The Diagnosis and Treatment of Acute Dislocation of the Acromioclavicular Joint

Proximal humerus fracture and acromioclavicular joint dislocation

Proximal humerus fractures and injuries to the acromioclavicular joint are among the most common traumatic diseases of the upper extremity. Fractures of the proximal humerus occur most frequently in older people and are an indicator fracture of osteoporosis. While a large proportion of only slightly displaced fractures can be treated non-operatively, more complex fractures require surgical treatment. The choice of optimal treatment and the decision between joint-preserving surgery by means of osteosynthesis or endoprosthetic treatment is often a difficult decision in which both fracture morphology factors and individual factors should be taken into account. If endoprosthetic treatment is indicated, satisfactory long-term functional and clinical results have been achieved with a reverse shoulder arthroplasty. Injuries to the acromioclavicular joint occur primarily in young, athletic individuals. The common classification according to Rockwood divides the injury into 6 degrees of severity depending on the dislocation. This classification forms the basis for the decision on non-operative or surgical treatment. The indication for surgical treatment for higher-grade injuries is the subject of controversial debate in the latest literature. In chronic injuries, an autologous tendon transplant is also performed. Whereas in the past, treatment was often carried out using a hook plate, which was associated with complications, the gold standard today is minimally invasive treatment using Endobutton systems. This review provides an overview of the two injury patterns and discusses the various treatment options.

Management of type III acromioclavicular joint dislocation: A Delphi consensus survey by Shoulder & Elbow Society, India (SESI)

PURPOSE

The study aimed to report the results of the Delphi survey conducted by the Shoulder, Elbow Society India (SESI), to achieve consensus on ambiguous topics in managing type III acromioclavicular joint (ACJ) dislocations.

METHODS

This study was based on responses from the Shoulder Elbow Society India (SESI) panel of peer-selected twenty senior surgeons practicing shoulder orthopedics. They participated in two rounds of the survey to obtain consensus on several topics pertaining to the management of type III ACJ dislocations. Consensus was achieved when at least 70 % of the panel members selected at least a 4-point on a 5-point Likert scale.

RESULTS

Our Delphi survey reached a consensus on seven topics of ambiguity. An anteroposterior and axillary view of the shoulder without any traction or weight in hand is sufficient in the setting of a suspected type III ACJ dislocation. Magnetic resonance imaging (MRI) is not routinely indicated in type III ACJ dislocation. Either cross-arm adduction X-rays or clinical examination may be used to distinguish between ISAKOS (International Society of Arthroscopy, Knee surgery and Orthopaedics Sports medicine) IIIA and B classification of ACJ to identify stable and unstable injuries. Conservative treatment can be offered to patients who have stable injuries and who are not high-demand individuals in acute type III ACJ dislocations. In conservative management of type III ACJ dislocation, a two-week sling suffices. Jones strapping has no clear advantage over a shoulder sling. Coracoclavicular reconstruction with an autograft is an acceptable way to treat symptomatic, chronic grade III ACJ dislocation.

CONCLUSION

The survey helped achieve consensus on several controversial issues related to type III ACJ dislocations. However, there remains ambiguity on the definition of chronicity of such dislocations, the necessity of bilateral Zanca views, and the duration of conservative trial before switching to a surgical line of management.

Physiotherapeutic Management for Acromioclavicular Joint Sprain With Volar Intercalated Segment Instability at the Wrist: A Case Report

Among sports enthusiasts and young individuals, acromioclavicular (AC) joint injuries are highly prevalent. In this, we discussed the comprehensive assessment and management of a 22-year-old male patient who is a student by occupation and a recreational badminton player who presented with left shoulder and wrist pain following a road traffic accident. The study highlights the clinical findings, diagnostic assessment, and therapeutic interventions for the patient with volar intercalated segment instability and a grade 1 AC joint sprain. The methodology involves a case report of the patient's clinical evaluation, including range of motion, manual muscle testing, and diagnostic imaging. The patient was managed conservatively with physiotherapy interventions, including Mulligan's movement with mobilization, cryotherapy, light amplification by stimulated emission of radiation, and progressive exercises. The results of the study demonstrate the successful implementation of a multidisciplinary conservative management approach for alleviating pain, restoring function, and promoting optimal recovery for the patient. The implications of the study underscore the significance of tailored physical therapy rehabilitation in the management of AC joint sprains and wrist instabilities.

