Anatomy of the clavicle and coracoid process for reconstruction of the coracoclavicular ligaments

The Effect of Clavicular Tunnel Position on Reduction Loss in Patients with Acute Acromioclavicular Joint Dislocations Operated with a Single-Bundle Suspensory Loop Device

OBJECTIVE

The treatment of acromioclavicular joint (ACJ) dislocations offers numerous options, and ongoing debates persist regarding their comparative effectiveness. Among these options, the suspensory loop device (SLD) is one of the most favored treatment modalities. Despite the observed high reduction loss rate associated with SLD, the treatment yields favorable clinical outcomes. This study aimed to investigate the clinical outcomes of patients with acute type 3 and 5 ACJ dislocations who underwent open and arthroscopic procedures using a single-bundle SLD, and to evaluate the effect of clavicular tunnel position on reduction loss.

METHODS

Thirty-seven eligible patients diagnosed with acute type 3 and type 5 ACJ dislocation who underwent open and arthroscopic surgery with a single-bundle SLD between January 2015 and March 2022 were evaluated retrospectively. Demographic data and radiological measurements including coracoclavicular (CC) interval, clavicle length (CL), and implant distance (ID) were recorded. The ID/CL ratio was calculated and a value between 0.17 and 0.24 was considered as "acceptable implant position". Reduction loss and other complications were noted. Patients were divided into two groups: open (Group 1) and arthroscopic (Group 2). Constant Murray Score (CMS) and Visual Analog Scale (VAS) were used for clinical and functional outcomes. Non-parametric tests were used for statistical analysis of variables.

RESULTS

The study included six females (16.2%) and 31 males (83.8%) with a mean age of 40.2 ± 14.7 years (range: 20-75). The mean follow-up period was 22.3 ± 16.7 months (range: 6-72). The average time from trauma to surgery was 6.3 ± 5.3 days (range: 1-18). At the last follow-up, the CMS was 89.3 ± 8.8 and the VAS score was 2.1 ± 0.9. The mean ID/CL ratio was 0.19 ± 0.1 and 19 patients (51.4%) were between 0.17 and 0.24. Reduction loss was observed in nine patients (24.3%). There were no significant differences between Group 1 and Group 2 regarding operation time (p = 0.998), ID/CL ratio (p = 0.442), reduction loss (p = 0.458), CMS (p = 0.325), and VAS score (p = 0.699). Of the 28 patients without reduction loss, 16 had an ID/CL ratio between 0.17 and 0.24 (p = 0.43). Furthermore, within the 0.17-0.24 interval, CMS was higher with an average of 91.8 ± 5.1 compared to the other intervals (p = 0.559).

CONCLUSION

The clinical and functional outcomes of acute type 3 and type 5 ACJ dislocation operated open and arthroscopically with single-bundle SLD are similar and satisfactory. A clavicular tunnel position in the range of 0.17-0.24 (ID/CL ratio) is recommended to maintain postoperative reduction.

Presurgical perspective and postsurgical evaluation of acromioclavicular joint instability

Acromioclavicular joint (ACJ) dislocations are a common cause of pain in patients of any age. Athletes who participate in contact sports, such as hockey, football, rugby, and soccer, are particularly susceptible to such injuries. The ACJ has an important role in the function of the upper limb, and its complexity of movement makes it susceptible to acute injuries and chronic dysfunction with debilitating effects that must be treated appropriately and promptly to preserve function. Recently, ACJ has received increasing attention due to the development of new surgical techniques for the restoration of normal function and stability. There is some agreement about the treatment of ACJ dislocations, but controversy remains about the treatment of Rockwood grade III dislocations, and a new approach to these injuries is suggested by ISAKOS. Overall, the paper summarizes new concepts in the anatomy of the ACJ and reviews the utility of imaging methods in ACJ dislocations as well as their treatment and complications.

Current trends in surgical treatment of the acromioclavicular joint injuries in 2023: a review of the literature

Background

This article examines the wide range of surgical reconstruction options available for acromioclavicular (AC) joint injuries. However, the lack of consensus regarding the most suitable surgical techniques is attributed to the high and variable failure rates observed with current approaches.

Methods

This article presents a comprehensive overview of the current surgical principles and techniques used by renowned experts in the field of AC shoulder injury management.

Results

It emphasizes the significance of addressing horizontal and rotational instability in AC injuries and highlights the impact of impaired scapular biomechanics.

Conclusion

By exploring these emerging concepts and strategies, the article aims to lay the foundation for future studies aimed at improving treatment outcomes and patient management.

Reconstruction of Coracoclavicular Ligaments with Semitendinosus Autograft and Temporary Kirschner Wires is a good option for Chronic Acromioclavicular Joint Instability

Introduction

This study reports the results of surgical anatomic reconstruction of torn coracoclavicular ligaments with an autogenous semitendinosus graft and temporary Kirschner wires (K-wires) in chronic acromioclavicular (AC) joint dislocations.

Materials and methods

Nineteen shoulders underwent surgical anatomic reconstruction of torn coracoclavicular (CC) ligaments with an autogenous semitendinosus tendon graft and temporary K-wires for Rockwood grade III, IV and V chronic AC joint dislocations. Pre-operative data included patients' demographic characteristics, injury characteristics and surgical histories. The primary outcome measures were the University of California Los Angeles (UCLA) shoulder rating scale and visual analogue pain scoring (VAS), and the complications were noted for each patient.

Results

Surgical anatomic reconstruction of torn CC ligaments was performed in 19 patients with a mean age of 41.6±16 years (range 21-72 years). All of the patients were satisfied and felt better after CC ligament reconstruction. The average UCLA shoulder rating scale score was good/excellent: 29.4 (range 23-34) out of 35 points. The average pre-operative VAS score was 7.7 points out of 10 and improved to 1.1 points post-operatively (p<0.05). None of the patients experienced failure during the follow-up. One patient had a mild subluxation, but the patient was satisfied with the result.

Conclusions

This technique is simple, reliable, and biologic without major complications. It is also a cost-effective procedure since it can be performed with Kirschner wires and autogenous grafts. It has a major advantage of leaving no implants inside the joint, which can lead to hardware complications, and it can be performed in basic operating room settings.

Current Concepts in Management of Acromioclavicular Joint Injury

Background: The management of acromioclavicular joint injuries requires a thorough understanding of the anatomy and biomechanics of the joint, as well as knowledge of the pertinent physical exam findings and classification to determine an appropriate treatment approach, whether operative or nonoperative. In this article, we present a narrative review of the current state of understanding surrounding these issues. Although there are a large number of options for operative intervention, we additionally present our experience with anatomic coracoclavicular ligament reconstruction (ACCR) with imbrication of the deltoid fascia. Methods: A retrospective review of prospectively collected data on a total of 45 patients who had undergone ACCR between 2003 and 2016 were collected. Results: We found that improvements were seen in American Shoulder and Elbow Surgeons Score (ASES) (53 ± 19 to 81 ± 23), Simple Shoulder Test (SST) (6 ± 3 to 12 ± 13), Constant-Murley (CM) (60 ± 18 to 92 ± 8), and Rowe (67 ± 14 to 89 ± 11) and the mean post-operative SANE score was 86 ± 17. Conclusions: ACCR has the advantage of addressing both horizontal and vertical stability with good outcomes.

Arthroscopic Anatomic Knotless Coracoclavicular Ligament Repair Without Coracoid Drilling

Acromioclavicular joint injuries are common in young active patients. A wide variety of surgical techniques exist to address specific complications associated with surgery. Complications after surgery include loss of reduction, fracture of the clavicle or coracoid, failure of fixation, and prominent and symptomatic hardware. This technique aims to reduce these complications with an arthroscopic anatomic coracoclavicular ligament repair using knotless adjustable loop buttons with fifth-generation suture tape and no drilling of the coracoid.

Size and morphology of the coracoid and glenoid in pediatric and adolescent patients: implications for Latarjet procedure

Background

Glenohumeral instability is a challenging problem in children and adolescents. For patients with anterior glenoid bone loss, the Latarjet procedure is an effective treatment option. However, concerns about coracoid size and morphology may limit its utilization within this patient population. The purpose of this study was to establish normative data on coracoid and glenoid size and morphology among a large cohort of adolescent patients and describe the anatomic relationships with demographic factors.

Methods

This is a retrospective cross-sectional study of a consecutive series of 584 patients aged 12-21 years after a chest computed tomography scan for non-shoulder related trauma at a single level I trauma center. Demographic characteristics were collected from the electronic medical record, and the following coracoid anatomic measurements were obtained from computed tomography scans: coracoid length, coracoid thickness, coracoid width, glenoid height, and glenoid width. The ratio of coracoid thickness to glenoid width was calculated to estimate the percent bone loss that could be addressed with a traditional Latarjet coracoid transfer. To ensure reliability among 3 reviewers, all measured the same 25 scans and inter-rater reliability was excellent with all Kappa coefficients >0.81. The remaining scans were divided equally and assessed separately by these reviewers. Correlation coefficients were used to quantify the relationships between all anatomic measures and the age, weight, and height of individuals. Growth curves for each measurement were modeled using quantile regression with height and height∗height as predictors. Additionally, we stratified the growth curves by sex, when significant. Of the 584 subjects, 55% were male, and average age was 19 years (range 12, 21).

