Treatment of Rockwood Type III Acromioclavicular Joint Dislocation

Clinical and radiographic outcomes following anatomic coracoclavicular ligament reconstruction using 4-strand taped suspensory fixation in an active-duty military population

Background

Acromioclavicular (AC) joint injuries are common in young, active populations. However, there is a paucity of literature reporting surgical outcomes following the treatment of AC joint injuries in the military population. Therefore, the purpose of this study was to evaluate the clinical and radiographic outcomes of active-duty military members who underwent arthroscopic-assisted anatomic coracoclavicular ligament reconstruction using a 4-strand suspensory fixation with taped sutures for treatment of high-grade AC joint injuries with a minimum 1-year follow-up.

Methods

A retrospective review was performed on all patients with Rockwood grade IIIB-V AC joint separations who underwent anatomic coracoclavicular ligament reconstruction using a 4-strand suspensory fixation with taped sutures at a single military treatment facility between January 2015 and May 2022. Clinical outcome measures included the Single-Assessment Numerical Evaluation (SANE) score and patient satisfaction using the Likert Scale. Radiographic outcomes were measured by classifying the amount of residual AC joint separation on postoperative radiographs utilizing the Rockwood classification.

Results

Coracoclavicular ligament reconstruction a using 4-strand suspensory fixation with taped sutures was performed in 15 consecutive patients, all of which were active-duty military males with a mean age of 35.8 years. Preoperatively, there were 10 patients with grade IIIB injuries, 1 patient with a grade IV injury, and 4 patients with grade V injuries. The average preoperative SANE score was 40.0. The average length of time from injury to surgery was 46.5 weeks. Patient-reported outcomes were available for 12 of the 15 patients (80%) at an average of 4.9 years postoperatively with an average postoperative SANE score of 77.1 (P = .0002); 11 of these 12 patients (92%) reported they were either satisfied or extremely satisfied with the outcome of the surgery. Postoperative radiographs were available for 14 of the 15 patients (93%) at an average of 2.7 years postoperatively revealing 13 patients had maintained grade I reduction while 1 patient had a grade III separation.

Conclusion

Coracoclavicular ligament reconstruction a using 4-strand suspensory fixation with taped sutures resulted in significantly improved radiographic and patient-reported outcomes in this retrospective review of active-duty military members with grade IIIB-V AC joint separations.

Surgeons consider Rockwood classification the most important factor for decision-making in acute, high-grade acromioclavicular dislocations

Purpose

The aim of this study is to investigate the influence of patient-specific factors, including age, lifestyle considerations as well as the extent of injury according to the Rockwood classification (RW), on the surgeon's decision-making in the choice between operative and nonoperative treatment for acute, high-grade acromioclavicular (AC) joint dislocations.

Methods

Orthopaedic and trauma surgeons were requested to complete an online questionnaire consisting of closed and open questions regarding the treatment of acute, high-grade AC joint dislocations and 24 fictive clinical scenarios.

Results

A total of 133 answered questionnaires were collected. 27 different nationalities from five continents were represented. The included participants had a median experience of 12 years (interquartile range: 2-41). Overall, the treatment option for surgery (answer: YES) was chosen in 2426 answers (76% of cases) compared to 'NO' in 766 (24% of cases). RW classification was considered the most important factor influencing surgical decision-making for most surgeons (69%). Two thirds of the participants answered that smoking does not impact their decision towards surgery and as to the influence of body mass index (BMI) on decision-making, half of the respondents would not alter their preferred treatment based on BMI. Finally, there were no significant differences in decision-making regarding the influence of the participant's demographics.

Conclusion

This study highlights that RW classification is the most important factor to consider in the surgeon's decision-making between operative and nonoperative treatment in acute, high-grade AC joint dislocations. Participants preferred operative treatment over nonoperative treatment in acute, high-grade AC joint dislocation in 76% of case scenarios, increasing up to 90% when RW Grade III lesions were not taken into account. These findings contrast with recent studies reporting good functional outcomes of conservatively treated acute, high-grade AC injuries and highlight the need to bridge the gap between evidence and practice.

