Primary Stability of an Acromioclavicular Joint Repair Is Affected by the Type of Additional Reconstruction of the Acromioclavicular Capsule

Comparative study of two different horizontal stabilisation methods in arthroscopically assisted coracoclavicular stabilisation for acute acromioclavicular joint dislocations-Good clinical outcome and no correlation to recurrent anteroposterior instability

PURPOSE

The hypothesis of this study was that acromioclavicular K-wire transfixation is noninferior to horizontal FiberTape cerclage in terms of vertical and horizontal stability in the short follow-up period of acute acromioclavicular joint (ACJ) dislocations fixed with an arthroscopically assisted coracoclavicular single bundle endobutton cerclage system. The secondary aim was to investigate the impact of postoperative recurrent instability on clinical outcomes in these populations.

METHODS

In this consecutive clinical trial, all patients who underwent surgery for acute AC joint dislocation between January 2017 and December 2021 were included. Two groups were formed according to the additional AC stabilisation technique (K-wire group, cerclage group). Clinical examination and bilateral radiologic analysis (Zanca stress view, Alexander view) were performed with a follow-up period of at least 12 months. Satisfaction, return to sports, active range of motion, global shoulder scores and specific shoulder scores including constant score, disabilities of the arm, shoulder and hand (DASH) score and ACJ instability score (ACJI) were evaluated. Complications, including recurrent instability, and revision rate were assessed.

RESULTS

Included were 59 patients (32 K-wire group, 27 cerclage group, 92% male, median follow-up 33 months). No significant differences were found in the clinical outcome parameters between the different techniques, except for the DASH value (superior in the K-wire group). Recurrent anteroposterior instability was radiographically detected in 27% of patients. No correlation was found between anteroposterior instability and clinical outcome parameters. There was no revision surgery due to chronic ACJ instability.

CONCLUSION

Horizontal ACJ stabilisation with temporary K-wire transfixation does not appear to be inferior to a FiberTape cerclage technique in acute ACJ dislocations stabilised in an arthroscopically assisted single bundle DogBone technique. Recurrent ACJ instability detected radiographically does not necessarily correlate with the functional outcome and can be well compensated.

LEVEL OF EVIDENCE

Level III.

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.

Quality and stability of reduction of operated acromioclavicular dislocation using dual acromioclavicular and coracoclavicular stabilization

INTRODUCTION

Dual stabilization is advocated in acute acromioclavicular dislocation (ACD), but has been little assessed.

OBJECTIVE

This preliminary study performed clinical and radiological assessment of dual acromioclavicular (AC) and coracoclavicular (CC) stabilization in acute ACD. The study hypothesis was that dual stabilization allows satisfactory reduction that remains stable over time.

MATERIALS AND METHODS

A button was used under endoscopy for CC stabilization. For AC stabilization, a short approach was used; the joint was cleansed then stabilized by an anchored tape between the acromion and the clavicle to promote ligament healing. Clinical assessment was based on a visual analog pain scale (VAS), joint range of motion and Quick-DASH and Constant scores. Radiological reduction was assessed on the ratio of CC distance between the operated and healthy sides on two views. MRI was used in follow-up to screen for ligament healing: thickening and continuity.

RESULTS

Thirty-five patients with stage 3-5 acute dislocation were included. At a minimum 24 months' follow-up, mean clinical scores were very satisfactory, with recovery of motion and pain relief. Radiography showed 94% stable reduction in both vertical and horizontal planes. MRI confirmed CC and AC ligament healing. Postoperative complications mainly comprised 4 cases of reduction loss (11%). One clavicle fracture occurred, at 6 months.

CONCLUSION

Dual AC-CC stabilization provided very good radiographic reduction in both horizontal and vertical planes. Functional results were very satisfactory, and complications were few, with some cases of reduction loss. These good results encourage us to continue with dual stabilization in acute ACD.

LEVEL OF EVIDENCE

II; prospective cohort.

Functional reconstruction of chronic acromioclavicular joint separation using a double suture technique combined with semitendinosus autograft

PURPOSE

We present the functional and clinical results of a combined surgical technique that functionally restores chronic Acromioclavicular Joint Instability (AJI). The method combines a double-looped suture fixation augmented with a semitendinosus autograft.

METHODS

Between 2017 and 2021, 15 patients were treated using the surgical technique. All patients suffered an Acromioclavicular Joint Separation that remained untreated for at least 6 (6-16) weeks after the initial injury. Four Ethibond sutures were passed below the coracoid process and through a 4.5 drill hole in the clavicle. The sutures provided adequate horizontal and vertical reduction and stabilization of the clavicle. A semitendinosus autograft was passed below the coracoid process and looped around the clavicle. The remaining graft limbs were used to reconstruct the acromioclavicular capsule. Patients were radiologically evaluated with bilateral anteroposterior (AP), Zanca, and Alexander views. The clinical evaluation was based on the Acromioclavicular Joint Instability Score and the Constant-Murley Score.

RESULTS

The mean follow-up period was 31.2 months (17-61). The mean last ACJIS and CMS scores were 96 (90-100) and 97.67 (87-100), respectively. Reduction of the clavicle was radiologically confirmed in all cases throughout the follow-up period. AC arthritis was reported in 1 case without associated clinical symptoms. No significant complications were reported, and all patients returned to the pre-injury activity level.

CONCLUSION

The presented functional reconstruction of the AC joint disruption in chronic cases is an effective and secure method with low complication rates and good clinical results.

LEVEL OF EVIDENCE III

This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Clavicular tunnel widening after coracoclavicular stabilization surgery: a systematic review and meta-analysis

BACKGROUND

This systematic review and meta-analysis aimed to (1) estimate the prevalence of clavicular tunnel widening (TW) after coracoclavicular stabilization surgery and its risk factors and (2) assess whether TW is correlated with clavicle fracture or loss of reduction of the acromioclavicular joint (ACJ).

METHODS

In January 2023, 3 electronic databases were searched to collect data on postoperative clavicular TW, its prevalence, magnitude, and correlation with fracture and ACJ loss of reduction. Studies were classified according to the time of surgical intervention, and the clavicular tunnels were categorized by their anatomic location. Mean differences were calculated using a DerSimonian-Laird random-effects model, while binomial outcomes were pooled using the Freeman-Tukey double arcsine transformation. Univariate and multivariate meta-regression analyses were performed to determine the effect of several variables on the proportion of cases with TW.

RESULTS

Fifteen studies (418 shoulders) were included. At the final follow-up, evidence of clavicular TW was found in 70% (95% confidence interval [CI]: 70%-87%; I2 = 89%) of 221 shoulders. Surgeries in acute cases had a lower prevalence of TW (52%) compared to chronic cases (71%) (P < .001). Significant TW was found in the central tunnel (3.2 mm; 95% CI: 1.8-4.6 mm; P < .001; I2 = 72%) for acute injuries and in the medial (1.2 mm; 95% CI: 0.7-1.7 mm; P < .001; I2 = 77%) and lateral (1.5 mm; 95% CI: 0.7-2.3 mm; P < .001; I2 = 77%) tunnels for chronic cases. Single central-tunnel techniques were positively associated with the prevalence of TW (P = .046), while biotenodesis screw fixation was associated with a lower prevalence (P = .004) in chronic cases. Reconstruction of the ACJ ligament complex with tendon grafts or sutures was associated with a higher prevalence of TW (P < .001). Drill sizes between 2.5 and 5 mm were significantly associated with a lower prevalence of TW, regardless of injury chronicity (P = .012). No correlation was found between TW and the loss of ACJ reduction or clavicle fractures.

CONCLUSIONS

This systematic review and meta-analysis explored TW occurrence following coracoclavicular stabilization surgery. TW was observed in 70% of patients at final follow-up, with a higher prevalence in chronic than in acute cases. Modifiable surgical variables, such as single-tunnel tendon graft constructs for acute or chronic injuries and knotted graft procedures for chronic injuries, were significantly associated with TW. Furthermore, the prevalence of TW increased with concomitant surgical treatment of the ACJ ligament complex, and decreased with drill sizes between 2.5 and 5 mm, regardless of lesion chronicity. These surgical variables should be considered when establishing transosseous tunnels for coracoclavicular stabilization. Clavicle fractures and TW mechanisms require further investigation.

3D C-arm navigated acromioclavicular joint stabilization

INTRODUCTION

Surgical treatment options for acromioclavicular joint separations are varied. Frequently, suspension devices (SD) are inserted for stabilization under arthroscopic view. This study investigates the feasibility and accuracy of three-dimensional (3D) digital-volume-tomography (DVT) C-arm navigated implantation with regard to the general trend toward increasingly minimally invasive procedures.

MATERIALS AND METHODS

The implantation of a TightRope® suture button system (SD) via a navigated vertical drill channel through the clavicle and coracoid was investigated in 10 synthetic shoulder models with a mobile isocentric C-arm image intensifier setup in the usual parasagittal position. Thereby, in addition the placement of an additive horizontal suture cerclage via a navigated drill channel through the acromion was assessed.

