orthopaedics

1. Four-Corner Concept: CT-Based Assessment
of Fracture Patterns in Distal Radius
P. R. G. Brink, MD, PhD1 D. A. Rikli, MD2
Department of Traumatology, Maastricht University Medical Center, Maastricht, The Netherlands
Department of Traumatology, Universitätsspital Basel, Basel,
Switzerland
J Wrist Surg 2016;5:147–151.
JOURNAL CLUB
Presenter : Dr. Amit Motwani
Chairperson :Dr. Satish Patil

2. • The four-corner concept is based
on the combination of the three-
column model of Rikli and
Regazzoni1 and Melone’s four-part
classification
• The three corners of the radius
actually correspond with the
osseoliga- mentous units,
described by Bain et al.
Fig. 1 An axial CT view allows four corners of the distal radius and ulna to be
distinguished. The volar and dorsal corner fragments are those involving the sigmoid
notch.

3. 3 COLUMN CONCEPT.
• Jakob et al interpreted the wrist as consisting of three distinct
columns.
• subjected to different forces and thus must be addressed as
discrete elements

5. A total of eight different fracture
patterns of the distal radius can be
distinguished.
(A)extra-articular
(B) theoretically six different
partial intra- articular patterns are
possible, but some will be extreme
rare in clinical practice.
(C)complete intra- articular
fracture patterns

6. Although the distal fragments were fixed with
a volar plate with seven screws, the dorsal
corner was not fixed, leading to an intra-
articular malunion with malalignment of the
DRUJ joint.
In this case the volar ulnar corner
was not captured with the volar T-
plate, resulting in secondary
displacement.

7. The “Key Corner”
• Although there is a large variety in the
size of the volar and dorsal corner, the
fragment that is in congruency of the
lunate is the key corner.
• This carpal subluxation is probably more
impor- tant than a step-off (without
subluxation) and should be corrected to
avoid chronic subluxation with alteration
of the entire joint kinematics.
• The fragment with which the lunate
goes is considered the “key corner” and
its control with reduction and stable
fixation should be the first step and
an integral part of the operative
strategy.
Saggital section of intermediate column

8. • Intra-articular fracture in which
the lunate is in line with the
dorsal corner (key corner) and
subluxated from the volar corner.
• Therefore, a dorsal approach and
fixation are preferred.
Classic shear-type fracture.
The lunate stays in contact with the
volar corner (key corner). Volar
approach with reduction and plate
fixation of the volar corner restores
alignment of the carpus in relation to
the radial shaft.

9. • Intra-articular fracture in which both
corners are involved.
• No key corner could be identified, but
both fragments are substantial,
indicated by sandwich plating.
• (sandwich or triple plating)

10. Conclusion :
• Classification, using CT scans are more reliable than plain X-rays.
• The axial view shows the relation between the volar/dorsalcorner while the saggital view shows
the relation of intermediate column with carpal i.e lunate.
• All fracture types can be characterized by subdividing the wrist joint into four corners.
• Each corner with its own characteristics in terms of mobility, stability, and transfer of forces in
the intact distal radius.

11. Continue…
• Recognition of the key corner is the most important first step and
mandatory to reduce and fix first.
• Recognition of the specific fracturetypes based on this four-corner concept
enables a tailored approach to treatment.
• The presence of metaphyseal comminution (especially onthe volar side)
is a sign of instability, which needs to be addressed and needs proper
reduction and adequate fixation and is an independent factor
concerning treatment strategy.

12. Current Concepts in Volar Fixed-angle
Fixation of Unstable Distal Radius Fractures
Jorge L. Orbay, MD; and Amel Touhami, MD
clinical orthopaedics and related research
number 445, pp. 58–67
© 2006 lippincott williams & wilkins

13. (A) The extensor tendons run in intimate contact with
dorsal plates. The flexor tendons only approach the volar
radius at the watershed line (*). (B) Magnetic resonance
im- aging shows the flexor tendons are well separated
from volar plates. The best location for the application of
fracture implants is the volar aspect of the distal radius.
Reprinted from Orbay J.Volar plate fixation of distal radius
fractures. Hand Clin. 2005; 21:347–354 with permission
from Elsevier.

