Articular facets of the coracoclavicular joint in Koreans

A review of the coracoclavicular joint: Description, etiology, and clinical significance

The coracoclavicular joint (CCJ) is a synovial joint that forms between the conoid tubercle of the clavicle and the coracoid process of the scapula in approximately 2.5% of the population. The number of bilateral to unilateral cases is almost equal. The number of right-sided and left-sided cases is also almost equal. It is found in both males and females but most often in male adults. Very few cases have been identified in juveniles. Found in populations all over the world, the highest frequencies of CCJ are in Asia. The etiology is unknown but it is most likely caused by metaplastic change of the trapezoid and surrounding tissue due to compression and friction of the coracoacromial ligament between the clavicle and coracoid process. Typically asymptomatic, but if so, the most common complaint is anterior should pain exacerbated by extreme abduction. Successful treatment includes steroid injection and surgical excision.

Prevalence and Morphology of the Coracoclavicular Joint: An Osteological Study of 2,724 Subjects Using Univariable and Multivariable Logistic Regression Analyses

Background: The coracoclavicular joint (CCJ) is an anomalous articulation between the surfaces of the inferior clavicle and superior coracoid and its etiology is controversial. Reportedly, symptomatic patients demonstrate significant functional limitations including shoulder abduction loss and potential for brachial plexus compression and impingement. Purpose: To determine the prevalence of CCJ across age, gender and ethnicity, and to identify clinically useful morphological characteristics. Methods: 2,724 subjects with intact clavicles and scapulae from the Hamann-Todd Osteological Collection were evaluated for the presence of CCJ. Logistic regression was used to determine the effect of age, height, gender, and race on prevalence of CCJ. 354 clavicles with CCJ were measured for size and location of the CCJ facet. Results: CCJ was observed in 9% of subjects. CCJ was more prevalent in African-Americans (12%) than Caucasian-Americans (6%) (p < 0.001) and more prevalent in females (11%) than males (8%) (p = 0.055). Facet location along clavicle length was consistent (average 25%, range 15-35%). But, facet location along clavicle width varied (average 60%, range 10-90%), with males having a more posterior location. For every 10-year increase in age, facet elevation (p = 0.001) and surface area (p < 0.001) increased. Conclusions: CCJ prevalence was 9% in our large osseous population, found more commonly in African-Americans and females. Facet location is predictable with respect to clavicle length, but less so along clavicle width. The clavicular facet may develop at some point in life and continue to grow in size after its appearance. Clinical Relevance: Presence of a CCJ represents a potential overlooked source of anterior shoulder pain and supracoracoid impingement. Epidemiologic and morphological characteristics presented in our study can aid in the identification, clinical understanding, and surgical excision of a symptomatic CCJ. Level of Evidence: Level IV.

Morphometric Study of Clavicular Facet of Coracoclavicular Joint in Adult Indian Population

INTRODUCTION

Anthropologists have used Coracoclavicular Joint (CCJ), a non-metric anatomical variant in population, as a marker for population migration from prehistoric times to present.

AIM

The aim of this osteological study was to determine the incidence and morphometry of articular facet of CCJ on conoid tubercle of clavicle in Indian population, as Indian studies are scanty and incomplete.

MATERIALS AND METHODS

The study was done on 144 adult human clavicles (76 right and 68 left; 93 males and 51 females) collected from osteology museum in Department of Anatomy, Maulana Azad Medical College, New Delhi, India. The presence of articular facet on the conoid tubercle was determined and Maximum Antero-Posterior (MAPD) and maximum transverse diameter (MTD) was measured by digital vernier calliper. The incidence was compared on the basis of sex, side and with other osteological studies in the world. Statistical analysis was done using the Chi-Square test for nominal categorical data and student's t-test for normally distributed continuous variables in Microsoft Excel 2007 to assess the relationship between the examined variables.