RESULTS

All vertical drill channels in the Coracoclavicular (CC) direction could be placed in a line centrally through the clavicle and the coracoid base. The horizontal drill channels in the Acromioclavicular (AC) direction ran strictly in the acromion, without affecting the AC joint or lateral clavicle. All SD could be well inserted and anchored. After tensioning and knotting of the system, the application of the horizontal AC cerclage was easily possible. The image quality was good and all relevant structures could be assessed well.

CONCLUSION

Intraoperative 3D DVT imaging of the shoulder joint using a mobile isocentric C-arm in the usual parasagittal position to the patient is possible. Likewise, DVT navigated SD implantation at the AC joint in CC and AC direction on a synthetic shoulder model. By combining both methods, the application in vivo could be possible. Further clinical studies on feasibility and comparison with established methods should be performed.

Mid-term clinical and sonographic outcomes of minimally invasive acromioclavicular joint reconstruction: mini-open versus arthroscopically assisted

INTRODUCTION

The current literature describes various operative stabilization strategies which achieve good clinical outcomes after acute acromioclavicular joint (ACJ) dislocation. The aim of this study was to compare the mid-term clinical and sonographic treatment outcomes after minimally invasive mini-open and arthroscopic reconstruction.

MATERIALS AND METHODS

We conducted a retrospective two-center study of patients with acute ACJ dislocation. Surgical treatment was performed using either a mini-open approach (MIOP) or an arthroscopic technique (AR). The primary outcome parameters of this study were the sonographically measured acromioclavicular (ACD) and coracoclavicular distances (CCD). Secondary outcome parameters included the Constant-Murley score (CS), range of motion (ROM), postoperative pain scale (VAS), return to daily routine, return to sports, complications, as well as operative revisions.

RESULTS

After a mean follow-up of 29 months, 30 patients were included in this study with an average age of 41.3 ± 14.8 years (MIOP) and 41.2 ± 15.4 years (AR). The sonographic ACD (MIOP 9.11 mm vs. AR 8.93 mm, p = 0.41) and CCD (MIOP 25.08 mm vs. AR 24.36 mm, p = 0.29) distances showed no statistically significant differences. Furthermore, there was no statistically significant difference when compared to the contralateral side (p = 0.42). With both techniques, patients achieved excellent clinical outcome parameters without statistically significant differences in CS (MIOP 95 vs. AR 97, p = 0.11) and VAS (MIOP 1.76 vs. AR 1.14, p = 0.18). The return to daily activity and return to sport rates did not differ. There were neither complications nor revisions in both groups.

CONCLUSION

Both minimally invasive techniques for acute ACJ stabilization achieved excellent clinical and sonographic outcomes without one technique being statistically superior to the other.

Management of Acromioclavicular Joint Injuries: A Historic Account

There has been a rapid evolution in best practice management of acromioclavicular (AC) joint injuries. AP, Zanca, scapular Y, and dynamic axillary radiographic views provide optimal visualization of the joint and may assess for the presence of horizontal AC instability. Severity of AC joint pathology is classified according to the 6-tier Rockwood scoring system. Over 160 surgical techniques have been described for AC joint repair and reconstruction in the last decade; as a result, determining the optimal treatment algorithm has become increasingly challenging secondary to the lack of consistently excellent clinical outcomes.

Arthroscopically Assisted Tensionable Cerclage Reconstruction of an Acromioclavicular Separation With Combined Fixation of the Coracoclavicular and Acromioclavicular Ligaments

A variety of surgical techniques are currently available to manage high-grade acromioclavicular (AC) separations, including hook plates/wires, nonanatomic ligament reconstruction, and anatomic cerclage with or without biological augmentation. Traditional reconstructions focused on the coracoclavicular ligaments alone and often were associated with high rates of recurrent deformity. Biomechanical and clinical data have suggested that additional fixation of the AC ligaments is beneficial. This Technical Note describes an arthroscopically assisted approach for combined reconstruction of the coracoclavicular and AC ligaments with a tensionable cerclage.

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.

Deltotrapezial Stabilization of Acromioclavicular Joint Rotational Stability: A Biomechanical Evaluation

Background

Despite advances in surgical management of acromioclavicular (AC) joint reconstruction, many patients fail to maintain sustained anatomic reduction postoperatively.

Purpose

To determine the biomechanical support of the deltoid and trapezius on AC joint stability, focusing on the rotational stability provided by the muscles to posterior and anterior clavicular rotation. A novel technique was attempted to repair the deltoid and trapezius anatomically.

Study Design

Controlled laboratory study.

Methods

Twelve human cadaveric shoulders (mean ± SD age, 60.25 ± 10.25 years) underwent servohydraulic testing. Shoulders were randomly assigned to undergo serial defects to either the deltoid or trapezius surrounding the AC joint capsule, followed by a combined deltotrapezial muscle defect. Deltotrapezial defects were repaired with an all-suture anchor using an anatomic technique. The torque (N·m) required to rotate the clavicle 20° anterior and 20° posterior was recorded for the following conditions: intact (native), deltoid defect, trapezius defect, combined deltotrapezial defect, and repair.

Results

When compared with the native condition, the deltoid defect decreased the torque required to rotate the clavicle 20° posteriorly by 7.1% (P = .206) and 20° anteriorly by 6.1% (P = .002); the trapezial defect decreased the amount of rotational torque posteriorly by 5.3% (P = .079) and anteriorly by 4.9% (P = .032); and the combined deltotrapezial defect decreased the amount of rotational torque posteriorly by 9.9% (P = .002) and anteriorly by 9.4% (P < .001). Anatomic deltotrapezial repair increased posterior rotational torque by 5.3% posteriorly as compared with the combined deltotrapezial defect (P = .001) but failed to increase anterior rotational torque (P > .999). The rotational torque of the repair was significantly lower than the native joint in the posterior (P = .017) and anterior (P < .001) directions.

Conclusion

This study demonstrated that the deltoid and trapezius play a role in clavicular rotational stabilization. The proposed anatomic repair improved posterior rotational stability but did not improve anterior rotational stability as compared with the combined deltotrapezial defect; however, neither was restored to native stability.

Clinical Relevance

Traumatic or iatrogenic damage to the deltotrapezial fascia and the inability to restore anatomic deltotrapezial attachments to the acromioclavicular joint may contribute to rotational instability. Limiting damage and improving the repair of these muscles should be a consideration during AC reconstruction.

Acromioclavicular reconstruction techniques after acromioclavicular joint injuries: A systematic review of biomechanical studies

BACKGROUND

Residual horizontal instability after surgical treatment for acromioclavicular joint injuries is seen as a potential cause of suboptimal clinical outcomes. Biomechanical studies have demonstrated that the acromioclavicular capsule/ligaments are the primary restraints for anteroposterior translation. However, limited studies have addressed the biomechanics of a reconstruction of the acromioclavicular capsule/ligaments. The aim of this systematic review was to evaluate the biomechanical role of acromioclavicular capsule/ligament reconstruction techniques after an acromioclavicular joint injury.

METHODS

A search was carried out on the databases Medline and EMBASE, and was conducted according to the PRISMA guidelines. Biomechanical studies addressing horizontal and vertical displacement or joint stiffness after reconstructing the acromioclavicular capsule/ligament with or without coracoclavicular ligament reconstruction, were included.

FINDINGS

Nineteen studies were included in this review after screening and eligibility assessment. Five of them investigated different sole acromioclavicular capsule/ligament reconstruction techniques. In 10 studies, a sole coracoclavicular ligament reconstruction was compared to a coracoclavicular ligament reconstruction with additional acromioclavicular capsule/ligament reconstruction. The remaining 4 studies compared different acromioclavicular capsule/ligament with coracoclavicular reconstruction techniques with each other.

INTERPRETATION

Several testing protocols to evaluate acromioclavicular capsule/ligament reconstruction have been described and can make it difficult to compare the results of the different studies. Acromioclavicular capsule/ligament reconstruction may provide increased anteroposterior and rotational stability but an optimal reconstruction technique, which mimics all biomechanical characteristics of the native joint is not yet available.

Current concepts in acromioclavicular joint (AC) instability - a proposed treatment algorithm for acute and chronic AC-joint surgery

BACKGROUND

There exists a vast number of surgical treatment options for acromioclavicular (AC) joint injuries, and the current literature has yet to determine an equivocally superior treatment. AC joint repair has a long history and dates back to the beginning of the twentieth century.

MAIN BODY

Since then, over 150 different techniques have been described, covering open and closed techniques. Low grade injuries such as Type I-II according to the modified Rockwood classification should be treated conservatively, while high-grade injuries (types IV-VI) may be indicated for operative treatment. However, controversy exists if operative treatment is superior to nonoperative treatment, especially in grade III injuries, as functional impairment due to scapular dyskinesia or chronic pain remains concerning following non-operative treatment. Patients with a stable AC joint without overriding of the clavicle and without significant scapular dysfunction (Type IIIA) may benefit from non-interventional approaches, in contrast to patients with overriding of the clavicle and therapy-resistant scapular dysfunction (Type IIIB). If these patients are considered non-responders to a conservative approach, an anatomic AC joint reconstruction using a hybrid technique should be considered. In chronic AC joint injuries, surgery is indicated after failed nonoperative treatment of 3 to 6 months. Anatomic AC joint reconstruction techniques along with biologic augmentation (e.g. Hybrid techniques, suture fixation) should be considered for chronic high-grade instabilities, accounting for the lack of intrinsic healing and scar-forming potential of the ligamentous tissue in the chronic setting. However, complication and clinical failure rates remain high, which may be a result of technical failures or persistent horizontal and rotational instability.

