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

The importance of a structured failure analysis in revision acromioclavicular joint surgery: A multi-rater agreement on the causes of stabilization failure from the ISAKOS shoulder committee

BACKGROUND

Acromioclavicular joint (ACJ) stabilizations are associated with a high overall failure rate with 9.5% of these patients requiring subsequent revision surgery. Consequently, understanding the specific cause of primary ACJ stabilization failure is paramount to improving surgical decision-making in this challenging patient cohort.

PURPOSE

To (1) identify risk factors and mechanisms for failure following primary arthroscopically-assisted ACJ stabilization to highlight the importance of conducting a detailed failure analysis and to (2) establish revision strategies based on real-life cases of primary failed ACJ stabilization.

STUDY DESIGN

Level of evidence IV.

METHODS

A survey was shared internationally among members of the International Society of Arthroscopy, Knee Surgery and Orthopaedic Sports Medicine (ISAKOS) shoulder committee. The survey contained failure analysis of 11 real-life cases of failed primary arthroscopically-assisted ACJ stabilization. For each case, a thorough patient history, standardized radiographs, and CT scans were provided. Participants were asked to give their opinion on bone tunnel placement, cause of failure (biological, technical, traumatic, or combined), the stabilization technique used, as well as give a recommendation for revision.

RESULTS

Seventeen members of the ISAKOS shoulder committee completed the survey. Biological failure was considered the most common cause of failure (47.1%), followed by technical (35.3%) and traumatic (17.6%) failure. The majority deemed two modifiable factors (i.e., patient's profession and sport) as well as non-modifiable factors (i.e., patient's age and time from trauma to initial surgery) to be risk factors for failure. In 10 of 11 cases, the correct fixation device was used in the primary setting (90.9%; 52.8-82.4% agreement); however, in eight of those cases, the technique was not performed correctly (80.0%; 58.8-100% agreement). In 8 of all 11 cases, the majority recommended an arthroscopically assisted technique with graft augmentation for revision (52.9-58.8% agreement).

CONCLUSION

Biological failure and technical failure are the most common reason for failure in primary ACJ stabilization followed by traumatic failure. Besides, biological failure can be triggered by technical errors such as clavicular or coracoidal tunnel misplacement. Consequently, a detailed failure analysis including preoperative CT should be conducted on the causes of primary ACJ failure, and, if possible, an arthroscopically-assisted technique with graft augmentation should be prioritized in revision ACJ surgery.

CLINICAL RELEVANCE

ACJ stabilizations are associated with a high overall failure rate - potentially due to biological and technical properties. When encountering failed arthroscopically-assisted ACJ stabilization, a detailed failure analysis should be conducted on the causes of primary ACJ failure. Furthermore, an arthroscopically-assisted revision stabilization is feasible in most cases.

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.

Open Anatomic Coracoclavicular Ligament Reconstruction for Acromioclavicular Joint Injuries

Open reconstruction of the coracoclavicular (CC) and acromioclavicular (AC) ligaments results in excellent reduction of severely displaced AC dislocations, most commonly Grades III and V. Anatomic CC reconstruction through clavicular bone tunnels can prevent vertical instability, whereas the addition of an acromial limb of the graft can increase horizontal stability. Autograft tendon is preferred in the young athletic group of collision sports participants, although allograft has had acceptable results. Accessory fixation may be placed to protect the graft during healing, or for severe instability, especially for athletes involved in contact sports.

Iatrogenic instability of the acromioclavicular joint leads to ongoing impairment of shoulder function even following secondary surgical stabilization

PURPOSE

Iatrogenic instability of the acromioclavicular joint (ACJ) following distal clavicle excision (DCE) represents an infrequent pathology. Revision surgery to restore ACJ stability and alleviate concomitant pain is challenging due to altered anatomic relationships. The purpose of this study was to evaluate the used salvage techniques and postoperative functional and radiological outcomes in retrospectively identify patients with a painful ACJ following DCE. We hypothesized that iatrogenic instability leads to ongoing impairment of shoulder function despite secondary surgical stabilization.

METHODS

9 patients with a painful ACJ after DCE (6 men, 3 women, 43.3 ± 9.4 years) were followed up at a minimum of 36 months after revision surgery. Besides range of motion (ROM), strength and function were evaluated with validated evaluation tools including the Constant score and the DASH score (Disability of the Arm, Shoulder and Hand questionnaire), specific AC Score (SACS), Nottingham Clavicle Score (NCS), Taft score and Acromioclavicular Joint Instability Score (AJI). Additionally, postoperative X-rays were compared to the unaffected side, measuring the coracoclavicular (CC) and acromioclavicular (AC) distance.

