Correlation of ultrasonographic findings to Tossy's and Rockwood's classification of acromioclavicular joint injuries

Diagnosis and Nonoperative Treatment of Acromioclavicular Joint Injuries in Athletes and Guide for Return to Play

Injury to the acromioclavicular (AC) joint accounts for approximately 40% to 50% of all shoulder injuries. In contact sports, the prevalence of AC joint injury increases. This injury is frequently encountered and treated by fellowship-trained as well as general orthopedic surgeons. As such, it is important to understand the diagnostic and treatment pathways for AC joint disruption. The treatment pathways in athletes may be different from those in the general population. This article will focus on the diagnosis and nonoperative treatment of AC joint injuries in athletes. We will also comment on return-to-play guidelines after this nonoperative treatment.

A relook at the reliability of Rockwood classification for acromioclavicular joint injuries

BACKGROUND

Controversies for treatment of acromioclavicular joint injuries in particular type III injuries may be partially attributed to the lack of a standardized method of radiography and measurement technique. Previous studies looking at the Rockwood classification showed poor inter- and intraobserver reliability (Kappa value approximately 0.20-0.50). We hypothesized that the use of unilateral instead of bilateral acromioclavicular joint radiographs was the cause of this finding. In this article, we standardized the methodology to perform the radiograph and to measure the coracoclavicular distances. We designed the study to focus on the reliability of differentiating type III and type V injuries.

METHODS

A standardized radiographic protocol for bilateral Zanca view was established in our institution. All patients who underwent this radiographic examination over a 3-year period were reviewed. Radiographs of 55 patients with significant (type III or V) injury met the inclusion criteria. For the interobserver reliability, a retrospective radiographic review was performed by 6 orthopedic surgeons and graded as either type III or V. For intraobserver reliability, a similar process was repeated by 3 observers after a period of 6 weeks.

RESULTS

Going by the majority agreement of the 6 reviewers, there were 34 type III injuries and 19 type V injuries. The Fleiss kappa for interobserver reliability was calculated to be 0.624. The Cohen kappa for intraobserver reliability was calculated to be 0.696.

DISCUSSION

The use of a standardized radiographic protocol-taking bilateral Zanca views on the same radiographic plate-would help eliminate a significant amount of variability and improve the reliability of classifying acromioclavicular joint injuries using the Rockwood classification, which uses a relative measure to the contralateral site as its definition criteria. Other possible sources of poor reliability may include the masking of injuries by muscle spasm, resulting in a misdiagnosis of a high-grade injury as a lower-grade one and the possible need to subclassify type III injuries.

CONCLUSION

Reliability of the Rockwood classification can be improved through the use of a standardized radiographic protocol to improve the detection of vertical instability. Similar to Rockwood dividing up Tossy grade 3 injuries when he noted the differential outcome and intervention, Rockwood type III injuries would likely require further subclassification as it remains an anomalous tool with high variability. Further studies are required to understand the pathologic basis of transition of type III into type V injury.

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.

Percutaneous minimally invasive repair of acromioclavicular joint dislocation using cannulated screws under ultrasonic vs. C-arm navigation: A prospective trial

INTRODUCTION

To compare percutaneous minimally invasive repair (PMIR) of acute acromioclavicular (AC) joint dislocation under ultrasound guidance (PMIR-UN) vs. C-arm navigation (PMIR-CN).

HYPOTHESIS

PMIR-UN has similar functional and radiographic outcomes as PMIR-CN.

MATERIALS AND METHODS

We treated 48 patients with acute grade III or V AC joint dislocation with surgical reduction and fixation with Kirschner wires and cannulated screws. The patients were randomly divided into a PMIR-UN group (n=24) and a PMIR-CN group (n=24). We assessed functional outcomes, operative duration, incision length, and intraoperative radiation exposure. Shoulder joint function was evaluated with the Constant-Murley score, and postoperative efficacy was evaluated using the Karlsson criteria.

RESULTS

The median follow-up duration was 13 months (range, 8-18 months). Satisfactory functional outcomes were obtained in both groups. Incision length, incidence of postoperative infection, pin migration, and postoperative efficacy did not differ between the two groups. Operative duration and intraoperative radiation dose were significantly greater in the PMIR-CN group than in the PMIR-UN group (P<0.05). Kirschner wires were removed at 4 weeks after surgery, and cannulated screws were removed at 12 weeks after surgery in both groups.

DISCUSSION

Based on the satisfactory results obtained in all patients, we conclude that PMIR-UN is a safe, easy, and reliable technique for the treatment of acute grade III or V AC joint dislocation.