Results

All growth curves illustrated increase anatomic size across the height range of 145-190 cm. The growth curve including all patients (Fig. 1) illustrated that the 50% percentile of median coracoid length increased from approximately 28 to 32 mm. In addition to height, sex was a significant predictor for coracoid width and glenoid width. The median coracoid width increased from approximately 9.5 to 10.2 mm for females compared to an increased width from approximately 10 to 11 mm for males. The median glenoid width for females increased from approximately 21 to 25 mm and for males the median glenoid width increased from just under 22 to 25.5 mm.

Conclusions

Among children and adolescents, coracoid and glenoid size are correlated with patient height. These data can help guide patient selection for the Latarjet procedure.

Arthroscopic Repair and Reconstruction of Coracoclavicular Ligament

Acromioclavicular joint separations are common shoulder injuries that require prompt recognition, diagnosis, and treatment. Deciding on a treatment algorithm relies on a detailed knowledge of anatomy and a thorough understanding of the specific functional demands of the patient in question. When a repair or reconstruction is indicated, arthroscopic assistance can be a helpful tool to ensure a safe, anatomic reconstruction that minimizes morbidity and maximizes the potential return to high-level function.

Operative Management for Displaced Distal Clavicle Fractures

This article reviews techniques and outcomes of surgical fixation for distal clavicle fractures. Near 100% union has been reported for several techniques. The most common are locked plating, coracoclavicular fixation and a combination of plating with CC fixation. Hook plates are useful for particular fracture patterns, but there can be complications specific to this implant. Low-profile constructs are favored due to the high rates of symptomatic hardware. Fixation of subacute and chronic injuries can provide reliable functional improvements, but is inferior to acute fixation. Surgery is generally the treatment of choice for displaced fractures in athletes.

Acromioclavicular Joint Anatomy and Biomechanics: The Significance of Posterior Rotational and Translational Stability

The shoulder girdle extends from the sternoclavicular joint to the scapular stabilizing muscles posteriorly. It consists of 3 joints and 2 mobile regions. The shoulder girdle is statically stabilized by the acromioclavicular and coracoclavicular capsuloligamentous structures and dynamically stabilized by the trapezius, deltoid, and deltotrapezial fascia. During humerothoracic elevation, the clavicle elevates, protracts, and rotates posteriorly through the sternoclavicular joint while the scapula tilts posteriorly and rotates upward. The purpose of this article is to review the anatomy and biomechanics of the acromioclavicular joint and the shoulder girdle.

Ligament Reconstruction and Interposition Arthroplasty of the Acromioclavicular Joint

Distal clavicle excision (DCE) for acromioclavicular (AC) joint primary osteoarthritis and post-traumatic arthritis has been shown to have good to excellent outcomes. However, there are studies that report significant rates of residual AC joint pain and distal clavicle instability after open and arthroscopic techniques. We describe a surgical technique for management of AC joint primary osteoarthritis, post-traumatic arthritis, and revision DCE that involves DCE with ligament reconstruction and tendon interposition arthroplasty. It provides distal clavicle stability and can theoretically reduce residual AC joint pain secondary to acromial abutment after DCE.

Acromioclavicular Joint Injuries in Sport

ABSTRACT

Sport-related shoulder injuries, including disruptions to the acromioclavicular joint (ACJ), are common. An ACJ injury is classified by the degree and direction of the clavicle displacement. Although the diagnosis can be made clinically, standard radiographic views are important to determine the severity of the ACJ disruption and assess for concurrent injuries. The majority of ACJ injuries can be managed nonoperatively; however, surgical treatment is indicated in some cases. Long-term outcomes are generally favorable for most ACJ injuries, and athletes generally return to sport without functional limitations. This article provides an in-depth discussion regarding all aspects of ACJ injuries, including clinically relevant anatomy, biomechanics, evaluation, treatment, and complications.

Biomechanical Efficacy of Tape Cerclage as an Augment or Stand-alone for Coracoclavicular Ligament Reconstruction

BACKGROUND

Loss of initial reduction of the acromioclavicular joint after coracoclavicular (CC) ligament reconstruction remains a challenge for various repair techniques. Previous studies using polydioxanone suture cerclage augments for CC ligament reconstruction demonstrated poor clinical and biomechanical outcomes. Tape-style sutures have recently gained popularity because of their added stiffness and strength relative to traditional sutures. These tape cerclage systems have yet to be biomechanically studied in CC ligament reconstruction.

PURPOSE

To determine the efficacy of a tape cerclage system as an augment to CC ligament reconstruction.

STUDY DESIGN

Controlled laboratory study.

METHODS

A total of 24 human cadaveric shoulders were utilized. These were divided into 4 repair groups: anatomic CC ligament reconstruction (ACCR), ACCR with a tape cerclage augment (ACCR + C), tendon graft sling with a cerclage augment (TGS + C), or tape cerclage sling alone (CS). The repairs underwent superior/inferior cyclic loading to evaluate for displacement. Specimens were visually inspected for cortical erosion by the tape cerclage after cyclic loading. Finally, the constructs underwent superior plane load-to-failure testing.

RESULTS

Less displacement after cyclic loading was observed in the ACCR + C (mean ± SD, 0.42 ± 0.32 mm), TGS + C (0.92 ± 0.42 mm), and CS (0.93 ± 0.39 mm) groups as compared with the ACCR group (4.42 ± 3.40 mm; P = .002). ACCR + C (813.3 ± 257.5 N), TGS + C (558.0 ± 120.7 N), and CS (759.5 ± 173.7 N) demonstrated significantly greater load at failure relative to ACCR (329.2 ± 118.2 N) (P < .001). ACCR + C (60.88 ± 17.3 N/mm), TGS + C (44.97 ± 9.15 N/mm), and CS (54.52 ± 14.24 N/mm) conferred greater stiffness than ACCR (27.43 ± 6.94 N/mm) (P = .001). No cortical erosion was demonstrated in any specimen after cyclic loading.

CONCLUSION

In a cadaveric model at time zero, repairs utilizing a tape cerclage system confer significantly greater load to failure and stiffness, as well as decreased displacement with cyclic loading, when compared with traditional ACCR repair.

CLINICAL RELEVANCE

Tape cerclage augmentation may provide a useful augment for CC ligament reconstruction.

Bone tunnel placement influences shear stresses at the coracoid process after coracoclavicular ligament reconstruction: a finite element study and radiological analysis

INTRODUCTION

Coracoid fractures after arthroscopic treatment of acromioclavicular (AC) joint separations lead to poor clinical outcomes. In this study, different configurations of bone tunnels in the lateral clavicle and coracoid were examined concerning the amount of stress induced in the coracoid.

METHODS

An authentic 3D finite element model of an ac joint was established. Three 2.4 mm bone tunnels were inserted in the lateral clavicle, which were situated above, medially and laterally of the coracoid. Then, two 2.4 mm bone tunnels were inserted in the latter, each simulating a proximal and a distal suture button position. Von Mises stress analyses were performed to evaluate the amount of stress caused in the coracoid process by the different configurations. Then, a clinical series of radiographs was examined, the placement of the clavicle drill hole was analyzed and the number of dangerous configurations was recorded.

RESULTS

The safest configuration was a proximal tunnel in the coracoid combined with a lateral bone tunnel in the clavicle, leading to an oblique traction at the coracoid. A distal bone tunnel in the coracoid and perpendicular traction as well as a proximal tunnel in the coracoid with medial traction caused the highest stresses. Anatomical placement of the clavicle drill hole does lead to configurations with smaller stresses.

CONCLUSION

The bone tunnel placement with the smallest amount of shear stresses was found when the traction of the suture button was directed slightly lateral, towards the AC joint. Anatomical placement of the clavicle drill hole alone was not sufficient in preventing dangerous configurations.

LEVEL OF EVIDENCE

Controlled laboratory study.

The stress and strain pattern in the ligaments of the acromioclavicular joint using a quasi-static model

BACKGROUND

The precise role of the acromioclavicular and coracoclavicular ligaments during shoulder motion is unclear. We evaluate changes in the stress-strain distribution of the acromioclavicular joint's ligaments during different shoulder passive motion positions.

METHODS

A 3D acromioclavicular joint model was reconstructed. A constitutive hyperelastic model was used for the ligaments. The kinematics of the shoulder girdle was taken to simulate shoulder abduction (Motion 1) and horizontal adduction (Motion 2). A computer-generated quasi-static and non-linear finite element model was used to predict the 3D stress-strain distribution pattern of the acromioclavicular ligament and the coracoclavicular ligament complex.

