Acromioclavicular Joint Instability on Cross-Body Adduction View: The Biomechanical Effect of Acromioclavicular and Coracoclavicular Ligaments Sectioning

Abstract Background The relationship between acromioclavicular (AC) joint dislocation, corresponding radiological evaluation, and ligament injuries remains controversial. We hypothesized that AC and trapezoid ligament injuries induce AC joint instability, and the clavicle can override the acromion on cross-body adduction view without conoid ligament injury. We aimed to investigate how biomechanically sectioning the AC and coracoclavicular (CC) ligaments contributes to AC joint instability in the cross-body adduction position using fresh-frozen cadaver models. Methods Six fresh-frozen cadaveric shoulders were used in this study, comprising five male and one female specimen, with a mean age of 68.7 (range, 51–87) years). The left side of the trunk and upper limb, and the cervical and thoracic vertebrae and sternum were firmly fixed with an external fixator. The displacement of the distal end of the clavicle relative to the acromion was measured using an electromagnetic tracking device. We simulated AC joint dislocation by sequential resection of AC ligament, AC joint capsule, and CC ligaments in the following order of stages. Stage 0: Intact AC and CC ligaments and acromioclavicular joint capsule; stage 1: Completely sectioned AC ligament and joint disc; stage 2: Sectioned trapezoid ligament; and stage 3: Sectioned conoid ligament. The superior clavicle displacement related to the acromion was measured in the horizontal adduction position, and clavicle overriding on the acromion was assessed radiologically at each stage. Data were analyzed using a one-way analysis of variance and post-hoc tests. Results Superior displacement was 0.3 mm at stage 1, 6.5 mm at stage 2, and 10.7 mm at stage 3. On the cross-body adduction view, there was no distal clavicle overriding at stages 0 and 1, and distal clavicle overriding was observed in five cases (5/6: 83%) at stage 2 and in six cases (6/6: 100%) at stage 3. Conclusion We found that AC and trapezoid ligament sectioning induced AC joint instability and that the clavicle could override the acromion on cross-body adduction view regardless of conoid ligament sectioning. AC and trapezoid ligament injuries may lead to significant AC joint instability, and the distal clavicle may subsequently override the acromion.

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The Role of the Acromioclavicular Ligament in Acromioclavicular Joint Stability: A Cadaveric Biomechanical Study

Orthopaedic Journal of Sports Medicine ◽

10.1177/2325967120982947 ◽

2021 ◽

Vol 9 (2) ◽

pp. 232596712098294

Author(s):

Shimpei Kurata ◽

Kazuya Inoue ◽

Hideo Hasegawa ◽

Takamasa Shimizu ◽

Akio Iida ◽

...

Keyword(s):

Biomechanical Study ◽

Joint Capsule ◽

Joint Stability ◽

Ac Joint ◽

Rockwood Classification ◽

Posterior Displacement ◽

Horizontal Stability ◽

Fresh Frozen ◽

Trapezoid Ligament ◽

Stage 1

Background: Acromioclavicular (AC) joint dislocation is evaluated using the radiologically based Rockwood classification. The relationship between ligamentous injury and radiological assessment is still controversial. Purpose/Hypothesis: To investigate how the AC ligament and trapezoid ligament biomechanically contribute to the stability of the AC joint using cadaveric specimens. The hypothesis was that isolated sectioning of the AC ligament would result in increased instability in the superior direction and that displacement >50% of the AC joint would occur. Study Design: Controlled laboratory study. Methods: Six shoulders from 6 fresh-frozen cadavers were used in this study. Both the scapula and sternum were solidly fixed on a customized wooden jig with an external fixator. We simulated distal clavicular dislocation with sequential sectioning of the AC and coracoclavicular (CC) ligaments. Sectioning stages were defined as follows: stage 0, the AC ligament, CC ligament, and AC joint capsule were left intact; stage 1, the anteroinferior bundle of the AC ligament, joint capsule, and disk were sectioned; stage 2, the superoposterior bundle of the AC ligament was sectioned; and stage 3, the trapezoid ligament was sectioned. The distal clavicle was loaded with 70 N in the superior and posterior directions, and the magnitudes of displacement were measured. Results: The amounts of superior displacement averaged 3.7 mm (stage 0), 3.8 mm (stage 1), 8.3 mm (stage 2), and 9.5 mm (stage 3). Superior displacement >50% of the AC joint was observed in stage 2 (4/6; 67%) and stage 3 (6/6; 100%). The magnitudes of posterior displacement were 3.7 mm (stage 0), 3.7 mm (stage 1), 5.6 mm (stage 2), and 9.8 mm (stage 3). Posterior displacement >50% of the AC joint was observed in stage 3 (1/6; 17%). Conclusion: We found that the AC ligaments contribute significantly to AC joint stability, and superior displacement >50% of the AC joint can occur with AC ligament tears alone. Clinical Relevance: The AC ligament plays an important role not only in horizontal stability but also in vertical stability of the AC joint.