3D C-arm navigated acromioclavicular joint stabilization

INTRODUCTION

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

MATERIALS AND METHODS

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

RESULTS

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

CONCLUSION

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

Mid-term clinical and sonographic outcomes of minimally invasive acromioclavicular joint reconstruction: mini-open versus arthroscopically assisted

INTRODUCTION

The current literature describes various operative stabilization strategies which achieve good clinical outcomes after acute acromioclavicular joint (ACJ) dislocation. The aim of this study was to compare the mid-term clinical and sonographic treatment outcomes after minimally invasive mini-open and arthroscopic reconstruction.

MATERIALS AND METHODS

We conducted a retrospective two-center study of patients with acute ACJ dislocation. Surgical treatment was performed using either a mini-open approach (MIOP) or an arthroscopic technique (AR). The primary outcome parameters of this study were the sonographically measured acromioclavicular (ACD) and coracoclavicular distances (CCD). Secondary outcome parameters included the Constant-Murley score (CS), range of motion (ROM), postoperative pain scale (VAS), return to daily routine, return to sports, complications, as well as operative revisions.

RESULTS

After a mean follow-up of 29 months, 30 patients were included in this study with an average age of 41.3 ± 14.8 years (MIOP) and 41.2 ± 15.4 years (AR). The sonographic ACD (MIOP 9.11 mm vs. AR 8.93 mm, p = 0.41) and CCD (MIOP 25.08 mm vs. AR 24.36 mm, p = 0.29) distances showed no statistically significant differences. Furthermore, there was no statistically significant difference when compared to the contralateral side (p = 0.42). With both techniques, patients achieved excellent clinical outcome parameters without statistically significant differences in CS (MIOP 95 vs. AR 97, p = 0.11) and VAS (MIOP 1.76 vs. AR 1.14, p = 0.18). The return to daily activity and return to sport rates did not differ. There were neither complications nor revisions in both groups.

CONCLUSION

Both minimally invasive techniques for acute ACJ stabilization achieved excellent clinical and sonographic outcomes without one technique being statistically superior to the other.

The V angle compliments radiographic assessment of acute acromioclavicular joint dislocations by differentiating between Rockwood types III versus V and by considering dynamic horizontal translation in coronal radiographs

PURPOSE

Acromioclavicular joint (ACJ) dislocations are usually graded radiographically according to Rockwood, but differentiation between Rockwood types III and V may be ambiguous. The potentially clinically relevant horizontal instability is barely addressed in coronal radiographs. It was hypothesized that a new radiologic parameter (V angle) would complement ACJ diagnostics on anteroposterior radiographs by differentiating between cases of Rockwood III and V while also considering the aspect of dynamic horizontal translation (DHT).

METHODS

Ninety-five patients with acute ACJ dislocations (Rockwood types III and V) were included retrospectively between 2017 and 2020. On anteroposterior views (weightbearing: n = 62, non-weight-bearing: n = 33), the coracoclavicular (CC) distance and the newly introduced V angle for assessing scapular orientation were measured bilaterally. This angle is referenced between the spinal column and a line crossing the superior scapular angle and the crossing point between the supraspinatus fossa and the medial base of the coracoid process, reported as the side-comparative difference (non-injured side *minus* injured side). DHT on Alexander views was divided into stable, partially unstable or completely unstable.

