Fig 1 A

Fig 1 B

Figure 1. Initial axial and antero-posterior radiographs showing a grossly displaced clavicle

Closed reduction was attempted under general anaesthesia but was unsuccessful. Open reduction of the fracture through a bra-strap incision revealed an intact acromioclavicular joint with epiphyseal-metaphyseal separation at the lateral end of the clavicle, corresponding to a Salter-Harris Type I injury.  The distal aspect of the clavicle was found penetrating the trapezius muscle.  The displacement of the clavicle had resulted in extensive immediate soft tissue damage causing complete disruption of the periosteum.  As a result the reduction was unstable and it was not possible to repair the periosteum as a sleeve around the clavicle. We therefore used a 1.6mm Kirschener wire to fix the clavicle to epiphysis (Fig 2).  

Figure 2. Anteroposterior radiograph showing K wire fixation one week post procedure

Figure 3. Anteroposterior radiograph showing bone healing and good position at 6 weeks

Figure 4. Anteroposterior radiograph at eight weeks post fixation revealing bone healing in position

He was discharged home in an arm brace and was reviewed at one and six weeks, with check X rays revealing no loss of position and good bone healing by six weeks (Fig. 3).  At six weeks the K wire was removed and the patient was allowed to mobilise his arm.  

At further follow-up, he was able to comfortably perform his activities of daily living, had good overhead range of movement and no bony deformity of the clavicle.  X ray revealed that the clavicle had healed in correct alignment with no shortening (Fig. 4).

Discussion :

Clavicular fractures are the most common fractures to occur in childhood.  Of these they most frequently occur in the middle one-third of the shaft.  Distal epiphyseal separations are relatively uncommon injuries4.  Dameron and Rockwood classified these in a scheme mimicking the adult acromioclavicular joint dislocation3.  Injuries mimicking Type IV dislocations need special consideration as they can be easily mistaken for Type II or Type III injuries on anteroposterior X-rays.  The significance of this is that the treatment of these varies significantly as does the potential for neurovascular injury. Type IV injuries which protrude deep into the muscle fibres are far less likely to unite properly without intervention and increase the risk of injury to important structures5.  Furthermore, because of the presence of coracoclavicular ligamentous attachment, the periosteum can be completely peeled off when the clavicle becomes displaced.  This combination of complete periosteal separation with the lateral end penetrating the trapezius muscle makes closed reduction an impossible task for severe degrees of Type IV injuries as seen in this case.  In the literature there is only one other case report of Type IV pseudodislocation of the acromioclavicular joint described which was not severe enough to necessitate open reduction2.   Rockwood and Green describe internal fixation by means of repair to the periosteal sleeve for fractures of the distal clavicle3.  Richard and Howard describe a case where they were able to successfully achieve closed reduction of a fractured clavicle, which had buttonholed through the periosteal sleeve and penetrated the trapezius muscle2.  However in our case, the periosteum was too badly disrupted to allow repair.  This is further substantiated by the fact that the follow-up X-ray shows a lack of periosteal reaction around the clavicle (See Fig. 4).  

Epiphyseal fractures such as this are of particular significance since the clavicle has two epiphyseal areas which ossify relatively late on in skeletal maturation.  The lateral plate fuses at age 19 and the medial at 25 6, consequently an epiphyseal injury in a 12 year old boy leaves him at risk of growth arrest, bony deformity and possible limitation of function of the affected arm if not treated appropriately.

Reference :

1. Black GB, McPherson JAM, Reed MH. Traumatic pseudodislocation of the acromioclavicular joint in children; a fifteen year review. Am J Sports Med 1991;19:644-646

2. Richards DP, Howard A. Distal clavicle fracture mimicking type IV acromioclavicular joint injury in the skeletally immature adult. Clinical J Sport Med 2001; 11:57-59

3. Sanders JO, Rockwood CA, Curtis RJ. Fractures and dislocations of the humeral shaft and shoulder. In: Rockwood CA, Wilkins KE, Beaty JH, eds. Fractures in Children. Philadelphia: J. B. Lippincott, 1991:970-977

4. Havaranek P. Injuries of distal clavicular physis in children. J Pediatr Orthop 1989:213-215

5. Dartoy C, Fennoll B, Hra D, Le-Nen D, Dubrana F, Jehannin B. Epiphyseal fracture-avulsion of the distal extremity of the clavicle. Apropos of a case Ann Radiol 1993:36:125-128

6. Gray H, The Clavicle In: Anatomy Of the Human Body 20th ed, Philadelphia: Lea & Febiger, 2000:1396