Coracoclavicular and acromioclavicular ligament reconstruction with a double-bundle semitendinosus autograft and cortical buttons for chronic acromioclavicular joint dislocations: clinical and imaging outcomes.

BACKGROUND: There are few clinical and radiographic studies of coracoclavicular (CC) ligament reconstruction in chronic acromioclavicular (AC) joint dislocation. Additionally, reported AC joint reduction rates vary. HYPOTHESIS: Arthroscopically assisted double-bundle semitendinosus tendon autografts with CC and AC ligament reconstruction for AC joint reconstruction provide AC joint stability and improved function at the final visit. METHODS: In this retrospective study of prospectively collected data, 21 patients surgically treated for chronic AC joint dislocation (Rockwood III-V) were assessed clinically and radiographically preoperatively, and at day 1, 3 months, 12 months, and at a final visit (>24 months) postoperatively. Clinical assessments included Constant and American Shoulder and Elbow Surgeons scores. The CC vertical distance (CCD) on the affected and unaffected sides [CCD ratio (%)] on the anterosuperior view were measured. AC joint vertical reduction loss was defined as an increase in the CCD ratio of >25%. Horizontal AC joint instability was evaluated on axillary views. Pearsons' correlation coefficients were generated to examine the relationships among postoperative clinical scores, CCD ratio, interval from injury to surgery, and age at the time of surgery. RESULTS: Twenty-one shoulders in 21 patients (mean age, 40.0 years at the time of surgery; 16 men, 5 women) were evaluated with a mean 31.7-month follow-up period. The mean Constant scores, American Shoulder and Elbow Surgeons scores, and CCD ratios significantly improved from preoperatively to the final visit (57.4 ± 10.1, 49.1 ± 12.1, 101.6 ± 64.1 preoperatively; 89.6 ± 5.3, 96.5 ± 4.2, 9.9 ± 34.5 at the final visit, respectively [P < .001 for all]). Vertical AC and horizontal AC joint instability were observed in 4 shoulders (19.0%) and in 1 shoulder (4.8%), respectively. However, there was no significant correlation between the increase in CCD and clinical scores at the final visit (Constant score; r = 0.179, P = .438: American Shoulder and Elbow Surgeons score; r = -0.260, P = .256) or the interval from injury to surgery (r = 0.099, P = .669) or age at the time of surgery (r = 0.019, P = .935). No clinical complications were associated with clinical symptoms. CONCLUSIONS: Patients who underwent the index procedure achieved significant improvement in shoulder function without complications related clinical symptom after a mean follow-up interval of 31.7 months. In contrast, the rates of total ACJ instability in the vertical and horizontal planes were unsatisfactory but compatible with those in previous studies.

Complications after operative treatment of high-grade acromioclavicular injuries.

BACKGROUND: Treatment of Rockwood type III-V acromioclavicular (AC) joint injuries remains controversial. Numerous reconstruction techniques have been proposed. The purpose of this study was to describe the complication profile in a large cohort of patients who underwent surgical management of AC joint separations using a variety of reconstruction strategies. METHODS: All patients who underwent surgery for AC joint injuries from 2013 to 2019 at a single institution were identified. Chart review was performed to capture patient demographics, radiographic measurements, operative techniques, postoperative complications, and revision surgery. Structural failure was defined as a radiographic loss of reduction of greater than 50% when comparing immediate and final postoperative imaging. Logistic regression analysis was performed to identify risk factors for complications and revision surgery. RESULTS: Of the 279 patients included in the study, 66 (24%) had type III separations, 20 (7%) type IV, and 193 (69%) type V. Fifty-three percent underwent surgery acutely (<6 weeks of injury), and 40% were chronic (>3 months). A total of 252 of the 279 surgeries (90%) were performed open and 27 (10%) were arthroscopically assisted. Allograft was used in 164 of 279 (59%) cases. Specific operative techniques (with or without allograft) included hook plating (1%), modified Weaver Dunn (16%), cortical button fixation (18%), and suture fixation (65%). At mean 28-week follow-up, 108 complications were identified in 97 patients (35%). Complications were identified at mean 20 ± 21 weeks. Sixty-nine structural failures (25%) were identified. Persistent AC joint pain requiring injection, clavicle fracture, adhesive capsulitis, and hardware complications were the other most common complications. Twenty-one patients (8%) underwent unplanned revision surgery at mean 38 ± 28 weeks after the index procedure, with the most common indication for structural failure, hardware complications, or fracture of the clavicle or coracoid. Patients who had surgery after 6 weeks from injury had a significantly greater risk of having a complication (odds ratio [OR] 3.19, 95% confidence interval [CI] 1.34-7.77, P = .009) and a significantly greater risk of having structural failure (OR 2.65, 95% CI 1.38-5.28, P = .004). Patients who had an arthroscopic technique had a greater risk of structural failure (P = .002). Complications, structural failure, and revision surgery were not significantly correlated with use of allograft or specific operative techniques. CONCLUSION: Surgical management of AC joint injuries is associated with a relatively high complication profile. Loss of reduction in the postoperative period is common. However, the revision surgery rate is low. These findings are important for patient preoperative counseling.