RESULTS

The V angle on the injured side alone (mean 50.0°; 95% confidence interval (CI), 48.6°-51.3°) showed no correlation with the side-comparative CC distance [%] (r = - 0.040; n.s.). Thus, the V angle on the non-injured side was considered, displaying a normal distribution (n.s.) with a mean of 58.0° (95% CI, 56.6°-59.4°). The side-comparative V angle showed a correlation with the side-comparative CC distance (r = 0.83; p < 0.001) and was able to differentiate between Rockwood types III (4.7°; 95% CI, 3.9°-5.5°; n = 39) and V (10.3°; 95% CI, 9.7°-11.0°; n = 56) (p < 0.001). A cut-off value of 7° had a 94.6% sensitivity and an 82.1% specificity (area under curve, AUC: 0.954; 95% CI, 0.915-0.994). The side-comparative V angle was greater for cases with complete DHT (8.7°; 95% CI, 7.9°-9.5°; n = 78) than for cases with partial DHT (4.8°; 95% CI, 3.3°-6.3°; n = 16) (p < 0.001). A cut-off value of 5° showed a sensitivity of 84.6% and a specificity of 66.7% (AUC 0.824; 95% CI, 0.725-0.924).

CONCLUSION

The scapular-based V angle on anteroposterior radiographs distinguishes between Rockwood types III and V as well as cases with partial or complete DHT.

STUDY DESIGN

Diagnostic study.

LEVEL OF EVIDENCE

Level II.

Position of scapula and clavicle in acute acromioclavicular joint dislocations: depressed scapula or elevated distal clavicle?

Background

Increased coracoclavicular distance due to acute acromioclavicular joint (ACJ) instability is often described as a pseudoelevation of the clavicle due to inferior hanging of the scapula, while the distal clavicle remains in its position. The aim of this study was to analyze whether the elevation of the distal clavicle, depression of the scapula, or both are associated with vertical instability and to evaluate the impact of weighted stress radiographs on the clavicle and scapular position in acute ACJ instabilities.

Methods

The cohort consisted of 505 patients (f = 52, m = 453; mean age 46 years) which presented to our emergency department or outpatient clinic and treated in our institution from 2006 to 2019 displaying an acute ACJ injury. The panorama views that displayed at least two vertebraes with their spinous processes were retrospectively evaluated. Two raters assessed the panorama views twice regarding the clavicular and coracoidal angle of both sides in relation to the cervicothoracal spine and the difference in height of both clavicles and coracoids.

Results

In our cohort, five types of displacement were distinguished: type A, only clavicle is elevated (N = 46); B, only scapula depressed (N = 36); C, the clavicle elevated and the scapula depressed (N = 67); D, both depressed (N = 133); and E, both elevated (N = 223). 123 patients had non-weighted radiographs and 353 patients stress views with 10 kg of axial load, whereas 29 patients had both radiological modalities. Among these 29 patients, a significant increase in coracoclavicular distance difference, clavicle, and scapula height (P < .05, respectively) was observed, when non-weighted radiographs were compared with weighted. A total of 13 shifts could be observed during the Rockwood type comparison of non-weighted radiographs with the weighted: six from Rockwood type II to III, two from type III to V, and five from type V to type III.

Conclusion

Acute injury to the ACJ does not exclusively lead to a depression of the scapula or an elevated distal clavicle but rather leads to various vertical displacement combinations, however mostly to the elevation of both structures possibly due to muscle spasm and pain. Comparing both radiological modalities of the same patients, the routine use of weighted views should be questioned, since often a shift of Rockwood stage can be observed might lead to on the one hand inadequate conservative treatment for underestimated injuries however on the other hand unnecessary surgery for overestimated dislocations.

Clinical outcomes for grades III-V acromioclavicular dislocations favor double-button fixation compared to clavicle hook plate fixation: a systematic review and meta-analysis

INTRODUCTION

The purpose of this study was to perform a systematic review and meta-analysis of both randomized controlled and observational studies comparing double-button suture fixation to hook plate fixation for types III-IV acromioclavicular joint dislocation.

METHODS

Systematic review of Medline, Embase, Scopus, and Google Scholar, including all levels 1-3 studies from 2000 to 2022. Clinical outcome scores, range of motion, and complications were included. Risk of bias was assessed using the Cochrane Collaboration's ROB2 tool and ROBINs-I tool. MINORS and modified Coleman Methodology Score (CMS) were used to assess within study quality. The GRADE system was used to assess the overall quality of the body of evidence. Heterogeneity was assessed using χ2 and I2 statistics.

