Biomechanical comparison of coracoclavicular reconstructive techniques

Anterior and coracoid base tunnel location combined with single -or double clavicular tunnel techniques using double-button fixation for coracoclavicular ligament reconstruction both restore horizontal stability. A biomechanical cadaver study

BACKGROUND

The placement of clavicle tunnels in coracoclavicular ligament reconstruction is well established, but the optimal position of the coracoid tunnel remains unclear. This study aimed to investigate how the coracoid tunnel's position affects horizontal stability during coracoclavicular ligament reconstruction using a double-button technique.

METHODS

Fifteen fresh frozen shoulder cadaver specimens were tested under various conditions: intact coracoclavicular ligaments, disrupted ligaments, and reconstructions with a single coracoid and clavicle tunnel or double clavicle tunnels. The coracoid tunnel was positioned at the coracoid base 1/9, and 1/5 anterior to the base. Specimens underwent displacement-controlled loading, with 2D motion analysis conducted on captured digital images using TEMA motion analysis.

FINDINGS

Mean displacement for intact coracoclavicular ligaments was 1.61 ± 0.92 mm, and 3.69 ± 1.09 mm for disrupted ligaments. For reconstructed conditions, displacements were as follows: Single-Tunnel Base (1.87 ± 0.64 mm), Single-Tunnel 1/9 (2.54 ± 1.13 mm), Single-Tunnel 1/5 (2.62 ± 1.17 mm), Double-Tunnel Base (1.25 ± 0.73 mm), Double-Tunnel 1/9 (2.03 ± 1.22 mm), and Double-Tunnel 1/5 (1.88 ± 1.20 mm). Differences among intact, reconstructed, and disrupted states were statistically significant (p = 0.01-0.0001), with all reconstruction techniques restoring horizontal displacement near the intact state.

INTERPRETATION

At point zero both single coracoid tunnel and single- and double-clavicle tunnel restored horizontal displacement to its intact state. Coracoid tunnel placement anterior to the base of the coracoid did not influence horizontal displacement but single coracoid at the coracoid base and single clavicle tunnel resulted in the most anatomic reconstruction. Single coracoid tunnel at the base and double-clavicle resulted in the most stable reconstruction.

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 .

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

BACKGROUND

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

PURPOSE

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

STUDY DESIGN

Controlled laboratory study.

METHODS

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

RESULTS

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

CONCLUSION

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

CLINICAL RELEVANCE

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

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.

Coracoid process transfer and distal clavicle resection for chronic acromioclavicular separation

Background

Dewar's procedure for transferring the coracoid process with the short head of biceps and coracobrachialis was reported in 1965 for treatment of both acute and chronic acromioclavicular (AC) joint separation, but little contemporary literature exists around the procedure. We report the clinical results of coracoid process transfer with excision of the lateral end of the clavicle for chronic AC joint separation.

Methods

Fifty-one patients (39 men and 12 women, mean age 46 ± 16 years) were included in the study. Clinical outcomes were evaluated using the American Shoulder and Elbow Surgeons and the Japanese Orthopaedic Association scores, as well as by measuring active range of motion in the shoulder, before-after (minimum follow-up time of 24 months [27 ± 3 months]) surgery. Plain radiographs were used to examine stability of the AC joint and bone union of the graft.

Results

The mean American Shoulder and Elbow Surgeons and Japanese Orthopaedic Association scores increased (from 61 ± 14 to 91 ± 6, and from 54 ± 9 to 89 ± 8, respectively) at the time of final follow-up. There were no differences in active elevation and external rotation between before-after operation. Six patients whose grafts were fractured or displaced showed complete or partial loss of reduction of the AC joint.

Conclusion

By transferring the coracoid process, the AC joint regained stability after chronic joint separation. Although potential complications related to the graft still need to be addressed, Dewar's procedure and lateral clavicle resection could be a reliable treatment of chronic AC joint separation.

Computed Tomography‐Based Determination of the Optimal Locations of Bone Tunnels for Coracoclavicular Ligament Reconstruction

Objective

An agreement has not been reached on optimal locations of bone tunnels for coracoclavicular ligament (CCL) reconstruction for acromioclavicular joint dislocation (ACD). This study aims to identify the convergence point (cP) between the coracoid process and clavicle in the Chinese population to assist surgeons in reconstructing the CCL for ACD.

Methods

From 2014 to 2020, 483 CT scans of the shoulders of 270 male and 213 female patients (247 right and 236 left shoulders) were collected and studied retrospectively. By overlapping the images of the transverse plane of the coracoid process and the clavicle, points a and b, and the midpoint ab (cP) were determined. Then, a series of parameters through point cP in the transverse and sagittal planes were measured. In the transverse plane this included the distance from point cP to the tip of the coracoid process (cP‐cor),the distance between the medial and lateral margins of the coracoid process through point cP (Med‐lat cor), the distance from point cP to the acromioclavicular joint (cP‐ac), and the distance between the anteroposterior margin of the clavicle through point cP (Ap‐clav). In the sagittal plane, this included the craniocaudal segment of the coracoid process (Cc‐cor), and the craniocaudal segment of the clavicle (Cc‐clav). The sex and side differences of these measurements were also analyzed by two radiologists.

Results

Based on the following measurements, point cP was determined. For male patients, the cP‐cor was 28.02 ± 3.43 mm, Med‐lat cor was 22.78 ± 2.80 mm, Cc‐cor was 15.11 ± 2.13 mm, cP‐ac was 29.24 ± 3.84 mm, Ap‐clav was 18.27 ± 2.46 mm, and Cc‐clav was 10.09 ± 1.56 mm. For female patients, the cP‐cor was 25.20 ± 3.26 mm, Med‐lat cor was 20.21 ± 2.97 mm, Cc‐cor was 13.03 ± 1.77 mm, cP‐ac was 26.66 ± 3.45 mm, Ap‐clav was 16.10 ± 2.30 mm, and Cc‐clav was 8.91 ± 1.40 mm. All the measurements of female patients were lower than those of male patients (p < 0.01). Between sides, only cP‐ac of the left shoulders was significantly lower than those of the right shoulders (p < 0.05), with no significant differences in other parameters between sides (p > 0.05).

Conclusion

The results of this study identified the locations of bone tunnel‐cP in the coracoid process and clavicle for the CCL reconstruction in ACD. Moreover, the findings indicated that surgeons should be more cautious in operating on female patients and that the cP‐ac of left shoulders should be set lower than that of right shoulders.

Combination of Clavicular Hook Plate with Coracoacromial Ligament Transposition in Treatment of Acromioclavicular Joint Dislocation

OBJECTIVE

To evaluate the clinical efficacy of Arbeitsgemeinschaft für Osteosynthesefragen (AO) clavicular hook plate (CHP) combined with coracoacromial ligament transposition for Rockwood III-V dislocation of AC joint, providing an alternative choice for AC joint dislocation treatment.

METHODS

Twenty-five patients diagnosed with Rockwood III-V dislocation of acromioclavicular (AC) joint, including 18 males and seven females, aged 43.5 ± 2.4 years old on average, who had undergone open reduction and AO CHP in combination with coracoacromial (CC) ligament transposition between January 2010 and December 2015, were retrospectively analyzed. Among them, 17 cases were diagnosed as type III, five cases were type IV, and three cases were type V. The surgery mainly included three main steps: bone flap incision, drilling in the clavicle, and hook plate fixation and AC joint reposition. The treatment efficacy was evaluated through clinical examinations and imaging studies for the shoulder joint, including gross observation and measuring coracoid clavicle distance (CC-Dist) using orthophoria X-ray before and 1 year after the surgery, and University of California (UCLA) shoulder rating scale.

RESULTS

All the patients were followed up three to four times in 18 months (12-24 months) on average, and the UCLA rating results showed that there were 17 excellent cases (68%), five good cases (20%), and three fair cases (12%). The CC-Dist values after the surgery reduced to 9.7 ± 0.7 mm, which was significantly (P < 0.05) lower compared to that before the surgery (15.8 ± 1.6 mm). Most (88%) of the cases showed almost normal joint function and good anatomical arrangement of the acromioclavicular joint, without any secondary dislocation, and for them, 12 ± 2 weeks on average were needed to regain the normal function of shoulder joint movement.