CONCLUSION

Future research should focus on addressing horizontal and rotational instability, to restore native physiological and biomechanical properties of the AC joint.

Arthroscopic-Assisted Coracoclavicular Stabilization With Anchorless Transosseous Double-Row Acromioclavicular Ligament Complex Repair: The Acute Acromioclavicular Joint Dislocation

The current concept procedures in the acute acromioclavicular joint dislocation should be divided into 2 types of structure restoration: those that provide coracoclavicular stabilization, which affects the primary healing of the coracoclavicular ligaments by vertically stabilizing the clavicle and coracoid in their anatomical positions, and those that attempt to repair the superior acromioclavicular ligament complex, which controls both horizontal and rotational stabilization. The acute acromioclavicular joint dislocation clinical outcome will be achieved if you perform both procedures. It's difficult to stabilize the acromioclavicular joint in both vertical and horizontal planes, and most current techniques aren't always effective. In this Technical Note, we discuss an arthroscopic-assisted technique that reconstructs the coracoclavicular and acromioclavicular ligaments under image intensifier guidance to achieve bidirectional (vertical and horizontal) and rotational stability.

The Role of the Trapezius in Stabilization of the Acromioclavicular Joint: A Biomechanical Evaluation

Background

Acromioclavicular joint (ACJ) injuries are common, and many are adequately treated nonoperatively. Biomechanical studies have mainly focused on static ligamentous stabilizers. Few studies have quantified ACJ stabilization provided by the trapezius.

Purpose/Hypothesis

To elucidate the stabilization provided by the trapezius to the ACJ during scapular internal and external rotation (protraction and retraction). It was hypothesized that sequential trapezial resection would result in increasing ACJ instability.

Study Design

Controlled laboratory study.

Methods

A biomechanical approach was pursued, with 10 cadaveric shoulders with the trapezius anatomically force loaded to normal. The trapezius was then serially transected over 8 trials, which alternated between clavicular defects (CD) and scapular defects (SD); each sequential defect consisted of 25% of the clavicular or scapular trapezial attachment. After each defect, specimens were tested with angle-controlled scapular internal and external rotation (12°) with rotary torque measurements to evaluate ACJ stability.

Results

The mean resistance in rotary torque for 12° of scapular internal rotation (protraction) with native specimens was 7.0 ± 2.0 N·m. Overall, internal rotation demonstrated a significant decrease in ACJ stability with trapezial injury (P < .001). Eight sequential defects resulted in the following significant percentage decreases in rotary torque from native internal rotation: 1.5% (25% CD; 0% SD), 5.6% (25% CD; 25% SD), 5.1% (50% CD; 25% SD), 6.5% (50% CD; 50% SD), 3.8% (75% CD; 50% SD), 7.1% (75% CD; 75% SD), 6.7% (100% CD; 75% SD), and 12.3% (100% CD 100% SD) (P < .001). The mean resistance in rotary torque for 12° of scapular external rotation (retraction) with native specimens was 7.1 ± 1.7 N·m. External rotation did not demonstrate a significant decrease in ACJ stability with trapezial injury (P = .596). The 8 sequential defects resulted in decreases in rotary torque from native external rotation of 0%, 3.8%, 4.0%, 3.2%, 3.5%, 3.4%, 4.2%, and 0.7%.

Conclusion

Trapezial injury resulted in increased instability in the setting of scapular internal rotation (protraction) of the ACJ.

Clinical Relevance

These findings validate the inclusion of deltotrapezial fascial injury consideration in the modified Rockwood classification system. Repair of the trapezial insertion on the ACJ may provide improved outcomes in the setting of ACJ reconstruction.

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

Purpose

Methods

Results

Conclusions

Clinical Relevance

Combined Vertical, Horizontal, and Rotational Acromioclavicular Joint Stabilization: "Closing the Circle" Technique

The biomechanical and anatomical complexity of the acromioclavicular joint makes its repair techniques particularly challenging. High rates of reduction subsidence and construction failures transversally affect both anatomic and nonanatomic repair techniques. The importance of addressing both vertical and horizontal instability has been highlighted in recent years. The authors aim to describe a surgical technique that combines vertical, horizontal, and rotational stabilization, in an attempt to restore the coracoacromioclavicular circle of stability.

Acromioclavicular joint stabilization with a double cow-hitch technique compared to a double tight-rope: a biomechanical study

INTRODUCTION

The aim of the present biomechanical study was to evaluate the stability of a novel simple and cost-effective mini-open double cow-hitch suture button technique of acromioclavicular (AC) joint stabilization in comparison to a well-established double tight-rope technique.

MATERIALS AND METHODS

A total of 12 fresh-frozen cadaveric shoulders were randomized into two treatment groups. In either a coracoclavicular stabilization with a standard double tight-rope technique (Group 1; n = 6, age 78 years ± 10) or a double cow-hitch with two No. 5 FiberWire strains looped in a bicortical button placed at the bottom of the coracoid process (Group 2; n = 6, age 80 years ± 13). Both techniques were equally augmented with an AC joint cerclage using a FiberTape. All shoulders were tested in a servo-hydraulic material testing machine for elongation/cyclic displacement (in mm) after cyclic loading (70 N cyclical load, 1500 cycles), stiffness (N/mm) and ultimate load to failure (N). The mechanism of failure was recorded. All tests were performed in a previously published testing setup.

RESULTS

After 1500 cycles, group 2 showed a cyclic displacement of 1.67 mm (SD 0.85), compared to 1.04 mm (SD 0.23) cyclic displacement in group 1 (p = 0.11). The cyclic displacement after AC reconstruction in group 1 was 0.36 mm lower than in the native state with intact ligaments (p = 0.19), whereas the cyclic elongation in group 2 was 0.05 mm higher compared to the native situation (p = 0.87). Stiffness after reconstruction was significantly higher in group 1 compared to the native specimen (p = 0.001), in group 2 it was similar as before the reconstruction (p = 0.64). Ultimate load to failure and stiffness were higher in group 1 with 424 N (SD 237) and 68.6 N/mm (SD 8.2), compared to 377 N (SD 152) and 68 N/mm (SD 13.3) in group 2, without reaching statistical significance (p = 0.69 and 0.89). The most common failure modes were clavicular fractures at the tight rope drill holes (n = 2) and clavicular fractures medially at the fixation site (n = 2) in group 1, and coracoid button break-through (n = 3) and clavicular fractures medially at the fixation site (n = 2) in group 2.

CONCLUSIONS

Stabilization of the AC joint with a novel mini-open double cow-hitch suture button technique resulted in a similar low elongation, high stiffness and ultimate load to failure compared to a double tight-rope technique. This cost-effective technique for AC joint stabilization could demonstrate a sufficient biomechanical stability with especially high stiffness and load-to-failure.

LEVEL OF EVIDENCE

Biomechanical study.

Differences between Coracoclavicular, Acromioclavicular, or Combined Reconstruction Techniques on the Kinematics of the Shoulder Girdle

BACKGROUND

Although the coracoclavicular (CC) ligaments are classically reconstructed after acromioclavicular (AC) joint injuries, biomechanical studies over the past decade have indicated the importance of an additional reconstruction of the AC ligaments. To date, no kinematic study has investigated the kinematic differences between these reconstruction strategies.

PURPOSE

To evaluate the restoration of shoulder motion after an AC injury using a CC ligament, an AC ligament, or a combined reconstruction technique.

STUDY DESIGN

Controlled laboratory study.

METHODS

After creating a Rockwood grade V lesion in 14 cadaveric shoulders, the AC joint injury was treated with either a CC ligament reconstruction using a suspension device, an in situ AC ligament reconstruction using 2 coupled soft tissue anchors, or a combination of these 2 techniques. Joint motions were registered during humerothoracic elevation in the coronal plane and protraction in the intact shoulder in a Rockwood V lesion and after the 3 reconstruction strategies. An optical navigation system measured 3-dimensional rotation in the sternoclavicular and scapulothoracic joints, and both rotation and translation were analyzed in the AC joint.

RESULTS

In the sternoclavicular joint, the CC and combined reconstruction techniques adequately restored clavicular axial rotation, while the AC reconstruction technique showed a better correction of clavicular elevation. Scapulothoracic joint rotations were best restored by reconstructing the AC ligaments. In the AC joint, the relative tilting position and the lateral rotation of the scapula compared with the clavicle were best restored by the suspension device and combined reconstruction. The AC ligament reconstruction technique demonstrated a better restoration of the relative protracted position and resulted in a better correction of the translation of the scapula relative to the clavicle.

CONCLUSION

This study illustrates that there are kinematic differences between AC, CC, or combined ligament reconstruction strategies. Although each technique was able to restore different elements of the joint kinematics, none of the strategies completely restored the shoulder girdle to its preinjured state.

CLINICAL RELEVANCE

Humerothoracic movements after Rockwood V lesions are best restored using the CC reconstruction technique, and scapulothoracic movements are best restored using the AC ligament reconstruction technique.

