Distal Radius Shortening as a result of Fracture - Philippa Rust 14/5/2005

Normal measurements
  • Distal radial length 11 –12mm
More than 2mm shortening unacceptable
  • Volar angulation 0-22° mean 12°
Acceptable 10° loss of volar angulation
  •   Radial inclination (tilt) 19 - 29° mean 22°
Acceptable 5° loss
  •   Reduce with less than 2mm step in articular surface.
 
Distal Radial Length
  • Shortening results from extensive comminution and impaction of fracture fragments into the metaphysis;
  • Radial shortening following distal radial fracture may lead to
                            acquired positive ulnar variance,    ulnar impaction syndrome and   instability ;
  • Patients will often have significant loss of pronation and supination as the DRUJ is affected
  • Some authors note that radial shortening is only important in so much that it reflects a change in ulnar variance;
  • Usually a change of more than 3 mm of ulnar variance will lead to symptoms
 
Acceptable Reduction
  • Normal length of radius averages 9-12 mm;
  • Shortening of up to 3-5 mm can be associated with a satisfactory result, as long as there is an accurate articular restoration,
  • However, one should strive to achieve less than 2 mm of shortening;
  • Greater than 10 mm of shortening is often associated with symptoms, including involvement of distal RU joint .


Management

When radial shortening is due to comminution, then external fixation maybe the most reliable method of restoring length;
 

Change in Ulnar Variance
Functional anatomy
In neutral variance, 80% of load is born by radius and 20% by ulna
2 mm increase in ulnar variance will increase load borne by ulno-carpal joint from 18% to 42%
2.5 mm decrease in the ulno-carpal variance will decrease the load borne by the ulno-carpal joint to 4.3%
 
Effect of positive ulnar variance



Fibrocartilage complex abnormalities. (TFCC)
Significant loads are transmitted to the forearm unit through the distal ulna via the triangular fibrocartilage complex. The anatomic relationships between the distal radius and ulna and ulnar carpus are precise, and even minor modification in these relationships leads to significant load changes and resultant pain syndromes
Palmer m-A-K. Hand-Clin. 1987 Feb. 3(1). P 31-40.

The TFCC is ulnar continuation of distal radius & presents concave surface for articulation with lunate & triquetrium;
ulnar side of the wrist is supported by the TFCC, which articulates w/ both the lunate and the triquetrum;
TFCC is prone to injury due to the axial and shear forces that are applied to it as the carpi rotate over the radius and ulna;
Therefore with disruption of the normal smooth surface between the ends of the radius & ulna the TFCC is prone to tears
 
      
  • Ulnar impaction syndrome
 Impingement of distal ulna on carpi which may arise from
            positive ulnar variance or
            non union of distal ulnar fracture
 
Positive ulnar variance leads to
            loading of the ulnocarpal joint and
            resultant Lunotriquetral Dissociation, lunate chondral lesion, (and TFCC tears )
 
Exam Findings:
            positive ulnar stress test;
            tenderness with direct palpation of the ulnar carpal joint;
 
Radiographs :
radiographic findings may be subtle;
            may show flattening, subchondral sclerosis, and/or lytic changes in lunate and/or triquetrum with         similar changes seen over the distal ulna;
            patients may have increased ulnar variance ;
            in subtle cases, a pronation grip radiograph may demonstrate ulnar variance;
bone scan may be positive;

           
Lunotriquetral ligament tears & Lunotriquetral Dissociation
Ulnar side carpal instability;
Involves disruption of
            lunotriquetral &
            volar radiolunotriquetral ligaments &
            attentuation or rupture of dorsal radiotriquetral attachments
            with a isolated tear of the LT interosseous ligament,
 
 
There will be only a small amount of increased motion, however, even this is enough to cause symptoms;


Mechanism:
may occur as result of positive ulnar variance
injury occurs w/ forced extension or extension-radial deviation, as scaphoid induces the lunate into a further flexion stance while triquetrum extends;
w/ advanced injury, lunotriquetral, volar radiolunotriequetral, & dorsal radiotriquetral ligaments are torn;
VISI collapse deformity develops;


Other causes of positive ulnar variance:
previous excision of radial head
increasing age
may develop in child gymnasts, due to "stress related changes" in the distal radial physis; and chronic compressive loads borne by the radius, leads to premature closure of the distal radial physis;
 
Negative ulnar variance is associated w/ Kienbock's disease
 
 
Treatment

                Avoid mal-union of distal radius fractures, accurate reduction and fixation: use of locking plates or external fixators (non-bridging McQueen).  
                Correction osteotomy of distal radius, opening wedge and rigid buttress plate fixation
                young patients only, complex procedure, Jupiter advises caution
 