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Clinical and Radiological Results of Hook Plate Fixation in Acute Acromioclavicular Joint Dislocations and Distal Clavicle Fractures

Clinics in Shoulder and Elbow ◽

10.5397/cise.2018.21.2.95 ◽

2018 ◽

Vol 21 (2) ◽

pp. 95-100

Author(s):

Joo Han Oh ◽

Seunggi Min ◽

Jae Wook Jung ◽

Hee June Kim ◽

Jae Yoon Kim ◽

...

Keyword(s):

Plate Fixation ◽

Clavicle Fracture ◽

Hook Plate ◽

Distal Clavicle ◽

Ac Joint ◽

Joint Dislocation ◽

Group I ◽

Joint Dislocations ◽

Ac Joint Dislocation ◽

Group Ii

BACKGROUND: The purpose of this study was to evaluate the clinical outcomes and complications of hook plate fixation in acromioclavicular (AC) joint dislocations and distal clavicle fractures.METHODS: We retrospectively reviewed a series of 60 consecutive patients with hook plate fixation for AC joint dislocation (group I) and distal clavicle fracture (group II). Groups I and II had 39 and 21 patients, respectively. Clinical results were evaluated using the pain visual analogue scale (VAS), simple shoulder test, and Constant-Murley scores. In addition, subacromial erosion and stiffness were evaluated as complications.RESULTS: At the removal, the pain VAS was 2.69 ± 1.30 and 4.10 ± 2.14 in groups I and II, respectively, which were significantly different (p=0.003). The simple shoulder test score was 9.59 ± 1.60 and 7.81 ± 2.67 in groups I and II, respectively, which were also significantly different (p=0.002). Subacromial erosion was significantly more frequent in group II (14/21 patients, 66.7%) than in group I (15/39 patients, 38.5%) (p=0.037), and stiffness was also higher in group II (17/21 patients, 81.0%) than in group I (22/39 patients, 56.4%), but it was not significant.CONCLUSIONS: Hook plate fixation showed good clinical and functional results for the treatment of acute unstable AC joint dislocation and distal clavicle fracture. But, in distal clavicle fractures, there are more subacromial erosion and stiffness compare with acute unstable AC joint dislocation.

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Acromioclavicular joint instability: anatomy, biomechanics and evaluation

Joints ◽

10.11138/jts/2014.2.2.087 ◽

2014 ◽

Vol 02 (02) ◽

pp. 87-92 ◽

Cited By ~ 16

Author(s):

Maristella Saccomanno ◽

Carmine De Ieso ◽

Giuseppe Milano

Keyword(s):

Joint Instability ◽

Stress Test ◽

Radiographic Evaluation ◽

Common Source ◽

Type I ◽

Distal Clavicle ◽

Ac Joint ◽

Type Iii ◽

Type Iv ◽

Joint Dislocations

Acromioclavicular (AC) joint instability is a common source of pain and disability. The injury is most commonly a result of a direct impact to the AC joint. The AC joint is surrounded by a capsule and has an intraarticular synovium and an articular cartilage interface. An articular disc is usually present in the joint, but this varies in size and shape. The AC joint capsule is quite thin, but has considerable ligamentous support; there are four AC ligaments: superior, inferior, anterior and posterior. The coracoclavicular (CC) ligament complex consists of the conoid and trapezoid ligaments. They insert on the posteromedial and anterolateral region of the undersurface of the distal clavicle, respectively. The coracoid origin of the trapezoid covers the posterior half of the coracoid dorsum; the conoid origin is more posterior on the base of the coracoid. Several biomechanical studies showed that horizontal stability of the AC joint is mediated by the AC ligaments while vertical stability is mediated by the CC ligaments. The radiographic classification of AC joint injuries described by Rockwood includes six types: in type I injuries the AC ligaments are sprained, but the joint is intact; in type II injuries, the AC ligaments are torn, but the CC ligaments are intact; in type III injuries both the AC and the CC ligaments are torn; type IV injuries are characterized by complete dislocation with posterior displacement of the distal clavicle into or through the fascia of the trapezius; type V injuries are characterized by a greater degree of soft tissue damage; type VI injuries are inferior AC joint dislocations into a subacromial or subcoracoid position. The diagnosis of AC joint instability can be based on historical data, physical examination and imaging studies. The cross body adduction stress test has the greatest sensitivity, followed by the AC resisted extension test and the O’Brien test. Proper radiographic evaluation of the AC joint is necessary. The Zanca view is the most accurate view for examining the AC joint. The axial view of the shoulder is important in differentiating a type III AC joint injury from a type IV injury.

