A moderately obese thirty-five-year-old woman sustained multiple
upper extremity fractures after falling off a porch from a height of
approximately four feet. She was initially evaluated at a local emergency room
where physical examination and radiographs revealed a posterior elbow
dislocation of the left, nondominant arm
(Figs. 1-A and 1-B), an
ipsilateral displaced and comminuted intra-articular distal radial fracture,
and a displaced fracture of the base of the contralateral thumb metacarpal.
She was subsequently transferred to our facility for definitive treatment.
The patient had pain in the left wrist and elbow, with a limited range of
motion, and pain in the right thumb. She had an obvious dorsal deformity of
the distal part of the radius in the left arm with minimal swelling. The left
elbow was held at approximately 80° of flexion, and she had a painful and
limited range of motion. The right thumb was tender to palpation at the base
of the metacarpal with no obvious deformity. The neurovascular examination
revealed normal findings. An initial review of the radiographs revealed an
obvious posterior dislocation of the elbow.
The patient was managed with intravenous conscious sedation in the
emergency department, and a closed reduction of the ulnohumeral joint was
performed. The extremity was placed in a long arm posterior splint.
Radiographs made after the reduction showed persistent translocation of the
radius and ulna (Figs. 2-A and
2-B). The patient was then taken to the operating room for open
reduction and internal fixation of the left distal radial fracture and the
metacarpal fracture of the right thumb as well as reduction of the persistent
convergent dislocation of the left elbow.
Closed reduction of the proximal radioulnar joint was attempted, with the
patient under general anesthesia, but was unsuccessful. A lateral approach
between the extensor digitorum communis and the extensor carpi radialis longus
and brevis was used to expose the joint. The radial head was found to be
dislocated from the ulnar notch and was transposed to the medial side of the
ulna. Reduction of the radial head was performed by placing a Hohmann
retractor underneath it and supinating the forearm. This allowed the radial
head to be levered over the coronoid and to fall back to its normal position.
Examination of the radial head showed a shallow osteochondral defect involving
30% of the articular surface. The elbow was then taken through a limited range
of motion, from full extension to approximately 100° of flexion, and the
radioulnar joint was found to be unstable at 45°. A midsubstance
disruption of the annular ligament was evident with an intact insertion.
Additionally, the lateral collateral ligament was intact but visibly lax. When
the latter was imbricated to the underlying soft tissues, radioulnar stability
was obtained throughout a 100° range of flexion. On intraoperative
examination, the interosseous membrane was determined to be intact. The soft
tissues and skin were closed, and a long posterior splint was applied.
Postoperative radiographs confirmed congruent reduction of the olecranon and
trochlea with the restoration of the radiocapitellar joint
(Figs. 3-A and 3-B).
The patient was managed with immobilization in the long arm posterior
splint for three weeks. She was then managed with a hinged elbow brace with an
extension block at 90° and was allowed to begin range-of-motion exercises.
The patient was reassessed at two-week intervals, at which time the amount of
extension in the brace was increased by 15° to 20°. The use of the
brace was discontinued eight weeks after the date of the initial injury.
At six months after the initial injury, the range of motion of the elbow
was from 15° to 130°. Pronation and supination were 65° and
50°, respectively. The patient had minimal pain with range of motion and
was not limited in the activities of daily living. At the last visit,
twenty-five months after the initial injury, the patient had painless range of
motion from 10° to 130°, full supination and pronation, and no
evidence of instability.
We are aware of the cases of only ten patients who had convergent
elbow dislocations, and all were confined to the pediatric
population1-7.
El-Ghawabi described three adults who had elbow injuries that involved a
fracture of the radial neck with medial displacement of the radial head, but
only one of those patients had a concomitant posterior elbow dislocation and
none had translocation of the radius and
ulna8.
Translocation of the radius and ulna may be easily overlooked if the
radiographs are not carefully
evaluated1-4,7.
A correct initial diagnosis was made in only three of the ten previously
reported
cases5,6,
with the delay in diagnosis ranging from several hours to five weeks. In one
patient, the translocation was not recognized, even after open reduction and
internal fixation of a coronoid
fracture4. The
situation is further confounded by the relatively normal appearance of the
elbow. This stands in contrast to divergent dislocation, in which
there is usually gross deformity about the elbow.
When convergent dislocation is concomitant with a posterior elbow
dislocation, radiographic evidence of radial shortening will persist,
especially on the lateral radiographs made after the ulnohumeral reduction.
Transposition of the humeral articulating surfaces for the radius and ulna may
also be evident. The clinical manifestation is an inability to supinate the
forearm. This finding should alert the clinician that something other than a
simple posterior elbow dislocation might be present, and additional
radiographs or a fluoroscopic examination may be beneficial.
The mechanism of injury has been described as a fall onto the hyperpronated
hand with the elbow in full extension, producing an axial force on the
proximal aspect of the
radius9. This is
accompanied by anterior dislocation of the radial head. Axial loading may also
induce a posterior dislocation of the ulna. This mechanism seems consistent
with the findings in our patient who sustained a concomitant ipsilateral
distal radial fracture. Most authors have concurred that this type of fall is
the mechanism of
injury1,3-7,
with the exception of
Isbister5, who
believed the etiology to be iatrogenic. However, in the case of our patient,
as well as those in other
reports1,2-4,7,
prereduction radiographs clearly showed the transposition of the proximal
radioulnar joint prior to reduction.
Associated injuries seen with convergent elbow dislocations are similar to
those seen with acute elbow
dislocations10 and
have included documented fractures of the radial
head5,6
(three patients), radial
neck1,4
(three patients), or coronoid
process3,4
(two patients). Ulnar nerve palsy has occurred in three
patients2,3,5,
and in one of them it was iatrogenic in
nature2. All three
cases of ulnar nerve palsy eventually resolved. Our patient had none of the
above injuries, although the distal radial fracture attests to the large
amount of energy that is required for this type of injury to occur. Finally,
osteochondral injury, which was seen in our patient, is not uncommon in elbow
dislocations11.
In this limited number of
cases1-7,
closed reduction was successful in only four patients and all four reductions
were performed by one surgeon; six other instances of radioulnar
translocations required open reduction. Only MacSween reported a successful
closed reduction with the elbow flexed to 100° and the forearm fully
supinated1. If
closed reduction fails, an open approach is needed to leverage the radial head
into anatomic position. Given that ligamentous disruption occurs with this
injury7, primary
repair of the torn or attenuated ligaments and/or capsule is generally
required to achieve adequate radioulnar stabilization.
Complications of convergent elbow dislocations in children have included
osteonecrosis of the radial
head2, iatrogenic
ulnar nerve palsy2,
and mild heterotopic
ossification5, in
one patient each. Each of these complications, with the exception of the
heterotopic ossification, occurred in patients who had a delay in
diagnosis.
In conclusion, convergent dislocation of the elbow is a rare injury that
has previously been reported only in the pediatric population. The present
report is the first, as far as we know, to describe such an injury in an
adult. The failure to diagnose the translocation of the radius and ulna has
been associated with a decreased range of motion and other complications. In
all patients with such an injury, delayed intervention can be avoided by
careful scrutiny of the radiographs combined with a thoughtful clinical
examination. ?
The authors did not receive grants or outside funding in support of their
research or preparation of this manuscript. They did not receive payments or
other benefits or a commitment or agreement to provide such benefits from a
commercial entity. No commercial entity paid or directed, or agreed to pay or
direct, any benefits to any research fund, foundation, educational
institution, or other charitable or nonprofit organization with which the
authors are affiliated or associated.