Distal ulnar arthroplasty: selection depends on:
            slope of the distal RU joint surface
            whether it is congruent (an incongruent joint might be made congruent with an oblique ulnar shortening);
            whether it has degenerative changes (in which case, a resection arthroplasty or Sauve-Kapandji may be indicated);
 
Ulnar shortening/ realignment osteotomy
            Most indicated for ulnar impaction syndrome ; this procedure unloads the distal ulna, and thereby relieves distal ulnar impingement symptoms;



Osteotomy may be performed using a transverse, oblique, or step cut osteotomy


Wafer procedure
a wafer of upto 2-4 mm of distal ulnar head is removed, while the styloid process TFCC , and attached ligaments remain attached;
the procedure is contra-indicated if more than 4 mm of positive variance;
may be indicated for symptomatic positive ulnar variance , ulnocarpal impaction syndrome , or symptomatic TFCC tears ;
some authors feel that for this procedure to be successful, the TFCC must be intact;

Bower’s procedure
involves resection of ulnar articular head, leaving shaft and styloid relationship intact. It may be indicated to restore passive pronation and supination of the forearm.

Darrach procedure -
for symptomatic malunion of Colle's frx in elderly patients, low demand patient, especially when stiffness is present;

Sauve-Kapandji Procedure
is indicated for arthritic RU Joint w/ limitation of motion it can also be used following malunion of fractures resulting in arthritis as long as ulna is shortened as part of the procedure: osteotomy: performed just proximal to the RU joint articular cartilage, or just proximal to the flare of the ulnar head; a second cut is made 15 mm proximal to the first cut and the segment of ulna is removed; RU joint articular cartilage is removed & ulnar head is applied to the radius and is held.
 
Wrist fusion

Ulnar Sided Wrist Pain,  osseous related pain:
hamate fracture pisiform fracture or OA , ulnar styloid frx base of the fifth metacarpal
TFCC , distal radioulnar joint (DRUJ) , radioulnar joint instability ulnocarpal impingement syndrome
carpal instability : , triquetrolunate instability;  mid carpal instability , vascular related pain : hypothenar hand syndrome
neurologic related pain: ulnar nerve entrapment at Guyon's canal , ulnar dorsal sensory branch neuritis; tendon related pain:  extensor carpi ulnaris tendonitis., flexor carpi ulnaris
 
International Distal Radius Study Group                                 
http://www.eradius.com/
 
RADIAL SHORTENING :
 
1 BIOMECHANICAL STUDIES
a) Pogue, Viegas, Patterson, et al. (1990, JHS)
method: five cadavers, pressure-sensitive film, examine contact areas and pressures results: 2 mm shortening created statistically significant increase in the lunate contact areas
b) Adams (1993, JHS)
method: six cadavers
results: radial shortening was the most significant change affecting the kinematics of the DRUJ and the TFC
 
2 CLINICAL STUDIES
a) Jupiter and Masem (1988, Hand Clinics)
review article, Reconstruction of Post-Traumatic Deformity of the Distal Radius
> 6 mm of shortening caused DRUJ pain, decreased pro- and supination
radial shortening most disabling of malunited fractures
 
b) McQueen (1988, JBJS[B])
30 patients with Colles' fracture, four year follow-up
> 2 mm shortening statistically significant increase in symptoms in terms of strength, ADL, ROM, and pain
 
c) Jenkins (1988, JHS)
prospective study of 61 consecutive patients treated with closed reduction, cast immobilization
mean shortening was 4.0 mm
strong correlation between radial length and strength and ROM
mean radial shortening in patients with pain: 4.7 mm
mean radial shortening in patient without pain: 2.3 mm (statistically significant)
 
d) Kopylov (1993, JHS[B])
retrospective review of 76 patients, 26-36 years after distal radius fracture, average follow-up of 30 years
radial shortening most important factor after intraarticular step-off
1 mm radial shortening had a 50% increased risk of DJD in the DRUJ
1 mm radial shortening had a 20% increased risk of DJD in the RC joint
2 mm radial shortening had a 50% increased risk of DJD in the RC joint
 
3 RECOMMENDATIONS
Weiland (OKU-Trauma, AAOS, 1996)
Accept no > than 2 mm radial shortening
 
ASSH Regional Review Course (1994)
Accept no > than 3 mm radial shortening
 
ASSH Specialty Day at AAOS (Trumble, 1999)
Accept no > than 2 mm radial shortening
 
Kopylov (1993, JHS[B], 30 year follow-up study)
Goal: no > than 1 mm radial shortening
 
Baratz (ASSH Specialty Day at AAOS, 1998)
Accept no > 5 mm radial shortening
3 mm or less is optimal
 


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Title
Minor axial shortening of the radius affects outcome of Colles' fracture treatment
Author Aro HT , Koivunen T .
Department of Surgery, University of Turku , Finland .
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