surgery was 38.2 years (range, 19-57 years). Standardized pre- and intraoperative evaluation included assessment of ACLC tear patterns and cofactors related to the articular disc, the deltoid-trapezoidal (DT) fascia and bony ACJ morphology. Articular disc size was quantified as 0 = absent, 1 = remnant, 2 = meniscoid and 3 = complete.

RESULTS

All patients showed complete ruptures of the superior ACLC, which could be assigned to four different tear patterns. Clavicular-sided (AC-1) tears were observed in 46/65 (70.8 %), oblique (AC-2) tears in 12/65 (18.5 %), midportion (AC-3) tears in 3/65 (4.6 %) and acromial-sided (AC-4) tears in 4/65 (6.1 %) of cases. Articular disc size manifestation was significantly (P < .001) more pronounced in patients with AC-1 tears (1.89 ± 0.57) compared to patients with AC-2 tears (0.67 ± 0.89). Other cofactors did not influence ACLC tear patterns. ACLC dislocation with incarceration caused mechanical impediment to anatomical ACJ reduction in 14/65 (21.5 %) of cases including all Rockwood-4 dislocations. Avulsion "in continuity" was a consistent mode of failure of the DT fascia. Type-specific operative strategies enabled anatomical ACLC repair of all observed tear types.

CONCLUSIONS

Acute ACLC injuries follow distinct tear patterns. There exist clavicular-sided (AC-1), oblique (AC-2), midportion (AC-3) and acromial-sided (AC-4) tears. Articular disc size was a determinant factor of ACLC tear morphology. Mini-open surgery was required in Rockwood-4 and a relevant proportion of Rockwood-5 dislocations to achieve both anatomical ACLC and ACJ reduction. Type-specific operative repair of acute ACLC tears might promote biological healing and lower rates of horizontal ACJ instability following acute ACJ reconstruction.

Inter- and intraobserver reliability of the Rockwood classification in acute acromioclavicular joint dislocations

PURPOSE

The reliability of the Rockwood classification, the gold standard for acute acromioclavicular (AC) joint separations, has not yet been tested. The purpose of this study was to investigate the reliability of visual and measured AC joint lesion grades according to the Rockwood classification.

METHODS

Four investigators (two shoulder specialists and two second-year residents) examined radiographs (bilateral panoramic stress and axial views) in 58 patients and graded the injury according to the Rockwood classification using the following sequence: (1) visual classification of the AC joint lesion, (2) digital measurement of the coracoclavicular distance (CCD) and the horizontal dislocation (HD) with Osirix Dicom Viewer (Pixmeo, Switzerland), (3) classification of the AC joint lesion according to the measurements and (4) repetition of (1) and (2) after repeated anonymization by an independent physician. Visual and measured Rockwood grades as well as the CCD and HD of every patient were documented, and a CC index was calculated (CCD injured/CCD healthy). All records were then used to evaluate intra- and interobserver reliability.

RESULTS

The disagreement between visual and measured diagnosis ranged from 6.9 to 27.6 %. Interobserver reliability for visual diagnosis was good (0.72-0.74) and excellent (0.85-0.93) for measured Rockwood grades. Intraobserver reliability was good to excellent (0.67-0.93) for visual diagnosis and excellent for measured diagnosis (0.90-0.97). The correlations between measurements of the axial view varied from 0.68 to 0.98 (good to excellent) for interobserver reliability and from 0.90 to 0.97 (excellent) for intraobserver reliability.

CONCLUSION

Bilateral panoramic stress and axial radiographs are reliable examinations for grading AC joint injuries according to Rockwood's classification. Clinicians of all experience levels can precisely classify AC joint lesions according to the Rockwood classification. We recommend to grade acute ACG lesions by performing a digital measurement instead of a sole visual diagnosis because of the higher intra- and interobserver reliability.

LEVEL OF EVIDENCE

Case series, Level IV.

Ultrasound of the coracoclavicular ligaments in the acute phase of an acromioclavicular disjonction: Comparison of radiographic, ultrasound and MRI findings

OBJECTIVES

Acromioclavicular joint injuries are typically diagnosed by clinical and radiographic assessment with the Rockwood classification, which is crucial for treatment planning. The purpose of this study was to describe how the ultrasound findings of acromioclavicular joint injury compare with radiography and MRI findings.

METHODS

Forty-seven patients with suspected unilateral acromioclavicular joint injury after acute trauma were enrolled in this prospective study. All patients underwent digital radiography, ultrasound and 3T MRI. A modified Rockwood classification was used to evaluate the coracoclavicular ligaments. The classifications of acromioclavicular joint injuries diagnosed with radiography, ultrasound and MRI were compared. MRI was used as the gold standard.