CONCLUSION

Due to the stable fixation, fewer complications, and satisfactory therapeutic effect with great clinical value, the combination of AO CHP and CC ligament transposition is expected to be used for treating Rockwood III-V dislocation of AC joint.

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.

Modified Weaver-Dunn Technique Using Transosseous Bone Tunnels and Coracoid Suture Augmentation

INTRODUCTION

A modified Weaver-Dunn procedure for the management of acromioclavicular joint injuries that uses transosseous bone tunnels and coracoid suture augmentation is described with associated clinical results.

METHODS

A retrospective review of 39 consecutive patients who underwent a primary mWD procedure by a single surgeon from January 2013 to July 2019 was conducted. Patient charts and radiographs were reviewed for clinical course, complications and management, and radiographic evaluation. Satisfaction, American Shoulder and Elbow Surgeons (ASES), Single Assessment Numeric Evaluation, and Simple Shoulder Test scores were obtained.

RESULTS

A total of 28 patients (72%) with a mean follow-up of 37.5 (12 to 84 months) and a mean age of 44.3 ± 15.1 years were included. Postoperative ASES, Simple Shoulder Test, Single Assessment Numeric Evaluation, and satisfaction scores were 90.6 ± 14.2, 11.1 ± 1.5, 87.3 ± 10.2, and 4.4 ± 1.2 (out of 5), respectively, with a significant improvement in ASES of 42.2 ± 21.8 points (P < 0.001). All patients had significant decrease in coracoclavicular distance (P < 0.001). Three patients (10.7%) had complications, with two (7.1%) requiring additional surgery.

CONCLUSION

Excellent functional and radiographic outcomes can be achieved with this modified Weaver-Dunn technique. Complication and revision rates are comparable with those that are found in the literature.

LEVEL OF EVIDENCE

Level IV, Retrospective cohort study.

Biomechanical testing of three coracoclavicular ligament reconstruction techniques with a 3D printing navigation template for clavicle-coracoid drilling

Background

The identification and precise clavicle-coracoid drilling during coracoclavicular (CC) ligament reconstruction for acromioclavicular (AC) joint dislocation require a high level of experience and surgical skills. Furthermore, the improvement of flexible fixation, such as Endobutton techniques for CC ligament reconstructions is ongoing. We have developed a 3D printing technique navigation template for clavicle-coracoid drilling and a novel implant for the reconstruction. This study aimed to determine the efficiency of the navigation template for clavicle-coracoid drilling and to evaluate the biomechanical performance of the novel CC ligament reconstruction technique.

Methods

A total of 24 fresh-frozen human cadaveric shoulders were randomly assigned to 1 of 3 reconstruction groups or a control group: TightRope, Triple Endobutton, and the Adjustable Closed-Loop Double Endobutton technique. Computed tomography scans, navigation template designs, and 3D printing were performed for the shoulders. Then, AC joint dislocation was simulated in the reconstruction groups, and 3 CC ligament reconstruction techniques were operated via the 3D printing template separately. Furthermore, biomechanical protocols including the translation test (load from 5 to 70 N) and the load-to-failure test were performed to characterize the behaviors and strengths. One-way ANOVA test analyzed differences in displacement under the translation load and the load at failure.

Results

CC ligament reconstructions were performed successfully along with the 3D printing navigation template in the 3 reconstruction groups. During the translation test, no significant difference was found in displacements among the 4 groups. Meanwhile, the mean load of all reconstruction groups at failure (Adjustable Closed-Loop Double Endobutton, 722.1620 N; TightRope, 680.4020 N; Triple Endobutton, 868.5762 N) was significantly larger than the control group (564.6264 N, P<0.05). The Triple Endobutton group had the maximum load at failure (P<0.05), however, no significant difference was noticed between the other 2 reconstruction groups (P>0.05).

Conclusions

The 3D printing navigation template may become helpful and reliable for AC joint dislocation surgery. Among the 3 CC ligament reconstruction techniques, the Triple Endobutton technique has the best strength in terms of biomechanics, while the biomechanical strength of the Adjustable Closed-Loop Double Endobutton technique is reliable in comparison with the TightRope technique.

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

BACKGROUND

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

METHODS

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

FINDINGS

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

INTERPRETATION

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

Risk of Iatrogenic Axillary Nerve Injury During Acromioclavicular Joint Reconstruction

Anatomical reconstruction of the coracoclavicular ligaments involves drilling the base of the coracoid or looping a graft around it, placing the axillary nerve at risk for injury. Rockwood type V acromioclavicular (AC) separation injuries involve disruption of the AC joint capsule and coracoclavicular ligaments, resulting in inferomedial displacement of the scapulohumeral complex and alteration of the normal anatomical relations of the shoulder girdle structures. This study evaluated the effect of Rockwood type V AC separation on the anatomical relation of the axillary nerve to the coracoid base. Ten shoulders of 6 adult human cadavers were dissected to determine the dimensions of the coracoid. A digital caliper was used to measure the coracoclavicular distance and the minimal distance between the coracoid base and the axillary nerve. A Rockwood type V AC separation was created by transecting the AC joint capsule and coracoclavicular ligaments, and applying 15 kg of longitudinal tension to the upper extremity. Changes in the distance between the coracoid base and the axillary nerve were measured. Mean width, length, and thickness of the coracoid was 15.05±0.93 mm, 23.1±1.75 mm, and 11.88±1.33 mm, respectively. Mean distance between the coracoid base and the axillary nerve was 26.0±3.9 mm. After simulated Rockwood type V AC separation, mean distance was 22.0±3.4 mm; this difference was statistically significant (P=.0263; 95% CI, 2.0-5.9 mm). The axillary nerve is closer to the coracoid base during simulated Rockwood type V AC separation than previously reported in the orthopedic literature. Anatomical reconstruction of the coracoclavicular ligaments for Rockwood type V AC separation presents a higher risk for axillary nerve iatrogenic injury than previously reported. [Orthopedics. 2021;44(1):e68-e72.].

Arthroscopic Coracoclavicular Ligament Stabilization Using Coracoid Cortical Suspension in Acute Acromioclavicular Joint Injury; Precision of Drill Tunnel

Acute acromioclavicular joint separation is a common injury of the shoulder. There are several methods for treating this condition; however, there is no gold standard established. Herein, we propose an arthroscopic method for the treatment of acute acromioclavicular joint separation using a simple cortical suspension device at the coracoid base via a transclavicular-transcoracoidal tunnel and tieing the suture at the clavicle. This method has the advantages of making a precision drilling tunnel using small implants and small stab incisions, with better cosmetic results and less implant irritation.

Review of Weaver and Dunn on treatment of acromioclavicular injuries, especially complete acromioclavicular separation

This classic discusses the original publication "Treatment of acromioclavicular injuries, especially complete acromioclavicular separation" by Weaver and Dunn, which collaborated to develop a technique for acromioclavicular joint reconstruction in 1972. Their surgical technique described resection of 2 cm of the distal clavicle and transfer of the acromial end of the coracoacromial ligament into the medullary canal of the distal clavicle. (modified) Weaver-Dunn procedures have been regarded as one of the most effective techniques to treat complete acromioclavicular joint dislocation for a long time. However, anatomic reconstructions have taken over this position since recent biomechanical studies have demonstrated superior results. Although the Weaver-Dunn procedure has fallen out of favour, it remains of historical significance. For this reason, this review will comprise the historical overview of the Weaver-Dunn procedure, the men behind the eponym and the clinical implication then and now.

Radiographic features and complications following coracoclavicular ligament reconstruction

OBJECTIVE

To report radiographic features and complications of coracoclavicular ligament reconstruction and the association of radiographic features with symptomatology.

MATERIALS AND METHODS

Retrospective picture archiving and communication system query (1/2012-8/2018) identified subjects with prior coracoclavicular ligament reconstruction. Post-operative radiographs were reviewed with attention to the following: (1) acromioclavicular alignment, (2) coracoclavicular width, (3) distal clavicular osteolysis, (4) osseous tunnel widening, and (5) hardware complication or fracture. Medical records were reviewed to determine purpose of imaging follow-up (symptomatic versus routine). Statistical analysis determined associations between binary features and outcomes, and inter-reader agreement.

