Anatomy and biomechanics of the acromioclavicular and sternoclavicular joints

Are the shoulder joint function, stability, and mobility tests predictive of handstand execution?

Handstand is a basic element common across gymnastic disciplines and physical education classes that is frequently evaluated for quality in competition or skill acquisition. The correct handstand execution relies on maintaining balance, for which the shoulders seem particularly important. This study explores the relationship between shoulder joint function and the quality of handstand execution in novice college athletes (n = 111; aged 19-23 years). We assessed the shoulder joint function using standardized field tests (Upper Quarter Y Balance Test and Closed Kinetic Chain Upper Extremity Stability Test) and evaluated handstand execution on official rating scale. Ordinal logistic regression models showed no relationship between the quality of handstand execution (E-score) and measures of shoulder joint stability or mobility in our sample (POR = 0.97 [0.91, 1.03] and 1.00 [0.91, 1.09] for E-score). Two major factors may have caused an observed pattern of results. Firstly, the standardized tests assess shoulder joints in different loads and ranges of motion compared to handstands. Secondly, our novice sample was not able to perform the handstand sufficiently well. In our sample of novice college athletes, shoulder function seems not related to handstand execution as other latent factors hindered their performance.

[Pathologies of the shoulder joint : Anatomy and examination techniques]

CLINICAL ISSUE

The movements and stability of the human shoulder are a complex dynamic interaction between several joints, muscles and ligaments, which on the one hand enable extensive mobility and on the other hand must provide the necessary stability. Furthermore, the complexity of the shoulder is increased by a large number of normal variants. This article aims to explain the relevant anatomical structures and the radiological examination techniques necessary to visualize them.

STANDARD RADIOLOGICAL PROCEDURES

Various modalities contribute to the examination of the shoulder. These include X‑rays, computed tomography (CT), magnetic resonance imaging (MRI) and ultrasound.

METHODOLOGICAL INNOVATION

It is important to use the various procedures appropriately. Especially with MRI arthrography, it is necessary to pay attention to suitable sequences and possibly additional examination positions.

PRACTICAL RECOMMENDATION

The multimodal examination of the shoulder can contribute to the diagnosis of numerous clinical pictures. Anatomical and methodological foundations are essential for this.

Management of Acromioclavicular Joint Injuries: A Historic Account

There has been a rapid evolution in best practice management of acromioclavicular (AC) joint injuries. AP, Zanca, scapular Y, and dynamic axillary radiographic views provide optimal visualization of the joint and may assess for the presence of horizontal AC instability. Severity of AC joint pathology is classified according to the 6-tier Rockwood scoring system. Over 160 surgical techniques have been described for AC joint repair and reconstruction in the last decade; as a result, determining the optimal treatment algorithm has become increasingly challenging secondary to the lack of consistently excellent clinical outcomes.

Surgical Pearls and Pitfalls for Anatomic Acromioclavicular/Coracoclavicular Ligament Reconstruction

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

Multimodal Chiropractic Management of a Postsurgical Sternoclavicular Injury Utilizing Gamified Rehabilitation: A Case Report

Objective

The purpose of this study was to describe how gamification was incorporated into postoperative rehabilitation of a patient recovering from a sternoclavicular dislocation.

Clinical Features

A 23-year-old man sought chiropractic care from an academic chiropractic clinic for persistent right-sided, sternoclavicular joint, moderate-to-severe pain that was exacerbated with shoulder movements and overhead activities. His shoulder was treated previously with reconstructive surgery and a 6-week trial of physical therapy; however, he reported minimal improvement in his pain, and his functional ability was suboptimal.

Intervention and Outcome

Multimodal chiropractic treatment consisted of manual therapy in conjunction with active rehabilitation. The rehabilitation program incorporated gamification principles, such as competition, point scoring, and task focus. After 8 treatments, a clinically significant reduction in his upper extremity functional index score and numerical pain rating was observed.

Conclusion

The patient was managed using a gamified approach to postsurgical sternoclavicular joint rehabilitation and responded positively. Chiropractors may consider including gamified, multimodal care for patients with postoperative musculoskeletal concerns.

Sternoclavicular Joint Reconstruction With Gracilis Tendon Autograft

Clinical instability of the sternoclavicular (SC) joint is a challenging problem. Recurrent subluxation and pain can lead to significant functional limitations. Although many patients respond positively to conservative treatment, chronic dislocations often require operative intervention. The complex anatomy of the diarthrodial SC joint and the existence of concomitant SC joint degenerative changes compounded with close-by neurovascular structures present a surgical challenge. The purpose of this Technical Note is to describe a technique for the open management of symptomatic sternoclavicular joint instability using a figure-of-8 reconstruction with a gracilis autograft. The present authors believe this technique provides a technically safe and reproducible method for reconstructing the SC joint without compromising biomechanical strength.

Physeal injuries of the clavicle: pediatric counterparts to adult acromioclavicular and sternoclavicular joint separations

The epiphyses at the medial and lateral ends of the clavicle are small, ossify relatively late, and may not fuse until early adulthood. Because of this unique anatomy, pediatric and young adult injuries that involve the clavicle often differ from the patterns typically seen in older adults. Clavicular trauma that affects the acromioclavicular joint laterally or sternoclavicular joint medially often results in a physeal fracture and as such, can go unrecognized or be mistaken for a joint dislocation. Radiographic assessment is challenging, particularly when the epiphysis is not yet ossified. However, MR imaging allows for visualization of the cartilage, periosteum and perichondrium, and ligaments of the affected joints. Lateral clavicle physeal injuries can be categorized by the Dameron and Rockwood system, the pediatric correlate to the Rockwood classification of adult acromioclavicular joint injuries. Medial clavicle physeal fractures, similar to adult sternoclavicular joint dislocations, may result in anterior or posterior displacement. Because of their great ability to heal and remodel, clavicular physeal fractures respond better to conservative management than true acromioclavicular or sternoclavicular joint dislocations. Therefore, it is essential to recognize the true nature of these injuries, as there are implications for successful treatment and appropriate prognosis.

Two cases of sternoclavicular joint replacement arthroplasty: A case report. A novel prosthesis and surgical technique for recalcitrant instability, arthropathy of the sternoclavicular joint with medial clavicular bone loss

Instability arthropathy of the sternoclavicular joint is most commonly managed by rehabilitation, injection, and either arthroscopic or open debridement with or without interposition arthroplasty. When these options fail to achieve symptom relief, excision arthroplasty is an option. This is associated with a risk of persistent instability and incomplete pain relief. We describe two cases in which custom sternoclavicular joint replacement was performed for painful insufficiency of scapular suspension. Although the prostheses remained secure in both cases, the first case was complicated by persistent instability due to insufficient reconstruction of the intrinsic sternoclavicular capsular ligaments. This was recognised and corrected for in the second case, in which stability of the sternoclavicular joint replacement has been noted on more than a 5-year review. We conclude that sternoclavicular joint replacement is an option for patients in whom instability arthropathy remains an intrusive problem in daily life after other conventional treatments have not controlled symptoms. Stability of the joint remains a concern. We offer one method of achieving stability through an iterative design process including the ability to reconstruct the intrinsic capsular ligaments around the articulation.

