Factors Predicting the Outcome After Arthroscopically Assisted Stabilization of Acute High-Grade Acromioclavicular Joint Dislocations

Double figure of eight technique using fiber tape for acute high-grade acromioclavicular joint dislocations - Reconstruction technique

Acromioclavicular (AC) joint dislocations are not uncommon injuries. High-grade dislocations can be managed by arthroscopic as well as open techniques, but the most important thing is to address both vertical and horizontal stability. The purpose of this study is to evaluate the functional outcome of a cost effective double figure of eight technique of stabilizing both coracoclavicular and acromioclavicular ligaments in acute high-grade disruption (Type IIIB -VI) using fibre tape. This study was performed at our tertiary care centre from 2017 to 2020 after appropriate IRB approval and patient consent. Out of 134 cases, 23 high-grade AC joint disruptions treated with our technique were included in the study. Demographic data analysis, pre-op and post-op Constant score and UCLA scoring were done to assess the functional outcome; Coracoclavicular distance (CCD) and CCD ratio were used to assess the radiological outcome. Significant improvement in Constant and UCLA shoulder scores were observed from pre-op to final follow up. With respect to the radiological outcome, all cases had a significant improvement in CCD and CCD ratio from baseline to final follow-up. To conclude, our double figure of eight technique is more anatomical, addresses both vertical and horizontal stability, easily reproducible, cost-effective and safe technique.

3D C-arm navigated acromioclavicular joint stabilization

INTRODUCTION

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

MATERIALS AND METHODS

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

RESULTS

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

CONCLUSION

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

Management of Acute High-Grade Acromioclavicular Joint Dislocations: Comparable Clinical and Radiological Outcomes After Bidirectional Arthroscopic-Assisted Stabilization With the Single Low-Profile Suture Button Technique Versus Double-Suture Button Technique

PURPOSE

To compare the 2-year clinical and radiological outcomes of an arthroscopic-assisted bidirectional stabilization procedure using a single low-profile (LPSB) or double-suture button (DSB) technique with additional percutaneous acromioclavicular (AC) cerclage fixation for patients with acute high-grade AC joint dislocation.

METHODS

This retrospective cohort study compared male patients aged between 18 and 56 years with acute high-grade AC joint dislocation fixed with either a LPSB or DSB technique. Patients were examined at least 24 months after surgery. Subjective Shoulder Value (SSV), Taft (TF), and Acromioclavicular Joint Instability (ACJI) scores were evaluated. Coracoclavicular difference, ossification, AC joint osteoarthritis, and dynamic posterior translation (DPT) were assessed on bilateral anteroposterior stress radiographs and modified Alexander views. The revision rate due to implant conflict and duration of surgery were reported. Group outcome differences were analyzed using standardized hypothesis tests.

RESULTS

28 patients aged 39.2 (LPSB) and 36.4 years (DSB) (P = .319; CI: -2.77-8.34) were eligible per cohort. The follow-up was 30.5 (LPSB) and 37.4 months (DSB) (P = .02; CI: -12.73-1.08). LPSB patients rated a significantly higher SSV (93.2% vs 81.9% [DSB]; P = .004). TF and ACJI scores were similar between the groups. Coracoclavicular difference markedly decreased from 12 mm to 3 mm for both cohorts (P < .001). Ossification was identified in over 85% in both cohorts (P = .160; CI -0.77-0.13) and osteoarthritis in 21.4% (LPSB) and 39.3% (DSB) (P = .150). Persistent DPT was found in around 30% for both cohorts (P = .561; CI -0.26-0.48). The revision rates were 0% (LPSB) and 7% (DSB) (P = .491). LPSB surgery was shorter (59.7 vs 71.5 mins [DSB]) (P = .011).

CONCLUSIONS

The results of the LPSB and DSB techniques with additional percutaneous AC cerclage fixation showed comparable outcomes with excellent clinical and satisfactory radiological results. The assessment of the subjective patient satisfaction was in favor of the LPSB technique and no postoperative revision event was observed following this procedure.

LEVEL OF EVIDENCE

Level III, retrospective comparative therapeutic trial.