RESULTS

Fifteen studies were included. Three of the four included LOE II and eleven of the LOE III studies had a high risk of bias. Study quality was considered poor and fair for 67% by MINORS criteria and 93% for CMS criteria. The pooled estimate (SMD 0.662) for all clinical outcomes was statistically significant and in favor of button repair (p = 0.0001). The pooled estimate (SMD 0.662) for all VAS pain scores was statistically significant, again in favor of button repair (p = 0.001).

CONCLUSIONS

The results of this meta-analysis demonstrated significantly better outcomes of button repair for acute ACJ dislocations when compared to clavicle hook plate. Button repair is also associated with a 2.2 times lower risk for complications. However, risk of bias is high, and study quality within and between studies was low. These results, therefore, must be viewed with caution.

LEVEL OF EVIDENCE

Level III; systematic review and meta-analysis.

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

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

Open Acromioclavicular Repair With a Suture Cerclage Tensioning System: A Case Series

Introduction Numerous surgical techniques to address a type III and type V acromioclavicular (AC) joint separation have been described in the literature, but a preferred standard approach is still in debate. Current approaches include anatomic reduction, coracoclavicular (CC) ligament reconstruction, and anatomic reconstruction of the joint. In this case series, subjects received a surgical approach that avoids metal anchors and utilizes a suture cerclage tensioning system to achieve adequate reduction. Surgical technique An AC joint repair was achieved with a suture cerclage tensioning system, which allows the surgeon to apply a specific amount of force on the clavicle to achieve adequate reduction. This technique repairs the AC and CC ligaments, restoring the anatomy of the AC joint while avoiding some of the common risks and disadvantages associated with metal anchors. Methods From June 2019 to August 2022, 16 patients underwent repair of the AC joint with a suture cerclage tension system. Inclusion criteria included the diagnosis of type III or type V AC joint separation with another concomitant injury, acute and chronic injury, and patients who attended all their postoperative visits. Exclusion criteria included patients who lost to follow-up or patients who missed any of their postoperative visits. Radiographic images were taken during each subject's preoperative and postoperative visits, and the CC distance was measured to determine the integrity of the all-suture cerclage repair. Results Of the 16 patients included in this case series, radiographic images taken during each subject's postoperative visit showed a stable construct with little changes in the CC distance. The average change in CC distance when comparing the two-week and one-month postoperative follow-up is 0.2mm. The average change in CC distance when comparing the two-week and two-month postoperative follow-up is 1.45mm. The average change in CC distance when comparing the two-week and four-month postoperative follow-up is 2.6mm. Conclusion Overall, an AC joint repair with the suture cerclage tension system can be a viable, cost-effective technique for restoring vertical and horizontal stability. Although follow-up, larger-scale studies are required to determine the biomechanical integrity of the construct with an all-suture approach, this case series presents 16 subjects whose postoperative radiographic images showed only a small change in CC distance at two to four months after surgery.

Current concepts in acromioclavicular joint (AC) instability - a proposed treatment algorithm for acute and chronic AC-joint surgery

BACKGROUND

There exists a vast number of surgical treatment options for acromioclavicular (AC) joint injuries, and the current literature has yet to determine an equivocally superior treatment. AC joint repair has a long history and dates back to the beginning of the twentieth century.

MAIN BODY

Since then, over 150 different techniques have been described, covering open and closed techniques. Low grade injuries such as Type I-II according to the modified Rockwood classification should be treated conservatively, while high-grade injuries (types IV-VI) may be indicated for operative treatment. However, controversy exists if operative treatment is superior to nonoperative treatment, especially in grade III injuries, as functional impairment due to scapular dyskinesia or chronic pain remains concerning following non-operative treatment. Patients with a stable AC joint without overriding of the clavicle and without significant scapular dysfunction (Type IIIA) may benefit from non-interventional approaches, in contrast to patients with overriding of the clavicle and therapy-resistant scapular dysfunction (Type IIIB). If these patients are considered non-responders to a conservative approach, an anatomic AC joint reconstruction using a hybrid technique should be considered. In chronic AC joint injuries, surgery is indicated after failed nonoperative treatment of 3 to 6 months. Anatomic AC joint reconstruction techniques along with biologic augmentation (e.g. Hybrid techniques, suture fixation) should be considered for chronic high-grade instabilities, accounting for the lack of intrinsic healing and scar-forming potential of the ligamentous tissue in the chronic setting. However, complication and clinical failure rates remain high, which may be a result of technical failures or persistent horizontal and rotational instability.