RESULTS

Articular facet on conoid tubercle was found in 8 cases (5.6%). Seven (9.2%) were present on the right side and one (1.5%) on the left side. Seven cases (7.5%) were present in males and one case (2%) was found in females. The facets were generally oval, with MAPD and MTD of 12.28 and 17.17 mm respectively. A significant side variation was present with right sided facet being more common. The left sided facet was more transversely elongated than right. In males, the facets were more elongated antero-posteriorly than in females.

CONCLUSION

The Indian population showed an incidence of 5.6%, which was comparable to other ethnic groups in world population. The morphometric and side differences could be attributed to the occupational factors and range of movements associated with the CCJ. The CCJ should be borne in mind as a differential diagnosis for thoracic outlet syndrome and in general for shoulder pain.

The coracoclavicular joint. A systematic review and meta-analysis

The coracoclavicular joint (CCJ) is considered as a rare articulation in humans. Though rarely it could be symptomatic, its presence should be acknowledged by physicians. The aim of this systematic review is to conduct an evidence synthesis on the prevalence of this condition in different ethnic populations. Thirty nine studies including 51 sub-studies met the inclusion criteria. The meta-analytical results showed true prevalence values of ≃5%, ≃7% and ≃2.7% from skeletal, cadaveric and radiological studies, respectively. The bilateral occurrence of CCJ was found to be approximately the half of the crude prevalence and that in all study types. European populations showed the least frequency whereas the Eastern Asian and Native American populations showed the highest values in skeletal/cadaveric studies. European, modern American, Native American and modern South American populations showed the least CCJ occurrence rates in radiological studies. The Chinese population stood out from all other ancestries with a prevalence of 21%, followed by the Southeast Asians with a frequency of 6%. No association was found with variables such as sex or side. This evidence-based anatomical and anthropological review shed the light on the rare and poorly investigated CCJ. It yielded more accurate overall and ancestry-based frequencies from skeletal, cadaveric and radiological studies.

Evaluation of the coracoid and coracoacromial arch geometry on Thiel-embalmed cadavers using the three-dimensional MicroScribe digitizer

BACKGROUND

Understanding the geometry of the coracoid and coracoacromial arch will improve surgical intervention in shoulder surgery.

METHODS

Thirty pairs of scapulae from 20 female and 10 male deceased donors, average age of 82 years (range, 62-101 years), were scanned and measurements taken using the 3-dimensional (3D) MicroScribe digitizer (Immersion Corp, San Jose CA, USA) and Rhino software (McNeel North America, Seattle, WA, USA).

RESULTS

The following mean angles were determined: coracoid slope, 44° ± 11°; coracoid deviation, 35° ± 6°; coracoid root to glenoid, 115° ± 14°; coracoid head to glenoid, 110° ± 11°; scapular spine angle, 35° ± 6°; and coracoacromial angle, 63° ± 9°. The following mean distances were also determined: coracoid height, 10 ± 3 mm; coracoacromial distance, 42 ± 7 mm; coracoacromial arch height, 20 ± 5 mm; and coracoid (anterior, 29 ± 6 mm; middle, 20 ± 4 mm; posterior tip, 18 ± 6 mm) to the glenoid fossa. The coracoid root-to-glenoid angle was significantly correlated with the coracoacromial angle. In addition, coracoid slope was significantly correlated with coracoid root-to-glenoid angle and also with coracoid deviation. Left shoulders had a significantly higher coracoid-to-glenoid angle (P < .029) than right shoulders. Women had a significantly higher coracoid root-to-glenoid angle than men (P < .042), and men had a significantly higher coracoid deviation (P < .011), anterior (P < .006) and posterior coracoid-to-glenoid distances (P < .03), and coracoacromial arch height (P < .07) than women.

CONCLUSIONS

This is the first time that the 3D MicroScribe digitizer has been used to evaluate the geometry of the coracoacromial arch and coracoid process.