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Quantitative and Qualitative Surgical Anatomy of the Acromioclavicular Joint Capsule and Ligament: A Cadaveric Study

The American Journal of Sports Medicine ◽

10.1177/0363546521995504 ◽

2021 ◽

pp. 036354652199550

Author(s):

Philip-C. Nolte ◽

Joe J. Ruzbarsky ◽

Kaare S. Midtgaard ◽

Kira K. Tanghe ◽

Bryant P. Elrick ◽

...

Keyword(s):

Surgical Anatomy ◽

Joint Capsule ◽

Ac Joint ◽

Measuring Device ◽

Mean Values ◽

Precise Knowledge ◽

Horizontal Stability ◽

Fresh Frozen ◽

The Mean ◽

Superior Portion

Background: The acromioclavicular (AC) capsule and ligament have been found to play a major role in maintaining horizontal stability. To reconstruct the AC capsule and ligament, precise knowledge of their anatomy is essential. Purpose/Hypothesis: The purposes of this study were (1) to determine the angle of the posterosuperior ligament in regard to the axis of the clavicle, (2) to determine the width of the attachment (footprint) of the AC capsule and ligament on the acromion and clavicle, (3) to determine the distance to the AC capsule from the cartilage border of the acromion and clavicle, and (4) to develop a clockface model of the insertion of the posterosuperior ligament on the acromion and clavicle. It was hypothesized that consistent angles, attachment areas, distances, and insertion sites would be identified. Study Design: Descriptive laboratory study. Methods: A total of 12 fresh-frozen shoulders were used (mean age, 55 years [range, 41-64 years]). All soft tissue was removed, leaving only the AC capsule and ligament intact. After a qualitative inspection, a quantitative assessment was performed. The AC joint was fixed in an anatomic position, and the attachment angle of the posterosuperior ligament was measured using a digital protractor. The capsule and ligament were removed, and a coordinate measuring device was utilized to assess the width of the AC capsule footprint and the distance from the footprint to the cartilage border of the acromion and clavicle. The AC joint was then disarticulated, and the previously marked posterosuperior ligament insertion was transferred into a clockface model. The mean values across the 12 specimens were demonstrated with 95% CIs. Results: The mean attachment angle of the posterosuperior ligament was 51.4° (95% CI, 45.2°-57.6°) in relation to the long axis of the entire clavicle and 41.5° (95% CI, 33.8°-49.1°) in relation to the long axis of the distal third of the clavicle. The mean clavicular footprint width of the AC capsule was 6.4 mm (95% CI, 5.8-6.9 mm) at the superior clavicle and 4.4 mm (95% CI, 3.9-4.8 mm) at the inferior clavicle. The mean acromial footprint width of the AC capsule was 4.6 mm (95% CI, 4.2-4.9 mm) at the superior side and 4.0 mm (95% CI, 3.6-4.4 mm) at the inferior side. The mean distance from the lateral clavicular attachment of the AC capsule to the clavicular cartilage border was 4.3 mm (95% CI, 4.0-4.6 mm), and the mean distance from the medial acromial attachment of the AC capsule to the acromial cartilage border was 3.1 mm (95% CI, 2.9-3.4 mm). On the clockface model of the right shoulder, the clavicular attachment of the posterosuperior ligament ranged from the 9:05 (range, 8:00-9:30) to 11:20 (range, 10:00-12:30) position, and the acromial attachment ranged from the 12:20 (range, 11:00-1:30) to 2:10 (range, 13:30-14:40) position. Conclusion: The finding that the posterosuperior ligament did not course perpendicular to the AC joint but rather was oriented obliquely to the long axis of the clavicle, in combination with the newly developed clockface model, may help surgeons to optimally reconstruct this ligament. Clinical Relevance: Our results of a narrow inferior footprint and a short distance from the inferior AC capsule to cartilage suggest that proposed reconstruction of the AC joint capsule should focus primarily on its superior portion.

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Interaction of Loading and Ligament Injuries in Subtalar Joint Instability Quantified by 3D Weightbearing Computed Tomography

Journal of Orthopaedic Research® ◽

10.1002/jor.25126 ◽

2021 ◽

Author(s):

Burssens Arne ◽

Nicola Krähenbühl ◽

Amy L. Lenz ◽

Kalebb Howell ◽

Chong Zhang ◽

...