Fracture edge features of diaphyseal clavicular fractures: a morphologic study

BACKGROUND

Previous researchers used transverse fractures centered over the midpoint of the clavicle as the diaphyseal clavicular fracture models. However, as a result of shear stress concentration in sigmoid-shaped structures, most diaphyseal clavicular fractures have coronal fracture edges and are located distal to the midpoint. The purpose of this study was to quantify the morphology and utilize these parameters to establish clinically relevant fracture models.

METHODS

The computed tomographic DICOM data of 100 consecutive patients were included. We investigated the morphologic characteristics of the fracture edges after virtual fracture reduction. The fracture orientation was determined based on the normal vectors of the best-fit plane of the fracture edges. The fracture location was measured by the extreme points of the edges. The fracture configuration was evaluated using fracture maps.

RESULTS

There were 28 simple, 43 wedge, and 29 multifragmentary types. Coronal oriented fracture edges accounted for more than 70% of the simple, wedge, and multifragmentary types. The most proximal point of the proximal edge was located at 46.7% (42.0%-56.5%), 47.6% (42.5%-50.1%), and 46.3% (42.0%-49.3%) of the endpoint line in the simple, wedge, and multifragmentary types, respectively (P = .548). The most distal point of the distal edge was located at 72.2% (68.4%-75.0%), 73.2% (69.5%-76.9%), and 74.0% (69.6%-77.1%) of the endpoint line (P = .353). The longest proximal main fragments occurred in the simple types at 71.9% (66.3%-75.4%) of the endpoint line (P < .001), and the shortest distal main fragments occurred in the multifragmentary types at 55.8% (49.8%-59.3%) of the endpoint line (P = .001). The heatmaps showed a high concentration of anteriorly distributed wedge fragments (88%; n = 38/43) and coronally distributed multifragmentary fragments (62%; n = 18/29).

CONCLUSIONS

We showed that typical diaphyseal clavicular fractures have coronal fracture edges and are located within the distal half of the diaphyseal segment. The fractured fragments were initiated anteriorly in the wedge types and then propagated coronally in the multifragmentary types. The features of these fracture edges could be useful in designing osteotomy models and provide different perspectives of anterior and superior plating techniques.

Sternoclavicular Joint Reconstruction with Semitendinosus Allograft and Suture Anchors after Recurrent Posterior Dislocation in a Professional North American Football Player

Background:

Posterior sternoclavicular joint dislocations are an extremely rare but potentially life-threatening injury that can occur in sports. A variety of surgical procedures have been proposed, but there is no consensus on the treatment of choice. It is also largely unknown if a safe return to high-risk sports is possible.

Case Presentation:

We present a case of a posterior sternoclavicular joint dislocation in a 22-year-old male professional North American football player who had a recurrent irreducible posterior dislocation after initial injury management by closed reduction. The patient’s desire to return to football presented unique challenges to management. His sternoclavicular joint was subsequently reconstructed with semitendinosus allograft in a figure-of-eight augmented with suture anchors. After recovery, he returned to play as a running back in professional football symptom-free.

Conclusion:

Our patient's successful return to playing professional football after the sternoclavicular joint reconstruction suggests that this should be considered an effective treatment option when managing posterior sternoclavicular dislocation in high level contact sports players.

Acromioclavicular Joint Injury and Repair

The acromioclavicular (AC) joint is commonly injured in athletes participating in contact and overhead throwing sports. Injuries range from simple sprains to complete ligamentous disruption, and they are classified by the established Rockwood grading system. High-grade injuries are associated with fractures around the AC joint and disruption of the superior shoulder suspensory complex, a ring of osseous and ligamentous structures at the superior aspect of the shoulder. Radiographs are the mainstay of imaging of the AC joint, with magnetic resonance imaging reserved for high-grade injuries to aid classification and plan surgical management. Low-grade AC joint injuries tend to be managed conservatively, but a wide range of surgical procedures have been described for higher grade injuries and fractures around the AC joint. This review illustrates the anatomy of the AC joint and surrounding structures, the imaging features of AC joint injury, and the most commonly performed methods of reconstruction and their complications.

A Comprehensive Radiologic Review of Shoulder Girdle Trauma

Radiologic knowledge of different fracture patterns involving the shoulder girdle is an important tool to generate clinically relevant reports, identify concomitant injuries, guide management decisions, and predict and minimize complications, such as nonunion, osteoarthritis, osteonecrosis, and hardware failure. Complex unstable injuries like scapulothoracic dissociation can also occur because of shoulder girdle trauma. Management options may vary from conservative to surgical, depending on the fracture type and patient factors. Injuries around the shoulder girdle can involve the glenohumeral articulation, scapula, superior shoulder suspensory complex, acromioclavicular joints, and scapulothoracic articulation.

Operative treatment outcomes of anterior sternoclavicular joint dislocation using two experimental methods - an acromioclavicular joint hook plate versus a locking plate: a retrospective study

Background

We aimed to compare the intraoperative and early postoperative clinical outcomes of using an acromioclavicular joint hook plate (AJHP) versus a locking plate (LP) in the treatment of anterior sternoclavicular joint dislocation.

Methods

Seventeen patients with anterior sternoclavicular joint dislocation were retrospectively analyzed from May 2014 to September 2019. Six patients were surgically treated with an AJHP, and 11 were surgically treated with an LP. Five male and one female patients composed the AJHP group, and nine male and two female patients composed the LP group. The mean age of all patients was 49.5 years.

Results

Reduction and fixation were performed with AJHP or LP in all 17 patients. The mean operative blood loss, operative time, and length of incision in the AJHP group were significantly better than those in the LP group. Shoulder girdle movement of the AJHP group was significantly better than that of the LP group.

Conclusions

This study revealed that AJHP facilitated glenohumeral joint motion, reduced the risk of rupture of mediastinal structures, required a shorter incision, and had lesser blood loss and a shorter duration of operation compared with LP. However, some deficiencies require further improvement.

Supplementary information

The online version contains supplementary material available at 10.1186/s12891-022-05293-x.

Anterior Dislocation of the Sternoclavicular Joint – A Case Report

Dislocation of joints in the human body is a common occurrence, with the upper limb being commonly involved in most dislocations. Despite the common occurrence of upper limb dislocations, sternoclavicular dislocation is rare, comprising just 1% of all dislocations seen. This is attributed to a combination of restricted range of movements and strong ligaments around it. A thorough search of literature revealed a handful of cases of sternoclavicular dislocation. We report a case of a 35-year-old firefighter who presented to us an hour after his injury. He was diagnosed with anterior dislocation of the left sternoclavicular joint and was successfully managed by the closed reduction maneuver. We present this case to highlight the rarity of this unusual dislocation and also shed light on its etiopathogenesis and current management trends.

A modified single-endobutton technique combined with nice knot for treatment of Rockwood type III or V acromioclavicular joint dislocation

PURPOSE

Double-endobutton technique, as a widely accepted strategy for the treatment of acromioclavicular joint dislocation, is undergoing constant improvement. This study aims to assess the clinical effect of a modified single-endobutton combined with the nice knot in the fixation of Rockwood type III or V acromioclavicular joint dislocation.