Level of Evidence

Level V.

Outcomes of arthroscopic coracoclavicular management for acromioclavicular joint injuries: A systematic review

Introduction

Various surgical procedures for coracoclavicular (CC) ligament repair have been described for symptomatic acromioclavicular joint dislocations, with none emerging as a clear gold standard. There has been increased interest in arthroscopic approaches. This systematic review evaluates clinical outcomes after arthroscopic surgeries used to treat chronic and acute AC joint dislocations.

Methods

We searched three databases (PubMed, EMBASE, and OVID [MEDLINE]) from database inception to December 20, 2022. Studies were included if they met the following criteria: studies evaluating humans, English language studies, level of evidence I to IV, and studies investigating clinical outcomes in patients following arthroscopic surgery for coracoclavicular ligament reconstruction. Studies on open reconstruction techniques only were excluded. Primary outcomes included function/pain scores, coracoclavicular distances, complications, and revision rates.

Results

Fifty-two studies were included. In 33 studies, postoperative Constant-Murley scores ranged from 82.8 to 99 points. Postoperative VAS scores ranged from 0.3 to 4.1 in 16 studies. In 46 studies, revision rates ranged from 0 % to 44.4 %. We did not observe a difference in revision rates between chronic and acute cases (P = 0.268). Complications were more common in chronic than acute cases (25.5 % vs. 16.4 %; P < 0.001).

Conclusions

Arthroscopic surgery for chronic and acute CC ligament injuries exceeds the MCID and PASS for several outcomes, with low failure rates. Arthroscopic CC reconstruction is a safe and effective alternative for chronic AC joint dislocations.

Level of evidence

IV (Systematic Review of Level I-IV Studies).

Comparative efficacy of operative versus conservative treatment for Rockwood type III acromioclavicular joint dislocation: a systematic review and meta-analysis of randomized controlled trials

BACKGROUND

Optimal management of Rockwood type III acromioclavicular joint (ACJ) dislocation is still debated. Our aim is to conduct a meta-analysis of clinical studies evaluating the functional outcomes of operative versus conservative treatment for Rockwood type III ACJ dislocation.

METHODS

We conducted a systematic search across PubMed, EMBASE, Web of Science, and the Cochrane Library, including only randomized controlled trials (RCTs) focusing exclusively on type III ACJ dislocation. A total of 244 patients from four studies were included. Outcomes measured included Constant scores (CS), coracoclavicular distance (CCD), pain, and complication rates. Heterogeneity was assessed and managed to ensure robust conclusions.

RESULTS

The pooled results showed no significant difference in long-term functional outcomes, measured by CS, between surgical and conservative treatments (MD: 4.82, 95% CI: -6.42 to 16.06, P = 0.400). Surgical treatment provided better early pain relief and superior CCD at all follow-up points but did not improve long-term outcomes. Complication rates were similar for both treatments, though surgical intervention had a higher incidence of posttraumatic osteoarthritis and hardware-related issues. Conservative treatment resulted in fewer complications and comparable long-term results.

CONCLUSIONS

Based on the evidence, while surgical treatment may offer early benefits in pain relief and CCD improvement, it does not enhance long-term functional outcomes and is associated with higher specific complication rates. Conservative treatment provides a viable alternative with fewer complications and similar long-term outcomes. These findings highlight the need for individualized treatment plans based on patient-specific factors and suggest further high-quality, long-term studies to refine management strategies for Type III AC joint dislocations.

Using Dynamic Stereo X-ray Imaging for In Vivo Acromioclavicular Joint Kinematics Assessment: A Preliminary Investigation

Background

Acromioclavicular joint (ACJ) disruption occurs frequently in athletes engaged in contact sports. However, the current understanding of ACJ biomechanics during muscle-driven functional activities and the influence of different treatment approaches (eg, reconstruction surgery vs nonoperative methods) on ACJ kinematics and stability remains limited. The absence of precise in vivo biomechanical measurement modalities for scapular and clavicular kinematics contributes significantly to this lack of understanding.

