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CASE REPORT

Rare Example Of Pseudodislocation Of Acromioclavicular Joint In A 12 Year Old Boy

 Gella S *, Cooper AP **, Tulwa N #

* Clinical research fellow,
** Senior House officer
#Consultant Orthopaedic Surgeon
Department of Orthopaedics,Pinderfields
General Hospital , Wakefield , UK

Address for Correspondence:

MR S Gella
6 Riverdale crescent
Wakefield , WF3 4JZ
United Kingdom
Tel: 01924 360735
Email: mrgella@hotmail.co.uk

Abstract:

We report a rare case of a 12 year old boy who sustained a traumatic pseudodislocation of the lateral epiphysis of the clavicle mimicking type IV acromioclavicular dislocation. He was managed operatively with internal fixation.  Pseudodislocation and complete disruption of the periosteal sleeve are extremely rare features and make this unusual case very interesting.

J.Orthopaedics 2008;5(1)e13

Keywords:
Carpal tunnel syndrome, Median nerve, wrist sonography, carpal tunnel diameter.

Introduction:

True dislocations of the acromioclavicular joint in children are very rare.  Pseudodislocation (distal epiphyseal-metaphyseal separation) mimics the adult form of acromioclavicular dislocation in its behaviour1. In particular, pseudodislocations mimicking Type IV variety acromioclavicular joint dislocations are very rare and present an interesting challenge for the surgeon.  We report a case of distal epiphyseal injury of the clavicle, mimicking the Type IV acromioclavicular joint dislocation, treated with open reduction and stabilisation with a Kirschener wire.  In the literature, only one similar case of pseudodislocation has been reported, however in contrast to the case we present here, the previous example was not severe enough to require open reduction2.  Cases such as this are seldom seen and as such their management raises interesting issues, which we highlight here.

Case Report :

A 12 year old boy attended the accident and emergency department after he injured his left non-dominant shoulder region when he fell off his bicycle whilst attempting a stunt.  He complained of immediate pain in his shoulder and a reduced range of movement, limited mainly by discomfort.  On examination, the left shoulder was swollen with a loss of the clavicular prominence on the lateral aspect.  The acromion process was readily palpable with marked tenderness.  A bony prominence could be felt posteriorly within the trapezius muscle.  The skin was intact and he had no neurovascular deficit.  Anteroposterior and axial X-ray radiographs (Figure 1) showed left distal epiphyseal separation of the clavicle mimicking a posteriorly displaced type IV acromioclavicular dislocation3. The patient was treated with a broad arm sling and admitted for further management.  

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

 

This is a peer reviewed paper 

Please cite as : Gella S : Rare Example Of Pseudodislocation Of Acromioclavicular Joint In A 12 Year Old Boy  

J.Orthopaedics 2008;5(1)e13

URL: http://www.jortho.org/2008/5/1/e13

ANNOUNCEMENTS

 


 

CTIC 2008


Lectures, Interactive sessions
Case Discussions & Wardrounds

July  12 & 13, 2008

At Port City of Calicut, Kerala, India

For Registration
Dr Rajesh Purushothamman,
Dept of Orthopaedics,
Medical College, Calicut, Kerala, India

Ph:+91 9846268964

E-Mail:
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