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Wheeless' Textbook of Orthopaedics

Fractures of the Distal Radial Physis  


- Discussion:
    - occurs in children between ages of 6-10 yrs who sustain injury by falling on an outstretched hand;
    - shearing forces of hyperextension & supination displace the distal radial epiphysis dorsally;
    - great majority are Salter I and II:
          - physeal frxs of of distal radius and ulna:
          - w/ type I: look for anterior displacement of pronator quadratus fat pad;
          - type II are usually displaced dorsally (account for about 60% of distal radius frx);
          - type V frxs are impossible to dx until 6-12 months after time of injury (before obliteration of the physis is seen);
    - prognosis:
          - distal radial and ulnar physes provide 75-80% of total growth of forearm, so there is excellent potential for remodeling (correction of deformity);
          - while distal radius physis is most frequently traumatically separated physis in the child, subsequent growth disturbance is unusual;

- Associated Injuries:
    - in about one half of cases there will be a concomitant distal ulnar frx;
    - may be assoc w/ green stick frx of metaphysis of ulna;
    - there may also be separation of the distal ulnar epiphysis, or avulsion frx of the tip of the ulnar styloid process;
           - non union of ulnar styloid after separation thru unossified styloid process becomes evident only after ossification occurs (usually by the end of 1st decade)
                  - occassionally causes symptoms with forearm rotation;

- Exam:
    - soft tissue swelling can be impressive even in minimally displaced fractures;
    - acute carpal tunnel syndrome is a reported complication;

- Radiographs:
     - lateral radiograph will best show posterior displacement of epiphysis;
     - dorsal metaphyseal bone frag is small, requiring scrutiny for detection;
     - hemorrhage into pronator quadratus fat pad will indicate amount of swelling;
     

- Reduction:
    - w/ acute presentation closed reduction is usually easy;
    - over reduction is difficult becuase of intact dorsal periosteum;
    - if one or two attempts at closed reduction fail, consider leaving epiphysis displaced;

- Treatment:
    - acceptable amount of displacement is not specifically known, however, 30% physeal displacement heals readily and 50% displacement may often completely remodel in 1.5 years;
    - delayed presentation: (after 1-2 weeks)
            - manipulation of fracture is not advised;
            - repeated forceful manipulations are esp to to be avoided in SH I and II;
            - forceful attempts at reduciton are likely to damage growth plate;
            - distal radial physis has good remodeling potential which allows a displaced epiphysis to be left unreduced;
            - w/ in 2 to 3 years, distal radial epiphysis will regain its normal relation to radial metaphysis;
    - splint position:
            - apply long arm splint w/ slight wrist flexion (25 deg) and ulnar deviation (15 deg), and with the arm in supination;
            - initial casting is not advised with significant soft tissue swelling;
            - splint is worn for 2 weeks, is then changed, & worn for 3 more wks;
    - length of immobilization:
            - immobilize in long arm cast for 3 to 4 weeks;

- Complications:
    - compartment syndrome
            - Compartmental syndrome complicating Salter-Harris type II distal radius fracture.
    - growth plate arrest (see growth plate anatomy and physeal bone bridge)
            - need to determine extent of the growth arrest;
            - question is whether or not the arrest is resectable;
            - CT scan will evaluate the extent of the growth arrest;
            - if the arrest is not resectable then lengthening of the radius and epiphysiodesis of the ulna would adjust the appropriate length and alignment;
            - references: 
                  - Remodeling of Salter-Harris Type II Epiphyseal Plate Injury of the Distal Radius.
                  - Distraction Osteogenesis for Correction of Distal Radius Deformity After Physeal Arrest
                  - Growth and development of the distal radius and ulna
                  - Surgical management of posttraumatic distal radial growth arrest in adolescents.



Original Text by Clifford R. Wheeless, III, MD.

Last updated by Data Trace Staff on Tuesday, December 11, 2012 1:45 pm