Subject-specific computational modeling of acromioclavicular and coracoclavicular ligaments.

BACKGROUND: Disruption of the acromioclavicular joint is a common injury. Despite the different surgical procedures described for treating this injury, complications such as loss of reduction and failure of fixation remain unacceptably high. We developed a computer model of the acromioclavicular joint to better understand the biomechanical contributions of the ligaments that are typically injured. METHODS: Six fresh frozen human cadaveric shoulders were tested on an AMTI VIVO 6-degree of freedom test platform to measure force-displacement in inferior translation, anteroposterior translation, and internal rotation before and after sequentially transecting the coracoclavicular and acromioclavicular ligaments. These data were used to construct computer models of each specimen. Three-dimensional computed tomographic scans were used to generate a rigid-body dynamics model using the AnyBody Modeling System. The scapula and clavicle were connected by the acromioclavicular joint capsule, the conoid ligament, and the trapezoid ligament. Subject-specific ligament properties were calculated by matching computer predictions to experimental force-displacement data. RESULTS: The calculated free lengths of the conoid, trapezoid, and acromioclavicular ligaments were 13.5 (±3.2), 11.8 (±2.4), and 11.0 (±2.7) mm, respectively. The calculated stiffnesses of the conoid, trapezoid, and acromioclavicular ligaments were 34.3 (±6.3), 28.4 (±3.2), and 33.8 (±8.2) N/mm, respectively. Root mean square deviation (RMSD) of predicted force-displacement curves relative to experimental force-displacement curves (during inferior and anteroposterior translation) was less than 1 mm. For validation of subject-specific models, after ligament properties were calculated, the RMSD of the predicted torque over 15° of internal rotation was 12% of maximum rotational torque (average for 6 specimens). DISCUSSION AND CONCLUSION: Acromioclavicular disruption results in multidirectional instability, which requires careful consideration of the individual contributions of the injured ligaments. In addition, variations in patient anatomy can significantly affect the biomechanical stability of the reconstruction. Subject-specific models can enhance our understanding of the individual and collective biomechanical contributions of the injured soft tissues to the multiaxial stability of the acromioclavicular joint. These models may also be useful for analyzing and assessing biomechanical stability after various types of surgical reconstruction.