FINDINGS

In motion 1, from 20 to 90° the peak von Mises stress was found in the conoid (4.14 MPa) and the anteroinferior bundle (2.46 MPa), while from 90 to 120° it was found in the conoid and the trapezoid. However, there were no significant differences between the mean stress values between anteroinferior bundle and trapezoid throughout the motion (p = 0.98). In Motion 2, from 20 to 80° the maximum equivalent elastic strain was found in the anteroinferior bundle (0.68 mm/mm) and the conoid (0.57 mm/mm), while from 80 to 100° it was higher in the conoid (0.88 mm/mm) than in the anteroinferior bundle (0.77 mm/mm).

INTERPRETATION

The coracoclavicular ligament complex demonstrated a high stress-strain concentration during simulated passive shoulder abduction. Additionally, it was shown that the acromioclavicular ligament plays an important role in joint restraint during passive horizontal adduction, changing the primary role with the trapezoid and conoid at different motion intervals.

Comparing the Anatomical Landmarks Versus the Coracoid-Based Landmarks Techniques for Coracoclavicular Stabilization After High-Grade Acromioclavicular Injury: A Biomechanical Study

BACKGROUND

In acute high-grade acromioclavicular (AC) joint injuries, the aim of treatment is robust reduction and stabilization of the joint. The anatomical landmarks method is most commonly used for stabilization, but loss of reduction often occurs because of the suture tunnels.

PURPOSE/HYPOTHESIS

The purpose was to evaluate and compare the stability of coracoclavicular (CC) stabilization using the anatomical landmarks and coracoid-based landmarks techniques in treating a high-grade AC joint injury. It was hypothesized that stabilization using coracoid-based landmarks would provide better stability.

STUDY DESIGN

Controlled laboratory study.

METHODS

Twenty fresh-frozen cadaveric shoulders (8 male and 2 female pairs) were randomized into 2 operative technique groups: 10 shoulders in the anatomical landmarks group and 10 shoulders in the coracoid-based landmarks group. The CC ligaments and AC capsule were cut at the midlevel, and CC stabilization and AC capsule repair were performed. For the anatomical landmarks technique, two 2.5-mm clavicular tunnels were created at 25 and 45 mm from the AC joint, while for the coracoid-based landmarks technique, two 2.5-mm clavicular tunnels were drilled using the medial and lateral borders of the coracoid base to choose the tunnel sites. Before injury creation and after stabilization, each shoulder underwent a loading force of 70 N in the superior and anteroposterior directions, and the displacement distance and stiffness were compared between the 2 techniques using the paired t test.

RESULTS

The mean difference in displacement before and after stabilization was higher in the anatomical landmarks technique than the coracoid-based landmarks technique (1.82 ± 3.52 vs -0.18 ± 4.78 mm in the superior direction and 7.47 ± 9.35 vs 1.76 ± 3.91 mm in the anteroposterior direction), but none of the differences in displacement or stiffness were statistically significant between the groups.

CONCLUSION

No significant biomechanical differences in displacement or stiffness were seen between the anatomical landmarks technique and the coracoid-based landmarks technique.

CLINICAL RELEVANCE

Either stabilization technique can be utilized for repair of the CC ligaments in an acute AC injury setting.

Osseous microarchitecture in frequent fracture zones of the distal clavicle

Background

Fracture classifications of the distal clavicle are based on ligamentous integrity. The influence of osseous microarchitecture on fracture occurrence, morphology, and the lesion's stability has not yet been investigated. We aimed to characterize osseous microarchitecture according to common fracture classification systems based on ligamentous integrity and investigated the possible effects of age, gender, and osteoporosis in distal clavicle fractures.

Methods

N = 20 human cadaveric distal clavicles were scanned using XtremeCT with an isometric voxel size of 82 μm. In the sagittal plane, each data set was evaluated in 11 sections of approximately 7 mm thickness. Three topographic regions were defined: the bone lateral to the trapezoid (LTR), intertubercular (ITR), and medial to the conoid (MCR) ligament. Cortical bone mineral density (BMD) [mgHA/cm³] and cortical porosity (1- (BV/TV) [%]) were determined and evaluated relative to age and gender.

Results

Along the mediolateral axis, there was an >20-fold increase in median cortical porosity (P ≤ .001). There were significant differences in cortical porosity between LTR and ITR (P ≤ .001) but not between ITR and MCR (P = .09). In ITR, cortical porosity was significantly greater in >60-year-old compared to younger donors (P = .01). For BMD, there was an >2-fold decrease toward the distal apex (P ≤ .001). BMD was significantly greater in ITR compared to LTR (P ≤ .001) and in MCR compared to ITR (P = .02). In ITR and MCR, clavicles of >60-year-old donors had significantly lower BMD values compared to younger donors (P < .01). Across all 3 regions, frequency distribution of low bone mass did not significantly differ between <60-year-olds and >60-year-olds (P > .6).

Conclusion

The distal clavicle features a characteristic bony microarchitecture. The present study revealed a significant difference in bone quality of lateral, intertubercular, and medial zones of the distal clavicle and could specify target areas and strategies for surgical treatment of unstable fractures. Age, gender, and osteoporosis have a limited effect on bone quality and fracture genesis. In contrast, ligamentous quality is supposed to exert a substantial influence on fracture characteristics, especially in ITR. Fracture morphology of the distal clavicle is determined by a bony-ligamentous conjunction, which remains to be characterized.

Qualitative and Quantitative Anatomic Descriptions of the Coracoclavicular and Acromioclavicular Ligaments: A Systematic Review

Purpose

Methods

Results

Conclusions

Clinical Relevance

Reconstruction of the coracoclavicular ligament with palmaris longus tendon and Mersilene tape for acromioclavicular dislocations

Background

Acromioclavicular (AC) joint dislocation is common among shoulder injuries, and various surgical methods have been introduced for effective ligament reconstruction. Reconstruction of the coracoclavicular (CC) ligament in the anatomical position using autologous tendons is a recent surgical trend. This study is to report clinical and radiologic results of reconstruction of the CC ligament using an autologous palmaris longus tendon interweaved with Mersilene tape (PLMT) with a minimum 2-year follow-up.

Methods

This retrospective study analyzed 76 patients (mean age, 43.4 ± 11.2 years) with AC joint dislocation treated by reconstruction of the CC ligament with PLMT, from March 2004 to February 2017. The mean follow-up period was 28 ± 6.7 months (range, 24–66 months). The Visual Analog Scale (VAS) for pain assessment, American Shoulder and Elbow Surgeons rating scale (ASES), and Constant Score (CS) were used to evaluate clinical outcomes at the preoperative and the final follow-ups. CC and AC distances were measured using anteroposterior (AP) X-ray preoperatively and at the final follow-up for radiologic outcomes. Complications were also assessed.

Results

The mean preoperative VAS for pain, ASES, CS were 5.7 ± 0.7, 77.1 ± 6.2, and 61.5 ± 5.2, respectively. These scores at the final follow-up improved to 2.1 ± 0.5, 90.9 ± 4.3, and 94 ± 7.0, respectively (p = 0.043, p <  0.001, p <  0.001). The mean preoperative CC and AC distances were 16.49 ± 3.73 mm and 13.84 ± 3.98 mm, respectively. The final follow-up CC and AC distances were 9.29 ± 2.72 mm and 5.30 ± 2.09 mm, respectively (p <  0.001, p <  0.001). Although a slight re-widening of the CC distance occurred in 10 patients (13.1%), most patients regained full range of motion of the affected shoulder at the final follow-up.

Conclusion

The CC ligament reconstruction with PLMT for the treatment of AC joint dislocation showed good clinical and radiological results. This technique could be a good alternative treatment for AC dislocations.

Relation between diameter of a lateral screw and pull-out strength in distal clavicle fracture in plates with different geometry: A cadaveric biomechanical study

Plate fixation has recently gained popularity among the various surgical methods used to treat Neer type II distal clavicle fractures. The use of a low-profile distal clavicle locking plate is logically considered a better option when there is no significant difference in the fixation strength between insertions of 3.5- and 2.7-mm diameter screws. Therefore, the purpose of this biomechanical study was to investigate any differences in fixation strength among varying sizes of screws that are used to treat distal clavicle fractures. The study was performed with 20 paired shoulder girdles from 10 fresh frozen cadavers. To create a type IIA fracture of Neer classification, osteotomy was performed perpendicularly to the longitudinal axis of the clavicle at the medial end point of the conoid ligament. Two custom-made fixtures designed to be attached to both upper and lower sides of the Instron were fabricated for the evaluation. The mean maximum pull-out strength for fixation using 3.5-mm diameter screws was 241.9 ± 67.8 N, whereas the mean pull-out strength in fixation with 2.7-mm diameter screws was 228.1 ± 63.0 N. There was no statistically significant difference between the two groups. Distal fragment fixation with distal clavicle locking plates using two 2.7-mm diameter screws showed comparable biomechanical pull-out strength at the time-zero setting to fixations with a hook plate using two 3.5-mm diameter screws. Therefore, the fixation of the distal fragment with a low-profile plate and 2.7-mm screws may be preferred as an alternative option if the distal fragment of the fractured clavicle is not extremely small.