Surgical excision of a symptomatic congenital coracoclavicular joint

The coracoclavicular joint is a rare anatomic variant that consists of an articulation between the conoid tubercle of the clavicle and the superior surface of the coracoid process of the scapula. The coracoclavicular joint is most often asymptomatic and is found incidentally. A symptomatic coracoclavicular joint is exceedingly rare, with only 17 cases reported from 1915 to 2009. Symptoms may include limited range of motion, paresthesia, and brachialgia with radiation to the ipsilateral extremity. In the case of symptomatic coracoclavicular joints for which treatment data are reported, the response to conservative management with rest, analgesics, and physical therapy has been poor. Operative management resulted in complete resolution of symptoms in most patients and symptomatic improvement in the rest. This article reports the case of a 63-year-old man who presented with chronic left anterior shoulder pain exacerbated by forward flexion and overhead activities. Radiographs and computed tomography scan of the affected shoulder showed a bony articulation between the clavicle and the coracoid process of the scapula. The patient did not achieve long-term relief through conservative measures and corticosteroid injections, so the joint was surgically excised by an open procedure. Intraoperative findings were significant for a fully formed synovial joint with a capsule articulating between the clavicle and the coracoid process. After resection, the patient had minimal residual pain, improved range of motion, and symptomatic improvement with activity. The current case provides further data that the coracoclavicular joint can be the cause of significant shoulder pain and can be treated successfully with total resection of the joint if symptoms do not improve with conservative non-operative measures.

Functional aspects of the coracoclavicular space

BACKGROUND

The coracoclavicular joint has been described as an articulation found inconstantly between the coracoid process and clavicle. We often observe a small space bordered by the fascia which covers the anterior surface of the subclavius muscle and the coracoclavicular ligament. The aim of this study was to observe the space in detail and to discuss the functional role of the coracoclavicular joint.

MATERIALS AND METHODS

Sixteen shoulder girdles from eight Japanese cadavers were used in this study. The scapula, clavicle, and anterior half of the first rib were extracted en bloc together with the subclavius muscle and the surrounding fascia. After observing the motion of the scapula and clavicle, we investigated macroscopically the attachments of the coracoclavicular ligaments and the subclavius muscle, and the extension of the fascia.

RESULTS

The fascia divided laterally into two sheets: the anterior sheet attached to the trapezoid ligament and the posterior to the conoid ligament. Among the two sheets, the coracoclavicular ligaments, coracoid process, and clavicle, a small space was observed. This small space can be recognized as a part of the coracoclavicular joint. When manually moving the inferior angle of the scapula with the sternal end of the clavicle fixed, we observed that the clavicle collided with the trapezoid ligament on the superior surface of the coracoid process within the space and that the scapular motion was restricted by this collision.

CONCLUSION

The coracoclavicular joint could be much more recognizable than in previous papers and play an important role in the normal function of the shoulder joint.

LEVEL OF EVIDENCE

Basic science study.

Symptomatic coracoclavicular joint: incidence, clinical significance and available management options

PURPOSE

Coracoclavicular joint (CCJ) is a rare anomalous joint occasionally found between the coracoid process of scapula and the conoid tubercle of clavicle. The articulation has been extensively studied by means of anatomical, osteological and radiological investigations. Most cases are discovered incidentally, with the symptomatic variety remaining an exceptional rarity. Our aim was to review all reported symptomatic CCJ to increase the level of evidence and formulate a treatment algorithm to aid clinicians in management planning.

METHODS

A thorough literature search was performed, and data from 17 (n = 17) symptomatic cases of CCJ were analysed.

RESULTS

CCJ is a rare finding and mostly an incidental discovery, which is rarely symptomatic. However, when symptomatic, the most common symptom is shoulder pain. The mean age at presentation is 42 years, with a male:female ratio of 1.4:1. Brachial plexus involvement was the most common pathophysiological explanation provided. First-line treatment was conservative, with a very low success rate of 5.9%. Surgical intervention in the form of excision of anomalous joint by osteotomy had success rate of 100%.

CONCLUSIONS

Symptomatic CCJ is rare, and its rarity leads to lack of awareness in the general orthopaedic community. When symptomatic, CCJ may lead to delayed diagnosis or inappropriate management due to lack of evidence and poor description in most orthopaedic textbooks. Despite its low success rate, conservative treatment is advocated before embarking upon surgical intervention.