CONCLUSION

Future research should focus on addressing horizontal and rotational instability, to restore native physiological and biomechanical properties of the AC joint.

[Injuries of the shoulder in winter sports]

Skiing as a sport has come a long way from the first competitive event in Norway in 1767 to about 200 million skiers today worldwide. With Germany alone recording around 8000 injuries annually, there is an increased need for awareness for winter-sport-related injuries and their management. According to the latest report by "Auswertungsstelle für Skiunfälle" (ASU, evaluation center for ski accidents), shoulder injuries alone account for more than 20% of injuries to all body regions (men 26.1% and women 13%). The most common injuries affecting the shoulder girdle are rotator cuff strains, glenohumeral dislocations, acromioclavicular dislocations and clavicle fractures. These injuries are primarily the result of four mechanisms: direct impact, axial load on an extended arm, resisted forced abduction of the arm, and external rotation forces resulting from a firmly planted ski pole in the grasp of a skier during a fall. In this article, we describe the three most common shoulder girdle injuries in winter sports along with their management and answer the most important questions for the athlete.

Clavicular hook plate for acute high-grade acromioclavicular dislocation involving Rockwood type V: clinical and radiological outcomes and complications evaluation

Background

The surgical treatment of high-grade acromioclavicular joint dislocation remains a matter of debate. Clavicular hook plate internal fixation was widely used in the treatment of acromioclavicular dislocation because of its easy-to-master surgical technique. This study aimed to evaluate outcomes using hook plate fixation for acromioclavicular dislocation.

Methods

A consecutive series of 57 patients with acute acromioclavicular joint dislocation involving Rockwood type V were treated between November 2013 and September 2019 using hook plate fixation. The functional outcomes (using the visual analogue score, Constant-Murley score, and University of California Los Angeles score), the quality of surgical reduction (using the coracoclavicular distance), and post-operative complications were assessed with about 46 months of follow-up.

Results

The mean Constant-Murley score increased from 72.6 before surgery to 87.6 at final follow-up. The mean University of California Los Angeles score was 14.1 pre-operatively and 31.6 at final follow-up. Meanwhile, the visual analogue scores were significantly reduced from 3.4 pre-operatively to 1.3 post-operatively. The coracoclavicular distance decreased from 19.4 mm pre-operatively to 10.9 mm at the last follow-up. Post-operative functional and radiological outcomes were significantly improved compared with pre-operative outcomes (P < 0.01). The overall excellent and good result was 35.1% (20/57) and 54.1% (31/57), respectively. At follow-up, the overall complication rate was 15.8% (9/57) including subacromial impingement (three patients), acromial osteolysis (three patients), reduction loss (one patient), acromioclavicular joint osteoarthritis (one patient), and calcification (one patient).

Conclusion

Hook plate fixation was a viable treatment approach, and achieved good clinical outcomes in the treatment of acute acromioclavicular dislocation involving V. But some complications of hook plate fixation should not be ignored.

The acromioclavicular joint injuries treatment

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Ligamentous healing potential of the acromioclavicular ligament following acute anatomical reconstruction

BACKGROUND

Horizontal instability following acute acromioclavicular joint (ACJ) reconstruction still occurs with a high prevalence. Although the human acromioclavicular ligament complex (ACLC) represents the major horizontal ACJ stabilizer, experimental studies on healing characteristics are lacking. Therefore, the purpose of this histological study was to investigate the healing potential of the ACLC following acute anatomical reconstruction METHODS: In this prospective clinical-experimental study, 28 ACLC biopsies were performed in patients with complete ACJ dislocations (Rockwood type 4 or 5) during acute hook plate stabilization (IG: implantation group; n = 14) and hook plate removal (EG: explantation group; n = 14). Histological analyses included Giemsa staining, polarized light microscopy and immunostaining against CD68, αSMA and collagen type I and type III. Histomorphological evaluation entailed cell counts, collagen expression score, ligament tissue maturity index (LTMI) and descriptive analysis of specific ligamentous structures. Statistics consisted of nonparametric Mann-Whitney U tests and a level of significance of P < .05.