[Minimally Invasive Techniques for the Treatment of Acute and Chronic Acromioclavicular Joint Instabilities]

Acromioclavicular joint instabilities are one of the most common injuries of the shoulder girdle. Diagnostic measures include the vertical and horizontal components of instability. The main goals of treatment include pain reduction, joint stabilization, and return to physical activity. For operative treatment, there are numerous techniques available. Recently, minimally-invasive techniques were developed and showed equal results as with open approach. These procedures facilitate simultaneous treatment of concomitant shoulder lesions and reduce soft tissue trauma as well as the risk of infection. This article presents an overview of such minimally-invasive techniques for both acute and chronic instabilities. Both techniques address the aspect of horizontal instability, which was found to compromise clinical results. For an acute injury, we describe the use of a low-profile button system combined with an additional acromioclavicular cerclage. In the chronic setting with a bidirectional (vertical and horizontal) instability, a free tendon graft combined with a single TightRope augmentation is recommended.

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.

High Early-onset acromioclavicular secondary pathologies after acute arthroscopic joint reduction: a cohort study

PURPOSE

The research aim was to determine the prevalence and risk factors of early secondary acromioclavicular (AC) joint disease in patients undergoing acute arthroscopic AC joint reduction and fixation and early complications of acute surgical treatment in patients with high-grade AC joint dislocation.

METHODS

Overall, 102 patients diagnosed with Rockwood type V AC joint dislocation and undergoing arthroscopic coracoclavicular fixation were included. Early clinical and radiological complications were evaluated, as well as risk factors of secondary AC joint pathology.

RESULTS

Twenty-nine patients (28%) presented with a secondary AC joint pathology, with 24 and 5 cases of osteolysis and osteoarthritis, respectively. The main complication was a loss of reduction of ≥ 1 mm (78%). Patients aged > 55 years were more likely to develop a secondary AC joint disease (odds ratios (OR) = 10.1, 95% confidence interval (CI): 1.42 - 72.55, p = 0.021). Patients with osteolysis (OR = 3.2, 95% CI 1.16 - 9.27, p = 0.025) or loss of reduction of > 5 mm (OR = 7.4, 95% CI 2.31 - 24.08, p = 0.001) were more likely to develop AC joint pain. Patients with an initial over-reduction were less likely to develop a subluxated AC joint (OR = 0.033, 95% CI 0.0021-0.134, p = 0.001) CONCLUSION: Age > 55 years and female sex were identified as risk factors of early-onset secondary AC joint disease. Osteolysis and a loss of reduction of > 5 mm were risk factors of AC joint pain but not of revision surgery. The main early complication was a loss of reduction of ≥ 1 mm. An initial over-reduction of the distal clavicle was a protective factor to avoid AC joint subluxation.

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

Purpose

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

Methods

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

Results

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

Conclusions

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

Level of Evidence

Level IV, therapeutic case series.

All-Arthroscopic Coracoacromial Ligament Transfer: The Modified Neviaser Procedure for Acromioclavicular Dislocations

Over the course of the years, the topic of optimizing the management of acromioclavicular joint dislocations has gained popularity, remaining a subject of debate. It has been determined that posterior horizontal instability appears to be one of the factors influencing both clinical and radiographic outcomes, postsurgical reconstructions with coracoclavicular techniques. In contrast, the acromioclavicular ligament complex (ACLC) has been experimentally demonstrated to play a crucial role in horizontal translation and rotational stability of the clavicle. Although several strategies have been established, perfect surgical timing, and its potential impact during the healing process, remain poorly defined. Furthermore, appropriate surgical techniques to restore normal acromioclavicular joint kinematics while ensuring an adequate biological environment remain unclear. Due to the existence of multiple features present in acromioclavicular joint reconstruction techniques, an ideal approach involves ACLC and coracoclavicular combination reconstruction, minimal clavicular drilling, and biological enhancement to ensure anatomical reduction and an adequate process of ligament healing. The purpose of this Technical Note is to present a modified surgical technique of the Neviaser procedure. This modified surgical technique combines an all-arthroscopic single tunnel coracoclavicular fixation with the transfer of the coracoacromial ligament to reconstruct the ACLC.