RESULTS

The agreement between the ultrasound and MRI findings was very good, with a correlation coefficient of 0.83 (95 % CI: 0.72-0.90; p < 0.0001). Ultrasound detected coracoclavicular ligament injuries with a sensitivity of 88.9 %, specificity of 90.0 %, positive predictive value of 92.3 % and negative predictive value of 85.7 %. The agreement between the ultrasound and radiography findings was poor, with a correlation coefficient of 0.69 (95 % CI: 0.51-0.82; p < 0.0001).

CONCLUSION

Ultrasound is an effective examination for the diagnostic work-up of lesions of the coracoclavicular ligaments in the acute phase of an acromioclavicular injury.

KEY POINTS

• Ultrasound is appropriate for acute acromioclavicular trauma due to its accessibility. • Ultrasound contributes to the diagnostic work-up of acute lesions of the coracoclavicular ligaments. • Ultrasound is appropriate in patients likely to benefit from surgical treatment. • Ultrasound could be a supplement to standard radiography in acute acromioclavicular trauma.

Reliability of radiographic measurements for acromioclavicular joint separations

INTRODUCTION

The treatment of acromioclavicular (AC) joint separations is controversial, particularly for Rockwood type III injuries. Rockwood type IV injuries, which correspond to horizontal instability, are very likely under-diagnosed. The objective of this study was to evaluate the inter- and intra-observer reproducibility of the Rockwood classification through an evaluation of standard radiographs, as described in the original article.

MATERIAL AND METHODS

This was a prospective radiographic study using protocol-based data from the 2014 symposium of the French Society of Arthroscopy (SFA). Fifteen anonymized radiological records were analysed by six independent examiners on two occasions, 1 week apart. The records consisted of a comparative A/P view of the two acromioclavicular joints (Zanca view), an axillary lateral view and dynamic lateral views (Tauber protocol) to uncover dynamic horizontal instability. A detailed analysis protocol was implemented that included absolute and relative measurements on each view; the relative measurements were used to account for radiographic magnification.

RESULTS

The inter- and intra-observer reproducibility on the A/P radiographs was good to excellent. The reproducibility was fair to good on the lateral views, but the measurements varied greatly from one subject to another, and significant errors were found with certain records. The reproducibility of the dynamic views proposed by Tauber was poor to fair.

DISCUSSION

Radiographic analysis of AC joint separations is reproducible in the vertical plane, which makes it possible to diagnose Rockwood type II, III and V injuries. On the other hand, static and dynamic analyses in the horizontal plane do not have good reproducibility and do not contribute to make an accurate diagnosis of Rockwood type IV injuries.

LEVEL OF EVIDENCE

Level I, Diagnostic study.

Transarticular fixation by hook plate versus coracoclavicular stabilization by single multistrand titanium cable for acute Rockwood grade-V acromioclavicular joint dislocation: a case-control study

BACKGROUND

Hook plate (HP) is popularly used for acute and severely displaced acromioclavicular (AC) dislocations. However, subacromial impingement and acromion osteolysis induced by transarticular fixation are notorious. The current case-control study was to compare transarticular fixation by HP to coracoclavicular (CC) stabilization by single multistrand titanium cable (MSTC).

METHODS

Between January 2006 and August 2009, 24 patients with acute AC dislocations were surgically treated by open reduction and transarticular fixation with HP. These patients were matched to a series of 24 patients, who were managed by CC stabilization with MSTC in the same period. All AC dislocations were graded as Rockwood type V. Implant was removed 8-12 months after the primary operation in all patients, and 12 months at least were needed to assess the maintenance of AC joint. Functional results were evaluated before implant removal as well as in the last follow-up based on Constant-Murley criteria.

RESULTS

There were no differences of demographic data including age, dominant gender and side, injury-to-surgery interval, operation time and follow-up period. In terms of functionality, Constant score was 95.8 ± 4.1 in MSTC group, while 76.7 ± 8.0 in HP group before implant removal (P < 0.001). In detail, MSTC was superior to HP in pain, ROM and activities. Constant score was significantly improved to 86.1 ± 5.7 after hardware removal for patients in HP (P < 0.001). Degenerative change of acromioclavicular joint presented in 16 patients (66.7%) in patients treated by HP, while it was found in only 3 patients (12.5%) treated by MSTC (P < 0.001).

CONCLUSIONS

MSTC is superior to HP for the treatment of Rockwood type-V acromioclavicular dislocation both before and after removal of the implant. Hardware removal is of great benefits for functional improvement in patients treated by HP.

Bilateral weighted radiographs are required for accurate classification of acromioclavicular separation: an observational study of 59 cases

INTRODUCTION

Misinterpretation of the Rockwood classification system for acromioclavicular joint (ACJ) separations has resulted in a trend towards using unilateral radiographs for grading. Further, the use of weighted views to 'unmask' a grade III injury has fallen out of favour. Recent evidence suggests that many radiographic grade III injuries represent only a partial injury to the stabilising ligaments. This study aimed to determine (1) whether accurate classification is possible on unilateral radiographs and (2) the efficacy of weighted bilateral radiographs in unmasking higher-grade injuries.