RESULTS

At follow-up survey (55.8 ± 18.8 months) all patients but one demonstrated clinical ACJ stability after arthroscopically assisted anatomical ACJ reconstruction with an autologous hamstring graft. Reconstruction techniques were dependent on the direction of instability. The functional results demonstrated moderate shoulder and ACJ scores with a Constant Score of 77.3 ± 15.4, DASH-score of 51.2 ± 23.4, SACS 32.6 ± 23.8, NCS 77.8 ± 14.2, AJI 75 ± 14.7 points and Taft Score 7.6 ± 3.4 points. All patients stated they would undergo the revision surgery again. Mean postoperative CC-distance (8.3 ± 2.8 mm) did not differ significantly from the contralateral side (8.5 ± 1.6 mm) (p > 0,05). However, the mean AC distance was significantly greater with 16.5 ± 5.8 mm compared to the contralateral side (3.5 ± 1.9 mm) (p = 0.012).

CONCLUSION

Symptomatic iatrogenic ACJ instability following DCE is rare. Arthroscopically assisted revision surgery with an autologous hamstring graft improved ACJ stability in eight out of nine cases (88.9%). However, the functional scores showed ongoing impairment of shoulder function and a relatively high overall complication rate (33.3%). Therefore, this study underlines the importance of precise preoperative indication and planning and, especially, the preservation of ACJ stability when performing AC joint resection procedures.

LEVEL OF EVIDENCE

Case series, LEVEL IV.

Management of Acromioclavicular Injuries - Current Concepts

Introduction

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

Material and Methods

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

Results

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

Conclusion

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

Acromioclavicular and coracoclavicular ligamentous insertion distances depend on the scapular tilt and decrease with anterior direction of the inferior scapula angle

PURPOSE

A variety of reconstruction techniques exist for the operative treatment of a ruptured acromioclavicular and coracoclavicular ligamentous complex. However, the complication rate remains high; between 5 and 89%. The intraoperative distance between the clavicle, acromion and coracoid is important for the refixation quality. In this study, the influence of scapular deflection on coracoclavicular and acromioclavicular distances was analysed.

METHODS

The ligamentous insertions of 24 fresh-frozen human scapulae were exposed. The coracoclavicular and acromioclavicular ligaments were referenced and captured in a rigid body system using a three-dimensional (3D) measurement arm. The inferior angle of the scapula was manually pulled into maximum anterior and posterior deflection, simulating a patient positioning with or without dorsal scapular support, respectively. Based on the rigid body system, the distances between the ligamentous insertions were calculated. Statistical evaluation was performed by setting the distances in anterior deflection to 100% and considering the other distances relative to this position.

RESULTS

The scapular deflection had a considerable impact on the distance between the ligamentous insertions. Concerning the conoid ligament, the mean distance was almost doubled when the inferior angle pointed posteriorly compared to anterior deflection (195.3 vs 100.0%; p = 0.028). The insertion of the acromioclavicular capsule also showed a significant association with the direction of deflection (posterior = 116.1% vs. anterior = 100%; p = 0.008).

CONCLUSION

Dorsal support shifting the inferior angle of the scapula anteriorly reduces the distance between the ligamentous insertions. Therefore, a patient position on a shoulder table with posterior support of the scapula is recommended to reliability reduce the acromioclavicular joint.

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.

Treatment of Failed Coracoclavicular Ligament Reconstructions: Primary Acromioclavicular Ligament and Capsular Reconstruction and Revision Coracoclavicular Ligament Reconstruction

Acromioclavicular (AC) joint dislocations are a common injury affecting 2 of every 10,000 people in the general population and comprise 9% to 12% of all injuries to the shoulder. Most injuries occur through contact activity, which drives the acromion inferiorly with the clavicle remaining in its anatomic position, initiating a cascade of injury propagating from the AC ligament followed by failure of the coracoclavicular ligaments. Many techniques have been described for AC joint injuries, without a consensus gold standard. The revision setting offers even less consensus on treatment options and countless difficulties for surgeons. There have been more than 60 described procedures regarding AC and coracoclavicular ligament reconstructions, with significant controversy regarding the optimal intervention for each injury. When these techniques fail, it is important to pinpoint the mechanism of failure to construct a successful plan for revision. The purpose of this Technical Note is to describe our preferred method of primary AC and revision coracoclavicular reconstruction using a combination of autograft and allograft semitendinosus as well as TightRope fixation.