Low rate of substantial loss of reduction immediately after hardware removal following acromioclavicular joint stabilization using a suspensory fixation system

PURPOSE

To evaluate immediate loss of reduction in patients undergoing hardware removal after arthroscopically assisted acromioclavicular (AC) joint stabilization using a high-tensile suture tape suspensory fixation system and to identify risk factors associated with immediate loss of reduction.

MATERIALS AND METHODS

Twenty-two consecutive patients with a mean age of 36.4 ± 12.6 years (19-56), who underwent hardware removal 18.2 ± 15.0 months following arthroscopically assisted stabilization surgery using a suspensory fixation system for AC joint injury between 01/2012 and 01/2021 were enrolled in this retrospective monocentric study. The coracoclavicular distance (CCD) as well as the clavicular dislocation/acromial thickness (D/A) ratio were measured on anterior-posterior radiographs prior to hardware removal and immediately postoperatively by two independent raters. Loss of reduction, defined as 10% increase in the CCD, was deemed substantial if the CCD increased 6 mm compared to preoperatively. Constitutional and surgical characteristics were assessed in a subgroup analysis to detect risk factors associated with loss of reduction.

RESULTS

Postoperatively, the CCD significantly increased from 12.6 ± 3.7 mm (4.8-19.0) to 14.5 ± 3.3 mm (8.7-20.6 mm) (p < 0.001) while the D/A ratio increased from 0.4 ± 0.3 (- 0.4-0.9) to 0.6 ± 0.3 (1.1-0.1) (p = 0.034) compared to preoperatively. In 10 cases (45%), loss of reduction was identified, while a substantial loss of reduction (> 6 mm) was only observed in one patient (4.5%). A shorter time interval between index stabilization surgery and hardware removal significantly corresponded to immediate loss of reduction (11.0 ± 5.6 vs. 30.0 ± 20.8 months; p = 0.007), as hardware removal within one year following index stabilization was significantly associated with immediate loss of reduction (p = 0.027; relative risk 3.4; odds ratio 11.67).

CONCLUSIONS

Substantial loss of reduction after hardware removal of a high-tensile suture tape suspensory fixation system was rare, indicating that the postoperative result of AC stabilization is not categorically at risk when performing this procedure. Even though radiological assessment of the patients showed a statistically significant immediate superior clavicular displacement after this rarely required procedure, with an increased incidence in the first year following stabilization, this may not negatively influence the results of ACJ stabilization in a clinically relevant way.

LEVEL OF EVIDENCE

IV.

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.

Biologic and synthetic ligament reconstructions achieve better functional scores compared to osteosynthesis in the treatment of acute acromioclavicular joint dislocation

PURPOSE

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

METHODS

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

RESULTS

One hundred and thirty-three studies were included for a total of 4473 shoulders. Mean age of participants was 36.9 years. Mean follow-up was 42.06 months. Arthroscopy showed better ASES (p < 0.0001) and lower VAS pain score (p = 0.0249) compared to an open approach. Biologic and synthetic reconstructions demonstrated better results over osteosynthesis techniques. Biologic techniques showed overall better Constant (p = 0.0001) and DASH (p = 0.0215) scores, while synthetic reconstruction showed better UCLA score (p = 0.0001). Among suture buttons, triple button showed overall better results in Constant (p = 0.0001) and VAS (p = 0.0001) scores, while better results in DASH score (p = 0.0003) were achieved by 2 double button techniques. Overall, the level of evidence was low.

CONCLUSION

Biological and synthetic reconstructions achieved better functional scores compared to osteosynthesis. Among suture buttons, the triple button showed better functional performance.

LEVEL OF EVIDENCE

IV.

Acute high-grade acromioclavicular joint dislocation patients treated with titanium cable insertion under a homemade guider

Backgrounds

To describe a new technique for implanting a double-bundle titanium cable to treat acromioclavicular (AC) joint dislocation via the new guider, and evaluate clinic outcomes.

Methods

A retrospective study of patients treated for acute high-grade acromioclavicular joint dislocation from June 2016 to January 2020 in our trauma center, twenty patients with AC joint dislocation were managed with double-bundle titanium cable. It includes the following steps: (1) Put the guider under the coracoid close to the cortical; (2) drill proximal clavicle; (3) place the titanium cable; (4) perforate distal clavicle, (5) reset the acromioclavicular joint and lock titanium cable; and (6) suture the acromioclavicular ligament. An independent reviewer conducted functional testing of these patients, including the use of coracoclavicular distance (CCD), visual analog scale (VAS) scores, and Constant–Murley scores (CMS).