Purposes/Hypothesis

The purposes of this study were to determine whether dynamic stereo x-ray (DSX) imaging can be used to evaluate the in vivo kinematics of the ACJ and to provide preliminary comparative data on ACJ kinematics, range of motion, and isometric strength of surgically reconstructed or nonoperatively treated ACJ shoulders and their uninjured contralateral shoulders. It was hypothesized that ACJ kinematics could be measured successfully using DSX and that surgically and nonoperatively treated shoulders would show abnormal 3-dimensional (3-D) ACJ kinematics compared with the uninjured contralateral.

Study Design

Controlled laboratory study.

Methods

In this cross-sectional study, 11 participants who had undergone unilateral ACJ reconstruction surgery and 3 patients who received nonoperative treatment were enrolled. ACJ kinematics were assessed during active forward flexion, scaption, and abduction through high-speed DSX imaging, complemented by 3-D bone models obtained via computed tomography (CT) scans. To gauge kinematic differences, a 1-dimensional statistical parametric mapping method was employed, which compared outcomes in the index limb to those in the uninjured counterpart. In addition, the range of motion and isometric strength at various abduction angles were analyzed, employing a repeated-measures analysis of variance to compare the affected and uninjured sides.

Results

Leveraging a combination of DSX imaging and patient-specific CT bone models, ACJ kinematics was measured successfully during movements along anatomic planes. Preliminary findings from this investigation revealed no detectable differences between the surgically reconstructed and uninjured sides in ACJ biomechanics, shoulder range of motion, and isometric strength outcomes. However, on average, the nonoperatively treated shoulders demonstrated increased internal rotation, upward rotation, and posterior tilting of the scapula relative to the clavicle (no statistical analyses were performed due to the small sample size).

Conclusion

DSX imaging is a promising tool for evaluating potential in vivo kinematic abnormalities in the ACJ during muscle-driven activities, laying the groundwork for further investigations in both ACJ-reconstructed and nonreconstructed patients. This study furnished essential data for conducting power analyses and designing future studies with an adequate sample size to investigate the impact of different treatment approaches on shoulder girdle mechanics.

Clinical Relevance

With its potential for accurately characterizing shoulder girdle kinematics post-ACJ injury, DSX imaging can offer valuable insights for future clinical studies, facilitating informed decisions regarding the short- and long-term impacts of treatment choices on shoulder health and function.

Acromioclavicular joint dislocation with loop double endobutton fixation assisted by orthopaedic surgery robot positioning system

OBJECTIVE

Acute acromioclavicular (AC) joint dislocation is a common orthopedic injury that can significantly impair shoulder function and reduce quality of life. Effective treatment methods are essential to restore function and alleviate pain. To investigate the short-term clinical efficacy of the minimally invasive closed-loop double endobutton fixation assisted by orthopaedic surgery robot positioning system (TiRobot) in the treatment of AC joint dislocation, and to evaluate its feasibility and safety.

METHODS

The clinical data of 19 patients with AC joint dislocation who underwent treatment with closed-loop double Endobutton fixation assisted by TiRobot between May 2020 and December 2022 were retrospectively analyzed. Visual Analog Scale (VAS) pain scores, the Constant Murley Score (CMS), and shoulder abduction range of motion were assessed and compared preoperatively and at the last follow-up. Computed tomography (CT) parameters of the acromioclavicular joint, including acromioclavicular distance (ACD), the distance between the upper and lower Endobutton (DED), the horizontal distance between the anterior edge of the distal clavicle and the anterior edge of the acromion (DACC), the diameter of the clavicular tunnel (DCT), and coracoid tunnel diameter (DC), were compared at 2 days, and 1 month after surgery, as well as at the last follow-up, along with the evaluation of intraoperative and postoperative complications.

RESULTS

The postoperative VAS, CMS, and shoulder-abduction range of motion were significantly improved compared with the preoperative (all, P<0.05). The statistical analysis showed no significant difference in the CT image parameters of the acromioclavicular joint at 2 days and 1 month after surgery(all, P>0.05). Comparisons of DCT and DC revealed statistically significant differences between the last follow-up and 1 month after surgery (P<0.05), and no statistically significant difference was found in ACD, DED, and DACC(all, P>0.05). There were no complications such as infection or vascular or neurological damage, no cases of rostral or clavicle fractures, loss of reduction, heterotopic ossification, shoulder stiffness, and no loosening or breaking of internal fixations.

