Keywords
chronic - dislocation - distal radioulnar joint - wrist
Palabras clave
luxacion - cronica - articulacion radiocubital distal - muñeca
Introduction
The distal radioulnar joint (DRUJ) is an articulation located between the sigmoid
notch of the radius and the ulnar head. Because these articular surfaces have different
radii of curvature, the soft tissues are important stabilizers of the joint.[1] The main soft tissues stabilizing structures are the triangular fibrocartilage complex
(TFCC), the pronator quadratus, and the interosseous membrane.[2]
A DRUJ dislocation is a rare entity. It is usually associated with a distal radius
fracture, and a DRUJ dislocation without a radius fracture is an even rarer injury.
This injury, if misdiagnosed or mistreated, results in a complete loss of pronation-supination,
which entails a great functional limitation.
The purpose of the present report is to describe a rare clinical case and to discuss
the treatment that was chosen for it.
Clinical Case
A 30-year-old manual laborer fell on his outstretched hand. On the first evaluation
at the emergency room department, a complete dislocation of the DRUJ associated with
a fracture of the ulnar styloid was diagnosed ([Figs. 1], [2] and [3]). A closed reduction and immobilization with a cast and splint for three weeks were
attempted. After the removal of the splint, he was sent to rehabilitation. After several
weeks, the patient complained of pain and low range of movement. At this point, he
was referred to us.
Fig. 1 Initial X-ray - AP View.
Fig. 2 Initial X-ray - Lateral View.
Fig. 3 Initial CT Scan.
At our first evaluation, 4 months after the initial injury, the patient was found
to have no supination and 10° of pronation. He had ulnar wrist pain. The flexion and
extension of the injured wrist were similar to that of the other wrist. X-rays and
a computed tomography (CT) scan confirmed a complete volar dislocation of the DRUJ
and a non-united fracture of the ulnar styloid ([Fig. 4]). We concluded that either the initial closed reduction was not effective, or that
the joint re-dislocated while still immobilized in the splint.
Fig. 4 CT Scan at 4 months.
A closed reduction was attempted with no success. Surgical treatment was performed.
A dorsal approach through the 5th compartment was performed, as described by Garcia-Elias
et al.[3] An open reduction of the dislocation was performed ([Fig. 5]). The ulnar styloid fracture reduced spontaneously after the reduction of the DRUJ.
After the reduction, the pronation was found to be complete and stable, but every
attempt at supination resulted in a new volar dislocation of the ulnar head. The TFCC
had ruptured from the fovea, and was fixed to it with a bone anchor. The dorsal capsule
was closed and reinforced with a plicature. The DRUJ was temporarily fixed with two
Kirschner wires in neutral position. The patient was immobilized with a cast and splint
below the elbow. After two weeks, the sutures were removed, and full flexion and extension
of the wrist and elbow were allowed. A block of the pronation and supination was maintained
until 7 weeks after surgery, when the Kirschner wires were removed. Then the patient
was allowed to perform full pronation, but used a dynamic splint that would block
supination. Then, he initiated the rehabilitation. Twelve weeks after surgery, total
range of movement was allowed.
Fig. 5 Dorsal approach to the DRUJ.
Six months after surgery, the patient had full pronation and 20° of supination. His
wrist was stable, pain-free, and had the same strength as his uninjured side ([Fig. 6]). The X-rays showed a healed ulnar styloid and a reduced DRUJ ([Fig. 7]). He resumed his previous occupation without limitations.
Fig. 6 Final clinical result.
Fig. 7 Final X-ray.
Discussion
A DRUJ dislocation without an associated radius fracture is a rare injury. Some reports
state that a dorsal dislocation is more common than a volar dislocation.[2] Most articles on this subject refer to cases diagnosed and treated in the acute
setting. This makes the case herein reported even less common.
Garrigues and Aldridge[4] described a case of volar DRUJ dislocation treated in the acute stage in which no
ulnar styloid fracture occurred. Closed reduction was not possible, and open reduction
was necessary. Ellanti and Grieve[5] also described a case of volar acute DRUJ dislocation in which an open reduction
with TFCC reattachment was also necessary. Rijal et al[6] described a volar DRUJ dislocation treated in the acute setting with closed reduction
and percutaneous fixation. Acar[7] presented three cases of isolated DRUJ dislocations. Two of these were dorsal dislocations,
one was a volar dislocation, and all were treated with closed reduction and pinning.
In our case, the treatment option (open reduction, TFCC reattachment and dorsal plicature)
is similar to the treatment chosen by other authors.[4]
[5] After the first two weeks, we chose to allow extension and flexion of the wrist
and elbow while maintaining the pronation-supination blocked with Kirschner wires.
This was a risky decision, because it increased the risk of Kirschner-wire breakage.
It was allowed because we believed the patient to be able to understand the risk and
not to try to force forbidden movements. During this time he came to the hospital
weekly.
The range of motion obtained, namely the supination, was below what we expected. This
might be attributed to a plicature of the dorsal capsule that was too tense, or to
the fact that the patient was only allowed to try making supination 12 weeks after
the operation. This period of immobilization was superior to that chosen by other
authors, and we believe it was excessive. A better clinical result might have been
achieved had supination been allowed after six or seven weeks under the care of a
therapist, and that is what we would now recommend in similar cases.
The patient was involved in a work compensation situation that may have also influenced
the clinical outcome. However, he was pleased with the final result, did not desire
further surgery, and was especially pleased for being able to resume his previous
occupation.
The literature seems to indicate that while diagnosed in the acute setting, a reduction
of an isolated DRUJ dislocation should always be attempted. It is, however, important
to make sure that complete reduction is obtained, and that it is stable. Pinning the
joint is safer than a simple cast in maintaining reduction. If a closed reduction
is not possible, an open reduction should be performed, as well as a reattachment
of the TFCC.
In a chronic setting, closed reduction is less likely to be possible, and open reduction
and stabilization will probably be necessary in most cases.