METHODS

From January 2016 to June 2019, 16 adult patients (13 males and 3 females) with Rockwood type III or V acromioclavicular joint dislocation were treated with a modified single-endobutton technique combined with the nice knot in our department. The age ranged from 18 to 64 years old with an average of 32.8 years old. Operative time, intraoperative blood loss, post-operative clinical outcomes and radiographic results were recorded and analyzed. Preoperative and last follow-up scores in the Constant-Murley Scale, Neer score, Rating Scale of the American Shoulder and Elbow Surgeons and VAS scale and complications such as infection, re-dislocation, implant loosening, medical origin fracture and hardware pain were recorded and evaluated.

RESULTS

Sixteen patients were followed up for 6 to 18 months with an average of 10.3 months. The operative time was 50-90 min with an average of (62.5 ± 3.10) min. The intraoperative blood loss was 30-100 ml, with an average of (55.0 ± 4.28) ml. The complications, such as wound infection, internal fixation failure and fractures, were not found in these cases. According to Karlsson criteria, there were excellent in 14 cases, good in 2 cases at the final follow-up. The mean VAS score of the patients was 5.88 ± 0.26 preoperatively, compared with 0.19 ± 0.14 at the final follow-up evaluation. The difference was statistically significant (P < 0.05). The mean Constant score was 45.5 ± 2.0 preoperatively, compared to 94.0 ± 0.73 at the final follow-up evaluation. The difference was statistically significant (P < 0.05). Patients had statistically significant preoperative and postoperative AC (acromioclavicular distance) and CC (coracoclavicular distance) distances (P < 0.05); 6 months postoperatively the AC(P = 0.412) and CC(P = 0.324) distances were not statistically significant compared to the healthy side.

CONCLUSION

Nice knot provides a reliable fixation for the single-endobutton technique in the treatment of acromioclavicular dislocations. The modified single-endobutton technique combined with the nice knot can achieve good clinical outcomes in the treatment of Rockwood type III or V acromioclavicular joint dislocation.

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.

Repair of sternoclavicular joint ligament: a novel approach

BACKGROUND

Posterior sternoclavicular dislocations are common in younger patients and are frequently due to high energy sporting incidents.

AIM

We aim to demonstrate a novel technique that is safe and aims to provide good functional post-operative outcomes for patients with this injury.

METHODS

This was a single-surgeon case series of four young patients from October 2017 to July 2019. The operative technique involved relocating the joint and holding it in situ with nylon suture tape. The tape was anchored in holes drilled in the sternum and passed through tunnels drilled into the medial clavicle. All of the patients were contacted retrospectively and a Nottingham Clavicle Score (NCS) was performed for each patient on a post-operative basis.

RESULTS

No intra-operative or post-operative complications were noted. All of the patients demonstrated a significant improvement in their functional outcomes after the operation. The average NCS for the four patients was 82/100.

DISCUSSION

There are a variety of techniques described in the literature to repair this ligament using either plates or tendon grafts. All of these techniques describe the drilling of anteroposterior holes in the manubrium and clavicle which run the intra-operative risk of perforating a major vessel. This paper is the first one to describe a technique which uses superior inferior holes which minimizes the risks, making the procedure safer for the patient.

CONCLUSIONS

We believe this novel technique is safer than the existing described techniques, and it does not compromise on functional outcomes.

Complications after sternoclavicular surgery

BACKGROUND

Sternoclavicular joint (SCJ) pathologies such as instability are rare; therefore, SCJ surgery is performed infrequently. Complications of these surgeries can be devastating. This study evaluated complications, and particularly infections, after SCJ surgery.

METHODS

A retrospective cohort of 68 patients who underwent SCJ surgery with a minimum follow-up of 1 year was reviewed. Patients' characteristics, intraoperative, and postoperative complications were retrieved. In case of a reoperation, relevant data from the reoperation and microbiological findings were collected.

RESULTS

Twenty-two men and 46 women with a mean age of 37.5 years (range, 13-70 years) were analyzed. A complication occurred in 26 of 68 patients (38.2%). In 16 patients (23.5%), this was an infection. Cutibacterium acnes was the pathogen in 14 of these infections. Infection occurred more often in men than in women (P = .02). A total of 26 reoperations were performed in our cohort: 14 due to clinical signs of infection, 9 due to instability, 1 due to complaints of SCJ osteoarthritis, and 2 due to other causes.

CONCLUSION

Complications after SCJ surgery occur more often than previously described. C. acnes infections are often seen. When left untreated, these complications can lead to persistent complaints or recurrent instability due to failure of reconstruction. Therefore, it is of utmost importance to identify infections at an early stage, or better, to prevent them. The use of benzoyl peroxide gel preoperatively seems effective in reducing early C. acnes infections in this type of surgery.

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

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.

Nonanatomic and Suture-Based Coracoclavicular Joint Stabilization Techniques Provide Adequate Stability at a Lower Cost of Implants in Biomechanical Studies When Compared With Anatomic Techniques: A Systematic Review and Meta-Analysis

Purpose

To compare the stability and cost of the used implants in nonanatomic and anatomic acromioclavicular joint repair/reconstruction (ACCR) techniques tested in cadaveric shoulder biomechanical studies during the last decade.

Methods

A systematic review and meta-analysis were performed following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines and prospectively registered in PROSPERO. Two independent reviewers searched PubMed, Embase, and Virtual Health Library databases. Studies evaluating 3-direction stability under 70-N loads and load-to-failure protocols with servohydraulic testing systems were included. A meta-analysis of the mean differences of anterior, posterior, and superior direction; relative stability value in 3 directions; superior direction load-to-failure; stability/cost index; and load-to-failure/cost index was performed using a continuous random-effects model and 95% confidence interval.

Results

Eighteen articles were included. Both non-ACCR and ACCR techniques exceeded the minimum acceptable threshold of stability and load-to-failure. ACCR techniques were biomechanically better in terms of anterior stability (P = .04) and relative stability value (mean difference 64.08%, P = .015). However, supraphysiological stability and failure loads were achieved with non-ACCR techniques at a lower cost of implants. Techniques combining 2 clavicular tunnels separated by at least 10 mm, a mean of 2 sutures, and/or suture tapes had the greatest stability/cost index and load-to-failure/cost index among the included techniques (confidence interval 99%).

Conclusions

Non-ACCR and ACCR techniques exceeded the minimum acceptable threshold of stability and failure loads in controlled biomechanical testing. However, non-ACCR and techniques combining 2 clavicular tunnels separated by at least 10 mm, a mean of 2 sutures, and/or suture tapes provide supraphysiologic stability and failure loads at a lower cost of implants.

Clinical Relevance

Non-ACCR and suture-based techniques may provide more cost-effective and greater value treatment for acromioclavicular joint injury and could be considered in the surgical management of normal activity individuals and cost-sensitive populations.

Image registration analysis of the motion characteristics of sternoclavicular joints in sagittal motion of the upper limbs

OBJECTIVE

This study aims to accurately measure the range of motion of the sternoclavicular (SC) joint using 3D reconstruction and image registration. The motion of the SC joint is analyzed by means of axial angle representation to identify the kinematical characteristics of this joint.

METHODS

A total of 13 healthy volunteers were enrolled in the study. The limit postures of four SC joint movements were scanned by computerized tomography. The images were integrated with reconstruction and registration techniques. The range of motion of the SC joint was measured using 3D modelling. The axial angle was used to indicate the range of motion of the SC joint. The difference between the dominant side and non-dominant side was compared and the differences in axial angle of the SC joint in different postures were compared.