The Morphology of the Acromioclavicular Joint Does Not Influence the Postoperative Outcome Following Acute Stabilization—A Case Series of 81 Patients

Purpose

To specifically evaluate the influence of the acromioclavicular (AC)-joint morphology on the outcome after arthroscopically assisted coracoclavicular (CC) stabilization surgery with suspensory fixation systems and to investigate whether an additional open AC-joint reduction and AC cerclage improves the clinical outcome for patients with certain morphologic AC-joint subtypes.

Methods

Patients with an acute acromioclavicular joint injury, who underwent arthroscopically assisted CC stabilization with suspensory fixation systems with or without concomitant AC cerclage between January 2009 and June 2017 were identified and included in this retrospective cohort analysis. AC-joint morphology was assessed on preoperative radiographs and categorized as “flat” or “non-flat” (“oblique”/“curved”) subtypes. After a minimum of 2 years of follow-up, postoperative Single Assessment Numeric Evaluation (SANE), American Shoulder and Elbow Surgeons (ASES), and visual analog scale (VAS) scores for pain were collected. A subgroup analysis of clinical outcomes depending on the surgical technique and morphological subtype of the AC joint was performed.

Results

Eighty-one patients (95% male, mean age 35 ± 12 years) could be included at a mean follow-up of 57 ± 14 months. Radiographic assessment of AC-joint morphology showed 24 (30%) cases of flat type, 38 (47%) cases of curved type, and 19 (23%) cases of oblique morphology. Postoperatively, no clinically significant difference could be detected after the treatment of AC joint injury via CC stabilization with or without concomitant AC cerclage (VAS_rest: P = .067; VAS_max: P = .144, ASES: P = .548; SANE: P = .045). No clinically significant differences were found between the surgical techniques for the flat morphologic subtype (VAS_rest: P = .820; VAS_max: P = .251; SANE: P = .104; ASES: P = .343) or the non-flat subtype (VAS_res: P = .021; VAS_max: P = .488; SANE: P = .243, ASES: P = .843).

Conclusions

In arthroscopically assisted AC stabilization surgery with suspensory fixation systems for acute AC-joint injury, the AC-joint morphology did not influence the postoperative outcome, independent of the surgical technique. No clinical benefit of performing an additional horizontal stabilization could be detected in our collective at mid-term follow-up.

Level of Evidence

Level IV, therapeutic case series.

Combination of Surgical Techniques Restores Multidirectional Biomechanical Stability of Acromioclavicular Joint

PURPOSE

To measure the multiaxial stability of the acromioclavicular joint before and after transection of the acromioclavicular capsule and coracoclavicular ligaments and after sequential repair of acromioclavicular and coracoclavicular ligaments.

METHODS

Biomechanical testing was performed on fresh-frozen human cadaveric shoulders (N = 6). Translational and rotational stability in the vertical and horizontal planes was measured in intact specimens, after transecting the acromioclavicular and coracoclavicular ligaments, and after sequentially performing the following procedures: single-bundle coracoclavicular repair (CCR), modified Weaver-Dunn procedure (WD), and acromioclavicular stabilization (ACS).

RESULTS

Resecting the acromioclavicular and coracoclavicular significantly reduced translational stiffness in the inferior and anteroposterior directions, as well as rotational stiffness about the vertical and anteroposterior axes. All 3 surgical procedures increased inferior translational stiffness relative to the intact condition (Intact: 38 ± 9 N/mm, CCR: 54 ± 23 N/mm (P = .03), CCR+WD 52 ± 20 N/mm (P = .07), CCR ± WD+ACS 50 ± 21 N/mm (P = .17)). However, the combination of CCR, modified WD, and ACS resulted in the greatest increase in stiffness in internal rotation (Intact: 12.5 ± 7.4 cNm/deg, CCR: 1.2 ± 1.1 cNm/deg, CCR+WD 7.2 ± 3.0 N∗m/deg [P = .023], CCR+WD+ACS 11.6 ± 4.9 cNm/deg [P = .055]).

CONCLUSIONS

The cumulative stability of CCR, WD reconstruction, and ACS appears to be additive. Our findings provide a biomechanical justification for combining all three techniques. Biomechanical studies assessing the performance of various acromioclavicular repairs and reconstructions should therefore incorporate multiaxial testing in their protocols.

CLINICAL RELEVANCE

Multiple points of fixation that provide multidirectional stability have the potential to improve clinical outcomes and reduce failure rates of acromioclavicular joint repair or stabilization.

Hybrid coracoclavicular and acromioclavicular reconstruction in chronic acromioclavicular joint dislocations yields good functional and radiographic results

PURPOSE

Optimal treatment of chronic unstable acromioclavicular (AC) joint dislocations (stage 3-5 according the Rockwood classification) is still debated. Anatomic coracoclavicular (CC) reconstruction is a reliable option in terms of two-dimensional radiographic reduction, clinical outcomes, and return to sports, but there remain concerns regarding anterior-posterior stability of the AC joint with CC ligament reconstruction alone. The aim of the present study was to describe the mid-term results of a new hybrid technique with CC and AC ligament reconstruction for chronic AC joint dislocations.

METHODS

Twenty-two patients surgically treated for chronic AC joint dislocations (grade 3 to 5) were retrospectively reviewed. All patients were assessed before surgery and at final follow-up with the Constant-Murley score (CMS) and the American Shoulder and Elbow Surgeons (ASES) score. The CC vertical distance (CCD) and the CCD ratio (affected side compared to unaffected side) were measured on Zanca radiographs preoperatively, at 6 months postop and at final follow-up. The same surgical technique consisting in a primary fixation with a suspensory system, coracoclavicular ligaments reconstruction with a double loop of autologous gracilis and acromioclavicular ligaments reconstruction with autologous coracoacromial ligament was performed in all cases.

RESULTS

Twenty-two shoulders in 22 patients (19 males and 3 females) were evaluated with a mean age of 34.4 ± 9 years at the time of surgery. The mean interval between the injury and surgery was 53.4 ± 36.7 days. The mean duration of postoperative follow-up was 49.9 ± 11.8 months. According to the Rockwood classification, there were 5 (22.6%) type-III and 17 (77.2%) type-V dislocations. Mean preoperative ASES and CMS were 54.4 ± 7.6 and 64.6 ± 7.2, respectively. They improved to 91.8 ± 2.3 (p = 0.0001) and 95.2 ± 3.1 (p = 0.0001), respectively at final FU. The mean preoperative CCD was 22.4 ± 3.2 mm while the mean CCD ratio was 2.1 ± 0.1. At final FU, the mean CCD was 11.9 ± 1.4 mm (p = 0.002) and the mean CCD ratio was 1.1 ± 0.1 (p = 0.009). No recurrence of instability was observed. One patient developed a local infection and four patients referred some shoulder discomfort. Heterotopic ossifications were observed in three patients.

CONCLUSIONS

The optimal treatment of chronic high-grade AC joint dislocations requires superior-inferior and anterior-posterior stability to ensure good clinical outcomes and return to overhead activities or sports. The present hybrid technique of AC and CC ligaments reconstruction showed good clinical and radiographic results and is a reliable an alternative to other reported techniques.

LEVEL OF EVIDENCE

Level IV.

Arthroscopically assisted single tunnel reconstruction for acute high-grade acromioclavicular joint dislocation with an additional acromioclavicular joint cerclage

PURPOSE

Purpose of this study was to demonstrate that a single tunnel reconstruction of high-grade acromioclavicular (AC) joint instabilities with implants of the second generation is sufficient for stabilisation, especially in combination with an AC cerclage.

METHODS

Patients with an acute AC-joint dislocation type Rockwood III-B and V were included. Besides clinical follow-up examination, radiographs were analysed. The functional outcome measures were Constant Score (CS), Taft score (TS), ACJI score and patient's satisfaction. Horizontal instability was evaluated by clinical examination and radiological with an Alexander view.

RESULTS

Thirty-five patients with a mean follow-up of 29 months were included. Ninety-seven per cent were satisfied with their result, with an average Subjective Shoulder Value of 90%. The CS averaged at 90 ± 10 points, TS at 11 ± 1 points and ACJI at 78 ± 18 points. Radiologically, 3 of 29 patients (10%) showed a persisting horizontal instability. The coracoclavicular (CC) distance improved from 22 preoperative to 10 mm postoperative, which was comparable to the contralateral side (10 mm, p = 0.103). At follow-up the CC distance increased to 13 mm (p = 0.0001).

CONCLUSION

AC-joint stabilisation with a single tunnel reconstruction using a second-generation implant results in good to excellent clinical results with high patient satisfaction. The additional AC augmentation improves stability in horizontal instable AC-joints and is recommended in all high-grade AC joint stabilisations. Nonetheless, reduction was slightly lost over time due to an elongation or suture failure of the coraco-clavicular fixation.

LEVEL OF EVIDENCE

IV.

All-suture technique for fixation of unstable displaced distal clavicle fracture

Background

Displaced Neer type II and V clavicle fractures are usually treated surgically in active patients. However, distal fragment fixation remains a challenge, and no consensus has been established regarding the optimal surgical treatment. Osteosuture techniques have been popularized over the last decade, and multiple different techniques have been described. The aim of this study was to describe an all-suture technique in patients with displaced type II and V clavicle fractures and report its outcome in a prospective case series.