Coracoclavicular joint, an osteological study with clinical implications: a case report

INTRODUCTION

The presence of an anomalous coracoclavicular joint was studied in a human male skeleton aged 73 years old from the Osteology Collection of our Department.

CASE PRESENTATION

We describe the exact morphology of this variation that is occasionally reported as an anatomical or radiological curiosity in the literature (0.55-21%).

CONCLUSION

Although coracoclavicular diarthrosis is of no significance other than academic, it is important to recognize this variation and the clinical symptoms that may occur, as it is a cause of shoulder pain and arthritis in this or the adjacent sternoclavicular and acromioclavicular joint. Consequently, it is vital to apply the appropriate treatment.

A symptomatic coracoclavicular joint

Bilateral coracoclavicular joints were found in a 44-year-old male patient following a fall. He had an Indonesian mother and a Dutch father. Prior to the injury he was asymptomatic and had full range of movement in both shoulders but the trauma resulted in pain and limitation of movement in the left shoulder which required resection of the anomalous joint, after which full pain-free movement was restored.

Anatomy and biomechanics of the acromioclavicular and sternoclavicular joints

The acromioclavicular and sternoclavicular joints have important soft-tissue static constraints that, based on biomechanical studies, imply a great deal of stability. The infrequency of significant symptoms following dislocations of these joints certainly highlights the fact that the dynamic muscle support is also very important. In performing resections of these joints for degenerative disease, our goal should be to preserve these important ligamentous supports by minimizing the amount of bone excised, as this seems to optimize results [84]. Precise isometric reconstruction of these complex, three-dimensional ligamentous structures merits further investigation in the laboratory and clinical settings.

Coracoclavicular joint: osteologic study of 1020 human clavicles

We examined 1020 dry clavicles from cadavers of Italian origin to determine the prevalence of the coracoclavicular joint (ccj), a diarthrotic synovial joint occasionally present between the conoid tubercle of the clavicle and the superior surface of the horizontal part of the coracoid process. Five hundred and nine clavicles from individuals of different ages were submitted to X-ray examination. Using radiography, we measured the entire length and the index of sinuosity of the anterior lateral curve, on which the distance between the conoid tubercle and the coracoid process depends. We also used radiography to record the differences in prevalence of arthritis in two neighbouring joints, the acromioclavicular and sternoclavicular joints. Of the 1020 clavicles, eight (0.8%) displayed the articular facet of the ccj. No statistical correlation was found between clavicular length and the index of sinuosity of the anterior lateral curve. The prevalence of arthritis in clavicles with ccj was higher than that revealed in clavicles without ccj. The prevalence of ccj in the studied clavicles is lower than that observed in Asian cohorts. Furthermore, ccj is not conditioned by either length or sinuosity of the anterior lateral curve of the clavicle. Finally, the assumption that ccj is a predisposing factor for degenerative changes of neighbouring joints is statistically justified.

Anatomic variance of the coracoclavicular ligaments

The coracoclavicular ligaments vary widely in morphology and anatomic descriptions. Few authors have adequately described the coracoclavicular ligaments' anatomy, and a number of discrepancies exist in the anatomy literature. This study examines the complex anatomy of the coracoclavicular ligaments and their relationships to clinically important bony landmarks. The geometric dimensions of 24 coracoclavicular ligament specimens from fresh human cadaveric shoulders were examined and quantified with 13 different measurements. Particular attention was given to any inter-specimen anatomic variance. The coracoid insertions of the conoid ligaments displayed high variance, with 33% (8/24) being confluent with the lateral fibers of the superior transverse scapular ligament. A further 15% (3/24) presented an additional lateral fascicle. The distance from the lateral trapezoid ligament to the distal clavicle averaged 15.3 mm. Three distinct and previously unreported conoid ligament variants lend themselves to an anatomic classification (types I, II, and III). A safety margin of 15 mm is suggested for distal clavicle resection in incomplete acromioclavicular joint injuries to preserve the intact coracoclavicular ligament.