METHODS

Complete bilateral non-weighted and weighted sets of radiographs for patients presenting with an acromioclavicular separation over a 10-year period were analysed retrospectively, and they were graded I-VI according to Rockwood's criteria. Comparison was made between grading based on (1) a single antero-posterior (AP) view of the injured side, (2) bilateral non-weighted views and (3) bilateral weighted views. Radiographic measurements for cases that changed grade after weighted views were statistically compared to see if this could have been predicted beforehand.

RESULTS

Fifty-nine sets of radiographs on 59 patients (48 male, mean age of 33 years) were included. Compared with unilateral radiographs, non-weighted bilateral comparison films resulted in a grade change for 44 patients (74.5%). Twenty-eight of 56 patients initially graded as I, II or III were upgraded to grade V and two of three initial grade V patients were downgraded to grade III. The addition of a weighted view further upgraded 10 patients to grade V. No grade II injury was changed to grade III and no injury of any severity was downgraded by a weighted view. Grade III injuries upgraded on weighted views had a significantly greater baseline median percentage coracoclavicular distance increase than those that were not upgraded (80.7% vs. 55.4%, p=0.015). However, no cut-off point for this value could be identified to predict an upgrade.

CONCLUSIONS

The accurate classification of ACJ separation requires weighted bilateral comparative views. Attempts to predict grade on a single AP radiograph result in a gross underestimation of severity. The value of bilateral weighted views is to 'unmask' a grade V injury, and it is recommended as a first-line investigation.

Acromioclavicular dislocation: postoperative evaluation of the coracoclavicular ligaments using magnetic resonance

OBJECTIVE

To radiologically evaluate the healing of the coracoclavicular ligaments after surgical treatment for acromioclavicular dislocation.

METHODS

Ten patients who had undergone surgical treatment for acromioclavicular dislocation via a posterosuperior route at least one year earlier were invited to return for radiological assessment using magnetic resonance. This evaluation was done by means of analogy with the scale described in the literature for studying the healing of the anterior cruciate ligament of the knee and for measuring the healed coracoclavicular ligaments.

RESULTS

A scar structure of fibrous appearance had formed in 100% of the cases. In 50% of the cases, the images of this structure had a good appearance, while the other 50% were deficient.

CONCLUSION

Late postoperative evaluation using magnetic resonance, on patients who had been treated for acute acromioclavicular dislocation using a posterosuperior route in the shoulder, showed that the coracoclavicular ligaments had healed in 100% of the cases, but that this healing was deficient in 50%.

Skeletal developmental patterns in the acromial process and distal clavicle as observed by MRI

OBJECTIVE

To provide an MRI timeline of normal skeletal developmental patterns in the acromial process and distal clavicle in children up to 18 years of age.

MATERIALS AND METHODS

Retrospective review of all shoulder MRIs obtained at our institution between January 2003 and March 2012, in children up to age 18, was performed. When available, radiographs and CT scans for these children were also reviewed. The following variables of the distal acromion and clavicle, with attention to morphology and MRI signal, were assessed: (1) Chondro-osseous junction and (2) Development and fusion of the secondary ossification centers.

RESULTS

Ninety-eight children with 116 MR studies were identified from the data search. Of these, 13 patients were excluded and the final cohort included 85 children with 102 MRI studies. Forty-one of these patients also had shoulder radiographs. The cartilaginous precursors of the distal clavicle and acromion conformed to the final shape of these structures. The chondro-osseous interphases became progressively more lobulated and notched in the distal acromion and clavicle respectively. Appearance and fusion of the secondary ossification centers was significantly earlier in our study than previously reported. Acromial secondary ossification centers began forming at age 10 and clavicular ones, while uncommon, began forming at age 11. Fusion of acromial primary and secondary ossification centers began at age 14 and was generally complete after age 16.

CONCLUSIONS

Based on MR imaging the development and fusion of the acromion and distal clavicle in children occur earlier than previously reported. They follow a sequential pattern and can serve as a blueprint for evaluating imaging studies of pediatric shoulders.

Reliability of the classification and treatment of dislocations of the acromioclavicular joint

BACKGROUND

We evaluated interobserver and intraobserver reliability of the classification and treatment of acromioclavicular (AC) joint dislocations and assessed the impact of adding 3-dimensional computed tomography (3D CT) on the reliability of classification and treatment choice.