CONCLUSION

Closed-loop double endobutton internal fixation assisted by TiRobot is an ideal method for the treatment of acute acromioclavicular (AC) joint dislocation. This method has the advantages of relatively simple operation, more accurate localization of bone tunnel during operation, less surgical trauma, and good recovery of shoulder function.

Type III acromioclavicular dislocation: Mid term results after operative and non-operative treatment

INTRODUCTION

Controversy exists in the literature about the best treatment for type III acromioclavicular dislocations. The aim of this study is to compare functional results between surgical and conservative treatment in type III acromioclavicular joint dislocations.

MATERIAL AND METHOD

We retrospectively evaluated the records of 30 patients from our area with acute type III acromioclavicular dislocations that were treated from January 1st, 2016 to December 31st, 2020. Fifteen patients were treated surgically and 15 conservatively. Follow up mean time was 37.93 months in operative group and 35.73 months in non-operative group. Results obtained on the Constant score was the main variable analysed and results obtained on the Oxford score and the Visual Analogue Scale for pain were the secondary variables. Epidemiological variables were analysed, as well as range of mobility in injured shoulder and subjective and radiological variables (distance between the superior border of the acromion and the superior border of the clavicle's distal end and presence of osteoarthritis in the acromioclavicular joint).

RESULTS

Functional evaluation scores did not show differences between the two groups (Constant: operative 82/non-operative 86.38, p 0.412; Oxford: operative 42/non-operative 44.80, p 0.126) nor did Visual Analogue Scale (operative 1/non-operative 0.20, p 0.345). Subjective evaluation of the injured shoulder was excellent or good in 80% of the patients in both groups. Measurement of the distance between the superior border of the acromion and the superior border of the clavicle's distal end were significantly higher in non-operative group (operative 8.95/non-operative 14.21, p 0.008).

CONCLUSIONS

Although radiographic results were better in the surgical treatment group, functional evaluation scores did not show significant differences between the two groups. These results do not support the routine use of surgical treatment for grade III acromioclavicular dislocations.

[Translated article] Type III acromioclavicular dislocation: Mid term results after operative and non-operative treatment

INTRODUCTION

Controversy exists in the literature about the best treatment for type III acromioclavicular dislocations. The aim of this study is to compare functional results between surgical and conservative treatment in type III acromioclavicular joint dislocations.

MATERIAL AND METHOD

We retrospectively evaluated the records of 30 patients from our area with acute type III acromioclavicular dislocations that were treated from January 1st, 2016 to December 31st, 2020. Fifteen patients were treated surgically and 15 conservatively. Follow-up mean time was 37.93 months in operative group and 35.73 months in non-operative group. Results obtained on the Constant score was the main variable analysed and results obtained on the Oxford score and the Visual Analogue Scale for pain were the secondary variables. Epidemiological variables were analysed, as well as range of mobility in injured shoulder and subjective and radiological variables (distance between the superior border of the acromion and the superior border of the clavicle's distal end and presence of osteoarthritis in the acromioclavicular joint).

RESULTS

Functional evaluation scores did not show differences between the two groups (Constant: operative 82/non-operative 86.38, p 0.412; Oxford: operative 42/non-operative 44.80, p 0.126) nor did Visual Analogue Scale (operative 1/non-operative 0.20, p 0.345). Subjective evaluation of the injured shoulder was excellent or good in 80% of the patients in both groups. Measurement of the distance between the superior border of the acromion and the superior border of the clavicle's distal end were significantly higher in non-operative group (operative 8.95/non-operative 14.21, p 0.008).

CONCLUSIONS

Although radiographic results were better in the surgical treatment group, functional evaluation scores did not show significant differences between the two groups. These results do not support the routine use of surgical treatment for grade III acromioclavicular dislocations.

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.