RESULT

Review of 55 charts identified 32 subjects (23 male, 9 females; age range 24-64; imaged 1-34 months following surgery) meeting inclusion criteria. Loss of acromioclavicular reduction was the most common imaging finding (n = 25, 78%), with 76% progressing to coracoclavicular interval widening. Distal clavicular osteolysis was seen in 21 cases (66%) and was significantly associated with loss of acromioclavicular joint reduction (p = 0.032). Tunnel widening occurred in 23 patients (82%) with more than one follow-up radiograph. Six (19%) had hardware complication or fracture. No radiographic feature or complication had significant correlation with symptomatology (p values 0.071-0.721). Inter-reader agreement was moderate to substantial for coracoclavicular interval widening and hardware complication, fair to substantial for tunnel widening, and fair to moderate for loss of acromioclavicular reduction and distal clavicular osteolysis.

CONCLUSION

Loss of acromioclavicular joint reduction, coracoclavicular interval widening, distal clavicular osteolysis, and tunnel widening are common radiographic features after coracoclavicular ligament reconstruction; however, they do not necessarily correlate with symptomatology.

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.

Comparison of two methods for coracoclavicular ligament reconstruction: A finite element analysis

OBJECTIVE

This study aimed to compare two different tendon grafting techniques for coracoclavicular ligament reconstruction from the data obtained using finite element analysis.

METHODS

Three different finite element models of the shoulder girdle were formulated using computerized tomography images: the reference model, coracoid loop technique (CLT), and drilling technique (DT) model. In all these models, forces were applied to the clavicle along three axes (x, y, and z) of the trapezius and sternocleidomastoid muscles. Thereafter, data regarding the loading values of the tendon grafts, loads on the coracoid base, and coracoclavicular vertical distance were measured.

RESULTS

While the reference model yielded the lowest values for all the loading conditions as well as the shortest coracoclavicular distance, the DT model demonstrated the highest values for all the loading conditions and the largest coracoclavicular distance.

CONCLUSION

Different tendon grafting techniques may offer different loading values on both bone surface and tendon graft during coracoclavicular ligament reconstruction. The drilling technique may be associated with increased loading on the tendon graft and bone surface, causing further loss of reduction and consequent complications.

Anatomic and non-anatomic reconstruction improves post-operative outcomes in chronic acromio-clavicular instability: a systematic review

PURPOSE

To systematize the surgical outcomes of anatomic and non-anatomic reconstruction in patients with chronic acromio-clavicular joint (ACJ) instability and determine which technique is superior.

METHODS

This review was conducted according to the PRISMA guidelines. PubMed and Cochrane Library databases were searched up to April 30th, 2018 for original articles that assessed the outcomes of one or more surgical techniques of anatomic and non-anatomic reconstruction in patients with chronic ACJ instability. The Methodological Index for Non-randomized Studies (MINORS) was used to assess study quality. Pre-to-post meta-analysis was performed for both anatomic and non-anatomic reconstructions.

RESULTS

Twenty-eight studies were included comprising 799 patients (mean age of 36.6 years old and 84% males) with a mean follow-up of 34.6 months (range 13 to 74). Surgical techniques included anatomic (tendinous or synthetic grafts/constructs) and non-anatomic reconstruction (Weaver-Dunn or Modified Weaver-Dunn, conjoined tendon transfer, or temporary hook plate). There were significant pre-to-post improvements on the constant score with an average improvement ranging from 11.1 to 50.7 (p < 0.01). Average failure rate was 7.6% (7.5% for anatomic and 8.5% for non-anatomic reconstruction). Non-comparative studies had a mean MINORS score of 9 points (out of 16) and comparative studies 17 (out of 24) with excellent interrater agreement (k = 0.910).

CONCLUSION

Both anatomic and non-anatomic ACJ reconstructions provide significant post-operative improvements, but definitive conclusions on optimal technique remain elusive. Notwithstanding, comparative studies support the use of anatomic ACJ reconstruction which should be preferably used. However, until superiority is demonstrated by robust studies, surgeons should supplement their decision-making with experience and patient preference.

LEVEL OF EVIDENCE

IV.

Biomechanical evaluation of acromioclavicular joint reconstructions using a 3-dimensional model based on the finite element method

BACKGROUND

This study aims to evaluate the influence of stabilization of acromioclavicular (AC) joint dislocation through the modified Weaver-Dunn technique and coracoclavicular (CC) ligaments using the finite element method. The goal is to determine which surgical technique allows behavior that is most similar to the joint, guaranteeing the necessary stability without restricting joint movements for the considered conditions.

METHODS

The analysis is based on the three-dimensional finite element models. The control group of this study is represented by a three-dimensional model of the whole structure based on finite element methods.

FINDINGS

The finite element models showed the stress and displacement values found in the intact acromioclavicular joint and surgical procedures. It was concluded that transferring the coracoacromial ligament to stabilize the acromioclavicular joint did not have a positive impact on the outcome.

INTERPRETATION

The finite element analysis on the treatment of acromioclavicular dislocation presented here provides medical teams with new parameters for choosing a suitable surgical procedure in the occurrence of acromioclavicular dislocation. The development and validation of the finite element models allow the variation of the conditions and enables different surgical configurations to be simulated.

Current Concepts in the Operative Management of Acromioclavicular Dislocations: A Systematic Review and Meta-analysis of Operative Techniques

BACKGROUND

Acromioclavicular (AC) instability is a frequent injury affecting young and athletic populations. Symptomatic, high-grade dislocations may be managed by a myriad of operative techniques that utilize different grafts to achieve reduction. Comparative data are lacking on the ability of these techniques to achieve excellent patient outcomes and stable AC reduction and to minimize complications.

PURPOSE

To systematically review the outcomes and complications of different techniques of AC joint reconstruction.

STUDY DESIGN

Systematic review and meta-analysis.

METHODS

The MEDLINE, Scopus, Embase, and Cochrane Library databases were accessed to perform a systematic review of the scientific literature from 2000 to 2018 using the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) criteria with the following keywords: "acromioclavicular" and "reconstruction." Included articles were evaluated for loss of reduction, complication rate, revision rate, and change in coracoclavicular distance. Articles were stratified by graft and surgical material used: suture only, Endobutton with suture, TightRope, GraftRope, synthetic artificial ligament, tendon graft, and Weaver-Dunn coracoacromial ligament transfer. These outcomes were pooled using a random-effects model and stratified by surgical technique and arthroscopic versus open reconstruction.

RESULTS

Fifty-eight articles were included in the analysis, with 63 homogeneous populations composed of 1704 patients. The mean age was 37.1 years (range, 15-80 years) with a mean follow-up of 34.3 months (range, 1.5-186 months). The overall failure rate was 20.8% (95% CI, 16.9%-25.2%). The overall pooled complication rate was 14.2% (95% CI, 10.5%-18.8%). The most common complications were infection (6.3% [95% CI, 4.7%-8.2%]), fracture to the coracoid or distal clavicle (5.7% [95% CI, 4.3%-7.6%]), and hardware/button failure (4.2% [95% CI, 3.1%-5.8%]). There were no differences between arthroscopic and open techniques in regard to loss of reduction (P = .858), overall complication rate (P = .774), and revision rate (P = .390). Open surgery had a greater rate of clavicular/coracoid fractures than arthroscopic surgery (P = .048). Heterogeneity, best assessed from the pooled loss of reduction, was measured as I² = 64.0%.

CONCLUSION

Open and arthroscopic AC joint reconstruction techniques have no differences in loss of reduction, the complication rate, and the revision rate based on the available literature. Complications are significant, and profiles vary between surgical techniques, which should be evaluated in the decision making of selecting the technique.