Efficacy of Transosseous Tunnel Placement for Triple Endobutton Plate in Acromioclavicular Joint Reconstruction: A Three-Dimensional Printing Guide Design Technology

Objective

Explore an accurate transosseous tunnel drilling method based on three‐dimensional (3D) printing technology for acromioclavicular joint reconstruction (ACD), design a guide design, and evaluate its accuracy.

Methods

Using Mimics software to reconstruct 100 cases of acromioclavicular joint computed tomography (CT) data. In design 2, the non‐collinear tunnel is superimposed on the 3D model, and a virtual drilling is performed between the clavicle and the coracoid using a triple inner gusset. Then, in the Geomagic Studio software model, an elliptical plane is calculated and extracted as a guide design for precise drilling. Then put the design and the 3D shoulder model together for 3D printing. Ten lengths were measured, and the effects of the virtual model, the actual model, and the guide rail design were compared.

Results

We successfully compared 10 parameters of 3D virtual model and actual model. There was no significant difference between actual and virtual bone tunnels in 10 measurements (P > 0.05).

Conclusions

The accuracy of ACD combined with 3D printing guidance design technology in the transosseous tunnel of adult shoulder is reliable.

Arthroscopic Coracoclavicular Reconstruction Combined with Open Acromioclavicular Reconstruction Using Knot Hiding Clavicular Implants Is a Stable Solution

Purpose

The purpose of this noninterventional, register-based study was to report the outcomes and wound healing of surgically treated chronic acromioclavicular (AC) dislocations using a tendon graft and knot-hiding titanium implants.

Methods

Thirty-two cases with chronic AC separation underwent an arthroscopic coracoclavicular (CC) ligament reconstruction and an open AC ligament reconstruction using knot-hiding titanium implants. The wound healing was assessed 2 months after the operation. The Nottingham Clavicle score, Constant score, and Simple Shoulder Test were obtained postoperatively and at a minimum of one-year postsurgery. The radiographic change in distance between the clavicular and coracoid cortices and clavicular tunnel diameter was measured. General patient satisfaction with the outcome (poor, fair, good, or excellent) was also assessed 1 year postoperatively.

Results

The mean Nottingham Clavicle score increased from a preoperative mean of 41.66 ± 9.86 to 96.831 ± 5.86 (P ≤ .05). The Constant score increased from a preoperative mean of 44.66 ± 12.54 to 93.59 ± 7.01 (P ≤ .05). The Simple Shoulder Test score increased from a preoperative mean of 7.00 ± 2.14 to 11.84 ± .63 (P ≤ .05). The coracoclavicular distance increased from 11.32 ± 3.71 to 13.48 ± 3.79 mm (P ≤ .05). The clavicular drill hole diameter increased from 6 mm to a mean of 6 to a mean of 8.13 ± 1.12 mm. Twenty-three (71.9%) patients reported an excellent outcome, and nine (28.1%) reported a good outcome. One clavicular fracture occurred but no coracoid fractures. There was one reconstruction failure leading to a reoperation.

Conclusions

In this series, combining the arthroscopic CC ligament reconstruction to an open reconstruction of the AC joint with a tendon graft proved to be a stable solution. The knot-hiding titanium implant effectively eliminated the problems related to the clavicular wound healing.

Level of Evidence

Level IV, therapeutic case series.

Comparison of single versus double TightRope system in the treatment of acute acromioclavicular joint dislocation

BACKGROUND

Reconstruction of the coracoclavicular (CC) ligament using a single TightRope (ST) system has some complications. We attempted to use a double TightRope (DT) system to reduce complications and obtain the ideal therapeutic effect.

PURPOSE

This investigation aimed to compare the ST and DT systems in terms of efficacy and safety in treating acromioclavicular (AC) joint dislocation.

METHODS

Sixty-six cases of acute AC joint dislocation between January 2013 and January 2018 were retrospectively reviewed. All patients were divided into 2 groups based on treatment with the ST or DT system. Patients were evaluated radiologically and clinically using the Disability of Arm, Shoulder, and Hand, Constant, and visual analog scale scores as clinical outcome measures at 1 day, 3 weeks, 6 weeks, 3 months, 6 months, 1 year, and 2 years after surgery. The CC distance and displacement ratio were assessed radiologically.