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

BACKGROUND: A synthetic ligament (LockDown, Worcestershire, England) has become available to treat complete acromioclavicular dislocation with promising clinical results and potential benefit to avoid postoperative loss of reduction. We investigated the biomechanics of this synthetic ligament in a simulated immediate postoperative rehabilitation setting, hypothesizing that the synthetic ligament would demonstrate less superior coracoclavicular displacement to cyclic loading and higher ultimate load-to-failure values than a coracoclavicular suspensory construct. METHODS: Seven matched-pair cadaveric shoulders (mean age at time of death, 79 years) were loaded cyclically and to failure. One specimen in each pair was randomly assigned to the synthetic ligament or coracoclavicular suspensory construct. Superiorly directed 70-N cyclic loading for 3000 cycles at 1.0 Hz was applied through the clavicle in a fixed scapula simulating physiologic states during immediate postoperative rehabilitation, followed by a load-to-failure test at 120 mm/min. RESULTS: After 3000 cycles, the superior displacement of the clavicle in the synthetic ligament (9.2 ± 1.1 mm) was 225% greater than in the coracoclavicular suspensory construct (2.8 ± 0.4 mm, 95% confidence interval [CI] 3.4, 8.3; P < .001). Average stiffness of the synthetic ligament (32.8 N/mm) was 60% lower than that of the coracoclavicular suspensory construct (81.9 N/mm, 95% CI 43.3, 54.9; P < .001). Ultimate load-to-failure of the synthetic ligament was 23% (95% CI 37.9, 301.5; P = .016) lower than the coracoclavicular suspensory construct (580.5 ± 85.1 N and 750.2 ± 135.5 N, respectively). CONCLUSION: In a simulated immediate postoperative cadaveric model, the synthetic ligament demonstrated poorer biomechanics than the coracoclavicular suspensory construct. These findings suggest that a coracoclavicular suspensory construct may be preferable to a synthetic ligament if early rehabilitation is intended.

Clavicle fracture at the suture hole after acromioclavicular joint reconstruction using a suture-button: a case report.

BACKGROUND: Intraosseous suture-button devices have been used for acromioclavicular joint reconstruction due to its relative simplicity compared with other procedures. However, the complications of acromioclavicular joint reconstruction using a suture-button are not fully understood. Here, we describe a case of a clavicle fracture at the suture hole following acromioclavicular joint reconstruction using a suture-button and hook plate. CASE PRESENTATION: A 28-year-old man presented at our hospital after a fall from his bicycle. The patient had a history of acromioclavicular joint reconstruction with a suture-button and a hook plate for right acromioclavicular joint dislocation, seven months ago at another hospital. The hook plate had been removed four months ago, while X-ray radiography before removal had shown the widening of a suture hole. In the current fall from the bicycle, X-ray radiography revealed a clavicle fracture through the previous drill hole for suture-button. We removed the suture-button and performed an open reduction and internal fixation for the clavicle fracture. CONCLUSION: The present case indicated that a clavicle fracture at the suture hole, although rare, is one of the complications after an acromioclavicular joint reconstruction using a suture-button. This case suggested that drilling to the necessary minimum when making suture holes and paying attention to the widening of suture holes are important to prevent a postoperative clavicle fracture.

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.

Coracoid bypass procedure: surgical technique for coracoclavicular reconstruction with coracoid insufficiency.

BACKGROUND: Failed acromioclavicular (AC) joint reconstruction secondary to a coracoid fracture or insufficiency of the coracoid is an uncommon but challenging clinical situation. We describe a surgical technique of revision coracoclavicular (CC) reconstruction, the coracoid bypass procedure, and report short-term results with this technique in 3 patients. METHODS: In the coracoid bypass procedure, reconstruction of the CC ligaments is performed by passing a tendon graft through a surgically created bone tunnel in the scapular body (inferior to the base of the coracoid) and then fixing the graft around the clavicle or through bone tunnels in the clavicle. Three patients treated with this technique were retrospectively reviewed. RESULTS: AC joint reconstruction performed for a traumatic AC joint separation failed in the 3 patients reported in this series. The previous procedures were an anatomic CC reconstruction in 2 patients and a modified Weaver-Dunn procedure in 1 patient. The coracoid fractures were detected postoperatively, and the mean interval from the index surgery to the coracoid bypass procedure was 8 months. The patients were a mean age of 44 years, and average follow-up was 21 months. At the last follow-up, all 3 patients were pain free, with full range of shoulder motion, preserved CC distance, and a stable AC joint. CONCLUSION: The coracoid bypass procedure is a treatment option for CC joint reconstruction during revision AC joint surgery in the setting of a coracoid fracture or coracoid insufficiency.