RESULTS

The active axial angle of the SC joint on the dominant side was approximately 1∘ higher than that of the non-dominant side when the upper limb moved from a rest position to a posteroinferior position. In the sagittal motion of the upper limbs, the axial angle of the SC joint was greatest when moving from a horizontal position to a posterosuperior position, with an average of 23.55∘. Of the flexion and extension movements of the upper limbs from a rest position to a horizontal position, 13.66% (the smallest proportion) were completed by the SC joint.

CONCLUSION

The combination of 3D reconstruction and image registration is a direct and accurate method of measuring the motion of the SC joint. Axial angle representation is an intuitive method of expressing rotation in a 3D space that allows for more convenient comparison; it is also more in line with the characteristics of human anatomy and kinesiology and therefore more accurately reflects the characteristics of joint motion. It is therefore useful for guiding clinical practice. In a physical examination, the extension of the upper limb from the horizontal position to the posterosuperior position and from the rest position to the posteroinferior position can best reflect the rotation function of the SC joint in the combined motion of shoulder joints.

Balser Plate Stabilization for Traumatic Sternoclavicular Instabilities or Medial Clavicle Fractures: A Case Series and Literature Review

Objective

This study was performed to observe the effect of internal Balser plate fixation for treating unstable sternoclavicular joints (SCJ) and displaced medial clavicle fractures.

Methods

From April 2009 to September 2016, 17 consecutive patients who underwent open reduction and internal Balser plate fixation for SCJ dislocations or medial clavicle fractures were retrospectively reviewed. There were 11 male and six female patients, with a mean age of 45.6 ± 15.5 years. Standardized treatment procedures consisted of reduction, creating a space posterior dorsal osteal face of the sternal manubrium, an inverted Balser plating, and postoperative immobilization. At follow‐up, plain radiographs were assessed for fracture union, implant loosening, degenerative changes, and joint congruity. Clinical evaluation included: completion of the Disability of the Arm, Shoulder, and Hand (DASH) questionnaire; determination of the Constant and Murley score and visual analog scale (VAS) score; and assessment of intraoperative and postoperative complications.

Results

All patients were followed up, at a mean follow‐up of 20.1 ± 7.9 months, each fracture had a solid union, and each dislocation showed no sign of recurrent dislocation. The mean shoulder forward flexion was 162.9° ± 8.1°. The mean DASH score was 5.2 ± 5.2 points. The mean Constant and Murley joint function score was 93.7 ± 7.9 points, with 15 excellent cases and two good cases. The mean VAS score was 1.1 ± 1.4 points, showing significant improvement compared with the VAS score preoperatively. Postoperative complications included one wound hematoma which was healed after a debridement and one recurrent instability due to hook migration, which underwent revision reconstruction. All patients were satisfied with their treatment outcome at the final follow‐up.

Conclusion

Sternoclavicular joints dislocation or medial clavicle fractures can be treated successfully with Balser plate fixation. This technique permits early functional exercise while preserving the SCJ.

Imaging of the Acromioclavicular Joint: Anatomy, Function, Pathologic Features, and Treatment

The acromioclavicular joint is an important component of the shoulder girdle; it links the axial skeleton with the upper limb. This joint, a planar diarthrodial articulation between the clavicle and the acromion, contains a meniscus-like fibrous disk that is prone to degeneration. The acromioclavicular capsule and ligaments stabilize the joint in the horizontal direction, while the coracoclavicular ligament complex provides vertical stability. Dynamic stability is afforded by the deltoid and trapezius muscles during clavicular and scapular motion. The acromioclavicular joint is susceptible to a broad spectrum of pathologic entities, traumatic and degenerative disorders being the most common. Acromioclavicular joint injury typically affects young adult males and can be categorized by using the Rockwood classification system as one of six types on the basis of the direction and degree of osseous displacement seen on conventional radiographs. MRI enables the radiologist to more accurately assess the regional soft-tissue structures in the setting of high-grade acromioclavicular separation, helping to guide the surgeon's selection of the appropriate management. Involvement of the acromioclavicular joint and its stabilizing ligaments is also important for understanding and classifying distal clavicle fractures. Other pathologic processes encountered at this joint include degenerative disorders; overuse syndromes; and, less commonly, inflammatory arthritides, infection, metabolic disorders, and developmental malformations. Treatment options for acromioclavicular dysfunction include conservative measures, resection arthroplasty for recalcitrant symptoms, and surgical reconstruction techniques for stabilization after major trauma.

Diagnosis and management of sternoclavicular joint infections: a literature review

The sternoclavicular joint (SCJ) is anatomically and clinically significant considering its proximity to important neuro-vascular structures like the subclavian vessels and the phrenic nerve. Infections of this joint masquerade multiple disorders, delay diagnosis and spread to the bone and deep tissues. There is no standardized workup and treatment protocol for sternoclavicular joint infections (SCJI) as defined in literature. Here, we review the existing literature to understand the current knowledge of the diagnosis and treatment of SCJI. We searched English publications in PubMed and included clinical trials, case reports, case series, retrospective cohort studies, literature and systematic reviews after excluding non-infectious etiology of SCJ pathologies. There are many risk factors for SCJI, such as immunocompromised status, intravenous drug use, trauma and arthropathies. But a large percentage of patients with disease have none of these risk factors. SCJIs can present with fever, joint swelling, immobility, and rarely with vocal cord palsy or dysphagia. While Staphylococcus aureus causes over 50% of SCJI cases, other pathogens such as Pseudomonas and Mycobacterium are frequently seen. When diagnosed early, the infection can be medically managed with antibiotics or joint aspirations. Most cases of SCJI, however, are diagnosed after extensive spread to soft tissue and bones requiring en-bloc resection with or without a muscle flap. Complications of undertreatment can range from simple abscess formation to mediastinitis, even sepsis. SCJIs are rare but serious infections prompting early detection and interventions. Most cases of SCJI treated adequately show complete resolution in months while retaining maximum functionality. Key features of proper healing include aggressive physiotherapy to prevent adhesive shoulder capsulitis and decreased range of motion.

Sternoclavicular Joint Instability: Symptoms, Diagnosis And Management

Sternoclavicular joint (SCJ) instability is a rare condition and results from either a traumatic high energy impact, such as a motor vehicle crash or contact sports injury, or non-traumatically as a result of structural pathology. The infrequency of this injury has contributed to its diagnosis being missed as well as the paucity of literature on treatment and outcomes. Patients with SCJ instability often report diminished range of motion as well as shoulder girdle pain. The presentation of instability in the sternoclavicular joint can vary in severity and anterior or posterior directionality. Variation in severity of the instability changes the course of treatment regarding either operative or non-operative interventions to stabilize the SCJ. In general, anterior instability of the SCJ (the medial clavicle is displaced anterior to the sternum) is less urgent and generally manageable by symptom alleviation and rehabilitation, although some anterior instability cases require surgical intervention. In the case of posterior SCJ instability (the medial clavicle is displaced posterior to the sternum), patients require prompt joint reduction as they are at the greater risk of life-threatening injury due to the location of critical structures of the mediastinum posterior to the SCJ. Computed tomography visualization is useful to confirm dislocation or subluxation direction to better formulate a proper treatment plan. The purpose of this review is to report the clinical presentation and management of SCJ instability including pertinent symptoms, the diagnostic approaches to evaluating SCJ instability, as well as operative and non-operative management of the joint instability.