Keyword(s):

Computed Tomography ◽

Subtalar Joint ◽

Joint Instability ◽

Ligament Injuries

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The use of the LARS system in the treatment of AC joint instability – Long-term results after a mean of 7.4 years

Orthopaedics & Traumatology Surgery & Research ◽

10.1016/j.otsr.2018.02.010 ◽

2018 ◽

Vol 104 (6) ◽

pp. 749-754 ◽

Cited By ~ 7

Author(s):

T.M. Tiefenboeck ◽

S. Boesmueller ◽

D. Popp ◽

S. Payr ◽

J. Joestl ◽

...

Keyword(s):

Joint Instability ◽

Long Term Results ◽

Ac Joint

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Treatment of chronic acromioclavicular joint dislocation in a paraplegic patient with the Weaver-Dunn procedure and a hook-plate

Orthopedic Reviews ◽

10.4081/or.2016.6371 ◽

2016 ◽

Vol 8 (2) ◽

Cited By ~ 1

Author(s):

Holger Godry ◽

Mustafa Citak ◽

Matthias Königshausen ◽

Thomas A. Schildhauer ◽

Dominik Seybold

Keyword(s):

Spinal Cord ◽

Spinal Cord Injury ◽

Weight Bearing ◽

Full Range ◽

Hook Plate ◽

Acromioclavicular Joint Dislocation ◽

Ac Joint ◽

Joint Dislocation ◽

Ac Joint Dislocation ◽

Cord Injury

Abstract In case of patients with spinal cord injury and concomitant acromioclavicular (AC) jointdislocation the treatment is challenging, as in this special patient group the function of the shoulder joint is critical because patients depend on the upper limb for mobilization and wheelchair-locomotion. Therefore the goal of this study was to examine, if the treatment of chronic AC-joint dislocation using the Weaver- Dunn procedure augmented with a hook-plate in patients with a spinal cord injury makes early postoperative wheelchair mobilization and the wheelchair transfer with full weightbearing possible. In this case the Weaver- Dunn procedure with an additive hook-plate was performed in a 34-year-old male patient with a complete paraplegia and a posttraumatic chronic AC-joint dislocation. The patient was allowed to perform his wheelchair transfers with full weight bearing on the first postoperative day. The removal of the hook-plate was performed four months after implantation. At the time of follow-up the patient could use his operated shoulder with full range of motion without restrictions in his activities of daily living or his wheel-chair transfers.

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Ipsilateral midshaft clavicle fracture and acromioclavicular joint dislocation: a review of literature and evidence-based diagnosis guidelines

10.21203/rs.3.rs-36221/v1 ◽

2020 ◽

Author(s):

Rongguang Ao ◽

Zhen Jian ◽

Jinhong Chen ◽

Dejian Li ◽

Xu Zhang ◽

...

Keyword(s):

Clavicle Fracture ◽

High Energy ◽

Shoulder Function ◽

Acromioclavicular Joint Dislocation ◽

Evidence Based ◽

Ac Joint ◽

Level Of Evidence ◽

Joint Dislocation ◽

Type Iv ◽

Ac Joint Dislocation

Abstract Background: Ipsilateral midshaft clavicle fracture and AC joint dislocation are rare, with very few cases reported. Once the AC joint dislocation were missed diagnosis, the shoulder function may be affected and medical dispute was easy to occur. The aim of this study was to gather data relating to ipsilateral midshaft clavicle fracture and AC joint dislocation to develop evidence-based diagnosis guidelines as none are currently available.Methods: A study was conducted of the PubMed and Google Scholar databases to identify cases of ipsilateral midshaft clavicle fracture and AC joint dislocation. Data collected about each case included age and gender of the patient, mechanism of injury, fracture and dislocation classification. The authors report 2 additional ipsilateral midshaft clavicle fracture and AC joint dislocation cases.Results: 21 cases were identified for inclusion in this research, 19 from the literature and 2 reported by the authors. All the patients were injured by high energy trauma. For the midshaft fracture, 16/21 (76.2%) patients belonged to Type A classification, and 5/21 (23.8%) patients belonged to Type B classification. For AC joint dislocation, 11/21 (47.6%) patients belonged to Type IV classification, 4/21 (19.0%) patients belonged to Type VI classification, 5/21 (23.8%) patients belonged to Type III classification and 1/21 (4.7%) patients belonged to Type V classification.Conclusions: There are limited data available about the diagnosis of ipsilateral midshaft clavicle fracture and AC joint dislocation. From the cases reviewed, we find that simple midshaft clavicle caused by high energy injuries may be associated with ipsilateral AC joint dislocation. Physical examination, careful observation of preoperative X-ray and fluoroscopy including the AC joint during operation were key to diagnose the injury. Level of Evidence Level III, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.