TYPE OF STUDY

Low-powered prospective randomized trial.

LEVEL OF EVIDENCE

Level II.

The medial coracoclavicular ligament: anatomy, biomechanics,and clinical relevance-a research study

Background

The medial coracoclavicular ligament (MCCL), is a structure that shows defined morphologic and histologic features. However, little attention has been paid to the MCCL to date. This study was conducted to (1) determine whether the MCCL is a constant structure, (2) analyze its mechanical properties, and (3) determine its possible role in acromioclavicular (AC) stability.

Methods

AC joints, lateral coracoclavicular ligaments (LCCLs; conoid and trapezoid), and MCCLs were dissected in 30 fresh frozen upper limbs. In 6 of these specimens, we performed a sequential sectioning following the aforementioned order. A 20-N cephalad force was applied to the lateral clavicle at each step, recording the AC distance and coracoclavicular space and their variation. In 6 other specimens, we evaluated the anteroposterior motion of the clavicle following the MCCL section. Biomechanical testing was performed in 8 specimens, comparing the resistance of the MCCL to the LCCLs.

Results

The MCCL in all of the specimens featured a sharp-edge bundle stretching from the coracoid process to the clavicle and subclavius sheath. It showed ligament-like mechanical properties although less tensile resistance than the LCCLs. Once the AC and LCCLs were sectioned, transection of the MCCL determined a significant increase in both cephalad and posterior displacement.

Conclusion

The MCCL is a constant structure with the mechanical behavior of a ligament. It may act as the last container of the coracoclavicular space both in cephalad and posterior directions, precluding additional displacement in the absence of the LCCLs.

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.

The anterior borders of the clavicle and the acromion are not always aligned in the intact acromioclavicular joint: a cadaveric study

BACKGROUND

The aim of this study was to find reliable anatomic landmarks of the normal acromioclavicular joint (ACJ) that could enable the precise evaluation of the horizontal displacement of the clavicle after dislocation. The hypothesis was that the anterior borders of the acromion and the clavicle are always aligned in intact ACJs.

MATERIALS AND METHODS

In 30 cadaveric specimens, the anterior and posterior borders of the ACJ's articular facets and the most prominent anterior and posterior bony landmarks of the acromion and the clavicle were identified. The anterior and posterior overhang of the acromion and the clavicle was measured in relation to the borders of the articular facets. Therefore, the possible anterior and posterior alignment of the ACJ was evaluated.

RESULTS

Anteriorly, only 18 ACJs (60%) were aligned whereas 7 (24%) had major overhang of the acromion and 3 (10%) had major overhang of the clavicle. Similarly, 18 cases (60%) were posteriorly aligned, whereas 6 (20%) had major clavicular overhang and 4 (14%) had major overhang of the acromion. In 78% of these cases, the ACJ was aligned as well anteriorly as posteriorly (P < .001). Finally, the larger the width of the acromion (P = .032) or the clavicle (P = .049), the better the posterior joint alignment.

CONCLUSION

Our hypothesis was not verified. The acromion and clavicle are not perfectly aligned in a significant number of specimens with intact ACJs (40% of cases). The most reliable landmarks remain their articular facets.

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.

Prognostic factors to succeed in surgical treatment of chronic acromioclavicular dislocations

INTRODUCTION

Treatment of chronic acromioclavicular joint dislocation (ACJD) remains a poorly known and controversial subject. Given the many surgical options, it is not always easy to determine which steps are indispensable.

METHODS

This article reports a multicenter prospective study. The clinical and radiological follow-up involved a comparative analysis of the preoperative and postoperative data at 1 year, including pain (visual analogue scale), subjective functional incapacity (QuickDASH), and the objective Constant score, as well as a comparative analysis of vertical and horizontal movements measured on simple x-rays.

RESULTS

Based on a series of 140 operated ACJDs, we included 24 chronic ACJDs. The mean time to surgery was 46 weeks (range, 1 month to 4 years). The patients' mean age was 41 years, with a majority of males (75%), 72% of whom participated in recreational sports. Professionally, 40% of the subjects had jobs involving manual labor. We noted 40% grade III, 24% grade IV, and 36% grade V injury according to the Rockwood classification. In 92% of cases, coracoclavicular stabilization was provided by a double button implant, reinforced with a biological graft in 88% of the cases. In 29%, millimeters to centimeters of the distal clavicle were resected and acromioclavicular stabilization was associated in 54%. We observed complications in 33% of the cases. At 1 year postoperative, 21 patients underwent clinical and radiological follow-up (87.5%). Only 35% of the patients were satisfied or very satisfied, whereas 100% of them would recommend the operation. Full-time work was resumed in 91% of the cases and all sports could be resumed in 86%. The pre- and postoperative values at 1 year changed as follows: the mean Constant score improved from 61 to 87 (p=0.00002); the subjective QuickDASH score decreased from 41 to 9 (p=0.00002); and radiologically significant reduction of the initial displacement was observed in the vertical plane (p<10(-3)) and the horizontal plane (p=0.022).