Optimal Management of Acromioclavicular Dislocation: Current Perspectives

Injuries to the acromioclavicular (AC) joint are common and mostly involve younger, male individuals. Whereas the majority of AC joint dislocations can be treated nonoperatively with a trial of immobilization, pain medication, cryotherapy, and physiotherapy, there are patients that do not respond well to conservative management and may require surgical treatment. Identifying and treating these patients according to the type and chronicity of AC joint dislocation is paramount. To date, a myriad of surgical techniques have been proposed to address unstable AC joint dislocations and are indicative of the uncertainty that exists in optimal management of these injuries. Historically research has focused on the restoration of the coracoclavicular ligament complex. However, recently the importance of the acromioclavicular capsule and ligaments has been emphasized. This review aims to provide the reader with an overview of current treatment strategies and research, as well as future perspectives.

Minimum 5-Year Clinical Outcomes, Survivorship, and Return to Sports After Hamstring Tendon Autograft Reconstruction for Sternoclavicular Joint Instability

BACKGROUND

Instability of the sternoclavicular (SC) joint is a rare but potentially devastating pathologic condition, particularly when it occurs in young or active patients, where it can lead to persistent pain and impairment of shoulder function. SC joint reconstruction using a hamstring tendon autograft is a commonly used treatment option, but midterm results are still lacking.

PURPOSE/HYPOTHESIS

The purpose of this study was to assess the clinical outcomes, survivorship, and return-to-sports rate after SC joint reconstruction using a hamstring tendon autograft in patients suffering from SC joint instability. We hypothesized that SC joint reconstruction would result in good clinical outcomes, high rate of survivorship, and a high rate of return to sports.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

All patients who underwent SC joint reconstruction with a hamstring tendon autograft for SC joint instability, with a minimum 5-year follow-up, were included. Patient-reported outcomes were assessed prospectively by the use of the American Shoulder and Elbow Surgeons (ASES) score, Single Assessment Numerical Evaluation (SANE) score, short version of the Disabilities of the Arm, Shoulder and Hand (QuickDASH) score, 12-Item Short Form Health Survey (SF-12) physical component summary (PCS), and patient satisfaction. Survivorship of reconstruction was defined as no further revision surgery or clinical failure such as recurrent instability or subluxation events. Return to sports and pain were assessed using a customized questionnaire.

RESULTS

A total of 22 shoulders that underwent SC joint reconstruction, with a mean patient age of 31.3 years (range, 15.8-57.0 years) at the time of surgery, were included. At the final evaluation, 18 shoulders, with a mean follow-up of 6.0 years (range, 5.0-7.3 years), completed a minimum 5-year follow-up. All clinical outcome scores improved significantly from preoperatively to postoperatively: ASES (50.0 to 91.0; P = .005), SANE (45.9 to 86.0; P = .007), QuickDASH (44.2 to 12.1; P = .003), and SF-12 PCS (39.4 to 50.9; P = .001). Median postoperative satisfaction was 9 (range, 7-10). The construct survivorship was 90% at 5-year follow-up. There were 2 patients with failed treatment at 82 and 336 days postoperatively because of instability or pain who underwent revision SC joint reconstruction and capsulorrhaphy. Another patient had a superficial wound infection, which was debrided once and resulted in a good clinical outcome. Of the patients who answered optional sports activity questions, 15 (17 shoulders, 77%) participated in recreational or professional sports before the injury. At final follow-up, 14 patients (16 of 17 shoulders, 94%) returned to their preinjury level of sports. The visual analog scale score for pain today (P = .004) and pain at its worst (P = .004) improved significantly from preoperatively to postoperatively.

CONCLUSION

SC joint reconstruction with a hamstring tendon autograft for SC joint instability resulted in significantly improved clinical outcomes with high patient satisfaction and 90% survivorship at midterm follow-up. Furthermore, 94% of this young and high-demand patient population returned to their previous level of sports. Concerns in terms of advanced postinstability arthritis were not confirmed because a significant decrease in pain was found after a minimum 5-year follow-up.

Acromioclavicular Joint: What to Look for

Acromioclavicular joint (ACJ) pathology is a common source of shoulder girdle pain, frequently coexisting with and sharing overlapping clinical features of rotator cuff and glenohumeral articular lesions. ACJ trauma and osteoarthritis dominate clinical presentation; however, an array of pathologies can affect the joint. MR imaging of the ACJ is a powerful secondary diagnostic tool in early diagnosis of ACJ pathology and in accurate assessment of ACJ injuries, helping to resolve clinically challenging cases and allowing for individualized treatment planning. Knowledge of ACJ anatomy, biomechanics, and pathology is fundamental to interpreting and providing a clinically relevant ACJ MR imaging report.

Arthroscopic Coracoclavicular Ligament Reconstruction of Chronic Acromioclavicular Dislocations Using Autogenous Semitendinosus Graft: A Two-Year Follow-up Study of 58 Patients

Purpose

To determine the results of operatively treated chronic acromioclavicular (AC) joint dislocations after 2-year follow-up.

Methods

Fifty-eight patients with chronic acromioclavicular separations underwent arthroscopic coracoclavicular ligament reconstructions using semitendinosus autografts. Constant and Simple Shoulder Test scores were determined before and 2 years after surgery as a part of standard clinical practice. General patient satisfaction with the outcome (poor, fair, or excellent) also was assessed. In addition, for purposes of routine clinical follow-up, the coracoclavicular distance was measured from the inferior cortex of the clavicle to the superior cortex of the coracoid using anteroposterior radiographs taken 2 years after surgery. The results were compared with postoperative radiographs and changes in the distance were recorded. The clavicular drill hole was similarly measured 2 years after surgery to detect possible tunnel widening.

Results

The mean preoperative Constant score increased from a preoperative mean of 52.6 ± 16.5 to 94.7 ± 7.9 at 2 years postoperatively (P = .000). The Simple Shoulder Test score increased from a preoperative mean of 7.7 ± 1.64 to 11.8 ± 0.7 (P = .000). The mean coracoclavicular distance increased from 10.5 ± 3.4 to 12.4 ± 3.9 mm (P = .009). The diameter of the clavicular drill hole increased from 6.0 mm to a mean of 8.4 mm. Two coracoid fractures were observed, but no clavicular fractures. One patient experienced a deep infection, leading to total reconstruction failure, and 2 patients had superficial postoperative infections. Forty-five patients (85%) reported excellent subjective outcomes, and 8 (15%) reported a fair outcome.

Conclusions

The outcomes of this series of coracoclavicular ligament reconstruction were favorable and the number of serious complications was small. However, clavicular wound issues were a significant problem. Coracoclavicular ligament reconstruction is a challenging procedure, but satisfactory results can be achieved with careful patient selection and good technique.

Level of Evidence

Level IV, therapeutic case series

Chronic Posterior Sternoclavicular Dislocation in a Contact Athlete: A Case Report

CASE

Traumatic posterior sternoclavicular dislocation (PSCD) is an uncommon injury that often presents in a delayed fashion and can be difficult to diagnose. Standard treatments include reduction of acute injuries and possible reconstruction for chronic injuries. We describe a 16-year-old male football player with a traumatic PSCD and initial dyspnea and dysphagia. He returned to playing contact sports without undergoing reduction.