Radiographic appearance of the distal clavicle in relation to the acromion after acromioclavicular joint reconstruction using a braided polyester mesh

ACJ stabilization using a braided polyester mesh has become popular in ACJ injuries. However, concerns have been raised about excessive anterior clavicle displacement. The purpose of this study was to report radiographic position of the distal clavicle in relation to the acromion after ACJ reconstruction using this device immediately postoperative and after 6 months follow-up compared with a healthy control group. Thirty-eight patients with ACJ instability treated with a braided polyester mesh were compared within group (pre-/postoperatively) and between groups (with age/sex matched controls). Biplane radiographic measurements by 2 observers were made preoperatively, immediate postoperatively and at 6 months follow-up. Inter-observer reliability was assessed and clinical outcome scores were recorded. ACJ stabilization significantly reduced vertical displacement immediately postoperatively (13.8 ± 4.2 to 3.5 ± 5.5 mm; p < 0.0001) towards controls (1.7 ± 2.3 mm,p < 0.0873). Slight further superior displacement (4.4 mm) occurred at 6 months follow-up compared to immediately postoperative (p = 0.0029) and 6.2 mm more than mean controls (p < 0.0001). In the axial plane, significant early reduction of posterior displacement was achieved (10.3 ± 8.0 to 1.1 ± 5.1 mm,p = 0.0240) and the clavicle settled back to a more posterior position at 4.5 ± 6.7  mm at 6 months post-surgery (p = 0.3062). At both time points, posterior displacement was comparable with the controls (3.4 ± 3.0 mm,p = 0.4371 postoperative, p = 0.563 at 6 months follow-up). Excessive anterior displacement has been observed in 2 of the 5 available axial radiographs early postoperative and in 4 of 14 available axial radiographs at 6 months. Constant, Oxford Shoulder and Nottingham Clavicle scores significantly improved (25 ± 12 to 43 ± 7:p < 0.0001, 46 ± 27 to 80 ± 19:p = 0.0038, 53 ± 14 to 80 ± 17:p < 0.0001). ACJ stabilization using a braided polyester device in ACJ instability is effective at reducing both superior and posterior clavicle displacement with excellent clinical outcome. Overcorrection in the axial plane seems to occur, however this is of no clinical and radiographic significance. Posterior displacement is significantly reduced towards control values at 6 months follow-up.

Surgical Volume and Postoperative Complications of Acromioclavicular Joint Separations: Analysis of the ABOS Part II Examination

BACKGROUND

High-grade acromioclavicular (AC) joint separations are relatively rare injuries that are often treated surgically, yet more information is needed about the risks of various surgical procedures in terms of considering and counseling patients regarding operative versus nonoperative treatment.

PURPOSE

To calculate whether the volume of surgical treatment of AC joint separations increased over a recent 12-year period; to examine the nature and frequency of complications, reoperations, and readmissions associated with these procedures; and to assess whether patient- and surgeon-specific factors or surgical technique affected these rates.

STUDY DESIGN

Cross-sectional study; Level of evidence, 3.

METHODS

The American Board of Orthopaedic Surgery (ABOS) database for orthopaedic surgeons taking the Part II examination was reviewed from 2005 to 2016 to identify surgical treatment of AC joint separations. The authors calculated the percentage of all surgical cases in the ABOS database and rates of complications, reoperations, and readmissions. Association of these sequelae with patient- and surgeon-specific factors and surgical techniques was assessed.

RESULTS

There was no difference in the number or percentage of cases per year over the study period. There was an overall complication rate of 24.5%, a reoperation rate of 7.3%, and a readmission rate of 1.9%. Patients ≥40 years of age had significantly higher complication, reoperation, and readmission rates as compared with patients <40 years of age. There were significant differences in complication, reoperation, readmission, and displacement rates dependent on the type of surgical procedure performed. The highest complication rates were seen with open suspensory fixation, screw fixation, open reduction internal fixation, and arthroscopic coracoclavicular ligament repair or reconstruction. The highest reoperation rates were seen with screw fixation, open reduction internal fixation, and open suspensory fixation.

CONCLUSION

The volume of surgical treatment for AC joint separations did not change significantly over the study period. Complication, reoperation, and readmission rates were dependent on the type of surgical procedure performed and patient age. This information should assist surgeons in discussing risks when considering and counseling patients regarding operative versus nonoperative treatment.

Challenges in Treating Acromioclavicular Separations: Current Concepts

Injuries to the acromioclavicular joint constitute approximately 3.2% of shoulder injuries. Although the overall goal of treatment continues to be return to activity with a pain-free shoulder, the treatment of acromioclavicular joint separations has been fraught with conflict since the earliest reports in both ancient and modern literature. Accurate diagnosis and classification are important to determine the optimal treatment. Nonsurgical therapy remains the mainstay for treatment of low- and most mid-grade injuries, although recent biomechanical and biokinetic data might suggest that patients are more affected than traditionally thought. High-grade injuries often necessitate surgical intervention, although little consensus exists on the timing or technique. New surgical techniques continue to evolve as more biomechanical data emerge and kinematic understanding improves. Challenges associated with management of this injury abound from diagnosis to reconstruction.

Biomechanical evaluation of native acromioclavicular joint ligaments and two reconstruction techniques in the presence of the sternoclavicular joint: A cadaver study

BACKGROUND

Where is over 100 reconstruction techniques described for acromioclavicular (AC) joint reconstruction. Although, it is not clear whether the presence of the sternoclavicular (SC) joint influences the biomechanical properties of native AC ligaments and reconstruction techniques. The purpose of the present study was to investigate the biomechanical properties of native AC joint ligaments and two reconstruction techniques in cadavers with the SC joint still present.

MATERIALS AND METHODS

We tested eight fresh-frozen cadaver hemithoraces for superior translation (70 N load) and translation increment after 1000 cycles (loading from 20 to 70 N) in a controlled laboratory study. There were three testing groups created: native ligaments, the single coracoclavicular loop (SCL) technique, and the two coracoclavicular loops (TCL) technique. Superior translation was measured after static loading. Translation increment was calculated as the difference between superior translation after cyclic and static loading.

RESULTS

Native AC ligaments showed significantly lower translation than the SCL ( p = 0.023) and TCL ( p = 0.046) groups. The SCL had a significantly lower translation increment than native AC ligaments ( p = 0.028). There was no significant difference between reconstruction techniques in terms of translation ( p = 0.865) and translation increment ( p = 0.113).

CONCLUSIONS

Native AC joint ligaments had better static properties than both reconstruction techniques and worse dynamic biomechanical properties than the SCL technique. The SCL technique appeared to be more secure than the TCL technique. The presence of the SC joint did not have an observable influence on test results.

Treatment of Rockwood Type III Acromioclavicular Joint Dislocation

While non-operative treatment with structured rehabilitation tends to be the strategy of choice in the management of Rockwood type III acromioclavicular joint injury, some advocate surgical treatment to prevent persistent pain, disability, and prominence of the distal clavicle. There is no clear consensus regarding when the surgical treatment should be indicated, and successful clinical outcomes have been reported for non-operative treatment in more than 80% of type III acromioclavicular joint injuries. Furthermore, there is no gold standard procedure for operative treatment of type III acromioclavicular joint injury, and more than 60 different procedures have been used for this purpose in clinical practice. Among these surgical techniques, recently introduced arthroscopic-assisted procedures involving a coracoclavicular suspension device are minimally invasive and have been shown to achieve successful coracoclavicular reconstruction in 80% of patients with failed conservative treatment. Taken together, currently available data indicate that successful treatment can be expected with initial conservative treatment in more than 96% of type III acromioclavicular injuries, whereas minimally invasive surgical treatments can be considered for unstable type IIIB injuries, especially in young and active patients. Further studies are needed to clarify the optimal treatment approach in patients with higher functional needs, especially in high-level athletes.

Functional Outcome of Modified Weaver Dunn Technique for Acromioclavicular Joint Dislocation

BACKGROUND

The debate about the ideal surgical procedure for acromioclavicular joint (ACJ) dislocation is still unresolved and newer techniques are being evolved continuously. The present study evaluates functional outcome of ACJ reconstruction using the modified Weaver Dunn procedure.