LUtarjet-limit unique coracoid osteotomy Latarjet (With video)

Background

The Latarjet procedure is an effective technique for the treatment of recurrent anterior shoulder dislocation with glenoid bone loss. However, the inevitable destruction of the coracoacromial arch may result in humeral head translation. The aim of the study is to introduce a modified Latarjet technique with coracoacromial arch preservation as well as its short term clinical outcomes.

Methods

We propose a novel individualized flexible arthroscopic suture button fixation Latarjet technique called `LUtarjet' with video. Precise measurements of the coracoid process, glenoid deficiency and osteotomy plane were made preoperatively. Only three arthroscopic portals were needed and limit unique coracoid osteotomy was performed with coracoacromial arch preservation. The mini window splitting of the subscapularis was performed from the posterior to the anterior direction and the split window was as small as 8–10 mm in length.

Results

A total of 27 patients (25.6 ± 5.4 years) were included in the study. The average surgical duration was 55.6 ± 6.3 min and the mean follow-up time was 8.1 ± 1.5 months. The functional score was significantly improved at the last follow-up. Radiologic evidence showed that the bone graft healing was placed in the desired position. No complications were found.

Conclusions

We present a fast, easy, accurate, safe arthroscopic ‘LUtarjet’ technique called FEAST that can simplify the arthroscopic Latarjet process and achieve a satisfactory bone graft position and satisfactory short-term clinical outcomes.

Level of evidence

IV, case series.

Arthroscopically Assisted Acromioclavicular and Coracoclavicular Reconstruction with a Looped Braided Polyester Suture Band and Buckle Device

Acromioclavicular (AC) joint injuries occur with a traumatic load to the lateral aspect of the shoulder and account for 9% of all shoulder girdle injuries. Rockwood classified AC joint injuries as type I though type VI, based on severity of injury, radiographic findings, and reducibility of the AC joint. Type I and II injuries are typically managed nonoperatively, whereas type IV, V, and VI are managed operatively to address the significant soft tissue disruption, persistent AC joint instability, and apical shoulder deformation. Treatment of type III injuries remain controversial. Several techniques have been described to treat AC joint injuries with no consensus for optimal treatment. "Anatomic" double-tunnel coracoclavicular ligament reconstruction is one currently popular technique to address AC joint injuries; however, clavicle and coracoid fractures are well-described complications of this technique. The objective of this technical report is to describe our preferred technique to address AC joint injuries. This technique involves using a looped braided polyester prosthetic band and low-profile buckle with allograft augmentation using a device to pass materials around the coracoid process.

Truly anatomic coracoclavicular ligament reconstruction with 2 EndoButton devices for acute Rockwood type V acromioclavicular joint dislocations: 5-year findings

BACKGROUND

To date, mid-term clinical and radiologic outcomes of treatment for acute Rockwood type V acromioclavicular (AC) joint dislocations using 2 EndoButton devices (Smith & Nephew, Andover, MA, USA) have not been reported in the literature.

METHODS

We reviewed 25 patients (15 men and 10 women) with acute AC joint separations who were treated with truly anatomic coracoclavicular ligament reconstruction using 2 EndoButton devices between May 2013 and October 2015. Clinical assessments consisted of the visual analog scale score and the Constant score. Radiologic evaluation was achieved by measuring the coracoclavicular distance and AC distance. Previously, this same patient cohort was reviewed after 2 years of follow-up using similar methods.

RESULTS

All 25 patients were available for mid-term follow-up 5 years after the operation. The mean duration of follow-up was 76 ± 7 months (range, 66-90 months). Of the patients, 23 (92%) continued to be satisfied or very satisfied with the treatment results. The visual analog scale score and Constant score improved significantly when compared with the baseline scores (0 ± 0 and 96 ± 3, respectively, at 5-year follow-up vs. 5 ± 1 and 45 ± 6, respectively, postoperatively) and remained essentially unchanged when compared with the 2-year follow-up data (0 ± 0 and 96 ± 3, respectively, at 5-year follow-up vs. 0 ± 1 and 95 ± 3, respectively, at 2-year follow-up). On the 5-year radiographs, 3 patients (12%) demonstrated loss of reduction and 5 patients (20%) had calcifications noted. There was, however, no significant difference in clinical outcomes or patient satisfaction when comparing patients with radiographically abnormal findings vs. patients with anatomic reduction.

CONCLUSION

Truly anatomic coracoclavicular ligament reconstruction using 2 EndoButton devices results in satisfactory functional outcomes at 5 years postoperatively. In contrast to baseline, all cases improved significantly.

Distal clavicle "A-frame" morphology: a reliable intraoperative guide for arthroscopic distal clavicle excision

BACKGROUND

The purpose of this cadaveric study was to describe the characteristics of the "A-frame" morphology of the distal clavicle via computed tomography (CT) to determine whether it can be used as a reliable intraoperative guide for arthroscopic distal clavicle excision.

METHODS

Twenty-eight fresh-frozen human cadaveric clavicles underwent a 3-dimensional CT scan using 1.0-mm cuts. The distance from the most lateral aspect of the clavicle to the point at which the superior cortex of the clavicle paralleled the inferior cortex was measured. Measurements were performed in a blinded fashion by a single author on 2 separate occasions.

RESULTS

The A-frame was present in all specimens (28 of 28). On the first measurement, the mean distance from the distal clavicle to the point at which the A-frame disappeared was 1.00 cm (range, 0.90-1.08 cm; standard deviation, 0.5 mm). On the second measurement, the mean distance was 1.02 cm (range, 0.90-1.11 cm; standard deviation, 0.6 mm). The intrarater reliability between measurement occasions was 0.65 (95% confidence interval, 0.36-0.82; P < .001).

CONCLUSIONS

This study demonstrated that the cross-sectional A-frame morphology of the distal clavicle was consistently visualized on CT scans. The A-frame disappeared 1.00-1.02 cm medial to the most lateral extent of the clavicle on CT scans. The disappearance of the A-frame morphology of the distal clavicle can serve as a reliable intraoperative guide for arthroscopic distal clavicle excision.

Coracoid tunnels in open and arthroscopic treatment of acromioclavicular dislocation: an experimental cadaveric study

PURPOSE

Treatment of acromioclavicular joint (ACJ) dislocation is not encoded uniquely. Type I and II injuries are usually treated conservatively, while types IV, V and VI surgically. Controversy still exists over the treatment of type III injuries. In the operative approach, there is no agreement on the best surgical technique. Our purpose is to compare the mini-open and arthroscopic approach focusing on the evaluation of the anatomical precision of the coracoid drilling.

METHODS

This is a controlled laboratory study. Ten fresh-frozen cadaveric shoulders were randomly assigned to the two techniques in order to compare them. We performed essential surgical gestures to drill the tunnel using MINAR® System (mini-open) and Dog-Bone® (ARTHREX, arthroscopic). The anatomical specimens were then subjected to CT-scan investigation. We statistically evaluated the precision of these two techniques analyzing DICOM files using two parameters. Parameter 1 evaluates the tunnel entry area on the superior side of the coracoid. Parameter 2 describes the orientation of the tunnel.

RESULTS

There are no statistically significant differences (95% confidence level) between arthroscopic and mini-open approach about the precision in the location of the coracoid hole, regarding the entry area (p = 1.00) and the orientation (p = 0.196).

CONCLUSION

The evidences collected enable the orthopedic surgeon to choose equally between the two techniques in the treatment of AC joint dislocation toward precision.

Three-Dimensional Footprint Mapping of the Deltoid and Trapezius: Anatomic Pearls for Acromioclavicular Joint Reconstruction

PURPOSE

To perform a quantitative anatomic evaluation of the deltoid and trapezius footprints in relation to the lateral clavicle and acromioclavicular (AC) joint capsule to assist in surgical technique of AC joint reconstructions.

METHODS

Fourteen fresh-frozen human cadaveric shoulders from 9 donors were analyzed. Meticulous dissection of the deltoid origin and trapezius insertions to the clavicle and AC joint was performed. Footprints were reconstructed using a MicroScribe digitizer. The inferior extension of the deltoid origin beneath the lateral clavicle and the footprints of the deltoid and trapezius onto the acromioclavicular ligamentous complex (ACLC) were quantified. Reproducibility was assessed by redigitizing 5 shoulders in a blinded and random fashion.

RESULTS

The anterior deltoid fibers extended on average 4.0 ± 1.6 mm inferiorly with respect to the anteroinferior clavicular ridge and attached to 90.9 ± 7.3% of the anterior ACLC. The trapezius inserted onto the posterior and superior ACLC, covering 15.3 ± 3.4% of the anterior-posterior width of the superior capsule. The deltopectoral interval was 6 cm, or 37% the length of the clavicle from the distal end of the clavicle.