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Minimally Invasive AC Joint Reconstruction System (MINAR®) in Modified Triple-Button Technique for the Treatment of Acute AC Joint Dislocation

Journal of Clinical Medicine ◽

10.3390/jcm8101683 ◽

2019 ◽

Vol 8 (10) ◽

pp. 1683 ◽

Cited By ~ 2

Author(s):

Robert Breuer ◽

Alexandra Unterrainer ◽

Micha Komjati ◽

Thomas M. Tiefenboeck ◽

Klemens Trieb ◽

...

Keyword(s):

Los Angeles ◽

Constant Score ◽

Sports Injury ◽

Negative Influence ◽

Time Interval ◽

X Rays ◽

Ac Joint ◽

Joint Dislocation ◽

Horizontal Instability ◽

Ac Joint Dislocation

Acute acromioclavicular (AC) joint dislocation is a frequent sports injury with more than 100 different operation methods described. A total of 65 patients with an acute AC joint dislocation were treated with the modified MINAR® system between 2009 and 2013. Clinical outcome, horizontal and vertical instability, as well as concomitant intraarticular injuries were assessed. We used Zanca, stress and axial X-rays for radiological assessment. A Constant score of 95 (±8.8), University of California Los Angeles Shoulder score (UCLA) of 31 (±4.9), Disabilities of Arm, Shoulder and Hand (DASH) of 9.1 (±14.3), and Visual Analogue Scale (VAS) of 0.9 (±0.126) was found. A total of 30 patients (59%) had no signs of reduction loss, nine patients (18%) a slight loss, 11 patients (22%) a partial loss, and one patient (2%) a total loss. No significant influence on the clinical scores could be shown. The postoperative coracoclavicular (CC) distance negatively affected the Constant (p = 0.007) and UCLA scores (p = 0.035). A longer time interval to surgery had a negative influence on all scores (p ≤ 0.001). We could not find any signs of persistent horizontal instability or intraarticular injuries at follow-up. The MINAR® system promises satisfactory functional and radiological results. When setting the correct indication, patients benefit from an early operation. No persisting horizontal instability was observed following suturing of the AC capsule and the delta fascia.

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The Infinity-Lock System for Chronic Grade III AC Joint Dislocation: A Novel Technique, Rehabilitation Protocol and Short Term Results

Journal of Clinical Medicine ◽

10.3390/jcm9082519 ◽

2020 ◽

Vol 9 (8) ◽

pp. 2519

Author(s):

Alfonso Maria Romano ◽

Pasquale Casillo ◽

Monica De Simone ◽

Guglielmo Nastrucci ◽

Donatella Risorto ◽

...

Keyword(s):

Constant Score ◽

Surgical Techniques ◽

Nonoperative Treatment ◽

Modified Technique ◽

Ac Joint ◽

Joint Dislocation ◽

Ac Joint Dislocation ◽

Choice Of Treatment ◽

Grade Iii

Background: the choice of treatment of chronic grade III acromioclavicular (AC) joint dislocation is controversial. Several surgical techniques have been described in the literature, responding differently to nonoperative treatment. The aim of this study is to describe a modified technique of stabilizing an AC joint dislocation with the new Infinity-Lock Button System, in order to demonstrate that it is effective in optimizing outcomes and decreasing complications. Methods: this is a retrospective study of 15 patients who underwent surgical stabilization of the AC joint dislocation between 2018 and 2019, through modified surgical technique using the Infinity-Lock Button System. Active range of motion (ROM), Specific Acromio Clavicular Score (SACS) and Constant Score (CS) were evaluated preoperatively and postoperatively at last 18 months follow up. Patients rated their outcomes as very good, good, satisfactory, or unsatisfactory. Results: a total of twelve patients rated their outcome as very good and three as good; no patients were dissatisfied with surgery. The mean Constant Score increased from 38 points preoperatively to 95 postoperatively, the average SACS score decreased from 52 points preoperatively to 10 postoperatively, both significantly. No complications were detected. Conclusion: the described technique is effective for treatment of chronic grade III AC joint dislocation, resulting in elevated satisfaction ratings and predictable outcomes. Nevertheless, further longer term follow-up studies are required.

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