CONCLUSIONS

Contrary to the literature that suggests reduction as a primary treatment of PSCD, this case shows that a contact-sport athlete may be able to return to competitive sports with a chronic PSCD.

Distal Clavicular Augmentation with Acromioclavicular and Coracoclavicular Ligament Reconstruction in the Setting of Iatrogenic Induced Acromioclavicular Instability

Although chronic pain and dysfunction of the acromioclavicular (AC) joint can reliably be treated with distal clavicle excision, disruption of the local stabilizing ligamentous structures may result in iatrogenic instability of the joint. Iatrogenic AC joint instability is a rare condition caused by over resection of the distal clavicle with unintended injury to the stabilizing ligaments in the treatment of AC joint pain. Addressing postresection instability can prove to be difficult because most reconstruction techniques are intended for patients with traumatic AC joint instability with the goal of creating an anatomically stable joint. However, in the setting of iatrogenic instability, the decreased bone stock of the distal clavicle results in instability of the AC joint, especially in the horizontal plane, and may cause these techniques to fail. Thus, operative management must aim to correct both the osseous and ligamentous deficits responsible for the genesis of this instability. In this Technical Note, we describe bony augmentation of the distal clavicle with an iliac crest bone autograft for chronic iatrogenic acromioclavicular joint instability with concomitant reconstruction of the AC and coracoclavicular ligaments.

Clinical Outcomes and Complications Following Surgical Management of Traumatic Posterior Sternoclavicular Joint Dislocations: A Systematic Review

BACKGROUND

Traumatic posterior sternoclavicular joint dislocations are rare orthopaedic emergencies. Treatment typically consists of closed reduction, with surgical management reserved for unstable cases. Because of the low prevalence of this condition, limited clinical evidence exists for a superior surgical stabilization technique.

METHODS

A systematic review of the literature following Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines was performed. MEDLINE and Embase databases were searched using a comprehensive search strategy. A descriptive and critical analysis of the results was performed.

RESULTS

Forty relevant studies (108 cases) were identified. Favorable subjective and objective outcomes were reported for all 5 categories of stabilization described. The overall complication rate was 16%, including 4 cases of recurrent instability. Ligament reconstruction using tendon graft had the lowest recurrent instability and complication rates, and open reduction and internal fixation techniques required a second operation for implant removal in 80% of cases.

CONCLUSIONS

A comprehensive review of the surgical management of traumatic posterior sternoclavicular joint dislocations is presented. Results suggest favorable outcomes for all of the methods of stabilization, with a modest complication rate. The trends observed have helped to guide the development of clinical care recommendations that aid in treatment decision-making for these injuries.

LEVEL OF EVIDENCE

Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Acromioclavicular Joint Injuries: Evidence-based Treatment

Injuries to the acromioclavicular (AC) joint are common in the athletic patient population. Most AC joint injuries occur in young males, typically from a direct fall onto the superior aspect of the shoulder when the arm is adducted. Numerous publications describing joint anatomy and biomechanics, surgical techniques for reconstruction, and rehabilitation protocols are available to guide treatment strategies for injuries to the AC joint. Treatment is typically nonsurgical for type I and II injuries and surgical for type IV and VI injuries. Controversy surrounds the indications for nonsurgical versus surgical treatment of type III and V injuries. Multiple surgical techniques have been described, including coracoclavicular (CC) screw fixation, coracoacromial ligament transfer, and numerous methods of CC ligament reconstruction. Anatomic CC ligament reconstruction can be performed either open or arthroscopically, with and without graft augmentation. This article will discuss clinically relevant anatomy and biomechanical properties of the AC joint and will review decision-making principles and treatment options for common AC joint injuries. An updated summary of clinical outcomes after AC joint treatment will also be presented.

Asymmetrical bilateral sternoclavicular joint dislocation combined with bilateral clavicular fracture: A case report

RATIONALE

Asymmetrical bilateral sternoclavicular joint (SCJ) dislocation consists of posterior SCJ dislocation on one side and anterior SCJ dislocation on the other side. This is an extremely rare injury and only a few cases have been reported in the literature. If not been diagnosed timely and accurately, asymmetrical bilateral SCJ dislocation can be life-threatening.

PATIENTS CONCERNS

We experienced a patient who has a life-threatening posterior dislocation of right SCJ and anterior dislocation on the left SCJ combined with bilateral clavicular fracture after a traffic accident.

DIAGNOSES

A computed tomography (CT) scan with three-dimensional reconstructions of SCJ showed potentially life-threatening posterior dislocation of right SCJ and anterior dislocation on the left SCJ combined with bilateral clavicular fracture.

INTERVENTIONS

Because of failed attempts at closed reduction, electively surgical intervention was made. We repaired the ruptured joint capsule and ligaments and fixed bilateral SCJ by Kirschner wire during the operation.

OUTCOMES

Three-dimensional CT scans confirmed bilateral SCJ reduction and alignment after operation 1 week as well as at the 2-month follow-up.

LESSONS

SCJ dislocation is an extremely rare and life-threatening injury. The aim of the operation is to repair the ruptured joint capsule and its ligaments and to fix the dislocated joints.

Chronic Instability and Pain of the Sternoclavicular Joint: Treatment With Semitendinosus Allograft to Restore Joint Stability

Chronic instability of the sternoclavicular (SC) joint is a challenging clinical problem, particularly in a patient population for which nonoperative forms of treatment prove ineffective. Patients present after experiencing recurrent subluxation events and subsequent pain, which commonly result in increasing functional limitation. Recurrent SC joint instability of this nature can lead to damage of the SC joint cartilage and bone, and in cases of posterior subluxation or dislocation, damage to mediastinal structures. While the precise treatment algorithm requires tailoring to individual patients and their respective pathologies, we have demonstrated successful outcomes in correcting chronic SC joint instability by means of SC joint reconstruction with semitendinosus allograft, SC joint capsular reconstruction, and, in cases of arthritic damage, resection of a small portion of the degenerative component of the medial clavicle. The purpose of this Technical Note is to describe a technique that uses a semitendinosus allograft to stabilize the SC joint combined with a capsular reconstruction in patients who have previously failed nonoperative treatment methods.

Chronic anterior sternoclavicular instability: technique and results of corrective clavicular osteotomy

BACKGROUND

Chronic anterior sternoclavicular (SC) instability is a rare but potentially disabling condition. It can arise in conjunction with trauma or hyperlaxity, or both. Numerous surgical techniques have been described, but no gold standard exists. SC instability is often position-dependent and can be reduced with the arm in a specific position.

METHODS

To directly address this issue, we used a technique of corrective osteotomy of the clavicle with the goal to reorient the articular portion of the medial end of the clavicle so that it remains stable in all functional positions of the arm. To illustrate the technique and the correction in space, we performed postoperative 3-dimensional computed tomography analyses of the shoulder girdle of 4 patients. Clinical scores were obtained at the final follow-up and compared with preoperative scores.