CONCLUSIONS

The deltoid has superior, anterior, and not as well described, inferior attachments to the lateral clavicle. Furthermore, the deltoid and trapezius muscles have intimate attachments to the AC joint capsule, particularly the trapezius to the posterior and posterosuperior capsule. Lastly, the deltoid origin attaches to the lateral 6 cm of the clavicle.

CLINICAL RELEVANCE

Subperiosteal elevation of the deltoid off the lateral clavicle starting superiorly, anteriorly, and lastly inferiorly will reduce deltoid muscle injury and improve visibility of the coracoid process during reconstruction. Furthermore, knowledge of the attachments of the deltoid and trapezius to the ACLC may help limit iatrogenic injury to these dynamic stabilizers.

Arthroscopic Anatomical Acromioclavicular Joint Reconstruction using a Button Device and a Semitendinosus Graft

Objective

To report a new technique for anatomical acromioclavicular (AC) joint reconstruction.

Methods

In order to minimize such complications, the authors describe a new anatomical and biological AC joint repair. This technique aims to provide greater stability by using two anatomically placed clavicular tunnels and a combined construct with a double endobutton cortical fixation for primary stabilization, and to be biologically advantageous by using an autologous semitendinosus (ST) tendon graft. Additionally, the coracoclavicular ligament reconstruction is complemented with an AC joint cerclage and capsular reinforcement, which will protect the biological construction in its initial stage of healing.

Results

This technique provides adequate primary and secondary biomechanical stability by passing both a semitendinosus autogenous graft and a double endobutton device, through anatomically placed and small diameter clavicle holes, without the need for coracoid drilling. Our technique showed encouraging results regarding pain resolution, range of motion, and function. At final follow‐up we experienced excellent results with average pain score of 1.6, and average ROM of 159° of forward flexion, 160° of abduction, 68° of external rotation, and internal rotation level at T11. Postoperative function also showed great improvements with average ASES of 85 points, an average Constant Score of 87 and a Subjective Shoulder Value of 89 points. This technique also achieved perfectly acceptable radiographic results, with an average coracoclavicular distance increase of 0.8 mm. Regarding complications, our sample showed one case of AC join subluxation, two cases of internal saphenous nerve injury, and two partial graft tears at the suture‐button interface, with none of these requiring surgical revision.

Conclusion

This technique is advantageous in treatment of acromioclavicular joint dislocation and can be performed in both the subacute and chronic setting.

Anteroinferior bundle of the acromioclavicular ligament plays a substantial role in the joint function during shoulder elevation and horizontal adduction: a finite element model

Background

Postoperative acromioclavicular (AC) ligament deficiency has been identified as a common cause of failure after isolated coracoclavicular reconstruction. The two-bundle arrangement of the acromioclavicular ligament has recently been reported in histological and anatomical research. In addition, a clear structural advantage of the superoposterior bundle (SPB) over the less consistent anteroinferior bundle (AIB) was also found. However, the current understanding of the function of the acromioclavicular ligament in joint stability is based on uniaxial bone loading experiments and sequential ligament sectioning. Consequently, these rigid biomechanics models do not reproduce the coupled physiological kinematics, neither in the normal joint nor in the postoperative condition. Therefore, our goal was to build a quasi-static finite element model to study the function of the acromioclavicular ligament based on its biomechanical performance patterns using the benefits of computational models.

Methods

A three-dimensional bone model is reconstructed using images from a healthy shoulder. The ligament structures were modeled according to the architecture and dimensions of the bone. The kinematics conditions for the shoulder girdle were determined after the osseous axes aligned to simulate the shoulder elevation in the coronal plane and horizontal adduction. Three patterns evaluated ligament function. The peak von Mises stress values were recorded using a clock model that identified the stress distribution. In addition, the variation in length and displacement of the ligament during shoulder motion were compared using a two-tailed hypotheses test. P values < 0.01 were considered statistically significant.

Results

The peak von Mises stress was consistently observed in the AIB at 2:30 in coronal elevation (4.06 MPa) and horizontal adduction (2.32 MPa). Except in the position 2:00, statistically significant higher deformations were identified in the two bundles during shoulder elevation. The highest ligament displacement was observed on the Y- and Z-axes.

Conclusions

The AIB has the primary role in restricting the acromioclavicular joint during shoulder motion, even though the two bundles of the AC ligament have a complementary mode of action. During horizontal adduction, the SPB appears to prevent anterior and superior translation.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13018-022-02966-0.

Clavicular Tunnel Complications after Coracoclavicular Reconstruction in Acute Acromioclavicular Dislocation: Coracoid Loop versus Coracoid Tunnel Fixation

Background

The purpose of this study was to compare clavicular tunnel complications after coracoclavicular (CC) reconstruction between a coracoid loop fixation group and a coracoid tunnel fixation group. We hypothesized that clavicular tunnel complications would be more common in the coracoid loop group.

Methods

This retrospective study evaluated 24 patients who underwent CC reconstruction using coracoid tunnel fixation (n = 14) and coracoid loop fixation (n = 10). Radiographic measurements included the CC distance and clavicular tunnel diameter. Clavicular tunnel complications such as tunnel widening and clavicular tunnel fractures were investigated. Clinical outcomes were assessed using the American Shoulder and Elbow Surgeons Shoulder score and the University of California at Los Angeles Shoulder score.

Results

The mean follow-up period was 17.5 months (range, 11–38 months). The final clavicular tunnel diameter and the increase in the clavicular tunnel diameter in millimeter and percentage were significantly greater in the coracoid loop group than in the coracoid tunnel group (all p < 0.05). Clavicular tunnel widening more than 100% was found in 5 patients, all belonging to the coracoid loop group. Clavicular tunnel fractures occurred in 3 patients (all in the coracoid loop group). Fracture was associated with severe tunnel widening (more than 100% increase). The mean value of the final clavicular tunnel diameter in patients with fractures was significantly larger than that in patients without (12.7 ± 3.3 mm vs. 8.4 ± 1.5 mm, p = 0.016).

Conclusions

Clavicular tunnel complications such as significant tunnel widening and fractures after CC reconstructions in acromioclavicular dislocations were common with the coracoid loop fixation technique. A greater clavicular tunnel widening and resultantly enlarged tunnel diameter might increase the risk of fracture through the clavicular tunnel.

The acromioclavicular joint injuries treatment

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Anatomical versus non-anatomical configuration of double coraco-clavicular tunnel technique in acromioclavicular joint reconstruction

PURPOSE

Horizontal instability is a common problem after acromioclavicular joint injuries. The aim of this study was to evaluate if there is a difference regarding horizontal stability between an anatomical and a non-anatomical configuration of the double tunnel coraco-clavicular ligament reconstruction of the acromioclavicular joint.

METHODS

Thirteen acromioclavicular joints of human cadaveric shoulders in ethanol-glycerin fixation were included in the study and underwent cyclic anterior and posterior translational testing at a load of 70 N using an electromechanical uniaxial testing machine. The shoulders were randomly assigned to the following groups: double coraco-clavicular tunnel technique in an anatomical configuration (DCTa) and double coraco-clavicular tunnel technique in an inverse configuration of the anatomical position (DCTb). The dislocation was recorded with a 3D optical measuring system.

RESULTS

The total horizontal displacement (p₁₀ = 0.0221; p₅₀₀₀ = 0.082) was significantly higher for the non-anatomical reconstruction (DCTb) compared to the anatomical reconstruction (DCTa) after every measured amount of cycles. The increase in displacement for DCTb group was overall higher than the increase in displacement for DCTa group but without significance.

CONCLUSION

Reconstruction of the CC ligaments in an anatomical configuration with two suture devices results in a significantly higher stability of the AC joint in the horizontal plane than reconstruction of the CC ligaments in a non-anatomical configuration. Based on the results of this biomechanical in vitro study, the use of a double coraco-clavicular reconstruction should focus on an anatomically correct position of the suture devices.

Anatomic reconstruction for acromioclavicular joint injuries: a pilot study of a cost-effective new technique

BACKGROUND

The treatment for acromioclavicular joint injuries (ACJI) ranges from a conservative approach to extensive surgical reconstruction, and the decision on how to manage these injuries depends on the grade of acromioclavicular (AC) joint separation, resources, and skill availability. After a thorough review of the literature, the researchers adopted a simple cost-effective technique of AC joint reconstruction for acute ACJI requiring surgery.

METHODS

This was a prospective single-center study conducted between April 2017 and April 2018. For patients with acute ACJI more than Rockwood grade 3, the researchers performed open coracoclavicular ligament reconstruction using synthetic sutures along with an Endobutton and a figure of 8 button plate. This was followed by AC ligament repair augmenting it with temporary percutaneous AC K-wires. Clinical outcomes were evaluated using the Constant Murley shoulder score.

RESULTS

Seventeen patients underwent surgery. The immediate postoperative radiograph showed an anatomical reduction of the AC joint dislocation in all patients. During follow-up, one patient developed subluxation but was asymptomatic. The mean follow-up period was 30 months (range, 24-35 months). The mean Constant score at 24 months was 95. No AC joint degeneration was noted in follow-up X-rays. The follow-up X-rays showed significant infra-clavicular calcification in 11 of the 17 patients, which was an evidence of a healed coracoclavicular ligament post-surgery.