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

Introduction: This study reports the results of surgical anatomic reconstruction of torn coracoclavicular ligaments with an autogenous semitendinosus graft and temporary Kirschner wires (K-wires) in chronic acromioclavicular (AC) joint dislocations. Materials and methods: Nineteen shoulders underwent surgical anatomic reconstruction of torn coracoclavicular (CC) ligaments with an autogenous semitendinosus tendon graft and temporary K-wires for Rockwood grade III, IV and V chronic AC joint dislocations. Pre-operative data included patients' demographic characteristics, injury characteristics and surgical histories. The primary outcome measures were the University of California Los Angeles (UCLA) shoulder rating scale and visual analogue pain scoring (VAS), and the complications were noted for each patient. Results: Surgical anatomic reconstruction of torn CC ligaments was performed in 19 patients with a mean age of 41.6±16 years (range 21-72 years). All of the patients were satisfied and felt better after CC ligament reconstruction. The average UCLA shoulder rating scale score was good/excellent: 29.4 (range 23-34) out of 35 points. The average pre-operative VAS score was 7.7 points out of 10 and improved to 1.1 points post-operatively (p<0.05). None of the patients experienced failure during the follow-up. One patient had a mild subluxation, but the patient was satisfied with the result. Conclusions: This technique is simple, reliable, and biologic without major complications. It is also a cost-effective procedure since it can be performed with Kirschner wires and autogenous grafts. It has a major advantage of leaving no implants inside the joint, which can lead to hardware complications, and it can be performed in basic operating room settings.

Double Fixation Technique for Acute Acromioclavicular Joint Dislocation Using the Two-Button Technique and Gracilis Autograft Reinforcement: A Case Report of an Elite Athlete Seeking a Rapid Return to Sports Activity.

Acromioclavicular joint dislocation is a relatively common injury in the general population, especially in younger ages. Although acromioclavicular injuries are a well-studied topic, there are many controversies concerning not only the best way to treat them by operative or conservative methods but also determining the most effective fixation methods, providing better functional outcomes, faster rehabilitation protocols, fewer complications, and lower recurrence rates. In this case report, we present a case of type III acromioclavicular dislocation in a young athlete who was treated operatively using a double fixation technique, aiming to address these controversies and offer insights into the optimal management of such injuries.

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.

Risk for Fracture with Acromioclavicular Joint Reconstruction and Strategies for Mitigation.

Acromioclavicular (AC) joint injuries are a common cause of shoulder pain, especially among athletes. Surgical reconstruction of the AC joint can lead to complications such as fracture of the coracoid process, clavicle or acromion, which can negatively affect the patient's outcome. The purpose of this review is to discuss the risk factors for fractures associated with AC joint reconstruction, as well as the strategies that can be used to mitigate this risk. Risk factors for fractures include low mineral density, coracoid/clavicle drilling, larger holes in the coracoid, and the number of tunnels used for reconstruction.

Surgical Pearls and Pitfalls for Anatomic Acromioclavicular/Coracoclavicular Ligament Reconstruction.

Injuries to the acromioclavicular (AC) joint are common shoulder injuries in contact/collision athletes. There are a number of different surgical options that can be used to treat these injuries. The majority of these injuries can be treated nonoperatively with an early return to play for type I and II injuries. Surgical intervention and AC/CC (coracoclavicular) ligament reconstruction have excellent postoperative outcomes if complications can be avoided. This review will focus on the pearls and pitfalls for anatomic AC and CC ligament reconstruction for high-grade AC joint injuries.

Tunnel-free acromioclavicular joint reconstruction is associated with improved initial reduction and higher patient satisfaction.