RESULTS

Total cell counts (cells/mm² 1491 ± 296 vs. 635 ± 430; P < 0.001) and collagen III expression (3.22 ± 0.22 vs. 1.78 ± 0.41; P < 0.001) were higher in EG compared to IG. Inversely αSMA + (11 ± 9 vs. 179 ± 186; P < 0.001) and CD68 + cell counts (56 ± 20 vs. 100 ± 57; P 0.009) were significantly lower in the EG. The EG revealed a comparable reorientation of ligamentous structures. Consistently, ACLC samples of the EG (21.6 ± 2.4) displayed a high total but differently composed LTMI score (IG: 24.5 ± 1.2; P < 0.001).

CONCLUSIONS

This experimental study proved the ligamentous healing potential of the human ACLC following acute anatomical reconstruction. Histomorphologically, the ACLC reliably showed a ligamentous state of healing at a mean of about 12 weeks after surgery. However, processes of ligamentous remodeling were still evident. These experimental findings support recent clinical data showing superior horizontal ACJ stability with additional AC stabilization in the context of acute ACJ reconstruction. Though, prospective clinical and biomechanical studies are warranted to evaluate influencing factors on ACLC healing and potential impacts of acute ACLC repair on clinical outcome.

STUDY TYPE

Controlled Laboratory Study.

Acromioclavicular joint separation treated with clavicular hook plate: a study of radiological and functional outcomes

INTRODUCTION

ACJ separation is a common shoulder injury. A variety of surgical techniques for high-grade ACJ separations have been described. A commonly used technique represents open reduction and fixation by a hook plate. Goal of the present study was to evaluate radiographic and functional outcome in patients with high-grade ACJ separations following surgical treatment with a hook plate before and after surgery as well as after hook plate removal.

MATERIALS AND METHODS

Patients undergoing surgery with a hook plate due to traumatic ACJ separation between 2012 and 2014 were included and examined during a follow-up control. Demographic and clinical data as well as radiographs pre- and postoperatively were evaluated. Additionally, range of motion, DASH Score and Constant-Murley Score (CMS) were analysed in a follow-up examination. Wilcoxon signed-rank test and Spearman's rank correlation were used for statistical analysis.

RESULTS

99 patients (88 m/11 w, 44 y) were included in the present study. 69 (64 m/5 w, 49 y) could be examined during long-term follow-up (38 month). After hook plate removal, the CCD increased significantly (13.7 ± 0.9 mm) compared to the hook plate in situ (9.9 ± 0.8 mm, p = 0.000001). 68% of all patients achieved a full range of motion post-operatively. Main limitations of range of motion affected external rotation as well as ante-/retroversion. Mean DASH Score was 5.6 ± 1 points and CMS 90.0 ± 1.4 points.

CONCLUSION

In contrast to a significant higher CCD after hook plate removal, nearly all patients achieved good to excellent functional results for DASH and CMS. This indicates that loss of reduction does not necessarily lead to poor functional outcome after ACJ separation surgery.

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

Purpose

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

Methods

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

Results

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

Conclusions

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

[Fracture diagnosis: upper extremities : Shoulder and shoulder girdle]

BACKGROUND

The shoulder girdle is a chain of bones and joints which connect the upper extremity to the axial skeleton. The shoulder as a biomechanical unit has a remarkable range of motion and is therefore frequently prone to injuries of the three major joints (sternoclavicular joint, acromioclavicular joint, glenohumeral joint) and the bony elements (clavicle, scapula, humerus). Projection radiography is still the first imaging modality for injuries of the shoulder and usually sufficient for initial diagnosis and injury classification. Computed tomography (including 3D reconstructions) and magnetic resonance imaging provide additional useful information for the detection of accompanying soft-tissue injury, for surgical planning and in cases of complex anatomy (e.g., scapular fractures).