Acromioclavicular joint separation: Controversies and treatment algorithm

In this article, we present an uptodate outline of acromioclavicular (AC) joint separation. A clear understanding of acromioclavicular joint injury in terms of the mechanism of injury, clinical picture, diagnostic imaging, and most updated surgical techniques used for the treatment can provide the best care for those patients. This article describes updated treatment strategies for AC separation, including type III AC separation which is known most controversial. Finally, we present a proposed treatment algorithm that can aid in the treatment of AC separation from the most updated evidence.

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.

Conservative treatment of Rockwood type III acromioclavicular joint separation: a randomized controlled trial sling vs. brace

Background

Management of Rockwood III acromioclavicular joint separations is a matter of ongoing debate, with nonoperative treatment being favored in recent literature. The aim of this study is to compare clinical and radiological outcomes of nonoperative treatment with a brace, which elicits a direct reduction force to the distal clavicle, to a sling. We hypothesized the brace might yield in better acromioclavicular joint (ACJ) reduction and cosmesis.

Methods

In this dual center prospective randomized controlled trial, all patients sustaining an acromioclavicular joint separation Rockwood III between July 2017 and August 2020 were included. Patients with previous ipsi- or contralateral ACJ injury or surgery were excluded. Randomization occurred in the emergency department to either the sling or brace group. Patients were followed up at 1, 6, and 12 weeks. Patient-reported outcome measures included subjective shoulder value (SSV) and American Shoulder and Elbow Surgeons (ASES) score at each follow-up and Constant Score at 6 and 12 weeks. Vertical distal clavicle displacement was assessed on bilateral non-weighted panoramic anteroposterior radiographs using coracoclavicular (CC) distance to calculate the CC-index.

Results

Thirty-five consecutive patients were included across the 2 sites, 18 (all male) in the brace and 17 (14 male) in the sling group. Baseline characteristics did not differ significantly between groups, the average age was 40 years, and body mass index 25.5 kg/m². Analysis revealed no statistical difference in CC-index between groups at the time of injury, 6 weeks and 12 weeks postinjury (P = .39, P = .11, and P = .21). SSV improved from 30 and 35 postinjury to 81 and 84 at 12 weeks in the sling and brace group, respectively (P = .59). ASES improved from 48 and 38 to 82 and 83, respectively (P = .84). Similarly, Constant Score improved from 64 and 67 to 82 and 81, respectively (P = .90). One patient in the brace group underwent ACJ stabilization with hamstring autograft at 4 months due to persistent pain.

Conclusion

This randomized controlled trial shows no statistically significant difference between the brace and sling group in clinical (SSV, ASES, Constant Score) or radiological (CC-index) outcomes after conservative treatment of Rockwood III injuries.

Management of Acromioclavicular Injuries - Current Concepts

Introduction

Treatment of a patient with acromioclavicular joint (ACJ) injury remains challenging for orthopedic surgeons. To date, there is debate over the optimal management of ACJ injuries. This review provides an overview of assessment, treatment, and future perspectives for the treatment of and research into ACJ.

Material and Methods

A scoping literature review was performed. The search was built including the following terms: acromioclavicular joint injuries or dislocation, and pathophysiology, etiology, anatomy, treatment, and trauma mechanism. The papers with evidence levels 1-3 were included in the current narrative review.

Results

A total of 2242 potential relevant studies were identified in the searches. After removal of duplicates, 432 studies were screened on their titles and abstracts, resulting in 35 studies being included in the review, based on the eligibility criteria.

Conclusion

The management of acute and chronic ACJ injuries is not clarified in the current literature. However, there is currently insufficient high-level evidence for the overall treatment options for ACJ injuries. If surgical intervention is decided upon in consultation with the patient, the complications may not outweigh the benefits. The multitude of existing techniques is indicative of the uncertainty surrounding this issue, and no gold standard has yet been established for treatment methods. An ideal classification would include not only vertical and horizontal instability, but also the severity of kinematic alterations of the shoulder complex. This indicates the need for a new and improved diagnostic tool for the classification of ACJ injuries.