RESULTS

The mean follow-up period was 49 months. Satisfactory clinical outcomes were obtained after CC fixation in both groups. No intergroup difference was found regarding the visual analog scale (P = .80), Disability of Arm, Shoulder, and Hand (P = .42), or Constant score (P = .28) at 2 years. However, there was a significant difference in the displacement ratio at 6 weeks (P < .0001), 3 months (P < .0001), 6 months (P < .0001), 1 year (P < .0001), and 2 years (P < .0001) postoperatively between the 2 groups. There were 3 complications in the ST group, including 1 case of secondary coracoid fracture, 1 case of AC joint arthrosis combined with ossification of the CC ligaments, and 1 case of clavicular erosion. All complications occurred in the ST group.

CONCLUSIONS

Both surgical methods are effective in treating AC joint dislocation, but the DT system is more reliable for reduction maintenance.

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

PURPOSE

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

METHODS

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

RESULTS

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

CONCLUSION

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

STUDY DESIGN

Case Series; Level of evidence, IV.

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

PURPOSE

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

METHODS

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

RESULTS

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

CONCLUSION

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

LEVEL OF EVIDENCE

IV.

Conversion to anatomic coracoclavicular ligament reconstruction (ACCR) shows similar clinical outcomes compared to successful non-operative treatment in chronic primary type III to V acromioclavicular joint injuries

PURPOSE

To compare the clinical outcomes of patients who underwent successful nonoperative treatment for type III-V acromioclavicular joint (ACJ) injuries to those who eventually required conversion to anatomic coracoclavicular ligament reconstruction (ACCR) at a minimum 5-year follow-up.

METHODS

Patients with primary, chronic type III-V ACJ injuries who either underwent successful conservative treatment or conversion to ACCR after failing a trail of conservative management between 2003 and 2014 with a minimum 5-year follow-up were included in the study. Clinical outcome measures comprised the American Shoulder and Elbow Surgeons (ASES) and Simple Shoulder Test (SST) score, collected preoperatively and at final visit for the ACCR group. Outcome scores for patients with successful conservative treatment were only collected at final visit. A Self- Assessment Numeric Evaluation (SANE) score was obtained at terminal follow-up for both groups.

RESULTS

Twenty-two patients (mean age: 40.1 ± 15.6 years) with successful nonoperative treatment and twenty-one patients (mean age: 43.6 ± 12.0 years) who required conversion to ACCR were included in the study. At final follow-up, patients with successful non-operative treatment achieved similar ASES (93.0±12.0NonOP vs. 86.1±16.8ACCR), SST (11.2±1.4NonOP vs. 10.7±2.0ACCR) and SANE scores (80.9±19.7NonOPvs. 90.5±14.7ACCR) compared to those who were converted to ACCR. Additionally, patients who underwent conversion to ACCR showed significant improvement in ASES (49.8±18.1pre vs. 86.1±16.8post; Δ36.3±19.7) and SST scores (6.5±3.2prevs. 10.7±2.0post; Δ4.2±4.0) from pre- to postoperative.

CONCLUSION

At a minimum 5-year follow-up, patients with successful non-operative treatment for type III-V ACJ injuries achieved similar clinical outcomes compared to those who were converted to ACCR. In patients with chronic severe ACJ dislocation a trial of conservative treatment may be attempted, astime from injuryto eventual conversion to ACCR had no significant influence on postoperative clinical outcomes.

LEVEL OF EVIDENCE

Level IV.

Treatment of a Failed Type V Acromioclavicular Separation Due to Coracoid Fracture: Revision of Acromioclavicular-Coracoclavicular Reconstruction and Coracoid Fixation

Acromioclavicular (AC) injuries are common, especially in the young and active population. AC joint dislocations account for 8% of all joint dislocations and are even more common in contact sports. These injuries are graded as type I through type VI on the basis of the Rockwood classification method. Types I and II are generally treated without surgery whereas types IV, V, and VI are best treated operatively. Type III dislocations remain controversial in terms of treatment, and many surgeons recommend nonoperative treatment first and operative treatment in case of continued symptoms such as pain, instability, or shoulder girdle dysfunction. The goal of operative treatment is to restore AC joint stability, which involves addressing both the coracoclavicular and coracoacromial ligaments to achieve a desirable patient outcome. The objective of this Technical Note is to describe our technique for management of a failed acromioclavicular stabilization, treated with a coracoclavicular and AC joint capsular reconstruction using tibialis anterior and semitendinosus allografts.

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

Background:

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

Purpose:

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

Study Design:

Case series; Level of evidence, 4.

Methods:

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

Results:

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

Conclusion:

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

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

Purpose

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

Methods

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

Results

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

Conclusions

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

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

Objective

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

Methods

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

Results

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

Conclusion

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