Methods

Between 2017 and 2020, 15 patients with displaced acute distal clavicle fractures were treated with an all-suture open technique performed by one shoulder specialized surgeon, with a minimum follow-up of 1 year. Osteosuture repair consisted in a coracoclavicular cerclage with 4 no6 Ethibonds and a figure-of-0 and figure-of-8 fracture cerclage with 2 no2 SutureTapes. Single assessment numerical evaluation (SANE) and adjusted Constant score were recorded at 6 months and 1 year. The radiologic union was assessed on plain radiographs.

Results

At 12 months, all patients reported excellent clinical results, with a mean SANE of 98.2 [± 5.2, range 80 to 100] and a mean adjusted Constant score of 99.0 [± 1.9, range 94 to 100]. One patient developed shoulder stiffness that resolved before the final follow-up. Fractures consolidated in 93% of the cases, with union happening between 3 and 6 months [range 3 to 12 months]. One patient developed an asymptomatic malunion.

Conclusion

Excellent clinical and radiological outcomes can be achieved with this minimally invasive all-suture fixation technique for displaced distal clavicle fractures, which allows for an anatomic reduction and stable fixation. This pilot study showed low complications and a high level of union after a follow-up of 1 year. Among the numerous advantages are a smaller exposure than for plate fixation, avoidance of hardware-related complications such as screw failure, coracoid fracture from drilling, or rotator cuff damage caused by hook-plates. Furthermore, it avoids a reoperation to remove symptomatic hardware.

Addressing Arthroscopic-Assisted Acromioclavicular Joint Reconstruction in the Beach Chair Position With Concomitant Labral Pathology in the Lateral Decubitus Position

High-grade Acromioclavicular (AC) injuries are complete dislocations, involving ruptures of the AC and coracoclavicular ligaments. They occur following trauma after a fall, direct-blow to an adducted arm, or indirectly by falling onto an abducted, outstretched extremity. Given this traumatic etiology, additional intra-articular pathologies can arise and may go unnoticed because of the painful and prominent AC joint (ACJ). Previous studies have evaluated patients with high-grade ACJ injuries with diagnostic arthroscopy at the time of an ACJ reconstruction. They found associated injuries to the labrum/biceps, rotator cuff, and articular cartilage. The arthroscopic-assisted ACJ reconstruction (AA-ACJR) technique has made it possible to identify the associated injuries and treat them concurrently. The previous studies have performed this reconstruction in the beach chair position (BCP) and have addressed the concomitant pathology in the same position. As opposed to the BCP, the lateral decubitus position (LDP) allows for easier application of traction to the arm and, thus, improves visualization of the glenoid, especially the inferior and posteroinferior portions. It is imperative to gain appropriate access to the inferior glenoid for anchor placement to address this component of traumatic instability. We present the technique for addressing high-grade ACJ injuries with AA-ACJR in the BCP preceded by labral repair in the LDP.

Clinical and radiological outcome of acute high-grade acromioclavicular joint dislocation: A retrospective cohort study on Hook plate versus arthroscopic assisted single coracoclavicular tunnel with DogBone™ button dual FiberTape® construct

Purpose

Hook plate (HP) is a popular implant of choice in the management of highgrade acute acromioclavicular joint (ACJ) dislocations. Recently, suspensory loop systems have drawn significant interest with comparable results and additionally does not warrant implant removal. However, no studies have compared the outcomes of HP vis-a-vis Dog Bone TM Button with dual FiberTape® (DB).

Methods

38 patients who underwent HP or Arthroscopic assisted single tunnel DB fixation to stabilize high-grade ACJ dislocations were retrospectively included in study for clinically and radiological evaluation at a minimum follow up of one year. American Shoulder and Elbow Society and Constant Murley scores were used for clinical assessment. The radiological evaluation was done by assessing quality of reduction, measuring coracoclavicular distance (CCD), and extent of subacromial erosion.

Results

For final follow up evaluation, both HP and DB group had 16 patients each. The mean follow-up was 55.38 ± 10.9 and 32.88 ± 14.0 months in HP and DB group, respectively. No significant difference in mean ASES (p=0.71) and CM score (p=0.62) was found between the two groups. The DB group revealed higher CCD at the final follow-up compared to the HP group (p=0.01). Although statistically insignificant, there were more subluxations and dislocations in the DB group (37.5%) compared to the HP group (25%). The subacromial erosion was noted in all cases of the HP group at time of implant removal.

Conclusion

Both groups revealed satisfactory functional and radiological outcome. However, the DB group showed a higher tendency of loss of reduction.

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.

Editorial Commentary: Arthroscopic-Assisted Coracoclavicular Ligament Reconstruction Leads to Improved Patient-Reported Outcomes, But Patient Satisfaction Is a Harder Threshold to PASS

There are numerous described techniques for surgical management of high-grade acromioclavicular (AC) joint injuries, and the associated clinical outcomes can be quite variable. Contemporary techniques are typically directed at anatomic reconstruction of the coracoclavicular (CC) ligaments through either an arthroscopy-assisted or an open approach. Most patients treated with acute surgery improve, whereas in chronic cases, the majority improve, but a significant number have persistent recurrent deformity due to loss of anatomic reduction. In addition, whether acute or chronic, over one quarter of patients do not have a PASS (patient acceptable symptomatic state). Of interest, PASS may not primarily be related to the final deformity in terms of coracoclavicular distance, and investigation is still required in terms of the effect of anteroposterior or rotational instability of the AC joint after injury and surgery. Finally, PASS values for AC separation are not well established, resulting in a current limitation of the strength of applying threshold values to this pathology.

Effect of Rotator Cuff Deficiencies on Muscle Forces and Glenohumeral Contact Force After Anatomic Total Shoulder Arthroplasty Using Musculoskeletal Multibody Dynamics Simulation

Anatomic total shoulder arthroplasty (ATSA) is widely used to treat the diseases of the glenohumeral (GH) joint. However, the incidence of rotator cuff tears after ATSA increases during follow-up. The effects of rotator cuff deficiencies after ATSA on the biomechanics of the GH joint are to be investigated. In this study, a musculoskeletal multibody dynamics model of ATSA was established using a force-dependent kinematics (FDK) method. The biomechanical effects were predicted during arm abduction under different rotator cuff deficiencies. The deltoid forces were increased under the rotator cuff deficiencies, the maximum deltoid forces were increased by 36% under the subscapularis deficiency and by 53% under the supraspinatus, infraspinatus, subscapularis, and teres minor deficiencies. The maximum GH contact forces were decreased by 11.3% under supraspinatus and infraspinatus deficiencies but increased by 24.8% under subscapularis deficiency. The maximum subscapularis force was decreased by 17% under only infraspinatus tear during arm abduction. The results suggested that the changes in the biomechanics of the GH joint induced by rotator cuff deficiencies after ATSA increase the deltoid muscle energy expenditure and joint instability, which result in postoperative less satisfactory clinical outcomes. The changes in rotator cuff muscle forces deserve more attention for understanding the evolution of rotator cuff tear after ATSA.

Radiographic alterations in clavicular bone tunnel width following anatomic coracoclavicular ligament reconstruction (ACCR) for chronic acromioclavicular joint injuries

PURPOSE

To evaluate tunnel widening and its relationship in loss of reduction and clinical outcomes in patients undergoing anatomic coracoclavicular ligament reconstruction (ACCR) using free tendon grafts for chronic acromioclavicular (AC) joint injuries.

METHODS

A retrospective chart review was performed on patients undergoing ACCR for type III-VI AC joint injuries between January 2003 and December 2017. For radiographic analysis, pre- and post-operative coracoclavicular distance (CCD) and tunnel width of the medial and lateral clavicular bone tunnel were measured at the earliest (EPO) and latest postoperative follow-up (LPO). To determine the clinical relevance of improvement in clinical outcome score (American Shoulder and Elbow Surgeons score) substantial clinical benefit (SCB), and patient acceptable symptomatic state (PASS) thresholds were used.

RESULTS

Twenty-four patients with a mean clinical follow-up of 37 ± 35 months (mean age 44.7 ± 13.4) were included in the study. Both the medial (5.6 ± 0.2 mm_EPO-6.6 ± 0.7 mm_LPO; p < 0.001) and lateral (5.6 ± 0.5 mm_EPO-6.8 ± 1 mm_LPO; p < 0.001) clavicular bone tunnel showed significant widening from EPO to LPO. There was a significant loss of reduction at LPO (CCD_LPO 10.1 ± 4 mm) compared to EPO (CCD_EPO: 6.2 ± 3.8 mm) (p < 0.001). No significant correlation between loss of reduction and medial (p = 0.45; r = - 0.06) or lateral (p = 0.69; r = - 0.06) tunnel widening was found. Alterations in tunnel width were shown having no influence on clinical outcomes.

CONCLUSION

Patients who underwent ACCR using a free tendon graft for the treatment of chronic type III-VI ACJ injuries showed significant clavicular bone tunnel widening during the postoperative course. No correlation between tunnel widening and loss of reduction was shown with radiographic findings having no influence on clinical benefit and satisfaction.

STUDY DESIGN

Case Series; Level of evidence, IV.