Background: Many surgical techniques have been described for acromioclavicular (AC) joint reconstruction. Creation of bone tunnels through the clavicle or coracoid has been shown to be a risk factor for fracture. Use of an AC reconstruction technique that does not create bone tunnels may obviate this risk. This study aims to evaluate clinical outcomes of AC joint reconstruction using a tunnel-free technique compared to reconstruction using a cortical button and clavicular drill holes. Methods: Consecutive patients who underwent AC joint reconstruction by a single surgeon in a subspecialty referral practice were included. One group of patients received cortical button fixation (button group), in which sutures were passed around the coracoid, brought up through a drill hole in the clavicle, and tied over a cortical button. The other group of patients received tunnel-free fixation, in which a self-locking tape suture was passed in a cerclage fashion around the base of the coracoid and the clavicle and tensioned with a tensioning device (cerclage group). Both groups underwent reconstruction of the coracoclavicular (CC) ligament and AC joint capsule using tibialis anterior allograft. Patient-reported outcome scores and satisfaction were collected and compared between groups. Radiographs were reviewed to evaluate CC ligament distance and loss of reduction. Results: Twenty-two patients were included in the study (button n = 10, cerclage n = 12). Preoperative demographics and injury characteristics were not different between groups. Average radiographic follow-up was not different between groups (button: 231 days, cerclage: 105 days). Postoperative American Shoulder and Elbow Surgeons, visual analog scale, and Single Assessment Numeric Evaluation scores were similar between groups. Two postoperative clavicle fractures were sustained in the button group. These occurred through clavicular drill holes and were preceded by tunnel widening. No fractures occurred in the cerclage group. CC distance at initial follow-up was significantly less in the cerclage group (button: 11.2 ± 4.5 mm, cerclage: 7.0 ± 2.9 mm, P =.023). Loss of reduction was similar throughout the postoperative period (button: 4.3 ± 2.6 mm, cerclage: 4.8 ± 4.1 mm, P >.05. Forty percent of patients were unsatisfied with their clavicle after button fixation (n = 4/10), compared with zero after cerclage fixation (n = 0/12, P =.03). Reasons for dissatisfaction were fracture (n = 2) and persistent cosmetic deformity (n = 2). Conclusion: Tunnel-free AC joint reconstruction is associated with improved initial radiographic appearance and patient satisfaction compared to single cortical button fixation. Postoperative clavicle fracture and persistent cosmetic deformity drive patient dissatisfaction, which may be minimized by avoiding clavicular drill holes and using a tensioned self-locking cerclage suture to improve initial reduction.

Biomechanical evaluation of an independent acromioclavicular ligament repair for acromioclavicular joint reconstruction.

BACKGROUND: A number of surgical techniques for the treatment of acromioclavicular joint separations have been described; however, few have been able to create a strong intra-operative construct that provides minimal joint translation. A biomechanical study was conducted to examine joint translation in an independent acromioclavicular ligament repair. METHODS: Three variations of a novel independent acromioclavicular ligament repair technique underwent testing using a Sawbones model. The technique involves threading sutures through two acromial bone tunnels in a suture-bridge configuration and anchoring them into the distal clavicle. Three groups of eight specimens underwent reconstruction; group 1 using FiberTape, group 2 using FiberWire and group 3 using FiberTape in a modified (under-over) suture-bridge configuration. Superior, anterior and posterior translation was tested at loads of 10, 20 and 30 N. RESULTS: Group 3 repair yielded the least translation in both anterior-posterior and superior-inferior planes, with a two-fold decrease in superior translation compared to groups 1 and 2 (P < .05). Both groups 1 and 3 using FiberTape resulted in significantly less anterior and posterior translation compared to the FiberWire group (P < .05). DISCUSSION: The independent acromioclavicular ligament repair, without repair of the coracoclavicular ligament, demonstrated significant translational stability in the anterior-posterior and superior-inferior planes.

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.

Current concepts in management of ACJ injuries.

Acromioclavicular joint injury is common in young individuals who suffer direct trauma to the shoulder. Treatment of acromioclavicular dislocation is controversial with regards to the indication of operative management, timing of surgery, whether to perform open or arthroscopic surgery, method of stabilisation (rigid or non-rigid) and type of graft used for repair or reconstruction. Current evidence supports conservative management for Rockwood types I and II, while types IV, V and VI benefit from surgery. The optimal management of type III injuries in high demand patients remains contentious. Surgical options include acromioclavicular fixation, coracoclavicular fixation and coracoclavicular ligament reconstruction. Few studies with a low level of evidence suggest arthroscopic techniques and anatomical ligament reconstruction have better outcomes when compared to older techniques of rigid coracoclavicular fixation. The aim of this article is to look at the current evidence and address these controversial issues.

