Duplication of the clavicle

Case report; the posttraumatic regeneration of the clavicle

Fractures of the lateral part account for 25% of all the clavicle fractures. In rare cases, especially with late presentation, the highly osteogenic periosteal sleeve will form bone from the distal epiphysis towards the medial part of the clavicle. In patients with trapezius muscle involvement, we suggest excision of the regenerated limb with a subsequent lock-down procedure of the posterior located clavicle in the periosteal sleeve.

Clavicle duplication following physeal injury

Clavicle duplication is a rare entity with limited number of cases reported. Congenital origin and trauma related mechanisms are the main hypotheses to explain this anatomical variation. In skeletally immature patient, trauma may cause physeal-metaphyseal injury in the distal clavicle rather than acromioclavicular strain. The distal epiphysis remains in continuity with acromion and has an intact periosteal sleeve. The periosteal sleeve is extremely osteogenic, and may lead to new bone formation between epiphysis and displaced metaphysis. This remodeling potential and the intact acromioclavicular joint allow the children to be followed by closed reduction. However, there can be new bone formation between epiphysis and displaced metaphysis, resulting in clavicle duplication. Herein, we present the radiographic and computed tomography findings of a post-traumatic duplication of the clavicle in a 5-year-old boy.

[Duplication of the acromioclavicular joint: A case dating from the end of the 19th century]

The duplication of the acromioclavicular joint is a very rare anomaly of shoulder girdle. Here, we present a new case of unilateral duplication of the acromioclavicular joint observed on an individual from the 19th century. In the literature, two hypotheses are proposed to explain the origin of this anomaly. The first is a congenital origin that could be explained by in utero displacement of one of the clavicle's primary ossification centers, or the existence of an additional ossification center. The second is a traumatic origin resulting from an acromioclavicular fracture that occurred during the growth period of the individual. Our macroscopic observations and CT-scan images show no sign of a healed fracture, of complications, or of a bone callus after healing. The hypothesis of a congenital origin for this acromioclavicular duplication is therefore preferred.

"Clavicular Duplication Causing Thoracic Outlet Obstruction": Unique Presentation of Unreported Association between Clavicular Duplication and Thoracic Outlet Syndrome

There are only few reports of clavicular duplication in the literature and all authors have agreed that duplicated clavicles are clinically insignificant. This is the first report of this unique association. A 22-year-old female student reported with features of neurogenic thoracic outlet syndrome mainly involving C8-T1 components of the brachial plexus, seemingly originating from involvement in costo-clavicular space. Radiograph of the shoulder revealed clavicular duplication. Neuro-physiological studies corroborated the diagnosis. Patient responded well to conservative treatment and was in follow-up for 1 year. Radiograph of the shoulder should be included in the workup of neurogenic thoracic outlet syndrome and anomalies of clavicle should be looked into and ruled out along with other common causes. Patient and symptom directed approach with dedicated physiotherapy and occupational therapy is required for optimum outcome.

Congenital pseudoarthrosis of the clavicle with bifurcation

Congenital pseudoarthrosis of clavicle is a rare clinical entity. It usually presents as a swelling in the clavicular region at birth or soon after birth. Fitzwilliam's original description of 60 subtypes of congenital pseudoarthrosis of clavicle have addressed several anatomical variants, e.g. association with cervical rib and abnormally vertical and elevated upper ribs. However, congenital pseudoarthrosis of clavicle associated with bifurcation is an atypical anatomic variant. To the best of our knowledge, this variant has never been mentioned in the literature. In the present report, we have described this subtype of symptomatic congenital pseudoarthrosis of the clavicle with bifurcation and its possible management.

Unilateral duplication of the acromioclavicular joint: case report and literature review

Clavicle duplication is a rare anatomical variation of the scapular belt: only seven cases have been reported in the literature to date, and only one took note of the existence of a duplication of the acromioclavicular joint. Two hypotheses have been proposed to interpret this variation: genetic factors, or trauma occurred in the growth period. Clavicle duplication should not be mistaken for a quite frequent coracoclavicular joint widely described. The authors report the case of a left acromioclavicular joint duplication in a 51-year-old male patient presenting with left shoulder pain. This case was the first of literature providing 3D CT-scan images.

Duplication of the clavicle with triplication of the coracoid process

A very rare case of duplication of the clavicle and triplication of the coracoid process of the scapula is presented. Duplication of the clavicle has been described in only six reports based on a search of the world literature. There is no mention of duplication or triplication of the coracoid process of the scapula in the world literature and this would appear to be the first report of this kind. A combination of bifurcation and triplication of the clavicle and coracoid process, respectively, in the present case illustrates that even anomalous bones search for their counterpart to form a joint. The process of duplication or triplication is explained with a new hypothesis.

'Duplication' of the clavicle or ossification in coracoclavicular ligament

A case is presented in which plain films revealed a short band of ossification adjacent to the inferior aspect of the lateral part of the clavicle. CT findings indicated that the ossification was situated in the coracoclavicular ligament and was not a manifestation of clavicular 'duplication'.