Results

All patients are presented following at a median duration of 15 months (12-24months) after the surgery. All patients based on X-ray evaluation and clinic evaluation. The median CCD was 7.5 (6–14) mm, the VAS score was 0.55 (0-2), the CMS score was 95.5 (92-99). One patient had subluxation again at the final follow-up based on X-ray examination.

Conclusions

This study demonstrates that the AC joint fixation anatomically with double-bundle titanium, acquired excellent outcomes in terms of the recovery of shoulder joint function and radiographic outcomes. It has a low complication rate and need not remove the hardware.

Functional and Radiographic Outcomes of Intraoperatively Decreasing the Coracoclavicular Distance to 50% of the Unaffected Side in Stabilization of Acute Acromioclavicular Joint Injury: A Retrospective Evaluation

Background:

The postoperative failure rate of acromioclavicular (AC) joint fixation using the coracoclavicular (CC) stabilization technique is high. Studies have reported that compared with normal intraoperative anatomic reduction, intraoperative overreduction of the AC joint is more successful in achieving a satisfactory anatomic radiographic outcome at 1- to 2-year follow-up.

Purpose:

To evaluate the functional and radiographic outcomes and complications in patients with acute AC joint injury who underwent combined CC stabilization and AC capsular repair in which the CC distance was intraoperatively decreased to 50% of the unaffected side.

Study Design:

Case series; Level of evidence, 4.

Methods:

In this retrospective study, we collected and analyzed the data of patients with an acute AC joint injury (Rockwood type 5) who underwent combined CC stabilization and AC capsular repair during which the CC distance was decreased 50% compared with the unaffected side. At 2-year follow-up, we evaluated functional outcomes (American Shoulder and Elbow Surgeons [ASES] score), radiographic outcomes (alignment of the AC joint in the vertical and horizontal planes, tunnel widening), and complications (infection, clavicular fracture).

Results:

The study included 20 patients with a mean ± SD age of 42.20 ± 10.10 years. The mean follow-up period was 33.75 ± 11.50 months. At the 2-year follow-up, the mean ASES score was 95.13 ± 5.61. The overreduction alignment, anatomic alignment, and loss reduction alignment rates were 0% (0/20 patients), 95% (19/20 patients), and 5% (1/ 20 patients), respectively. No statistically significant difference was found in the mean CC distance between the affected and unaffected sides on radiographic evaluation. The mean medial clavicular tunnel width and lateral clavicular tunnel width were 5.03 ± 0.68 mm and 4.47 ± 0.67 mm, respectively. None of the patients experienced fractures or infections.

Conclusion:

Excellent functional and radiographic outcomes and no complications were seen at 2-year follow-up in patients with acute AC joint injury who underwent combined CC stabilization and AC capsular repair with the CC distance intraoperatively decreased to 50% of the unaffected side.

Better Radiographic Reduction and Lower Complication Rates With Combined Coracoclavicular and Acromioclavicular Ligament Reconstruction Than With Isolated Coracoclavicular Reconstruction

Purpose

To determine whether combined acromioclavicular (AC) ligament reconstruction and coracoclavicular (CC) ligament reconstruction without bone tunnels would improve radiographic reduction maintenance and complication rates for type III to V AC dislocations.

Methods

This single-institution retrospective study analyzed all patients who underwent a hybrid synthetic/graft wrap CC reconstruction without tunnels with additional AC reconstruction/repair from January 2013 to August 2019. This 26-patient cohort was compared with a 1:1 sex- and age-matched control group who underwent CC reconstruction without AC reconstruction. CC distances on postoperative radiographs were compared with normal contralateral shoulders.