RESULTS

Mean follow-up was 64 months (range, 19-191 months). The mean Constant score improved from 58 (range, 45-68) preoperatively to 73 (range, 69-84) postoperatively and the Subjective Shoulder Value from 42 (range, 15-80) to 79 (range, 50-100). All patients reported good or very good stability of the SC joint at the last follow-up. We recorded no intraoperative or direct postoperative complications. During follow-up, 3 patients underwent removal of the plate, 1 of them for plate breakage. The mean postoperative correction for combined rotations is given as a 3-dimensional angle and averaged 28.0° (range, 8.6°-39.7°).

CONCLUSION

In this pilot study, medial corrective clavicular osteotomy using the described technique treated anterior SC instability with improvement of clinical shoulder function scores and good patient satisfaction. The technique appears simple and safe and deserves further evaluation.

Ultrasound of horizontal instability of the acromioclavicular joint : A simple and reliable test based on a cadaveric study

Background

Horizontal instability influences the clinical outcome after acromioclavicular joint (ACJ) injuries and in joint degeneration. A standardized, dynamic examination of the horizontal instability has not been described before. This current study presents a sonographic method to analyze the dynamics between the clavicle and acromion in the horizontal plane.

Methods

The horizontal joint play, the ACJ space and the offset between clavicle and acromion were sonographically assessed by a 45° ventrally angulated longitudinal section. A total of four investigators with different experience in the field of musculoskeletal ultrasound examining 20 ACJs in 10 human cadavers. Measurements in the absence of any pressure and under standardized anterior and posterior pressure onto the clavicle were carried out in different ligament status intact acromioclavicular (AC) and coracoclavicular (CC) ligaments as well as in a Rockwood (RW) II and III model. A two-sided t‑test was used to examine the differences between joint positions and ligament status.

Results

The horizontal joint play was 1.3 ± 0.9 mm with intact ligaments, 1.4 ± 1.2 mm by transecting the AC ligaments and 1.9 ± 1.3 mm after additionally transecting the CC ligament. The joint space was 3.3 ± 1.1 mm with intact ligaments, 4.1 ± 1.8 mm in an iatrogenic RW 2 injury, and 5.3 ± 3.3 mm in an iatrogenic RW 3 injury. Manipulating the clavicle by applying anterior or posterior pressure did not change the difference within one injury pattern. Interobserver reliability was 83.9%.

Conclusion

Apart from evaluating the ligaments and the joint capsule, measurement of the dynamic horizontal instability is possible in a human cadaver model. The ultrasound-based measurement of horizontal instability dynamics avoids radiation exposure, is readily available and cost-efficient.

Sternoclavicular joint

The sternoclavicular joint is a saddle shaped, synovial joint and is the only skeletal articulation between the axial skeleton and the upper limb. Here, a reviewis provided of the anatomy, biomechanics, traumatic and atraumatic conditions, and management options for the various conditions described.

Swellings of the sternoclavicular joint: review of traumatic and non-traumatic pathologies

The sternoclavicular joint (SCJ) is an integral part of the shoulder girdle that connects the upper limb to the axial skeleton.

Swelling of the SCJ is commonly due to trauma, degeneration, infections and other disease processes that affect synovial joints.

This review also focuses on uncommon conditions that could affect the SCJ, including SAPHO (synovitis, acne, pustulosis, hyperostosis, osteitis) syndrome, Friedrich’s disease and Tietze syndrome.

The scope of this review is limited to the analysis of the current evidence on the various conditions affecting the SCJ and also to provide an algorithm to manage these conditions.

Cite this article: EFORT Open Rev 2018;3:471-484. DOI: 10.1302/2058-5241.3.170078

Functional outcome of open acromioclavicular joint stabilization for instability following distal clavicle resection

Background

Acromioclavicular joint instability following distal clavicle resection can result in considerable pain and dysfunction.

Method

We present a review of 13 patients who underwent ACJ stabilization following one or more distal clavicle resection procedures.

Results

The mean Quick DASH and CM scores were 26(0-57) and 73(46-100) respectively. All but one patient reported an improvement in the pain component of their CM score and in the work component of the Quick DASH score.

Discussion

Open ACJ stabilization to treat instability following distal clavicle resection resulted in improved functional scores, pain scores and facilitated return to work in most patients.Level of evidence IV.

[Development and biomechanical study of anatomical locking plate of sternoclavicular joint]

Objective

To develop an anatomical locking plate in accordance with the anatomical characteristics of the sternoclavicular joint, which is reliable fixation and easy to operate, so as to provide an ideal internal fixation device for the treatment of sternoclavicular joint dislocation or peripheral fractures.

Methods

Gross measurement and CT measurement were performed on the 8 adult antiseptic and moist cadaver specimens (16 sides) to measure the parameters of surrounding bone structure of the sternoclavicular joint. The parameters included the thickness of presternum, sternal notch width, anteroposterior diameter of proximal 1/3 of clavicle, upper and lower diameters of proximal 1/3 of clavicle, angle between proximal end of clavicle and presternum in coronal plane, and angle of thoracoclavicular joint at anatomic position forward. According to the anatomical parameters and biomechanical properties of the specimens, the anatomical locking plate was designed and developed. The sternoclavicular ligament and joint capsule of all the specimens were completely cut off to make the sternoclavicular joint dislocation model. The left and right sternoclavicular joint of each specimen were randomly divided into experimental group (anatomic locking plate fixation) and control group (oblique T shape locking plate fixation). The sternoclavicular joint activity and common force mechanism was simulated on the universal mechanical testing machine, and the clavicular distal load test, sternoclavicular joint torsion test, and anti-pulling of steel plate manubrium part test were performed.

Results

The differences between the anatomical parameters of gross measurement and CT measurement were not significant ( P>0.05). In the clavicular distal load test, when the anatomical position perpendicular to the distal clavicle back loading to 20 N, the displacement of loading point in the experimental group was (8.455±0.981) mm, which was significantly less than that in control group [(10.163±1.379) mm] ( t=-3.012, P=0.020); the distal clavicle displacement of loading point of experimental group and control group were (5.427±1.154) mm and (6.393±1.040) mm, respectively, showing no significant difference ( t=-1.459, P=0.188)。In the sternoclavicular joint torsion test, the torque of experimental group was significantly greater than that of control group when the clockwise torsion angle was at 2, 4, 6, 8, and 10 degrees and the counterclockwise torsion angle was at 4, 6, 8, and 10 degrees ( P<0.05). The torsional stiffness in the experimental group under clockwise and counterclockwise condition was 0.122 and 0.108 N·m/° respectively, which were significantly higher than those in the control group (0.083 and 0.078 N·m/° respectively) ( F=67.824, P=0.000; F=20.992, P=0.002). In the anti-pulling of steel plate manubrium part test, the maximum pullout force of experimental group [(225.24±16.02) N] was significantly higher than that in control group [(174.40±21.90) N] ( t=5.785, P=0.001).

Conclusion

The new type of anatomical locking plate can realize the sternoclavicular joint three-dimensional fixation, and has the advantages of reliable fixation, simple operation, less trauma, superior biomechanical properties, and earlier functional exercise. It may be an ideal internal fixation device in clinical treatment of sternoclavicular joint dislocation or peripheral fractures.

Locking plate for treating traumatic sternoclavicular joint dislocation: a case series

Background

Traumatic sternoclavicular joint dislocations are rare; closed reduction is the primary treatment. The failure of closed reduction or a prominent insult to the skin may require surgery to ensure the best possible outcome.