MATERIALS AND METHODS

35 patients (26 males, 9 females) with ACJ dislocation, between the age group of 18-48 years (mean age 31 years), were operated using modified Weaver Dunn procedure at our center from May 2005 to June 2010. The dominant side was involved in 25 patients (22 right, 13 left). The mean period from the time of injury to the surgery was 14 days (range 4-26 days). All the patients were assessed with Oxford shoulder score and the time required to return to preinjury level was recorded.

RESULTS

At the mean followup of 95 months (range 72-120 months), the mean Oxford Shoulder Score improved from 25 ± 7.2 to 43 ± 6.9. 85% (30 out of 35) patients had satisfactory results, while 15% (5 out of 35) had mild shoulder dysfunction using this scoring system. Five patients had radiological evidence of Grade 2 ACJ subluxation. Out of these five patients, two developed ossification around the coracoclavicular ligament. Three patients had intermittent mild pain without any functional disability, and one had a moderate restriction of shoulder movements.

CONCLUSION

ACJ reconstruction, using the modified Weaver Dunn procedure in ACJ dislocation, is a reproducible procedure and provides a good functional outcome.

Clinical efficacies of coracoclavicular ligament reconstruction using suture anchor versus hook plate in the treatment of distal clavicle fracture

INTRODUCTION

Comparison of clinical efficacies between coracoclavicular ligament reconstruction using autologous gracilis tendon with suture anchor and clavicular hook plate for the treatment of acute Neer type II distal clavicle fracture.

HYPOTHESIS

Both coracoclavicular reconstruction with autologous gracilis tendon and clavicular hook plate could achieve satisfactory results for treating acute Neer type II distal clavicle fracture.

METHODS

Acute Neer type II distal clavicle fracture patients enrolled in this prospective randomized study were divided into the coracoclavicular ligament reconstruction group (using autologous gracilis tendon and suture anchor) and the hook plate group. Clinical outcomes were evaluated by shoulder X-ray, forward flexion, abduction and external rotation angle, Constant-Murley shoulder score and pain Visual Analogue Scale (VAS) at each follow-up for up to 24 months.

RESULTS

The current study enrolled a total of 42 acute Neer type II distal clavicle fracture patients attended our hospital from March 2010 to December 2013. All patients had achieved complete healing and followed up for an average of 26 months (range, 24-38 months). At 3-month and 6-month follow-ups, Constant-Murley score in the ligament reconstruction group was significantly higher (93.8±2.6 vs. 88.7±8.7; 95.9±2.7 vs. 93.0±7.0, P<0.05), while VAS score was poorer than those in the hook plate group (1.6±0.8 vs. 2.5±1.9; 1.1±1.0 vs. 1.6±1.7, P<0.05).

DISCUSSION

Reconstruction with autologous gracilis tendon improved VAS pain score in early postoperation follow-up; while Constant-Murley score and VAS score were significantly improved in the hook plate group after the implant was removed. These suggested that both coracoclavicular reconstruction with autologous gracilis tendon and clavicular hook plate could achieve satisfactory results.

LEVEL OF EVIDENCE

Level II, low-powered prospective randomized trial.

Modified closed-loop double-endobutton technique for repair of rockwood type III acromioclavicular dislocation

Acromioclavicular dislocation (ACD) is a common injury. According to the Rockwood classification, ACD is classified into six types (type I–VI); however, for type III injuries, it remains controversial whether or not operative treatment should be applied. Numerous studies have advocated early surgical treatment to ensure early rehabilitation activities. Thus, the present study aimed to investigate a modified closed-loop double-endobutton technique (MCDT), that may be used to repair Rockwood type III ACD. In the current study, 61 patients with Rockwood type III ACD were enrolled during a period of 5 years at the Affiliated Traditional Chinese Medicine Hospital of Southwest Medical University. Patients were divided into three groups according to the surgical method used, the MCDT group (n=20), the common closed-loop double-endobutton technique (CCDT) group (n=21), and the clavicular hook plate fixation (CHPF) group (n=20). Preoperative and intraoperative information were recorded. Furthermore, the functional scores of injured shoulder were evaluated prior to surgery and following surgery with a 1-year follow-up. Among the three groups, postoperative functional scores were significantly more improved compared with those prior to surgery (P<0.05), and no significant difference was observed regarding the coracoclavicular interval with the 1-year follow-up (P>0.05). Postoperative functional scores in the MCDT and CCDT groups were significantly more improved compared those in the CHPF group (P<0.05). In addition, the duration of surgery in the MCDT group was significantly shorter compared with that in the CCDT group (P<0.05). Furthermore, compared with the CHPF group, the incision length was significantly shorter with reduced hemorrhage in the MCDT group (P<0.05). In conclusion, the results of the current study suggest that MCDT is more simple, convenient and efficient compared with CCDT, and is worth popularizing.

Medialized Clavicular Bone Tunnel Position Predicts Failure After Anatomic Coracoclavicular Ligament Reconstruction in Young, Active Male Patients

BACKGROUND

Recent radiographic data have suggested that medialized conoid tunnel placement greater than 25% of absolute clavicular length is correlated with early failure after anatomic coracoclavicular ligament reconstructions. A comparison with a larger active duty military cohort of clinical and radiographic outcomes can serve as a basis for standardizing surgical technique.

PURPOSE

To establish the ideal radiographic tunnel position for anatomic coracoclavicular ligament reconstruction and to elucidate variables associated with early loss of reduction and ability to return to active-duty military service.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

A retrospective review of the military's electronic medical record between the years 2000 and 2013 was performed. All anatomic coracoclavicular reconstructions at a single institution were included for analysis, and nonanatomic or revision reconstructions were excluded. Radiographic failure was defined as 6 mm of superior clavicle displacement on immediate postoperative films.

RESULTS

A cohort of 38 patients underwent 39 anatomic coracoclavicular reconstructions. Average follow-up time was 26 months (range, 1.2-92 months). A total of 20 radiographic failures were identified, with an average conoid tunnel ratio of 0.27. When conoid tunnel ratios were compared with a reference ratio of 0.20 to 0.25, increased risk of failure was statistically significant with lateralization greater than 0.20 (P = .018; odds ratio [OR] = 40 [95% CI, 1.05-999.06]) or with medialization of 0.251 to 0.30 (P = .002; OR = 39 [95% CI, 1.58-944.36]) or greater than 0.30 (P = .029; OR = 21 [95% CI, 0.77-562.15]). Medialization of the trapezoid position greater than 0.16 (vs a range of 0.13-0.16) was also found to be significant for failure (P < .023; OR = 8 [95% CI, 1.33-48.18]). However, these significant findings did not correlate with symptoms or ability to return to duty (P > .05).

CONCLUSION

The optimal technique for treating acromioclavicular separations has yet to be determined. Recently, anatomic coracoclavicular reconstruction has demonstrated biomechanical superiority to previously described methods. The findings of optimal tunnel positioning in anatomic reconstructions from this large active-duty military cohort can assist preoperative planning to reduce failure rates when treating these difficult injuries.

Radiographic failure and rates of re-operation after acromioclavicular joint reconstruction: a comparison of surgical techniques

AIMS

To compare radiographic failure and re-operation rates of anatomical coracoclavicular (CC) ligament reconstructional techniques with non-anatomical techniques after chronic high grade acromioclavicular (AC) joint injuries.

PATIENTS AND METHODS

We reviewed chronic AC joint reconstructions within a region-wide healthcare system to identify surgical technique, complications, radiographic failure and re-operations. Procedures fell into four categories: (1) modified Weaver-Dunn, (2) allograft fixed through coracoid and clavicular tunnels, (3) allograft loop coracoclavicular fixation, and (4) combined allograft loop and synthetic cortical button fixation. Among 167 patients (mean age 38.1 years, (standard deviation (sd) 14.7) treated at least a four week interval after injury, 154 had post-operative radiographs available for analysis.

RESULTS

Radiographic failure occurred in 33/154 cases (21.4%), with the lowest rate in Technique 4 (2/42 4.8%, p = 0.001). Half the failures occurred by six weeks, and the Kaplan-Meier survivorship at 24 months was 94.4% (95% confidence interval (CI) 79.6 to 98.6) for Technique 4 and 69.9% (95% CI 59.4 to 78.3) for the other techniques when combined. In multivariable survival analysis, Technique 4 had better survival than other techniques (Hazard Ratio 0.162, 95% CI 0.039 to 0.068, p = 0.013). Among 155 patients with a minimum of six months post-operative insurance coverage, re-operation occurred in 9.7% (15 patients). However, in multivariable logistic regression, Technique 4 did not reach a statistically significant lower risk for re-operation (odds ratio 0.254, 95% CI 0.05 to 1.3, p = 0.11).