Anatomic reconstruction of the acromioclavicular joint provides the best functional outcomes in the treatment of chronic instability

PURPOSE

To systematically review the outcomes of surgical treatments of chronic acromioclavicular joint dislocation.

METHODS

Studies were identified by electronic databases (Ovid, PubMed). All studies reporting functional and radiological outcomes of surgical treatments of chronic acromioclavicular joint dislocations were included. Following data were extracted: authors and year, study design, level of evidence, number of patients, age, classification of acromioclavicular joint dislocation, time to surgery, surgical technique, follow-up, clinical and imaging outcomes, complications and failures. Descriptive statistics was used, when a data pooling was not possible. Comparable outcomes were pooled to generate summary outcomes reported as frequency-weighted values. Quality appraisal was assessed through the MINORS checklist.

RESULTS

Fourty-four studies were included for a total of 1020 shoulders. Mean age of participants was 38 years. Mean follow-up was 32.9 months. Arthroscopic techniques showed better results than open approach (p < 0.0001). Synthetic reconstructions demonstrated better functional outcomes compared to internal fixation and biologic techniques (p < 0.0001). Among biologic techniques, combined coracoclavicular and acromioclavicular ligaments reconstruction showed better Constant (p = 0.0270) and ASES (p = 0.0113) scores compared to isolated coracoclavicular ligaments reconstruction; anatomic biologic non-augmented graft reconstruction showed better Constant (p < 0.0001), VAS (p < 0.0001) and SSV (p = 0.0177) results compared to augmented techniques. No differences in functional outcomes could be found between anatomic biologic non-augmented graft versus synthetic reconstructions. Overall, methodological quality of the included studies was low.

CONCLUSION

Anatomic reconstructions, both synthetic and biologic, showed the best functional results.

LEVEL OF EVIDENCE

IV.

Anatomic coracoclavicular ligament reconstruction (ACCR) using free tendon allograft is effective for chronic acromioclavicular joint injuries at mid-term follow-up

PURPOSE

To evaluate the clinical and radiographic outcomes of patients undergoing anatomic coracoclavicular ligament reconstruction (ACCR) using free tendon allografts for the treatment of chronic acromioclavicular joint (ACJ) injuries with a minimum 1-year follow-up.

METHODS

Patients who underwent ACCR for chronic ACJ injuries between 2003 and 2017 were analyzed. Clinical outcome measures included American Shoulder and Elbow Surgeons (ASES), Constant-Murley (CM), Simple Shoulder Test (SST), and Single Assessment Numerical Evaluation (SANE) scores. Radiographic loss of reduction during follow-up was evaluated by calculating the difference (mm) in the coracoclavicular distance (CCD) of the involved side immediately postoperatively and at terminal follow-up.

RESULTS

Forty-two patients (mean age: 42.7 ± 12.8 years) were included in the study with an average follow-up of 3.8 ± 3.1 years (range: 1.1-11.5 years). Patients achieved significant improvement in ASES (50.2 ± 20.1 pre to 85.2 ± 16.3 post), CM (60.2 ± 18.5 pre to 88.2 ± 9.1 post), SST (6.1 ± 3.2 pre to 9.5 ± 3.7 post), and SANE (24.0 ± 25.7 pre to 89.0 ± 12.7 post) scores (P < 0.001, respectively). There were no significant differences in functional improvement when comparing type III and V injuries (n.s.). Mean increase in CCD of the involved side from immediately postoperative to final radiographic follow-up was 4.1 ± 3.9 mm, with no significant correlation to clinical outcomes scores. Complications occurred in 33.3% of cases, with postoperative heterotopic ossification being most frequent (14.3%).

CONCLUSION

Patients undergoing ACCR using free tendon allografts for chronic ACJ injuries achieved significant improvement in shoulder function at a mean follow-up of 3.8 years. No correlation was observed between the amount of loss of reduction and clinical outcome scores. Free tendon allografts may be a reliable alternative to autografts in the treatment of chronic ACJ dislocations.

LEVEL OF EVIDENCE

IV.

Arthroscopy-Assisted All-Suture Coracoclavicular and Acromioclavicular Joint Stabilization in Acute Acromioclavicular Joint Injuries

The existing literature agrees on surgical management for Rockwood grade IV and V injuries, but there is no consensus which type of surgery is the most appropriate one. More than 150 surgeries have been described for this condition in the literature. In an injury of less than 3 weeks, most surgeons prefer suture-button devices for coracoclavicular stabilization. Recent biomechanical studies have demonstrated that coracoclavicular stabilization provides good vertical stability but poor horizontal stability of acromioclavicular joint. Hence, they recommend acromioclavicular stabilization along with coracoclavicular stabilization. The use of a suture-button device for coracoclavicular stabilization requires special implants and instruments along with high surgical skills to drill precisely placed holes in the clavicle and the coracoid in order to avoid fractures from the drill hole. Due to relatively smaller clavicle and coracoid in Asian population, making holes in the clavicle and the coracoid has increased risk of fracture. We describe a technique in which no drill holes are made in the clavicle or the coracoid. In our technique, suture tape is used, which is looped around the coracoid and the clavicle, and the limbs are tied over the clavicle to maintain the coracoclavicular distance. The remaining limbs of suture tape is further looped through the tunnels made in acromion and tied over the acromion to augment the acromioclavicular ligament. The potential advantages of this technique are no costly implant and instruments are required, avoidance of complications associated with drill holes in coracoid and clavicle, both coracoclavicular and acromioclavicular joints are stabilized, direct repair of the acromioclavicular ligament can be performed, and no need of second surgery for implant removal.

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.

High degree of consensus achieved regarding diagnosis and treatment of acromioclavicular joint instability among ESA-ESSKA members

PURPOSE

To develop a consensus on diagnosis and treatment of acromioclavicular joint instability.

METHODS

A consensus process following the modified Delphi technique was conducted. Panel members were selected among the European Shoulder Associates of ESSKA. Five rounds were performed between October 2018 and November 2019. The first round consisted of gathering questions which were then divided into blocks referring to imaging, classifications, surgical approach for acute and chronic cases, conservative treatment. Subsequent rounds consisted of condensation by means of an online questionnaire. Consensus was achieved when ≥ 66.7% of the participants agreed on one answer. Descriptive statistic was used to summarize the data.

RESULTS

A consensus was reached on the following topics. Imaging: a true anteroposterior or a bilateral Zanca view are sufficient for diagnosis. 93% of the panel agreed on clinical override testing during body cross test to identify horizontal instability. The Rockwood classification, as modified by the ISAKOS statement, was deemed valid. The separation line between acute and chronic cases was set at 3 weeks. The panel agreed on arthroscopically assisted anatomic reconstruction using a suspensory device (86.2%), with no need of a biological augmentation (82.8%) in acute injuries, whereas biological reconstruction of coracoclavicular and acromioclavicular ligaments with tendon graft was suggested in chronic cases. Conservative approach and postoperative care were found similar CONCLUSION: A consensus was found on the main topics of controversy in the management of acromioclavicular joint dislocation. Each step of the diagnostic treatment algorithm was fully investigated and clarified.

LEVEL OF EVIDENCE

Level V.

Arthroscopically Assisted Acromioclavicular Joint Reconstruction Using the Infinity-Lock Button System With Allograft Augmentation

Acromioclavicular (AC) joint injuries are extremely common in the athletic population. Although most low-grade injuries can be managed nonoperatively, high-grade injuries often require reconstruction of the AC joint. Various reconstructive options have been described with varying risks and benefits to each. Implant or graft failure with loss of reduction as well as clavicle and coracoid fracture are a few of the more common complications following AC joint reconstruction surgery. Currently, no gold standard exists. This technical paper describes an arthroscopically assisted AC joint reconstruction technique using the Infinity-Lock Button System with hamstring allograft augmentation. This technique provides an anatomic, minimally invasive, low-profile reconstruction that may minimize risk of clavicle and coracoid fracture. It also provides augmented stabilization across the AC joint, which may also help resist naturally occurring horizontal and rotational displacing forces.

Minimum 10-Year Outcomes After Revision Anatomic Coracoclavicular Ligament Reconstruction for Acromioclavicular Joint Instability

Background:

Revision surgery in cases of previously failed primary acromioclavicular (AC) joint stabilization remains challenging mainly because of anatomic alterations or technical difficulties. However, anatomic coracoclavicular ligament reconstruction (ACCR) has been shown to achieve encouraging biomechanical, clinical, and radiographic short-term to midterm results.

Purpose:

To evaluate the clinical and radiographic long-term outcomes of patients undergoing revision ACCR after failed operative treatment for type III through V AC joint injuries with a minimum 10-year follow-up.

Study Design:

Case series; Level of evidence, 4.

Methods:

A retrospective chart review was performed on prospectively collected data within an institutional shoulder registry. Patients who underwent revision ACCR for type III through V AC joint injuries between January 2003 and December 2009 were analyzed. Clinical outcome measures included the American Shoulder and Elbow Surgeons (ASES) score, Simple Shoulder Test (SST), and Single Assessment Numeric Evaluation (SANE). The coracoclavicular distance (CCD) was measured for radiographic analysis immediately postoperatively and at last postoperative follow-up.