CONCLUSIONS

This study presents a simple cost-effective technique with a short learning curve for anatomic reconstruction of acute ACJI. The preliminary results have been very encouraging.

The Kite technique: a new all-arthroscopic technique for the treatment of acute acromioclavicular joint dislocation

PURPOSE

Although many open techniques have been developed, no all-arthroscopic technique has been introduced to reduce acute acromioclavicular joint dislocation (ACJD) and augment both coracoclavicular (CC) ligaments. The Kite technique is the first all arthroscopic technique with this aim.

METHODS

Forty-one consecutive patients [35M-6F; median: 29.2 years (range 23-36)] with acute type III and V acromioclavicular joint dislocation were treated with the Kite technique: it consists of positioning three titanium buttons connected by heavy sutures in an 8-strand configuration between clavicle and coracoid to restore the anatomy of CC ligaments. Patients were followed up for a median of 35 months (range 30-43 months).

RESULTS

Median operation time was 70.6 min (range 58-82), with no cases of intra-operative complications. At the final follow-up, the median post-operative Constant Score and SST were 94.1 (range 89-98) and 11.6 (range 10-12), respectively. At the final follow-up reduction maintenance was present in 39 patients; in one patient, signs of acromioclavicular joint dislocation recurrence were present 3 months post-op. In another patient, medial suture ruptures occurred 4 months after surgery with type II acromioclavicular joint dislocation recurrence but with scarce symptoms and full recovery to sport activity. Clavicle osteolysis was observed in four patients. Cosmetics of the arm were judged as excellent in 39/41. All patients, except two, were satisfied with the final result.

CONCLUSIONS

The kite technique is a safe and reproducible arthroscopic procedure to treat acute ACJD. In daily clinical practice, due to the excellent results and the low complication rate, this technique might be considered by surgeons when operative treatment of an acute acromioclavicular joint dislocation is planned.

LEVEL OF EVIDENCE

IV.

Clinical outcomes of arthroscopic and navigation-assisted two tunnel technique for coracoclavicular ligament augmentation of acute acromioclavicular joint dislocations

Background

The purpose of this study was to present a navigated image-free augmentation technique for the acromioclavicular joint (ACJ) and coracoclavicular (CC) ligaments and to report the clinical and radiological outcomes.

Methods

From 2013 to 2018, 35 eligible patients were treated with our navigated image-free ACJ- and CC-augmentation technique. The average follow-up was 3 years. Follow-up evaluations included the Constant-Murley Score, subjective shoulder value, Taft score, and the acromioclavicular joint instability (ACJI) score. The patients’ quality of life was assessed using the EuroQol-5D (EQ-5D) questionnaire. In addition, in accordance with the instability criteria, radiographs were evaluated before surgery, after surgery, and during follow-up.

Results

Overall, 25 patients (71%) suffered an acute type V disruption, 5 (14%) had a type IV disruption, and 5 (14%) had an acute Rockwood type IIIb injury. The mean Constant-Murley Score was 90 (range: 56–100; p = 0.53) on the injured side, and the mean subjective shoulder value was 92% (range: 80–100%). The mean Taft and ACJI scores were 10 (range: 4–12) and 86 (range: 34–100), respectively and the mean EQ-5D was 86 (range: 2–100). The mean CC difference of the injured side was 4 mm (range: 1.9–9.1 mm) at follow-up, which was not significantly different than that of the healthy side (p = 0.06). No fractures in the area of the clavicle or the coracoid were reported.

Conclusions

The arthroscopic- and navigation-assisted treatment of high-grade ACJ injuries in an anatomical double-tunnel configuration yields similar clinical and radiological outcomes as the conventional technique using an aiming device. Precise positioning of the navigation system prevents multiple drillings, which avoids fractures.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12891-021-04406-2.

There is direct relationship between bone bridge length and coracoclavicular fixation resistance to failure: Biomechanical study in a porcine model

BACKGROUND

This study aims to evaluate the relation between coracoclavicular resistance to failure and the distance between clavicular tunnels. The hypothesis is that a greater clavicular bone bridge between tunnels achieves a stronger coracoclavicular fixation.

METHODS

Descriptive Laboratory Study. Thirty-six (36) coracoclavicular models were constructed utilizing porcine metatarsals. Coracoclavicular stabilizations were performed using a subcoracoid loop fixation configuration through two clavicular tunnels, tied at the clavicle's superior cortex using a locking knot. Models were randomly assigned to 1 of 3 experimental groups of variable bone bridge length between clavicular tunnels: 5 mm, 10 mm, and 15 mm. Each group had 12 models. Fixation resistance was assessed through the ultimate failure point under an axial load to failure trial. Failure patterns were documented. A one-way ANOVA test was used, and a Tukey post hoc as needed (P < 0.05).

FINDINGS

Mean strength per bone bridge length: 5 mm = 312 N (Range: 182-442 N); 10 mm = 430 N (Range: 368-595 N); 15 mm = 595 N (Range: 441-978 N). The 15 mm group had a significantly higher ultimate failure point than the other two groups: 5 mm (P < 0.001) and 10 mm (P < 0.001). All fixations systematically failed by a superior cortex clavicle fracture at the midpoint between tunnels.

INTERPRETATION

A direct relationship between bone bridge length and coracoclavicular resistance to failure was demonstrated, being the 15 mm length a significantly higher strength construct in a tied loop model.

Editorial Commentary: Suture Button-Anchor Fixation Is Preferable to Hook Plate Fixation for Acute Acromioclavicular Joint Dislocations: Form and Function Need to Be United

Both hook plate fixation and suture button-anchor fixation have been reported to yield good results in the treatment of acute acromioclavicular joint reconstruction. In addition to a mandatory secondary procedure, hook plate fixation clearly has an increased prevalence of post-traumatic acromioclavicular arthritis in the short term that is likely to progress in the long term. Conversely, suture button-anchor fixation-a minimally invasive technique that creates less soft-tissue disruption, does not require hardware removal, and does not violate the acromioclavicular joint-is more likely to promote primary healing of the coracoclavicular ligaments, reduce the risk of late displacement, and minimize the development of post-traumatic acromioclavicular arthritis. As stated by the noted architect Frank Lloyd Wright, it is not only about form (i.e., alignment), it is about function as well.

Clinical Outcome of a Modified Coracoid Tunnel-Free Coracoclavicular Sling Technique With Remnant Preservation for the Treatment of High-Grade Acromioclavicular Joint Separation: A Report of 48 Cases With 2 to 5 Years of Follow-up

BACKGROUND

High-grade acromioclavicular (AC) joint separation injuries (Rockwood type IV or V) are surgically indicated because of complete disruption of the AC and coracoclavicular (CC) ligaments, leading to instability and pain. In surgical techniques that require a suspensory system, coracoid tunnel-related complications are not uncommon.

PURPOSE

To report subjective and objective clinical outcomes and complication rates of a modified coracoid tunnel-free CC sling technique combined with CC ligament remnant preservation for a minimum 2-year follow-up.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

Between January 2014 and January 2017, we prospectively enrolled patients who underwent a modified CC sling technique performed by 1 senior surgeon using the AC TightRope System in a coracoid tunnel-free fashion. The CC distance (CCD) and Rockwood AC joint classification were evaluated on radiographs preoperatively, immediately postoperatively, and at the final follow-up. The visual analog pain score, range of motion, American Shoulder and Elbow Surgeons score, Constant-Murley score, and University of California Los Angeles score were recorded preoperatively and at the final follow-up.

RESULTS

In total, 48 of 54 patients (88.9%) were included for the evaluation with a mean ± SD follow-up of 39.3 ± 8.9 months (range, 24.7-64.3 months). The CCD was significantly decreased from 22.7 ± 4.2 to 9.8 ± 2.3 mm (P < .01) immediately after surgery and to 11.2 ± 1.8 mm (P < .01) at final follow-up. At the final follow-up, the side-to-side difference of CCD was 3.5 ± 0.6 mm. Compared with the preoperative level, all subjective evaluations were significantly improved at the final follow-up. We observed that 4 of the 48 patients (8.3%) had a loss of reduction at the final follow-up, but no pain or instability was documented. Further, no coracoid-related complication or other complications were recorded.

CONCLUSION

The coracoid tunnel-free CC sling technique using the AC TightRope System combined with CC ligament remnant preservation demonstrated significant improvement regarding both clinical and radiological outcomes, with a reduction loss rate of 8.3%. It is a safe method that could achieve satisfactory result without any coracoid drilling-related complications.

Anatomy and Correlation of the Coracoid Process and Coracoclavicular Ligament Based on Three-Dimensional Computed Tomography Reconstruction and Magnetic Resonance Imaging

Background

The anatomy of the coracoid process and coracoclavicular (CC) ligament have been described and the correlation between them has been assessed based on 3-dimensional computed tomography (CT) reconstruction and magnetic resonance imaging (MRI), which provide a guide for coracoclavicular ligament reconstruction.