PURPOSE

We aim to describe the fundamentals of injuries of the shoulder girdle and the proximal humerus with special emphasis on radiological diagnostics.

MATERIALS AND METHODS

A selective PubMed literature search was performed using the following terms: "sternoclavicular joint dislocation", "clavicle fracture", "acromioclavicular joint injury", "scapular fracture", "shoulder dislocation", "proximal humerus fracture", and "shoulder girdle injuries".

RESULTS

The article describes the basics of the anatomy, the trauma mechanism and the epidemiology of the most common injuries of the shoulder girdle and the proximal humerus. Special emphasis is given to radiological diagnostics, including basic projection radiography and advanced cross-sectional imaging.

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

PURPOSE

Treatment of failed primary reconstruction of the unstable acromioclavicular (AC) joint remains challenging for orthopaedic surgeons. When approaching revision cases, the reason for failure has to be precisely identified. The purpose of this manuscript was to perform a critical review of the literature regarding treatment options for failed AC joint stabilization techniques and to provide a treatment algorithm for salvage procedures.

METHODS

A thorough search included electronic databases for articles published up to April 15th, 2019. Inclusion criteria were set as (1) studies that reported on clinical outcomes following surgical or conservative treatment of AC joint dislocation; (2) studies reporting on failure or complications of primary treatment; (3) chronic instabilities caused by delayed or secondary treatment as well as (4) revision and salvage procedures.

RESULTS

The search strategy identified a total of 3269 citations. The final dataset comprised 84 studies published between 1954 and 2019. A total of 5605 patients (9.63% females) were involved with a mean age of 34.5 years. Overall, complication rates varied between 5 and 88.9% in patients with AC joint instability.

CONCLUSION

In the current literature, evidence for treatment of revision AC joint instability is still lacking, however, surgical treatment continues to evolve. The importance of failure analysis and clinically relevant algorithms were highlighted in this review. Adequately restoring native joint biomechanics is needed for ensuring an optimal healing environment that will translate into patient satisfaction and long-term stability.

LEVEL OF EVIDENCE

V.

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.

Clavicle Elevation or Shoulder Girdle Depression in Acromioclavicular Joint Dislocation: A Radiological Investigation

Background:

The side-comparative coracoclavicular (CC) distance is used to describe the vertical instability component of acute acromioclavicular (AC) joint dislocations. Elevation of the clavicle or a depression of the shoulder girdle can lead to an increased CC distance. The dislocation direction has not yet been investigated and is not included in common classification systems.

Hypothesis:

Clavicle elevation is primarily responsible for vertical dislocation in AC joint separation.

Study Design:

Cross-sectional study; Level of evidence, 3.

Methods:

Weighted and nonweighted bilateral plain anteroposterior views of the shoulder girdles of patients with AC joint dislocations (Rockwood [RW] types III and V), diagnosed in our trauma department between 2001 and 2018, were included in this study. After determining the CC distance, a side-comparative determination of the positions of both the clavicle and shoulder girdle, with reference to the spinal column, was conducted.

Results:

In total, 245 bilateral plain anteroposterior views were evaluated (RW III, n = 116; RW V, n = 129). All patients showed a side-comparative clavicle elevation (mean ± SD: RW III, 5 ± 14 mm; RW V, 11 ± 17 mm) in weighted and nonweighted views. While no depression of the shoulder girdle was measured in RW III injuries (weighted and nonweighted views, 0 ± 11 mm), dropping of the shoulder girdle in RW V lesions on nonweighted views was observed (–5 ± 11 mm).

Conclusion:

Vertical dislocation is mostly associated with clavicle elevation in RW III injures, while in high-grade AC joint dislocations (RW V), a combination of clavicle elevation and shoulder girdle depression is present. A significantly greater superior displacement of the clavicle in RW V injuries was seen in weighted views, while a depression of the shoulder girdle could be detected in nonweighted views. For the first time, these results include the dislocation direction in the classification of an AC joint injury. Further studies are needed to investigate the extent to which dislocation types differ in optimal therapy and outcome.