Results:

A total of 8 patients with a mean age at the time of surgery of 44.6 ± 10.6 years and a mean follow-up of 135.0 ± 17.4 months (range, 120-167 months) were eligible for inclusion in the study. The time from initial AC joint stabilization until revision surgery was 10.2 ± 12.4 months (range, 0.5-36 months); 62.5% of the patients had undergone more than 2 previous AC joint surgical procedures. The ASES score improved from 43.9 ± 22.4 preoperatively to 80.6 ± 28.8 postoperatively (P = .012), the SST score improved from 4.4 ± 3.6 preoperatively to 11.0 ± 2.2 postoperatively (P = .017), and the SANE score improved from 31.4 ± 27.3 preoperatively to 86.9 ± 24.1 postoperatively (P = .018) at final follow-up. There was no significant difference in the CCD (P = .08) between the first (7.6 ± 3.0 mm) and final (10.6 ± 2.8 mm) radiographic follow-up (mean, 50.5 ± 32.7 months [range, 18-98 months]).

Conclusion:

Patients undergoing revision ACCR after failed operative treatment for type III through V AC joint injuries maintained significant improvement in clinical outcomes at a minimum 10-year follow-up.

The acromioclavicular ligament shows an early and dynamic healing response following acute traumatic rupture

Purpose

Symptomatic horizontal instability is clinically relevant following acute acromioclavicular joint dislocations. However, the intrinsic healing response is poorly understood. The present study sought to investigate time-dependent healing responses of the human acromioclavicular ligament following acute traumatic rupture.

Methods

Biopsies of the acromioclavicular ligament were obtained from patients undergoing surgical treatment for acute acromioclavicular joint dislocations. Specimens were stratified by time between trauma and surgery: group 1, 0–7 days (n = 5); group 2, 8–14 days (n = 6); and group 3, 15–21 days (n = 4). Time-dependent changes in cellularity, collagen (type 1 and 3) concentration, and histomorphological appearance were evaluated for the rupture and intact zone of the acromioclavicular ligament.

Results

Group 1 was characterized by cellular activation and early inflammatory response. The rupture zone exhibited a significantly higher count of CD68-positive cells than the intact zone (15.2 vs 7.4; P ≤ 0.05). Consistently, synovialization of the rupture end was observed. Within the second week, the rupture zone was subject to proliferation showing more fibroblast-like cells than the intact zone (66.8 vs 43.8; P ≤ 0.05) and a peak of collagen type 3 expression (group 1: 2.2 ± 0.38, group 2: 3.2 ± 0.18, group 3: 2.8 ± 0.57; P ≤ 0.05). Signs of consolidation and early remodeling were seen in the third week.

Conclusions

The acromioclavicular ligament exhibits early and dynamic healing responses following acute traumatic rupture. Our histological findings suggest that surgical treatment of acute ACJ dislocations should be performed as early as possible within a timeframe of 1 week after trauma to exploit the utmost biological healing potential. Prospective clinical studies are warranted to investigate whether early surgical treatment of ACJ dislocations translates into clinical benefits.

Novel Double Endobutton Technique Combined with Three-Dimensional Printing: A Biomechanical Study of Reconstruction in Acromioclavicular Joint Dislocation

Objective

To reconstruct the acromioclavicular (AC) joint using an adjusted closed‐loop double Endobutton technique via a guiding locator that was applied using three‐dimensional (3D) printing technology. At the same time, the reliability and safety of the novel double Endobutton (NDE) were tested by comparing the biomechanics of this technique with the TightRope (TR) approach.

Methods

This retrospective study was conducted between January 2017 and January 2019. The Department of Anatomy at Southern Medical University obtained 18 fresh‐frozen specimens (8 left and 10 right; 12 men and 6 women). First, the guiding locators were applied using 3D printing technology. After preparation of materials, specimens were divided into an NDE group, a TR group, and a normal group. In the NDE and TR groups, the navigation module was used to locate and establish the bone tunnels; after that, the NDE or TR was implanted. However, the Endobuttons were fixed while pressing the distal clavicle downwards and the length of the loop could be adjusted by changing the upper Endobutton in the NDE group while the suture button construct was tensioned and knotted after pressing down the distal clavicle in the TR. Finally, load testing in anterior–posterior (AP), superior–inferior (SI), and medial–lateral (ML) directions as well as load‐to‐failure testing in the SI direction were undertaken to verify whether the NDE or TR had better biomechanics.

Results

In the load testing, the displacements of the NDE and TR groups in the AP, SI, and ML direction were significantly shorter than those of the normal group (P < 0.05). In the load‐to‐failure testing, the ultimate load of the NDE and TR groups had significantly higher increases than the normal group (722.16 ± 92.04 vs 564.63 ± 63.05, P < 0.05; 680.20 ± 110.29 vs 564.63 ± 63.05, P < 0.05). However, there was no statistically significant difference between the two techniques for these two tests (P > 0.05). In the NDE group, four of six failures were a result of tunnel fractures of the coracoid, while two of six were due to suture breakage. In the TR, three failures were due to coracoid tunnel fractures, one was a result of a clavicle tunnel fracture, and the rest were due to suture breakage. In the normal group, half of the failures were a result of avulsion fractures of the conical ligament at the point of the coracoid process, and the other three were due to rupture of the conical ligament, fracture of the distal clavicle, and fracture of the scapular body.

Conclusion

As for the TR technique, the stability and strength of the AC joint were better in patients who underwent reconstruction using the NDE technique than in the intact state.

Posterior Rotational and Translational Stability in Acromioclavicular Ligament Complex Reconstruction: A Comparative Biomechanical Analysis in Cadaveric Specimens

BACKGROUND

Persistent posterior instability of the acromioclavicular (AC) joint is a reported complication after isolated coracoclavicular (CC) reconstruction. Thus, multiple techniques have been proposed attempting to restore biomechanics of the AC ligament complex (ACLC).

PURPOSE/HYPOTHESIS

The purpose was to evaluate the posterior translational and rotational stability of an ACLC reconstruction with a dermal allograft (ACLC patch) as compared with 3 suture brace constructs. It was hypothesized that the ACLC patch would better restore AC joint posterior stability.

STUDY DESIGN

Controlled laboratory study.

METHODS

A total of 28 cadaveric shoulders (mean ± SD age, 57.6 ± 8.3 years) were randomly assigned to 1 of 4 surgical techniques: ACLC patch, oblique brace, anterior brace, and x-frame brace. The force and torque to achieve 10 mm of posterior translation and 20° of posterior rotation of the AC joint were recorded in the following conditions: intact, transected ACLC, ACLC patch/brace repair, ACLC patch/brace repair with dissected CC ligaments, and ACLC patch/brace repair with CC ligament repair.

RESULTS

For posterior translation, transection of the ACLC reduced resistance to 16.7% of the native. With the native CC ligaments intact, the ACLC patch (59.1%), oblique brace (54.1%), and anterior brace (60.7%) provided significantly greater stability than the x-frame brace (33.2%; P < .001, P = .008, P < .001, respectively). ACLC patch, oblique brace, and anterior brace continued to have significantly higher posterior translational resistance than the x-frame (35.1%; P < .001, P = .003, P < .001) after transection and subsequent CC ligament repair. For posterior rotation, transection of the ACLC decreased the resistance to 5.4% of the intact state. With the CC ligaments intact, the ACLC patch (77.1%) better restored posterior rotational stability than the oblique (35.3%), anterior (48.5%), and x-frame (23.0%) brace repairs (P < .001, P = .002, P < .001). CC ligament transection and subsequent repair demonstrated the ACLC patch (41.0%) to have improved stability when compared with the oblique (16.0%), anterior (14.0%), and x-frame (12.7%) repairs (P = .006, P = .003, P = .002).

CONCLUSION

ACLC reconstruction with a dermal allograft better restored native posterior rotational stability than other brace constructs, with translational stability similar to the oblique and anterior brace technique at the time of surgery.

CLINICAL RELEVANCE

Horizontal stability of the AC joint is primarily controlled by the ACLC. Inability to restore AC joint biomechanics can result in persistent posterior instability and lead to functional impairment.

High grade acromioclavicular injury: Comparison of arthroscopic assisted acromioclavicular joint fixation and anatomic acromioclavicular joint reconstruction

Background

Injuries to the acromioclavicular (AC) joint disrupting the AC and Coracoclavicular (CC) ligaments could lead to loss of clavicular strut function. A High-grade AC joint injury remain challenging because of highly variety of treatment and limited evidence exists comparing clinical outcomes and complications after surgery.

Purpose

The purpose of this study was to compare the clinical and radiological outcome after arthroscopic assisted acromioclavicular Joint fixation and anatomic acromioclavicular joint reconstruction.

Study design

Retrospective Clinical Cohort Study.

Methods

Twenty-nine patients with a high grade (Rockwood Type III-V) Acromioclavicular Joint Injury, operatively treated with arthroscopic assisted acromioclavicular joint fixation and anatomic acromioclavicular joint reconstruction from 2012 to 2018. The clinical assessment consists of Specific AC Score (SACS) and Nottingham Score. The radiographic evaluations were performed to evaluate the stability of reduction and the complications are assessed.