14. An intraoperative photograph shows the (A) inter-
mediate fibrous zone. It is a strip of fibrous tissue and
perios- teum located between the wrist capsule and the
(B) pronator quadratus. In dorsal fractures, the pronator
quadratus is fre- quently ruptured at its junction with the
intermediate fibrous zone. The IFZ is therefore raised as
a narrow ulnar based flap during exposure. Reprinted
from Orbay J. Volar plate fixation of distal radius
fractures. Hand Clin. 2005;21:347–354 with permission
from Elsevier.

15. An illustration shows the extended FCR approach
used for volar management of complex fractures.
Rotating the proxi- mal fragment into pronation
provides the access needed for fracture
debridement and articular reduction. Reprinted from
Orbay J. Volar plate fixation of distal radius
fractures. Hand Clin. 2005;21:347–354 with
permission from Elsevier.

16. A four part articular fracture fixed by a volar
fixed-angle plate is shown.
(A) A preoperative PA radiograph shows a
four-part articular fracture.
(B) A preoperative lateral radiograph better
shows the displacement of the fracture.
(C) A postoperative PA radiograph shows all
the major articular frag- ments fixed by a
volar fixed-angle plate including the radial
styloid.
(D) A postoperative lateral radiograph
shows the pegs position at the subchondral
bone level.

17. The Distal Volar PlateTM (Hand Innovations) is
shown. Two rows of pegs create a three-
dimensional scaffold to sup- port the articular
surface. Threaded pegs help stabilize dis-
placement through a coronal fracture plane.
Reprinted from Orbay J. Volar plate fixation of
distal radius fractures. Hand Clin.
2005;21:347–354 with permission from
Elsevier.

18. A fixed-angle volar plate must
(1) avoid contact with flexor tendons by not
projecting beyond or above the water- shed
line.
(2) must provide sufficient distal buttressing sur-
face to control a volar marginal fragment.
Reprinted from Or- bay J. Volar plate fixation of
distal radius fractures. Hand Clin. 2005;21:347–
354 with permission from Elsevier.

19. Fixed-angle K-wires provide
temporary frac- ture stability and
anticipate future peg position.
(A) The K-wires assist in placing
the plate in the optimal position,
(B) where balance occurs between
(1) sup- port of the dorsal
subchondral bone and
(2) buttress-ing of the volar cortex.

21. REDUCTION INTERNAL FIXATION: FRAGMENT
SPECIFIC
(1) Application of small contoured plates
(2) Strong bone proximally.
(3) Gliding motion of tendons.
(4) The exposure cause minimal soft tissue disruption.
(5) Allow early range of motion.

25. INTRAMEDULLARY FIXATION
• Intramedullary devices – Advantages.
– Increase fracture stability .
– Allow load transfer across the fracture site.
– Minimize soft tissue problems by minimizing scarring
and adhesions.
– Maintain vascular blood supply to promote fracture
healing.

27. INTRAMEDULLARY FIXATION
• Two implants.
1. Micronail.
2. Dorsal Nail Plate
• Both are used for metaphyseal distal radius fractures .
• Incision made over the radial styloid.

28. INTRAMEDULLARY FIXATION
• Difficulties
– possible soft tissue irritation of the interlocking screws .
– possible screw penetration into the distal radioulnar joint.
– difficulty observing sagittal alignment secondary to use of
the jig

29. BIOABSORBABLE IMPLANTS
• Polylactic acid or polyglycolic acid.
• at least two years to degrade completely within the body.
• contourable after placing in a hot water bath
• The advantages.
– No need for hardware removal in the future
– do not incite an inflammatory response
– MRI compatible.
• Valid concerns
– initial fixation strength,
– slightly thicker than metal counterparts.
– cannot visualize the
– implants on radiographs.

30. Late Foreign-Body Reaction After Treatment of Distal Radial Fractures with
Poly-L-Lactic Acid Bioabsorbable Implants A Report of Three Cases
Chih-Yu Chen et al
J Bone Joint Surg Am, 2010 Nov 17; 92 (16): 2719 -2724