Material/Methods

Data were collected from 300 patients who underwent both CT and MRI of the shoulder joint from January 2017 to January 2019 at the Jiang’an Hospital of Traditional Chinese Medicine. The coracoid process was observed and classified and parameters of the CC ligament were measured according to different corneal types. All of the statistics were collected and classified by 2 radiologists, and average values were determined.

Measurements of segments were taken as follows: ab – In the coronal plane, the length of the CC ligament from the central point of the CC ligament at the clavicular attachment to the CC ligament at the center of the CC attachment); ac – The distance from the center point of the CC ligament at the supraclavicular attachment to the acromioclavicular joint; de – In the sagittal plane, the length of the CC ligament from the center of the clavicular attachment to the coracoid attachment point; fg – The maximum diameter of the CC ligament at the anterior and posterior margins of the clavicle attachment; hi – The largest diameter of the CC ligament at the anterior and posterior edge of the coracoid process attachment; dj – The distance of the coracoclavicular ligament from the center point of the coracoid process attachment to the coracoid process tip; kl – The distance in the supraclavicular plane from the coracoclavicular ligament to the subcoracoid process.

Results

The analysis showed that there are 5 types of coracoid process: gourd (31%), short rod (20%), long rod (22.3%), wedge (10.3%), and water drop (6.3%). There were statistically significant differences between the lengths of the ac and hi segments in the among the wedge and gourd-type and the short rod and water drop-type coracoid processes. There were statistically significant differences between the lengths of the ab, de, and fg segments in the short rod, gourd, and long rod-type coracoid processes. There were statistically significant differences between the lengths of the ac, fg, hi, dj, and kl segments in the water drop, gourd, and long rod-type coracoid processes.

Conclusions

The present study indicated that measurement of the CC ligament and the different shapes of the coracoid process provide an anatomical basis for the diagnosis and treatment of shoulder diseases and the data can be used to improve the safety of CC ligament reconstruction.

Quantitative and Qualitative Surgical Anatomy of the Acromioclavicular Joint Capsule and Ligament: A Cadaveric Study

BACKGROUND

The acromioclavicular (AC) capsule and ligament have been found to play a major role in maintaining horizontal stability. To reconstruct the AC capsule and ligament, precise knowledge of their anatomy is essential.

PURPOSE/HYPOTHESIS

The purposes of this study were (1) to determine the angle of the posterosuperior ligament in regard to the axis of the clavicle, (2) to determine the width of the attachment (footprint) of the AC capsule and ligament on the acromion and clavicle, (3) to determine the distance to the AC capsule from the cartilage border of the acromion and clavicle, and (4) to develop a clockface model of the insertion of the posterosuperior ligament on the acromion and clavicle. It was hypothesized that consistent angles, attachment areas, distances, and insertion sites would be identified.

STUDY DESIGN

Descriptive laboratory study.

METHODS

A total of 12 fresh-frozen shoulders were used (mean age, 55 years [range, 41-64 years]). All soft tissue was removed, leaving only the AC capsule and ligament intact. After a qualitative inspection, a quantitative assessment was performed. The AC joint was fixed in an anatomic position, and the attachment angle of the posterosuperior ligament was measured using a digital protractor. The capsule and ligament were removed, and a coordinate measuring device was utilized to assess the width of the AC capsule footprint and the distance from the footprint to the cartilage border of the acromion and clavicle. The AC joint was then disarticulated, and the previously marked posterosuperior ligament insertion was transferred into a clockface model. The mean values across the 12 specimens were demonstrated with 95% CIs.

RESULTS

The mean attachment angle of the posterosuperior ligament was 51.4° (95% CI, 45.2°-57.6°) in relation to the long axis of the entire clavicle and 41.5° (95% CI, 33.8°-49.1°) in relation to the long axis of the distal third of the clavicle. The mean clavicular footprint width of the AC capsule was 6.4 mm (95% CI, 5.8-6.9 mm) at the superior clavicle and 4.4 mm (95% CI, 3.9-4.8 mm) at the inferior clavicle. The mean acromial footprint width of the AC capsule was 4.6 mm (95% CI, 4.2-4.9 mm) at the superior side and 4.0 mm (95% CI, 3.6-4.4 mm) at the inferior side. The mean distance from the lateral clavicular attachment of the AC capsule to the clavicular cartilage border was 4.3 mm (95% CI, 4.0-4.6 mm), and the mean distance from the medial acromial attachment of the AC capsule to the acromial cartilage border was 3.1 mm (95% CI, 2.9-3.4 mm). On the clockface model of the right shoulder, the clavicular attachment of the posterosuperior ligament ranged from the 9:05 (range, 8:00-9:30) to 11:20 (range, 10:00-12:30) position, and the acromial attachment ranged from the 12:20 (range, 11:00-1:30) to 2:10 (range, 13:30-14:40) position.

CONCLUSION

The finding that the posterosuperior ligament did not course perpendicular to the AC joint but rather was oriented obliquely to the long axis of the clavicle, in combination with the newly developed clockface model, may help surgeons to optimally reconstruct this ligament.

CLINICAL RELEVANCE

Our results of a narrow inferior footprint and a short distance from the inferior AC capsule to cartilage suggest that proposed reconstruction of the AC joint capsule should focus primarily on its superior portion.

Comparison of the Results of Hook Plate and Endo-Button Used in the Surgical Treatment of Acromioclavicular Joint Separation

Purpose: Our study aimed to compare the clinical outcomes between endo-button and hook plate fixations for the treatment of acute unstable acromioclavicular (AC) joint dislocation.

Materials: A retrospective evaluation of patients with acute AC joint dislocation who were treated between February 2009 and December 2019 was performed. The study was conducted with 39 patients who met the inclusion criteria. Patients were divided into group 1, operated with a hook plate, and group 2, operated with an endo-button. The demographic features and postoperative complications were analyzed. The disability of arm, shoulder, and hand (DASH) scoring system, modified University of California at Los Angeles shoulder score (UCLA) scale, and the visual analog scale (VAS) scores were used to evaluate shoulder functions in these patients. Shoulder functions were evaluated one, three, six, and twelve months after surgery.

Results: There were 21 patients in group 1 and 18 patients in group 2. Gender distribution was 28 male and 11 female, and the average age was 30.9 years (18-50). There were no significant differences in age, sex, side of injury, or follow-up time from injury to surgery between the two groups. The UCLA scores of group 1 and group 2 one month after surgery were 17.2 and 27.2, respectively. DASH scores of group 1 and group 2 one month after surgery were 82 and 52, respectively. The VAS scores of group 1 and group 2 one month after surgery were 70 and 14, respectively. For all scores at first month post-surgery, there were statistically significant differences between groups, but scores became similar 12 months after surgery.

Conclusion: Postoperative shoulder scores of patients with endo-button showed superiority in the early stages. However, after a year of follow-up, the results of the surgery performed with an endo-button or a hook plate were similar.

Acromioclavicular Joint Separation: Repair Through Suture Anchors for Coracoclavicular Ligament and Nonabsorbable Suture Fixation for Acromioclavicular Joint

OBJECTIVE

To evaluate the clinical and radiographic outcomes of patients undergoing coracoclavicular (CC) ligament repair by two suture anchors and acromioclavicular (AC) joint (ACJ) fixation using heavy nonabsorbable sutures for the treatment of types III-V ACJ injuries with a minimum of 1-year follow-up.

METHODS

The clinical and radiographic outcomes of 36 consecutive patients (26 men and 10 women) who underwent anatomic reduction for acute ACJ dislocation using two suture anchors for CC ligament reconstruction and two strands of non-absorbable stitches for ACJ fixation between December 2013 and December 2018 were reviewed. Two 3.5 mm suture anchors with double-loaded sutures were separately inserted into the anterolateral and posteromedial portions of the coracoid process. The suture strands were passed through the hole created in the clavicle using 2.0 mm drill and tied over the clavicle. Additional ACJ augmentation using two strands of non-absorbable heavy sutures was performed in all patients. At 3, 6, and 12 months and last follow-up visit, the scores on the visual analog scale (VAS), the American Shoulder and Elbow Surgeons (ASES) score, Constant-Murley score, and simple shoulder test (SST) questionnaires were used to provide a final evaluation of shoulder function. Comparison between baseline and treatment results was performed. Radiographic analysis included vertical displacement and horizontal shift.