METHODS

Ten surgeons independently reviewed plain radiographs and 3D CT in 28 cases with AC joint dislocation. Images from each case were randomly presented to the observers, with plain radiographs alone being presented first, followed by plain radiographs plus 3D CT 2 weeks later. Four weeks later, they repeated the same survey to evaluate intraobserver reliability. Reliability was assessed on the basis of Fleiss κ values.

RESULTS

On the basis of plain radiographs alone, interobserver and intraobserver reliability of the Rockwood classification were fair (κ = .214) and moderate (κ = .474), respectively. Interobserver and intraobserver reliability of treatment were both fair (κ = .213 and .399, respectively). On the basis of a combination of plain radiographs and 3D CT, interobserver and intraobserver reliability of the Rockwood classification were slight (κ = .177) and moderate (κ = .565), respectively. Interobserver and intraobserver reliability of treatment were fair (κ = .253) and moderate (κ = .554), respectively. There were no significant differences in reliability between the two groups in terms of any κ values.

CONCLUSION

This study suggests an overall lack of reliability of the Rockwood classification of AC joint dislocations and of decisions regarding their treatment. There is especially poor agreement between experienced shoulder surgeons. The addition of 3D CT did not improve reliability of classification and treatment of AC joint dislocations.

Management of acromioclavicular joint injuries

Acromioclavicular joint injuries are among the most common shoulder girdle injuries in athletes and most commonly result from a direct force to the acromion with the arm in an adducted position. Acromioclavicular joint injuries often present with associated injuries to the glenohumeral joint, including an increased incidence of superior labrum anterior posterior (SLAP) tears that may warrant further evaluation and treatment. Anteroposterior stability of the acromioclavicular joint is conferred by the capsule and acromioclavicular ligaments, of which the posterior and superior ligaments are the strongest. Superior-inferior stability is maintained by the coracoclavicular (conoid and trapezoid) ligaments. Type-I or type-II acromioclavicular joint injuries have been treated with sling immobilization, early shoulder motion, and physical therapy, with favorable outcomes. Return to activity can occur when normal shoulder motion and strength are obtained and the shoulder is asymptomatic as compared with the contralateral normal extremity. The management of type-III injuries remains controversial and is individualized. While a return to the previous level of functional activity with nonsurgical treatment has been documented in a number of case series, surgical reduction and coracoclavicular ligament reconstruction has been associated with a favorable outcome and can be considered in patients who place high functional demands on their shoulders or in athletes who participate in overhead sports. Surgical management is indicated for high-grade (≥type IV) acromioclavicular joint injuries to achieve anatomic reduction of the acromioclavicular joint, reconstruction of the coracoclavicular ligaments, and repair of the deltotrapezial fascia. Outcomes after surgical reconstruction of the coracoclavicular ligaments have been satisfactory with regard to achieving pain relief and return to functional activities, but further improvements in the biomechanical strength of these constructs are necessary to avoid loss of reduction and creep with cyclic loading.

A novel radiographic index for the diagnosis of posterior acromioclavicular joint dislocations

BACKGROUND

Posterior acromioclavicular (AC) joint dislocations are frequently misclassified because posterior translation of the clavicle is difficult to evaluate in Zanca radiograph views. A novel radiographic index was used in this study to accurately diagnose posterior dislocations of the AC joint.

HYPOTHESIS

This novel index has a high degree of accuracy for the diagnosis of posterior AC joint dislocations.

STUDY DESIGN

Cohort study (diagnosis); Level of evidence, 2.

METHODS

This was an analytic, descriptive study of 150 patients with different grades of AC injuries according to the Rockwood classification (30 patients for each grade of injury: I, II, III, IV, and V). The diagnosis of an AC injury was made both clinically and radiographically by using comparative Zanca and axillary views. Two measurements were performed in Zanca views: the coracoclavicular distance and the AC width distance. A width index was calculated for each patient. The Student t test, Bonferroni test, logistic regression, linear regression, and receiver operating characteristic (ROC) curves were used for statistical analysis. Forty cases were impartially selected to obtain a κ concordance value.

RESULTS

The average value of the AC width index per group (according to the Rockwood classification) was as follows: type I, 2.1% (range, -12% to 25%); type II, 4.2% (range, -19% to 29%); type III, 19.1% (range, -59% to 91%); type IV, 110.3% (range, 47% to 181%); and type V, -3.8% (range, -71% to 62%). There was a significant difference between the average width index in the patients with type IV injuries and those in the remaining groups (P < .05). The ROC curve showed that a width index of 60% has a sensitivity of 95.7% and specificity of 97.5%, with a positive predictive value of 96.7% and negative predictive value of 95.6% to predict a type IV injury. Intraobserver reliability was rated as substantial agreement for each of 3 observers; the interobserver reliability of the 3 independent raters was almost perfect.

CONCLUSION

An AC width index of ≥60% is highly accurate for the diagnosis of a posterior AC joint dislocation, with high intraobserver and interobserver concordance.