CONCLUSION

In this study, the favorable prognostic factors found were: time to surgery less than 3 months (p=0.02), associated acromioclavicular stabilization, and postoperative immobilization with a sling extended to 6 weeks. However, resection of the distal clavicle did not influence the final result.

LEVEL OF PROOF

Level II prospective non-randomized comparative study.

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.

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.

Inter- and intraobserver reliability of the radiographic diagnosis and treatment of acromioclavicular joint separations

The management of acromioclavicular joint separations, in particular Rockwood types III and V, remains controversial. The purpose of this study was to investigate the observer reliability of shoulder surgeons when presented with the same cases of acromioclavicular joint separations. The authors retrospectively identified 28 patients who were diagnosed with a type III, IV, or V acromioclavicular joint separation. A PowerPoint presentation was compiled that contained an anteroposterior and axial radiograph from each patient prior to treatment. Radiographs were sent to surgeons, who diagnosed each injury according to the Rockwood classification and stated whether they recommended operative or nonoperative treatment for each patient.Inter- and intraobserver reliability were calculated from the surgeons' reviews. Repeat diagnoses were returned by 8 surgeons. A single-measure intraclass correlation coefficient (ICC) was used to determine interobserver reliability for the surgeons' Rockwood classifications (ICC=0.602) and their decision to operate (ICC=0.469). Intraobserver reliability also was calculated for Rockwood classifications (ρ=0.694) and decision to operate (κ=0.366). Two (25%) of 8 surgeons stated that they would have used open and arthroscopic techniques for repairing the dislocations, whereas the remaining (75%) surgeons would have performed open techniques. Individual surgeons were consistent in their grading of acromioclavicular joint dislocations, but less observer agreement existed among the surgeons. Poor agreement among surgeons for the decision to operate indicates that this decision is heavily influenced by clinical factors and the radiographic classification.

Ultrasound guidance improves the accuracy of the acromioclavicular joint infiltration: a prospective randomized study

Degeneration of the acromioclavicular joint (AC) often causes impaired shoulder function and pain. Its infiltration results in reportedly beneficial short-term effects. Misplacement of infiltrations is observed in high numbers. A previous study showed high accuracy of infiltrations of one surgeon comparing conventional palpation technique to ultrasound guidance. This study evaluates if ultrasound-guided AC joint infiltration is feasible for therapists of different levels of experience and if the accuracy can be increased. One hundred and twenty AC joints of 60 cadavers were enrolled into a prospective, randomized observer-blinded study. Six therapists of three different levels of experience infiltrated 20 AC joints each. Half of them were infiltrated after palpation of the joint space, half of them were ultrasound-guided infiltrated. Controls were performed pre- and post-infiltration by an independent radiologist. In total, accurate infiltration was observed in 70%. In 25%, misplacement of the infiltration was recorded in the palpation-, in 2% in the ultrasound- and in 3% in both groups. The difference between the two groups was significant (P = 0.009). Ultrasound-guided infiltration to the AC joint is significantly more accurate than conventional palpation technique. This method is simple, efficient and can be applied by therapists of all levels of experience.

Ultrasonography of the shoulder

The shoulder is the most common region to be evaluated with musculoskeletal ultrasound. The shoulder's complex anatomy enables an exceptional range of mobility at the expense of static stability. Consequently, the shoulder is susceptible to a multitude of traumatic and atraumatic injuries. This article presents an overview of shoulder anatomy, recommends a standardized approach to the sonographic shoulder evaluation, and discusses common sonographically apparent pathology of the shoulder.

Dynamic radiologic evaluation of horizontal instability in acute acromioclavicular joint dislocations

BACKGROUND

Biplane radiologic evaluation is indispensable for the correct diagnosis of acute acromioclavicular (AC) joint injuries. Thus far, no functional radiographic techniques have been quantified to evaluate horizontal instability in acute AC joint dislocations.

HYPOTHESIS

Supine dynamic axillary lateral shoulder views detect horizontal instability of the distal clavicle in patients with acute AC joint dislocations.