Methods

The records of 5 patients operated at our institution for sternoclavicular joint dislocation were reviewed. All patients were treated with open reduction and single 3.5-mm locking plate was used for fixation. Outcomes were evaluated with the Constant Shoulder Score (CSS) and Disability of the Arm, Shoulder, and Hand (DASH) questionnaire. Intraoperative and postoperative complications were recorded.

Results

All the patients had an average follow-up of 14 months (range, 11–16 months). At the final follow-up, the mean CSS score was 89.5 (range, 78–98) and the mean DASH score was 9.0 (range, 4–16). There were no early complications, including wound infection or neurologic or vascular deficits; there were also no broken or loosened screws or plates. No case of redislocation or arthrosis was observed.

Conclusion

Our study indicates that open reduction and fixation with a single locking plate for the treatment of traumatic sternoclavicular joint dislocation is a safe, relatively simple surgical procedure that can lead to satisfactory outcomes.

Sternoclavicular Joint Reconstruction in the Setting of Medial Comminuted Clavicle Fracture

A dislocation of the sternoclavicular joint is a particularly threatening injury given the close proximity of neighboring vital structures. Moreover, a traumatic injury resulting in a comminuted fracture of the medial clavicle in addition to joint instability results in even greater complexity. In the setting of sternoclavicular joint instability, definitive treatment that will lead to complete resolution of symptoms is necessary. Various treatment methods, both conservative and operative, with positive treatment outcomes have been described. The aim of this Technical Note is to describe our preferred surgical technique to treat a medial comminuted clavicle fracture with anterior sternoclavicular joint instability.

Arthroscopic Intra-articular Disk Excision of the Sternoclavicular Joint

The sternoclavicular joint (SCJ) has a complete intra-articular disk that can be damaged either as a result of trauma or as part of ongoing degenerative joint disease. Although often asymptomatic, SCJ disk tears may lead to mechanical symptoms and pain. Previously, isolated symptomatic SCJ disk tears have only occasionally been mentioned in the literature with a few associated case reports of diskectomy by open arthrotomy. With improved imaging and availability of magnetic resonance imaging scans and the advent of SCJ arthroscopy it is now possible to treat symptomatic SCJ disk tears by arthroscopic excision. In this Technical Note, we describe the diagnosis of a torn SCJ disk and the technique of arthroscopic excision of a torn SCJ disk.

Biomechanical Analysis of Intra-articular Pressure After Coracoclavicular Reconstruction

BACKGROUND

Recent biomechanical and clinical studies have demonstrated the effectiveness of suture button and pulley-type fixations for surgical treatment of acromioclavicular instability. Concerns remain that such procedures can "overconstrain" (overreduce the lateral clavicle in relation to the acromion to a nonphysiological position) the joint. Purpose/Hypothesis: The purpose of this study was to investigate the intra-articular pressure of native and reconstructed acromioclavicular (AC) joints in relation to the configuration of the joint. Anatomic (0 mm), overconstrained (-3 mm), and underconstrained (+3 mm) AC joint reconstructions were simulated. The hypothesis was that reconstructions using suture pulley systems do not increase the intra-articular pressure of the AC joint.

STUDY DESIGN

Controlled laboratory study.

METHODS

Eleven fresh-frozen cadaveric shoulders were used in this study (mean age ± SD, 60.8 ± 6.7 years). Each specimen underwent radiographic analysis by using a Zanca view to determine the basic configuration of the AC joint. A pressure Tekscan sensor was inserted in the AC joint. A servohydraulic materials testing system was used for testing. The specimens were kept in the testing machine, and the native AC position was marked at 0 mm. This allowed moving the clavicle during the surgical procedure with reference to the native anatomic position. Intra-articular pressure in the native AC joint during cyclic loading (1000 cycles; 1 Hz) was measured. After native testing, the AC ligaments and coracoclavicular ligaments were cut and reconstructed using a cortical button technique. Anatomic, -3 mm, and +3 mm positions, relative to the acromion, were cyclically loaded, and intra-articular pressure was documented.

RESULTS

According to the AC joint classification of inclination, we identified five type 1 (46%), four type 2 (36%), one type 3 (9%), and one incongruous (9%) configurations. Changes in superior displacement across the 4 conditions were not statistically significant (0.5 ± 0.8 [native], 0.01 ± 0.00 [0 mm repair], 0.02 ± 0.02 [-3 mm repair], and 0.01 ± 0.01 [+3 mm repair]; P = .162). Before testing (time point 1), pressure in the -3 mm repair (62.9 ± 70.1) differed between the native state (11.3 ± 21.8; P = .042) and the +3 mm repair (7.1 ± 18.4; P = .023). All other changes at time points 2 (after cyclic loading unloaded) and 3 (after cyclic loading loaded) in pressure were not significant. ( P = .086 and .226, respectively).

CONCLUSION

AC joint reconstruction (within -3 to +3 mm of reduction) with a coracoclavicular suture button device does not significantly increase the intra-articular pressure of the AC joint after cyclic loading in our experimental cadaveric setup.

CLINICAL RELEVANCE

Recent biomechanical and clinical studies have demonstrated the effectiveness of suture button and pulley-type fixations for coracoclavicular reconstruction of the joint. Concerns remain that such procedures would "overconstrain" the joint because of the high rigidity of these pulley systems and the preservation of the lateral clavicle. This overconstraining may potentially result in pain at the lateral end of the clavicle, osteolysis, or a later increased risk of early osteoarthritis. Therefore, our results indicate that within a range of ±3 mm to the anatomic position, overconstraining may not result in a higher intra-articular pressure.

Outcomes and complications following graft reconstruction for anterior sternoclavicular joint instability

PURPOSE

Publications describing tendon graft reconstruction for anterior sternoclavicular joint (SCJ) instability are rare and usually refer to small patient numbers. The aim of this study was to systematically review the literature regarding outcomes and complications following tendon graft reconstruction techniques for anterior SCJ instability.

METHODS

An online database was systematically searched to identify studies on graft reconstruction for anterior SCJ instability. Reported outcome scores were graded as excellent, good, fair and poor to summarize the study results. All reported complications were recorded.

RESULTS

Five articles with a total of 80 patients met the inclusion criteria. Reported outcomes were excellent in 10 %, good in 89 % and fair in 1 %. Recurrent instability was found in 10 % of the patients, and 5 % underwent revision surgery due to persistent impairment of shoulder function related to SCJ instability or osteoarthritis.

CONCLUSION

Surgical stabilization techniques for the SCJ using autologous tendon grafts have shown to be safe and reliable and make better patients' pain situation and shoulder function. However, a certain amount of impairment might persist, which needs to be discussed with patients. Severe complications were rare and revision rates were as low as 5 %. Therefore, graft reconstruction techniques should be considered for patients with chronic anterior SCJ instability after a course of failed conservative treatment. This study is valuable for clinicians in daily clinical practice when dealing with this difficult-to-treat pathology and can help surgeons to better predict the clinical outcomes and complications following SCJ graft reconstruction. It should, however, not lead to underestimation of the potential risks of the procedure.

LEVEL OF EVIDENCE

Systematic review, Level IV.