Results

There were a significant different between groups with AC joint reconstruction and fixation group (20 vs. 8, p < 0.005) and (19 vs. 10, p < 0.005) in SAC score and Nottingham score, respectively. There were no significant different in CC dstance between two groups. At the last follow up 6 patient develop loss of reduction with CC percentage >50% in AC joint fixation. Complication developed in 5 patients (17%) including 2 mild osteolysis, 1 superficial infection, 1 implant failure, and 1 clavicle fracture.

Conclusion

Anatomic AC joint reconstruction was associated with functional and radiologic benefits and better restored the stability.

Optimal Management of Acromioclavicular Dislocation: Current Perspectives

Injuries to the acromioclavicular (AC) joint are common and mostly involve younger, male individuals. Whereas the majority of AC joint dislocations can be treated nonoperatively with a trial of immobilization, pain medication, cryotherapy, and physiotherapy, there are patients that do not respond well to conservative management and may require surgical treatment. Identifying and treating these patients according to the type and chronicity of AC joint dislocation is paramount. To date, a myriad of surgical techniques have been proposed to address unstable AC joint dislocations and are indicative of the uncertainty that exists in optimal management of these injuries. Historically research has focused on the restoration of the coracoclavicular ligament complex. However, recently the importance of the acromioclavicular capsule and ligaments has been emphasized. This review aims to provide the reader with an overview of current treatment strategies and research, as well as future perspectives.

Reconstruction of the Acromioclavicular Ligament Complex Using Dermal Allograft: A Biomechanical Analysis

PURPOSE

To analyze the posterior translational and rotational stability of the acromioclavicular (AC) joint following reconstruction of the superior acromioclavicular ligament complex (ACLC) using dermal allograft.

METHODS

Six fresh-frozen cadaveric shoulders were used (mean age of 65.3 ± 6.9 years). The resistance force against posterior translation (10 mm) and torque against posterior rotation (20°) was measured. Specimens were first tested with both the intact ACLC and coracoclavicular ligaments. The ACLC and coracoclavicular ligaments were then transected so simulate a Type III/V AC joint dislocation. Each specimen then underwent 3 testing conditions, performed in the following order: (1) ACLC patch reconstruction alone, (2) ACLC patch with an anatomic coracoclavicular reconstruction (ACCR) using semitendinosus allograft, and (3) the transected ACLC with an ACCR only. Differences in posterior translational and rotational torque across testing conditions were analyzed with a one-way repeated analysis of variance analysis.

RESULTS

Mean resistance against posterior translation in the intact condition was 65.76 ± 23.8 N. No significant difference found between the intact condition compared with specimens with the ACLC-patch only (44.2 ± 11.3 N, P = .06). The ACCR technique, when tested alone, had significantly less posterior translational resistance compared with the intact condition (38.5 ± 8.94 N, P = .008). ACLC patch in combination with an ACCR was closest in restoring native posterior translation (57.1 ± 19.2 N, P = .75). For rotational resistance, only the addition of the ACLC patch with an ACCR (0.51 ± 0.07 N-m) demonstrated similar torque compared with the intact joint (0.89 ± 0.5 N-m, P = .06).

CONCLUSIONS

The ACLC-patch plus ACCR technique was able to closest restore the percent of normal posterior translational and rotational stability.

CLINICAL RELEVANCE

Recurrent posterior instability of the AC joint is a potential complication after coracoclavicular reconstruction surgery. In the in vitro setting, this study demonstrated increased AC joint stability with the addition of an ACLC reconstruction using dermal allograft.

Acromioclavicular joint reconstruction: an additional acromioclavicular cerclage does not improve horizontal stability in double coraco-clavicular tunnel technique

PURPOSE

Horizontal instability-especially in the posterior plane-is a common problem after acromioclavicular joint injuries. The purpose was to compare the stability of a single coraco-clavicular tunnel technique and a double coraco-clavicular tunnel technique for coraco-clavicular ligament reconstruction and to examine the influence of an additional acromioclavicular cerclage on the horizontal stability in the acromioclavicular joint.

METHODS

21 acromioclavicular joints of human cadaveric shoulders were randomly assigned to the following groups: single coraco-clavicular tunnel technique with horizontal augmented acromioclavicular cerclage (SCT + AC); double coraco-clavicular tunnel technique (DCT); double coraco-clavicular tunnel technique and acromioclavicular cerclage (DCT + AC). The specimens underwent cyclic horizontal testing and were recorded using a 3D optical measuring system.

RESULTS

The displacement and the increase in displacement in relation to the displacement after precondition for SCT + AC were significantly higher after every measured amount of cycles than for DCT (p₁₀ = 0.0023; p₅₀₀₀ = 0.0012) and DCT + AC (p₁₀ = 0.0006; p₅₀₀₀ = 0.0012). There was no significant difference in the total displacement, or in the increase in total displacement between double coraco-clavicular tunnel reconstructed groups with and without additional acromioclavicular cerclage.

CONCLUSION

Double coraco-clavicular tunnel technique with and without additional acromioclavicular cerclage results in a significant higher stability regarding the horizontal plane in comparison to single coraco-clavicular tunnel technique with acromioclavicular cerclage. Based on the results of this biomechanical in vitro study, the use of an additional acromioclavicular cerclage with single coraco-clavicular tunnel technique may not be indicated in most cases. The effect of an additional acromioclavicular cerclage seems to be negligible, at least in presence of a double-coraco-clavicular tunnel technique reconstruction. Techniques of AC joint reconstruction should focus on the use of double coraco-clavicular tunnel devices.

The importance of biomechanical properties in revision acromioclavicular joint stabilization: a scoping review

PURPOSE

Treatment of failed primary reconstruction of the unstable acromioclavicular (AC) joint remains challenging for orthopaedic surgeons. When approaching revision cases, the reason for failure has to be precisely identified. The purpose of this manuscript was to perform a critical review of the literature regarding treatment options for failed AC joint stabilization techniques and to provide a treatment algorithm for salvage procedures.

METHODS

A thorough search included electronic databases for articles published up to April 15th, 2019. Inclusion criteria were set as (1) studies that reported on clinical outcomes following surgical or conservative treatment of AC joint dislocation; (2) studies reporting on failure or complications of primary treatment; (3) chronic instabilities caused by delayed or secondary treatment as well as (4) revision and salvage procedures.

RESULTS

The search strategy identified a total of 3269 citations. The final dataset comprised 84 studies published between 1954 and 2019. A total of 5605 patients (9.63% females) were involved with a mean age of 34.5 years. Overall, complication rates varied between 5 and 88.9% in patients with AC joint instability.

CONCLUSION

In the current literature, evidence for treatment of revision AC joint instability is still lacking, however, surgical treatment continues to evolve. The importance of failure analysis and clinically relevant algorithms were highlighted in this review. Adequately restoring native joint biomechanics is needed for ensuring an optimal healing environment that will translate into patient satisfaction and long-term stability.

LEVEL OF EVIDENCE

V.

Functional and Radiographic Outcomes After Anatomic Coracoclavicular Ligament Reconstruction for Type III/V Acromioclavicular Joint Injuries

Background

Acromioclavicular (AC) joint separation is a common injury. The anatomic coracoclavicular ligament reconstruction (ACCR) technique is a viable treatment option, designed to restore the native joint anatomy.

Purpose

To evaluate the clinical and radiographic outcomes of patients undergoing ACCR for the treatment of type III and V AC joint injuries with a minimum 2-year follow-up.

Study Design

Case series; Level of evidence, 4.

Methods

A retrospective chart review was performed on prospectively collected data. Patients who underwent ACCR for type III or V AC joint injuries between January 2003 and December 2015 were analyzed. Clinical outcome measures included the American Shoulder and Elbow Surgeons (ASES) score, Rowe score, Simple Shoulder Test (SST), and Constant-Murley (CM) score. To determine the clinical relevance of the ASES score, the minimal clinically important difference (MCID), substantial clinical benefit (SCB), and patient acceptable symptomatic state (PASS) were used. The pre- and postoperative coracoclavicular distance (CCD) and side-to-side difference in the CCD were measured for radiographic analysis.

Results

A total of 43 patients (22 acute, 21 chronic) were included in the study. The mean patient age was 43.4 ± 11.4 years, with a mean follow-up of 3.4 years (range, 2.0-7.5 years). With regard to the ASES score, 92% of patients achieved the MCID, 81% achieved the SCB, and 49% reached or exceeded the PASS. There was no significant difference when stratifying by type (III vs V) or chronicity (acute vs chronic) of injury (both P > .05). The Rowe score improved from 66.6 ± 15.9 preoperatively to 88.6 ± 12.3 postoperatively, the CM score from 61.6 ± 18.8 to 87.4 ± 15.1, and the SST score from 6.2 ± 3.6 to 9.4 ± 3.7 (all P < .001). The postoperative side-to-side difference in the CCD was 3.1 ± 2.7 mm, with type III injuries (2.4 ± 1.9 mm) showing significantly lower measurements compared with type V (4.2 ± 3.4 mm) (P = .02). No significant trend was found between joint reduction and the improvement in clinical outcomes (P > .05).

Conclusion

Patients undergoing ACCR for acute and chronic type III and V AC joint injuries maintained significant improvement in clinical and radiographic outcomes at a minimum 2-year follow-up. Additionally, 81% of patients reached the SCB after surgical reconstruction.