CONCLUSION

In this retrospective series, anatomical CC ligament reconstruction using combined synthetic cortical button and allograft loop fixation had the lowest rate of radiographic failure.

TAKE HOME MESSAGE

Anatomical coracoclavicular ligament reconstruction using combined synthetic cortical button and allograft loop fixation had the lowest rate of radiographic failure.

Safety zone for posterosuperior shoulder access: study on cadavers

Objective

The posterosuperior shoulder access used in surgical treatment for acromioclavicular dislocation was constructed through dissection of 20 shoulders from 10 recently chilled adult cadavers, and the distances from this route to the nearby neurovascular structures were analyzed.

Methods

A Kirschner wire was introduced into the top of the base of the coracoid process through the posterosuperior shoulder access, in the area of the origin of the conoid and trapezoid ligaments, thus reproducing the path for inserting two anchors for anatomical reconstruction of the coracoclavicular ligaments. The smallest distance from the insertion point of the Kirschner wire to the suprascapular nerve and artery/vein was measured.

Results

The mean distance from the suprascapular nerve to the origin of the coracoclavicular ligaments at the top of the base of the coracoid process was 18.10 mm (range: 13.77–22.80) in the right shoulder and 18.19 mm (range: 12.59–23.75) in the left shoulder. The mean distance from the suprascapular artery/vein to the origin of the coracoclavicular ligaments was 13.10 mm (range: 9.28–15.44) in the right shoulder and 14.11 mm (range: 8.83–18.89) in the left shoulder. Comparison between the contralateral sides did not show any statistical difference.

Conclusion

The posterosuperior shoulder access route for anatomical reconstruction of the coracoclavicular ligaments in treating acromioclavicular dislocation should be performed respecting the minimum limit of 8.83 mm medially.

A biomechanical assessment of a novel double endobutton technique versus a coracoid cerclage sling for acromioclavicular and coracoclavicular injuries

PURPOSE

Recently, many acromioclavicular-coracoclavicular (AC-CC) ligament reconstruction techniques address only the CC ligament. However, many of these techniques are costly, time-consuming, and require the use of allogenic grafts, making them prone to creep and failure or novel devices making them challenging for orthopaedic surgeons. The purpose of this study was to compare the biomechanical characteristics of a double endobutton technique using a standard endobutton CL with those of a coracoid cerclage sling (CS) for reconstruction of the CC ligaments.

METHODS

Anterior-posterior (AP) translation and superior-inferior (SI) translation were quantified for eight matched pairs of intact AC joints. One shoulder from each pair underwent a double endobutton repair, using an endobutton CL modified with an additional endobutton (Smith & Nephew, Memphis, Tenn) and placed through holes in the coracoid and clavicle. The contra-lateral shoulder received a coracoid sling reconstruction using an anterior tibialis tendon. Translation testing was repeated after reconstruction, followed by load-to-failure testing. Paired t tests were used for statistical analysis.

RESULTS

The CS technique demonstrated a greater SI and AP translation than the double endobutton technique (p < 0.05). Additionally, the double endobutton technique had a greater stiffness (40.2 ± 11.0 vs. 20.3 ± 6.4 N/mm, p = 0.005), yield load (168.5 ± 11.0 vs. 86.8 ± 22.9 N, p = 0.002), and ultimate load (504.4 ± 199.7 vs. 213.2 ± 103.4 N, p = 0.026) when compared to the CS technique.

CONCLUSION

The double endobutton technique yielded less translation about the AC joint and displayed stronger load-to-failure characteristics than the CS reconstruction. As such, this technique may be better suited to restore native AC-CC biomechanics, reduce post-operative pain, and prevent recurrent subluxation and dislocation than an allogenic graft construct. The double endobutton technique may be a suitable option for addressing AC-CC injuries.

BIOMECHANICAL COMPARISON OF THE CORACOCLAVICULAR SPACE FIXATION USING THREE DIFFERENT SUTURE TECHNIQUES

Coracoclavicular space fixation with suture loops is a well-known surgical technique for the treatment of dislocations. However, out of 100 different surgical treatments no single one has been established as a gold standard. The following research aims to improve the technique and focuses on a development of new fixation technique using composite sutures, which would withstand forces during ligament healing process. Three different fixation techniques (one loop and two separate suture loops and W-system) were tested on a custom built mechanical testing device. Applied load was continuously increased at a loading rate of 30[Formula: see text]N/min until the failure of the sutures. Ultimate tensile strength and suture elongation at failure were measured. The W-system had statistically significant higher load to failure and higher stiffness compared to one loop and two separate loops techniques. Biomechanical properties of a suture fixation technique can be improved by connecting them into one system to create particular arrangement of the sutures. The measurements can be easily repeated and this testing protocol can serve as a good starting point to standardize procedures of evaluation of different joint fixation techniques and to develop new ones.

Arthroscopic Reconstruction of the Coracoclavicular Ligaments Using a Coracoid Cerclage Technique

This technical note discusses the arthroscopic coracoid cerclage technique for double-bundle coracoclavicular ligament reconstruction in patients with nonacute symptomatic high-grade acromioclavicular separation injuries. This technique allows for an anatomic graft reconstruction of the coracoclavicular ligaments through an arthroscopic approach without the requirement to drill into the coracoid process. Early results are promising with high patient satisfaction and excellent reported clinical and radiographic outcomes. We believe this technique to be an anatomic, less invasive alternative to a complex shoulder procedure while sparing the structural integrity of the coracoid process and also allowing the surgeon to convert easily to a more traditional open surgical technique as necessary.

Arthroscopic Stabilization of Chronic Acromioclavicular Joint Dislocations: Triple- Versus Single-Bundle Reconstruction

BACKGROUND

Arthroscopically assisted single-bundle (SB) or double-bundle coracoclavicular (CC) ligament reconstruction using autologous tendon grafts has been reported to provide acromioclavicular (AC) joint (ACJ) stability in chronic instability cases. Recently, additional AC ligament reconstruction to provide triple-bundle (TB) stabilization has been introduced but lacks a comparison of clinical and radiological outcomes.

HYPOTHESIS

Arthroscopically assisted anatomic TB CC and AC reconstruction yields superior clinical and radiological results when compared with nonanatomic SB CC reconstruction.

STUDY DESIGN

Cohort study; Level of evidence, 2.

METHODS

Twenty-six patients (mean [±SD] age, 46.9 ± 12.8 years) suffering from chronic high-grade ACJ instability underwent ACJ stabilization using autologous hamstring grafts. Twelve patients underwent combined anatomic TB CC and AC reconstruction using a semitendinosus tendon with clavicular interference screw fixation (TB group), and 14 underwent isolated SB CC reconstruction using the AC GraftRope system with a gracilis tendon (SB group). After a minimum follow-up of 2 years (mean, 29.0 ± 7.4 months), patients were evaluated radiologically and clinically using the Constant, American Shoulder and Elbow Surgeons (ASES), Taft, and Acromioclavicular Joint Instability Score (ACJI) outcome measures.

RESULTS

The mean Constant score increased significantly in both groups, from 71.6 preoperatively to 88.8 postoperatively in the TB group and from 67.8 to 82.6 in the SB group (P ≤ .009). No intergroup difference was found regarding the final Constant or ASES scores. Regarding the ACJ-specific scores, the final outcomes were significantly different: 10.9 (TB group) versus 9.0 (SB group) for the mean Taft score (P = .018) and 84.7 versus 58.4, respectively, for the mean ACJI score (P = .0001). No significant radiological difference was found regarding the mean CC distance (10.7 mm [TB group] vs 13.1 mm [SB group]). The TB group showed superior horizontal ACJ stability (P = .011), which was associated with a better clinical outcome according to the ACJI and Taft scores. In the SB group, the rate of ACJ instability recurrence was higher (21% vs 8% [TB group]).