ANATOMICAL AND BIOMECHANICAL ROLE OF STATIC STABILIZERS OF THE ACROMIOCLAVICULAR JOINT

OBJECTIVE

The aim: To determine the anatomical and biomechanical significance of the static stabilizers of the acromioclavicular joint by conducting numerical modeling using the finite element method and experimental investigation.

PATIENTS AND METHODS

Materials and methods: To ensure the study, modeling of the deformation processes of the clavicle and scapula systems with various combinations of ligament damage was conducted. The COMPAS-3D software package was used to build the simulation model, which allowed obtaining models that are closest to reality. To verify the results of the numerical modeling, corresponding studies of the mechanical characteristics and determination of the stiffness of the investigated systems were carried out using the upgraded TIRAtest-2151 testing stand.

RESULTS

Results: The stiffest system is the system in which all ligaments are intact, and the sequence of decreasing stiffness of the system is presented in the following order: damage to lig. trapezoideum; lig. conoideum; lig. claviculo-acoacromiale inferior; lig. claviculo-acoacromiale superior; the coracoclavicular ligament complex; the acromioclavicular ligament complex.

CONCLUSION

Conclusions: Static stabilizers in general, and their components in particular, are characterized by significant anatomical and functional features. The natural stabilization of the acromioclavicular joint is provided by their synergistic interaction, which is the basis for the development and implementation of surgical interventions, the scope of which includes the restoration of both ligament complexes. The loss of stiffness in the «clavicle-scapula» system is significantly more pronounced when lig. acromioclaviculare superior and inferior are damaged (8.5 N/mm) than when lig. conoideum and lig. trapezoideum are damaged (11.6 N/mm).

Reliability of the ISAKOS Modification to Subclassify Rockwood Type III Acromioclavicular Joint Injuries

Background

To improve clinical management, the International Society of Arthroscopy, Knee Surgery and Orthopaedic Sports Medicine (ISAKOS) developed a specific subclassification of Rockwood type III acromioclavicular (AC) injuries: IIIA (no overriding distal clavicle) and IIIB (overriding distal clavicle).

Purpose/Hypothesis

The study aimed to determine the inter- and intraobserver reliability of the radiographic classification proposed by ISAKOS for AC injuries. It was hypothesized that the strength of agreement for the ISAKOS modification will be substantial to almost perfect.

Study Design

Cohort study (diagnosis); Level of evidence, 3.

Methods

We evaluated 40 radiographs of all types of AC joint injuries from patients at a single institution. The images were distributed to 6 shoulder and elbow fellowship-trained orthopaedic surgeons, along with standardized assessment questionnaires. The evaluators measured the bilateral coracoclavicular distance and the coracoclavicular ratio and classified the severity of the injuries according to the modified ISAKOS Rockwood classification. Four of the surgeons repeated the evaluation 6 weeks later to calculate intraobserver agreement. The kappa (κ) statistic was calculated for categorical inter- and intraobserver reliability. Intraclass correlation coefficient (ICC) estimates were calculated for the reliability of the coracoclavicular distance measurement. A 2-tailed test was performed to assess statistical significance.

Results

Overall interobserver agreement was substantial (κ = 0.637; 95% CI, 0.595-0.680) among the 6 evaluators, and intraobserver agreement was also substantial among the 4 evaluators (κ = 0.616; 95% CI, 0.549-0.638). The interobserver agreement for evaluating types IIIA and IIIB was fair (κ = 0.215; 95% CI, 0.135-0.295) and moderate (κ = 0.473; 95% CI, 0.393-0.553), respectively. The agreement on the coracoclavicular distance measurements was excellent among the 6 evaluators on both the affected side (ICC, 0.982; 95% CI, 0.970-0.990) and the unaffected side (ICC, 0.930; 95% CI, 0.894-0.958).

Conclusion

Substantial agreement was found when categorizing AC joint injuries using the ISAKOS modification of the Rockwood classification, with excellent reliability demonstrated for the quantitative assessment of vertical displacement of the clavicle. Visual examination was unreliable in differentiating type IIIA injuries from type IIIB injuries.