RESULTS

A total of 29 patients (20 men and nine women) were included in the study. A total of seven, six, and 16 patients had Rockwood type III, type IV, and type V ACJ dislocations, respectively. The mean patient age was 42.8 ± 13.5 years, with a mean follow-up of 28 months (range, 12-56 months). At the 12-month follow-up, the mean ASES score was 92.1 ± 3.5, with a mean pain score of 0.5 ± 0.7 on the VAS and mean Constant-Murley score of 93.0 ± 2.4. The new number of positive answers on the SST was 11.5 ± 0.6. Compared with the baseline, the clinical results improved significantly (P < 0.05). No significant difference could be found between the 6- and 12-month follow-up evaluations (P > 0.05). Radiographs showed two partial loss of reduction, whereas no horizontal displacement was found in all patients. One patient developed a superficial wound infection 3 weeks postoperation. The wound healed after routine wound care. No neurovascular complications were recorded.

CONCLUSIONS

CC ligament reconstruction using two suture anchors and ACJ augmentation using two strands of non-absorbable heavy sutures on high-grade AC dislocation is a reliable technique for restoring stability to the ACJ and can obtain good to excellent clinical results.

Basic morphological characteristics of coracoid grafts obtained by open and arthroscopic Latarjet techniques: A comparative study

BACKGROUND

A knowledge of the anthropometric characteristics of the coracoid graft (CG) that can be obtained by the open and arthroscopic Latarjet techniques may be beneficial in the preoperative planning and intraoperative decision making for coracoid osteotomy and transfer. We have not found any study that compared the morphology of the CG that can be obtained from open and arthroscopic Latarjet techniques. The purpose of this study was to verify if the basic anthropometric characteristics of CGs are equivalent.

HYPOTHESIS

We hypothesize that the basic anthropometric characteristics of the CGs are similar.

METHODS

Twenty fresh-frozen human paired cadaveric shoulder specimens that had been randomly distributed in two groups of 10 specimens each were used. Two surgeons, each with experience in performing the open and arthroscopic Latarjet technique, performed these procedures in each of the respective groups (OG, open group; AG, arthroscopic group). A CT scan was performed. Using the volume rendering technique, a metric analysis of the volume, area and length of the CG were performed, evaluated and statistically analysed.

RESULTS

There were no significant differences in length (p=0.162) (mean length, 22.6mm for OG and 23.6mm for AG). There were significant differences in the volume (p=0.031) and area (p=0.007) of the CG, being lower in the OG (mean volume, 2.8 cm³ for OG and 3.6 cm³ for AG; mean area, 9.9 cm² for OG and 12.8 cm² for AG). No significant differences were observed by sex or laterality.

CONCLUSION

The mean lengths of the CGs that were obtained by each technique are equivalent. However, the areas and volumes of the grafts are different, being lower in the open surgery. These differences have not been an impediment to perform the technique. Our results corroborates that consolidation is more related to the preparation and placement than to the anthropometric characteristics of the CG. No significant differences were observed by sex or laterality.

LEVEL OF EVIDENCE

Basic Science.

Anatomic reconstruction of acromioclavicular joint dislocations using allograft and synthetic ligament

Background

Acromioclavicular (AC) separations are commonly seen shoulder injuries. Numerous surgical reconstruction techniques have been described. In this study, we present a series of patients who underwent an anatomic reconstruction using a synthetic ligament and allograft construct.

Methods

We performed a retrospective review of patients with type IV or V AC separations who underwent primary or revision AC reconstruction with a luggage-tag synthetic ligament and a semitendinosus allograft placed through the anatomic insertion sites of the coracoclavicular ligaments. Patient-reported outcomes, as well as complication rates, were recorded at a minimum 2-year follow-up.

Results

Ten patients with a mean age of 44.2 ± 14.9 years were included in the study. The mean Disabilities of the Arm, Shoulder and Hand score was 15.5 ± 15.4; mean Single Assessment Numeric Evaluation score, 81.8 ± 12.1; mean Simple Shoulder Test score, 11.4 ± 1.1; mean American Shoulder and Elbow Surgeons score, 84.6 ± 15.7; mean Constant score, 82.5 ± 11.6; and mean visual analog scale score, 2 ± 2.6.

Conclusion

The technique using a luggage-tag synthetic ligament along with an anatomic allograft coracoclavicular ligament reconstruction is a safe, effective alternative to other techniques described in the literature.

The variance of clavicular surface morphology is predictable: an analysis of dependent and independent metadata variables

Background

The anatomy of the clavicle is specific and varied in reference to its topography and shape. These anatomic characteristics play an important role in the open treatment of clavicle fractures. The complex and variable topography creates challenges for implant placement, contouring, and position. Hardware prominence and irritation does influence the decision for secondary surgical intervention.

Methods

Computerized tomographic scans of 350 adult clavicles with the corresponding patients' metadata were acquired and digitized. Morphologic parameters determining the shape of the clavicle were defined and computed for each digitized bone. The extracted morphologic parameters were correlated with patient metadata to analyze the relationship between morphologic variability and patient characteristics.

Results

The morphologic parameters defining the shape, that is, the radius of the medial and lateral curves, the apparent clavicle height and width, and the clavicle bow position, correlate with the clavicle length. The clavicle length correlates with the patients' height. Gender differences in shape and form were dependent and related to individual height distribution and clavicle length. Asian populations showed a similarly predictable, but shifted, correlation between shape and clavicle length.

Conclusion

This anatomic analysis shows that the clavicle shape can be predicted through the clavicle length and patients' stature. Smaller patients have shorter and more curved clavicles, whereas taller patients have longer and less curved clavicles. This correlation will aid surgeons in fracture reduction, implant curvature selection, and in optimal adaptation of clavicle implants, and represents the basis for anatomically accurate solutions for clavicle osteosynthesis.

Sagittal orientation of coracoclavicular ligament reconstruction affects the stability of surgical repair

BACKGROUND

The variation in the anatomic relationship between the coracoid and the clavicle affects the biomechanical stability of coracoclavicular ligament reconstruction (CCLR).

METHODS

Three-dimensional computed tomography reconstruction of 85 patients was analyzed. Anatomic landmarks were used to derive the coracoclavicular sagittal reconstruction angle (sRA). The lateral concave angle, which indicated the shape of the distal clavicle, and the offsets between the clavicle and coracoid were also measured. To investigate the biomechanical effects of the sRA on CCLR, 7 computed tomography scans with different sRAs were 3D printed. Two reconstructions, a single trans-coracoclavicular tunnel and a looped reconstruction technique, were performed sequentially. Models were cyclically loaded at 70 N in the anterior, posterior, and superior directions.

RESULTS

The mean sRA was 68° ± 9.3° (range, 47°-85°). The superoinferior offset between the clavicle and the coracoid and the lateral concave angle positively correlated with the sRA (r = 0.359 and 0.837, respectively; P ≤ .001), whereas the anteroposterior offset had a negative correlation (r = -0.925; P < .001). The sRA had a negative correlation with the anterior displacement of the clavicle (rho = -0.96; P < .001) and a positive correlation with the posterior displacement for both surgical techniques (rho = 1.0; P < .001).

CONCLUSION

The anatomic orientation of the native coracoclavicular ligaments is highly variable in the sagittal plane. Low sagittal angles can reduce anterior stability, whereas high sagittal angles can reduce posterior stability of CCLR.

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.

Synthetic coracoclavicular ligament vs. coracoclavicular suspensory construct for treatment of acromioclavicular dislocation: a biomechanical study

BACKGROUND

A synthetic ligament (LockDown, Worcestershire, England) has become available to treat complete acromioclavicular dislocation with promising clinical results and potential benefit to avoid postoperative loss of reduction. We investigated the biomechanics of this synthetic ligament in a simulated immediate postoperative rehabilitation setting, hypothesizing that the synthetic ligament would demonstrate less superior coracoclavicular displacement to cyclic loading and higher ultimate load-to-failure values than a coracoclavicular suspensory construct.

METHODS

Seven matched-pair cadaveric shoulders (mean age at time of death, 79 years) were loaded cyclically and to failure. One specimen in each pair was randomly assigned to the synthetic ligament or coracoclavicular suspensory construct. Superiorly directed 70-N cyclic loading for 3000 cycles at 1.0 Hz was applied through the clavicle in a fixed scapula simulating physiologic states during immediate postoperative rehabilitation, followed by a load-to-failure test at 120 mm/min.

RESULTS

After 3000 cycles, the superior displacement of the clavicle in the synthetic ligament (9.2 ± 1.1 mm) was 225% greater than in the coracoclavicular suspensory construct (2.8 ± 0.4 mm, 95% confidence interval [CI] 3.4, 8.3; P < .001). Average stiffness of the synthetic ligament (32.8 N/mm) was 60% lower than that of the coracoclavicular suspensory construct (81.9 N/mm, 95% CI 43.3, 54.9; P < .001). Ultimate load-to-failure of the synthetic ligament was 23% (95% CI 37.9, 301.5; P = .016) lower than the coracoclavicular suspensory construct (580.5 ± 85.1 N and 750.2 ± 135.5 N, respectively).

CONCLUSION

In a simulated immediate postoperative cadaveric model, the synthetic ligament demonstrated poorer biomechanics than the coracoclavicular suspensory construct. These findings suggest that a coracoclavicular suspensory construct may be preferable to a synthetic ligament if early rehabilitation is intended.