CONCLUSION

Combined arthroscopically assisted anatomic TB CC and AC ligament reconstruction using an autologous semitendinosus tendon graft provides superior clinical and radiological results compared with isolated nonanatomic SB CC ligament reconstruction using the AC GraftRope system. In particular, the TB technique can better restore horizontal ACJ stability, which is associated with superior ACJ-specific outcome scores.

Continuous Loop Double Endobutton Reconstruction for Acromioclavicular Joint Dislocation

BACKGROUND

Current anatomic methods for reconstruction of the dislocated acromioclavicular (AC) joint show improved clinical results but continue to be associated with significant rates of fixation loss and complications, limiting more widespread use.

PURPOSE

To determine the long-term clinical and radiologic outcomes of a novel surgical technique using a closed-loop double Endobutton device to reconstruct both acute and chronic dislocations.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

Between 2003 and 2012, a total of 35 patients (31 men, 4 women) at a mean age of 42 years (range, 25-70 years) were surgically treated for a Rockwood type III or greater AC joint dislocation with the described technique (26 chronic, 9 acute). Imbrication of the AC joint capsule and deltotrapezial fascia was performed in all patients. Biological bridging across the coracoclavicular (CC) interval was performed in all patients by use of coracoacromial (CA) ligament transfer in 28 patients and primary repair of the CC ligament in 7 patients. Complete follow-up information was obtained for 31 of 35 patients.

RESULTS

At a mean follow-up of 5.2 years (range, 27-144 months), the construct remained stable in all but 1 patient. The mean CC interval difference was 1.1 mm (range, -2.5 to 4.0 mm) and was <2 mm in 87% of patients. The mean Constant score was 98; the mean University of California, Los Angeles Shoulder Rating Scale score was 34; and the mean American Shoulder and Elbow Surgeons Shoulder Score was 98. Follow-up MRI evaluation in 10 patients consistently demonstrated a wide band of dense scar tissue between the coracoid and clavicle. No infections, fractures, or perioperative complications occurred.

CONCLUSION

Excellent results were obtained and maintained over long-term follow-up. The continuous loop device eliminated the possibility of knot slippage or breakage. MRI confirmed a robust healing response. The described technique resulted in outcomes that were significantly superior to historical reports of nonsurgical outcomes, and the technique can be recommended both for acute and chronic dislocations.

Outcome After Arthroscopic Reconstruction of the Coracoclavicular Ligaments Using a Double-Bundle Coracoid Cerclage Technique

PURPOSE

We report the outcome of an arthroscopic technique for coracoclavicular ligament reconstruction using an anatomic coracoid cerclage.

METHODS

Between March 2011 and September 2012, 12 consecutive patients with symptomatic chronic (>4 weeks from injury) type V acromioclavicular separation for which nonoperative treatment failed were treated with arthroscopic double-bundle reconstruction of the coracoclavicular ligaments using tendon allograft by the first author. The clinical records, operative reports, and preoperative and follow-up radiographs were reviewed. The visual analog scale score, Subjective Shoulder Value, Simple Shoulder Test score, and Constant-Murley score were evaluated preoperatively and at each follow-up appointment.

RESULTS

The study included 12 shoulders in 12 young active-duty soldiers with symptomatic high-grade acromioclavicular separation who were treated with a technique for arthroscopic reconstruction of the coracoclavicular ligaments. The mean age was 25 years (range, 20 to 35 years). The injury occurred during sports activity in 11 patients. One patient was injured in a motorcycle accident. The mean time from injury to surgery was 17.8 months (range, 1.5 to 72 months). The minimum length of follow-up was 24 months (mean, 30.4 months; range, 24 to 42 months). The mean preoperative and postoperative outcome scores were significantly different (P < .0001) for all subjective outcome measures. The mean Constant-Murley score improved from 58.4 (range, 51 to 76) to 96 (range, 88 to 100). The mean visual analog scale score improved from 8.1 (range, 7 to 10) to 0.58 (range, 0 to 2). The mean Subjective Shoulder Value improved from 32.9% (range, 10% to 70%) to 95% (range, 80% to 100%). The mean Simple Shoulder Test score improved from 6 (range, 5 to 8) to 11.83 (range, 11 to 12). All patients returned to their normal preinjury level of activity by 6 months. Radiographs at last follow-up showed no loss of reduction with maintenance of the coracoclavicular interval. There was 1 complication (8.5%), a postoperative superficial wound infection, that was treated accordingly.

CONCLUSIONS

We present an arthroscopic technique for double-bundle tendon graft reconstruction of the coracoclavicular ligaments using the coracoid cerclage technique. This method showed good outcomes and maintenance of radiographic reduction with high patient satisfaction and a low complication rate.

LEVEL OF EVIDENCE

Level IV, therapeutic case series.

Complications after arthroscopic coracoclavicular reconstruction using a single adjustable-loop-length suspensory fixation device in acute acromioclavicular joint dislocation

PURPOSE

The purpose of this study was to evaluate clinical and radiological outcomes after arthroscopically assisted coracoclavicular (CC) fixation using a single adjustable-loop-length suspensory fixation device for acute acromioclavicular dislocation and to report intraoperative and postoperative complications.

METHODS

Eighteen consecutive patients with acute acromioclavicular dislocation underwent arthroscopically assisted CC fixation using a single TightRope (Arthrex, Naples, FL). Using the Rockwood classification, 3 patients had grade III dislocations, one patient had a grade IV dislocation, and 14 patients had grade V dislocations.

RESULTS

The preoperative CC distance of the injured shoulder was 16.1 ± 2.7 mm (range, 11.2 to 21.0 mm), and it increased by 99% ± 36% (range, 17% to 153%) on average compared with the contralateral shoulder. The average CC distance was 10.5 ± 2.5 mm (range, 7.7 to 15.5 mm), and it increased by 30% ± 30% (range, -9.4% to 90%) at the final follow-up. Compared with immediate postoperative radiographs, the CC distance was maintained in 12 patients, increased between 50% and 100% in 4 patients, and increased more than 100% in 2 patients at final follow-up. However, there was no statistical difference in Constant scores between 6 patients with reduction loss (95.6 ± 4.5) and 12 patients with reduction maintenance (98.4 ± 2.5; P = .17). Perioperative complications occurred in 8 patients, including one case of acromioclavicular arthritis, one case of delayed distal clavicular fracture at the clavicular hole of the device, 3 cases of clavicular or coracoid button failures, and 3 cases of clavicular bony erosion.

CONCLUSIONS

Satisfactory clinical outcomes were obtained after CC fixation using the single adjustable-loop-length suspensory fixation device for acute acromioclavicular joint dislocation. However, CC fixation failure of greater than 50% of the unaffected side in radiological examinations occurred in 33% of the patients within 3 months after the operation. Additionally, 8 patients (44%) had complications associated with the adjustable-loop-length suspensory fixation device and surgical technical problems. Despite acceptable shoulder function restoration, adequate care should be exercised in surgical treatment of acute acromioclavicular dislocation with a single adjustable-loop-length suspensory fixation device for optimal radiological outcomes.

LEVEL OF EVIDENCE

Level IV, therapeutic case series.

Coracoclavicular ligament reconstruction: a systematic review and a biomechanical study of a triple endobutton technique

Operative intervention is recommended for complete acromioclavicular (AC) joint dislocation to restore AC stability, but the best operative technique is still controversial. Twelve fresh-frozen male cadaveric shoulders (average age, 62.8±7.8 years) were equally divided into endobutton versus the modified Weaver-Dunn groups. Each potted scapula and clavicle was fixed in a custom made jig to allow translation and load to failure testing using a Zwick BZ2.5/TS1S material testing machine (Zwick/Roell Co, Germany). A systematic review of 21 studies evaluating reconstructive methods for coracoclavicular or AC joints using a cadaveric model was also performed. From our biomechanical study, after ligament reconstruction, the triple endobutton technique demonstrated superior, anterior, and posterior displacements similar to that of the intact state (P>0.05). In the modified Weaver-Dunn reconstruction group, however, there was significantly greater anterior (P<0.001) and posterior (P=0.003) translation after ligament reconstruction. In addition, there was no significant difference after reconstruction between failure load of the triple endobutton group and that of the intact state (686.88 vs 684.9 N, P>0.05), whereas the failure load after the modified Weaver-Dunn reconstruction was decreased compared with the intact state (171.64 vs 640.86 N, P<0.001). From our systematic review of 21 studies, which involved comparison of the modified Weaver-Dunn technique with other methods, the majority showed that the modified Weaver-Dunn procedure had significantly (P<.05) greater laxity than other methods including the endobutton technique. The triple endobutton reconstruction proved superior to the modified Weaver-Dunn technique in restoration of AC joint stability and strength. Triple endobutton reconstruction of the coracoclavicular ligament is superior to the modified Weaver-Dunn reconstruction in controlling both superior and anteroposterior displacements with a failure load that approximates the intact ligament.