STUDY DESIGN

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

METHODS

Twenty-five consecutive patients with a mean age of 39 +/- 14 years with acute AC joint injury underwent biplane radiologic evaluation, including a conventional Zanca view and an axillary lateral view in a sitting position. In addition, supine axillary lateral views with the arm in 90 degrees of abduction and 60 degrees of flexion and extension were taken to evaluate the horizontal dynamics of the distal clavicle. The gleno-acromio-clavicular angle (GACA) was introduced and used to quantify the horizontal clavicular dynamics in terms of angle differences. The unaffected shoulders served as the control group.

RESULTS

Superior dislocation of the lateral clavicle in the Zanca view was classified as Rockwood type II in 7 patients, type III in 15, and type V in 3. The axillary lateral view in a sitting position showed posterior dislocation of the distal clavicle in 8 patients (Rockwood type IV injury). Dynamic radiologic evaluation revealed an average GACA difference between the neutral and anterior position of the arm of 7.1 degrees +/- 5.5 degrees for the unaffected shoulder. In the injured AC joints, 11 patients showed no radiologic evidence of horizontal instability (group A) with a GACA difference of 7.1 degrees +/- 4.8 degrees . Increased anteroposterior translation was evident in 14 patients (group B) with a GACA difference of 30.3 degrees +/- 14.3 degrees (P < .001).

CONCLUSION

Functional axillary radiologic evaluation seems to represent a simple imaging tool to reveal dynamic horizontal instability.

CLINICAL RELEVANCE

Horizontal instability of the distal clavicle in acute AC joint injuries represents an indication for surgical treatment. Dynamic axillary radiologic evaluation may detect previously missed unstable injuries. This evaluation might be relevant when deciding on surgical AC joint stabilization.

Biomechanical and radiographic analysis of partial coracoclavicular ligament injuries

BACKGROUND

A spectrum of acromioclavicular joint injuries may exist between type II acromioclavicular joint disruption (coracoclavicular strain) and type III acromioclavicular joint injuries (coracoclavicular disruption). This may help explain the variability in outcomes seen in patients with type II acromioclavicular injuries.

HYPOTHESIS

Injury to either the conoid or trapezoid ligaments would lead to instability of the acromioclavicular joint after complete acromioclavicular joint injury. A secondary hypothesis was that the resulting instability could be recognized with Zanca radiographs.

STUDY DESIGN

Controlled laboratory study.

METHODS

The acromioclavicular ligaments were sectioned in 40 cadaveric shoulder specimens. Ten intact specimens were loaded to failure to evaluate the normal failure patterns of the coracoclavicular ligaments. Thirty specimens then had either the conoid or trapezoid ligament sectioned after creation of complete acromioclavicular joint injury. Preinjury and postinjury radiographs and stability testing quantified the effect of coracoclavicular joint injury on acromioclavicular joint stability.

RESULTS

During failure testing, the conoid always failed first. Sectioning of the conoid led to significant increases in posterior and superior displacement on radiographs and with materials testing. Sectioning of the trapezoid led to significant increases in posterior displacement for materials testing and superior displacement on radiographs.

CONCLUSION

Sectioning of the acromioclavicular ligaments in conjunction with partial disruption of the coracoclavicular ligament complex led to significant changes in both radiographic and mechanical measures of acromioclavicular stability. The conoid fails first when a load is applied to the coracoclavicular complex in a superior direction.

CLINICAL RELEVANCE

Zanca radiograph may detect incomplete injury to the coracoclavicular ligaments associated with acromioclavicular disruption.

Acromioclavicular joint injury: enhanced technique of examination with dynamic maneuver

Acromioclavicular (AC) sprains can be graded in 3 to 6 different types according to Tossy or Rockwell, respectively. In mild sprains (Tossy and Rockwell I), movements in the AC joint are minimal, because the coraco-clavicular ligaments are intact. In these patients, stress radiography is usually normal, and sonographic examination at rest can be normal as well, showing minimal or no displacement between the 2 extremities of the bones. We present a simple dynamic maneuver to enhance the diagnosis of these mild sprains known as the cross-arm maneuver, in which the hand is placed on the opposite shoulder. The dynamic sonographic examination during this maneuver clearly shows abnormal movements in the clavicle's extremity, which "falls down" to the acromion in the cross-arm position and is raised and pulled from the acromion at rest. The maneuver is very easy to perform and may be useful when a mild AC joint sprain is suspected.

Isolated Trapezius Strain in a Patient with Multiple Sclerosis and Spasticity

Trapezius muscle injuries often occur in conjunction with high-grade acromioclavicular joint injuries [1], but to our knowledge, isolated trapezius injuries have not been described in the literature. We present a case of isolated trapezius strain in a spastic patient with multiple sclerosis documented with magnetic resonance imaging (MRI).