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

BACKGROUND: The synergistic effect of the acromioclavicular (AC) capsule and coracoclavicular (CC) ligaments on AC joint stability has gained recent recognition for its importance. Biomechanical and clinical studies have shown the benefit of combined reconstruction with multiple variations of surgical techniques for AC capsule augmentation. The ideal configuration remains unknown for such capsular repair aimed at achieving optimal stability with anatomic reconstruction. HYPOTHESIS: Primary AC joint stability can be restored by AC capsule augmentation, while position of the additional suture construct is critical. It was hypothesized that techniques that reconstruct the anterior capsular structures would restore native stability against rotations and translations. STUDY DESIGN: Controlled laboratory study. METHODS: Thirty fresh-frozen human cadaveric shoulders were used. Each sample was tested in the native state and served as its own control. After complete capsulotomy, 1 of 5 AC capsular repair configurations was performed: anterior, superior, posterior, O-frame, and X-frame. After testing of the AC capsular repair configurations, the tests were repeated after dissection of the CC ligaments and after CC ligament reconstruction with a suture button system. AC joint stability was immediately tested after each step under rotation and horizontal translation. To accomplish this, the AC joints were anatomically positioned on a custom fixture linked to a servohydraulic testing system. A 3-dimensional optical measuring system was used to evaluate the 3-dimensional joint motion. Clavicle posterior translation in relation to the acromion, rotation around the long axis of the clavicle, and displacement of the lateral clavicle in relation to the center of rotation were measured. The torques and forces required to rotate and translate the clavicle were recorded. RESULTS: In terms of translational testing, after the complete capsulotomy, a significant reduction of resistance force was found across all groups, with a mean 13% to 20% remaining ( P < .05). All AC suture augmentations were able to significantly increase the average resistance force as compared with the native ( P = .01) against posterior translation. Subsequent cutting of the CC ligaments did not result in a significant change in any of the groups ( P = .23). The synergistic effect of AC capsule augmentation and CC ligament reconstruction could be demonstrated without exception. In terms of rotational testing, the complete capsulotomy resulted in a significant reduction of resistance torque in all groups ( P < .05), with a remaining torque ranging between 2% and 11% across the groups. However, all AC suture constructs significantly increased the resistance torque as compared with the capsulotomy ( P = .01). The subsequent cutting of the CC ligaments resulted in a significant change in 2 of the 5 groups (O-frame, P = .01; X-frame, P = .02) and an overall remaining torque reduction ranging from 3% and 42%. The combined reconstruction of the AC capsule and CC ligaments achieved the highest percentage of regained resistance torque but remained significantly weaker than the native specimen ( P = .01). CONCLUSION: Native translational stability could be restored by the addition of AC capsule augmentation, while partial rotational instability remained. The tested constructs revealed no significant individual differences. CLINICAL RELEVANCE: Combined stabilization of the AC capsule and CC ligaments demonstrated the greatest capacity to restore the native stability against translational and rotational loads, with the specific configuration of the AC capsule repair to be chosen according to the personal preferences of the surgeon.

New insights in the treatment of acromioclavicular separation.

A direct force on the superior aspect of the shoulder may cause acromioclavicular (AC) dislocation or separation. Severe dislocations can lead to chronic impairment, especially in the athlete and high-demand manual laborer. The dislocation is classified according to Rockwood. Types I and II are treated nonoperatively, while types IV, V and VI are generally treated operatively. Controversy exists regarding the optimal treatment of type III dislocations in the high-demand patient. Recent evidence suggests that these should be treated nonoperatively initially. Classic surgical techniques were associated with high complication rates, including recurrent dislocations and hardware breakage. In recent years, many new techniques have been introduced in order to improve the outcomes. Arthroscopic reconstruction or repair techniques have promising short-term results. This article aims to provide a current concepts review on the treatment of AC dislocations with emphasis on recent developments.

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.