Simultaneous anatomic reconstruction of the acromioclavicular and coracoclavicular ligaments using a single tendon graft

PURPOSE

The purpose of this study was to introduce a novel surgical technique for simultaneous anatomic reconstruction of the acromioclavicular and coracoclavicular ligaments using a single tendon graft and to compare its biomechanical characteristics to those of a coracoid cerclage reconstruction of the coracoclavicular ligaments.

METHODS

Six matched pairs of human acromioclavicular joints with an average age of 54.8 ± 7.8 years were used. One shoulder from each pair received the single tendon acromioclavicular-coracoclavicular reconstruction; the contralateral shoulder received the coracoid cerclage reconstruction. Bovine extensor tendon was used for both techniques. The single tendon acromioclavicular-coracoclavicular reconstruction technique provided anatomic restoration of the two coracoclavicular ligaments and the superior and inferior acromioclavicular ligaments simultaneously using one coracoid hole, one acromion hole, and two clavicular holes with interference screws. Anterior-posterior and superior-inferior translations were quantified for all specimens before and after reconstruction, followed by load to failure testing.

RESULTS

Following coracoid cerclage reconstruction, total anterior-posterior translation was significantly greater than intact (10.0 ± 5.7 mm; p = 0.008). Following single tendon acromioclavicular-coracoclavicular reconstruction, there was no significant difference in anterior-posterior translation compared to intact (-1.6 ± 2.2 mm; n.s.). The coracoid cerclage technique demonstrated significantly greater anterior-posterior translation than the single tendon acromioclavicular-coracoclavicular technique (p = 0.007). Both techniques restored superior-inferior translation to the intact condition (n.s.). Ultimate load, deformation at ultimate load, and energy absorbed at ultimate load were significantly greater after acromioclavicular-coracoclavicular reconstruction than after coracoid cerclage reconstruction (p < 0.05).

CONCLUSIONS

This novel single tendon anatomic acromioclavicular-coracoclavicular reconstruction provided greater stability and stronger load to failure characteristics than the isolated coracoid cerclage reconstruction. A simultaneous acromioclavicular-coracoclavicular reconstruction technique using a single free tendon graft provided anatomic reconstruction of the conoid, trapezoid, and superior and inferior acromioclavicular ligaments and may reduce postoperative subluxation.

Biomechanical Consequences of Coracoclavicular Reconstruction Techniques on Clavicle Strength

BACKGROUND

Lateral clavicle fractures have been reported after coracoclavicular (CC) ligament reconstructions with bone tunnels through the clavicle.

PURPOSE

To biomechanically compare clavicle strength following 2 common CC reconstruction techniques with different bone tunnel diameters.

STUDY DESIGN

Controlled laboratory study.

METHODS

Testing was performed on 2 groups of matched-pair cadaveric clavicles. Clavicles were prepared with either 2.4-mm tunnels and cortical fixation button (CFB) devices or 6.0-mm tunnels with hamstring tendon grafts (TGs) and tenodesis screws; contralateral clavicles were left intact. A 3-point bending load was applied to the distal clavicles at a rate of 15 mm/min until failure. Ultimate failure load and anterior-posterior width of the clavicles 45 mm medial from the lateral border were recorded. Strength reduction was determined as the percentage reduction in ultimate failure load between paired intact and surgically prepared clavicles. Relative tunnel size was determined as the quotient of tunnel diameter and clavicle width, reported as a percentage.

RESULTS

The TG technique significantly reduced clavicle strength relative to intact (P = .011) and caused significantly more strength reduction (mean, -30.7%; range, 8.1% to -62.5%) than the CFB technique (mean, -3.8%; range, 34.2% to -28.1%; P = .031). The CFB technique was not significantly different from intact (P = .314). There was a significant correlation between clavicle width and strength reduction (τ = -0.36, P = .04) and between relative tunnel size and strength reduction (τ = 0.51, P = .005).

CONCLUSION

The TG reconstruction technique with 6.0-mm tunnels, grafts, and tenodesis screws caused significantly more reduction of clavicle strength compared with the CFB technique with 2.4-mm tunnels and CFB device. Additionally, relative tunnel width correlated highly with the strength reduction.

CLINICAL RELEVANCE

This information can influence intraoperative decision making based on the individual clavicle width and might influence postoperative treatment protocols. Large bone tunnels may predispose patients to clavicle fractures after anatomic CC reconstructions.

Complications after anatomic fixation and reconstruction of the coracoclavicular ligaments

BACKGROUND

Reconstruction of the disrupted acromioclavicular (AC) joint has historically resulted in high complication rates. As a result, there has been a move toward anatomic coracoclavicular (CC) ligament fixation and reconstruction, owing to its numerous biomechanical advantages and perceived clinical advantages.

PURPOSE

To report and analyze the unique complications associated with these anatomic CC ligament procedures using either cortical fixation buttons (CFBs) or tendon grafts (TGs) and to evaluate the effect that these complications have on patient outcomes.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

From January 2006 until May 2011, a total of 59 primary anatomic CC ligament procedures were performed using either CFBs or TGs. Demographic, surgical, subjective (including the American Shoulder and Elbow Surgeons [ASES], quick Disabilities of the Arm, Shoulder and Hand [QuickDASH], Short Form-12 [SF-12], and Single Assessment Numeric Evaluation [SANE] scores), and radiographic data along with surgical complications were prospectively collected and retrospectively analyzed. Construct survivorship, defined as the maintenance of reduction of the AC joint, was calculated using the Kaplan-Meier method at 12- and 24-month intervals.

RESULTS

Surgical treatment for AC joint dislocations was performed in 3 women (4 shoulders) and 52 men (55 shoulders) with a mean age of 43.6 years (range, 18-71 years); 13 shoulders (22.0%) underwent fixation using the CFB technique, and 46 shoulders (78.0%) underwent reconstruction using the TG technique. The overall complication rate was 27.1% (16/59) in this study. There were 3 complications (23.1%) in the CFB group, including 1 coracoid fracture and 2 cases of hardware failure resulting in a loss of reduction. There were 13 complications (28.2%) in the TG group, including 4 graft ruptures, 2 clavicle fractures, 1 case of hardware failure, 1 hypertrophic distal clavicle, 2 cases of hardware pain, 1 suture granuloma, 1 case of adhesive capsulitis, and 1 case of axillary neuropathy. Twelve- and 24-month construct survivorship was calculated to be 86.2% and 83.2%, respectively. Of the 43 shoulders that did not have a complication, mean ASES scores significantly improved from 57.5 (range, 0-97) to 91 (range, 63-100) (P < .001), and mean SF-12 physical component summary scores significantly improved from 45 (range, 25-58) to 56 (range, 43-65.8) (P < .001) after a mean 2.4-year follow-up (range, 1.0-5.7 years). There were no significant differences in outcomes between those that did and did not experience a complication, with the exception that those with complications had significantly decreased median patient satisfaction compared with those without complications (3.5 vs 9, respectively; P = .049).

CONCLUSION

Anatomic procedures to treat disrupted CC ligaments using either CFBs or TGs resulted in an overall complication rate of 27.1% (16/59). Construct survivorship was calculated to be 86.2% at 12 months and 83.2% at 24 months. Good to excellent outcomes could only be reported in those patients who did not have a complication.