Results

Of the 93 patients who underwent AC reconstructive surgery during this time period, 26 patients (96% male) met the inclusion criteria. The AC/CC cohort had 23.5% type III injuries, 23.1% type IV injuries, and 53.8% type V injuries, similar to the control group. Final radiographs of the operative shoulder’s CC distance were (mean ± standard deviation) 0.9 ± 4.0 mm greater than that of the contralateral shoulder (9.6 ± 8.7 mm) in the AC/CC cohort. Final radiographs of the operative shoulder’s coracoclavicular distance were 4.0 ± 4.7 mm greater than that of the contralateral shoulder (13.3 ± 9.3 mm) in the CC control group, a significant difference (P = .014). The AC/CC reconstruction group had fewer patients with a loss of reduction >5 mm (11.5% versus 38.5%, P = .025). The complication rate in the CC control group was higher than in the AC/CC cohort (30.7% versus 7.7%, P = .035). The reoperation rate was also greater in the CC control group (8 versus 1, P = .010).

Conclusion

This cohort study shows that the addition of AC reconstruction to CC reconstruction using synthetic tapes/grafts or allograft tissues without bone tunnels significantly improves durable radiographic outcomes, diminishes complication rates, and improves reoperation rates.

Level of Evidence

III, retrospective comparative study.

RR, Costa G, Verdalet I, Ezzeddine H, Rius X. Arthroscopically Assisted Comprehensive Double Cerclage Suture Fixation Technique for Acute Acromioclavicular Joint Separation

Acromioclavicular dislocations are some of the most frequently recorded and controversial injuries in the athletic population. These injuries have historically been a matter of disagreement between surgeons, particularly when it comes to the surgical technique used to treat them, its approach, or its timing. Consensus over the "gold standard" procedure to treat them is yet to be established. Even though numerous surgical techniques have already been described, the number of complications and loss of reduction remains a matter of concern for treating physicians. Here, we present an arthroscopically assisted coracoclavicular and horizontal acromioclavicular fixation technique in a modified figure-of-eight configuration using 2 strong FiberTape Cerclage sutures, with measurable tension, for the comprehensive treatment of acromioclavicular joint dislocations.

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.

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.

Vertical and Rotational Stiffness of Coracoclavicular Ligament Reconstruction: A Biomechanical Study of 3 Different Techniques

PURPOSE

To compare the biomechanical stability of 3 different coracoclavicular reconstruction techniques under rotational and vertical loading using a cadaveric model.

METHODS

In total, 12 cadaveric shoulders were used for testing. The native state was first tested then followed by 3 different reconstruction configurations using suture tapes and cortical buttons: coracoid loop (CL), single-bundle (SB), and double-bundle (DB). Superior displacement was measured by cycling an inferiorly directed force of 70 N to the scapula. The rotational stiffness of the scapula was determined by cycling the scapula in rotational displacement control between 15° of internal and external rotation. The rotational stiffness of the clavicle was determined by rotating the clavicle around its long axis 20° anteriorly and 30° posteriorly in rotational displacement control. All measurements were captured over 10 cycles at a rate of 200 Hz.

RESULTS

Both the CL and SB techniques demonstrated significantly less internal scapular rotation stiffness. (intact: 19.70 ± 9.07 cNm/deg, CL: 3.70 ± 2.63 cNm/deg, SB:4.30 ± 2.66 cNm/deg, P <.001) External scapular rotation stiffness was significantly decreased in all techniques (intact: 17.70 ± 4.43 cNm/deg, CL: 3.30 ± 1.37 cNm/deg, SB: 4.50 ± 1.56 cNm/deg, DB: 4.67 ± 1.99 cNm/deg, P < .001). The CL and SB reconstructions were significantly less stiff with regards to posterior rotation of the clavicle (intact: 5.60 ± 1.80 cNm/deg, CL: 2.90 ± 1.10 cNm/deg, SB: 1.40 ± 0.65 cNm/deg, P < .001). Anterior rotation stiffness of the clavicle was significantly lower in all of the reconstructions (intact: 6.95 ± 1.90 cNm/deg, CL: 3.08 ± 0.84 cNm/deg, SB: 3.64 ± 0.93 cNm/deg, DB: 4.48 ± 1.21 cNm/deg, P < .001).

CONCLUSIONS

None of the described techniques provided equivalent rotational stability in all planes compared with the native state. DB reconstruction presented stiffness characteristics closest to the native state under cyclic loading during internal scapular and posterior clavicular rotation.

CLINICAL RELEVANCE

Additional procedures such as tendon grafting or acromioclavicular ligament reconstruction may be required to control rotational stability.