A twenty-three-year-old man sustained an axial twisting load through the
foot when he fell off a motorbike at high speed. At the time of admission to
the casualty resuscitation room, the right ankle showed obvious deformation,
with tenting and abrasion of the skin on the medial side, compromising skin
vascularity.
An immediate attempt to reduce the deformity failed. Anteroposterior and
lateral radiographs revealed a superior and central dislocation of the ankle,
with an intact tibia and a high fibular fracture approximately 10 cm proximal
to the joint line (Figs. 1-A and
1-B). With the patient under sedation, another unsuccessful
attempt at reduction was made by the orthopaedic staff. It was thought that
there was a fixed bone block to relocation, with the talus wedged between the
tibia and the fibula.
The patient was then taken immediately to the operating room for further
management. After the patient was anesthetized, closed reduction was once
again attempted, without success. To facilitate reduction, the ankle joint was
first opened anteromedially, with the superficial skin abrasion avoided as
much as possible. A large hematoma evacuated spontaneously. The deltoid
ligament and the medial tendon sheaths were found to be ruptured, and the
tendons of the posterior tibial, flexor digitorum longus, and flexor hallucis
longus muscles were found to be dislocated anteriorly into the joint, thus
blocking the distal distraction of the talus and the reduction of the
dislocation (Fig. 2). The
neurovascular bundle remained behind the medial malleolus.
Because the reduction was still difficult, the lateral side of the ankle
was also opened, through a posterolateral approach. A large posterior
malleolar fragment from the distal aspect of the tibia (a Dupuytren fragment)
could be palpated. The posterior tibiofibular ligament remained attached to
this fragment, which, in retrospect, could be seen lying superior to the
talus, between the separated fibula and tibia, on the anteroposterior
radiograph (Fig. 1-A). From the
lateral side, the tibia appeared to be rotated forward in relation to the
fibula, with the talus jammed between the two.
By placing a retractor around the tendons from the medial side and applying
pressure laterally to disengage the talus from the fibula by pushing the talus
anteriorly and distally and by applying distal traction, it was possible to
reduce the ankle joint. The ankle was then irrigated, and no additional
osseous fragments were found.
Fixation was achieved with two syndesmosis screws placed from the lateral
side. A partially threaded cancellous screw was then placed through the distal
aspect of the tibia into the posterior malleolar fragment percutaneously from
the front. Stress radiographs made in the operating room at this point showed
the ankle to be stable. The deltoid ligament was repaired with absorbable
sutures, and the skin was closed subcutaneously over a drain. A plaster splint
was applied with the ankle in a neutral position to rest the tissues.
Postoperatively, the limb was elevated on a Bohler-Braun frame and the patient
was given antibiotics for prophylaxis against infection.
Forty-eight hours after surgery, the ankle was inspected on the ward. There
was little swelling, and the skin over the medial malleolus appeared viable. A
full below-the-knee cast was applied, and the patient was allowed to walk with
the aid of crutches without bearing weight on the affected ankle. Radiographs
of the ankle in the plaster cast (Figs. 3-A
and 3-B) demonstrated persistent good alignment of the ankle
joint.
The decision was made to remove the syndesmosis screws at six weeks because
it was thought that, once the posterior malleolar fragment had healed with the
attached intact posterior tibiofibular ligament, the ankle was stable enough
to permit full weight-bearing in a walking cast for the next two weeks. At
eight weeks after the operation, the cast was removed.
Six months after the injury, the patient had full range of movement of the
ankle joint and was able to perform all of his usual activities, including
sports activities and riding a motorcycle.
This injury proved to be difficult to treat. To disrupt the syndesmosis as
it did, the pattern of injury must have involved both axial loading and a
rotatory force, which usually would result in a pilon type of fracture
pattern. To our knowledge, a superior and central fracture-dislocation pattern
has not been reported previously in the literature.
Ankle fractures that involve entrapped tendons have been described
previously in the
literature3,4.
It was not possible to reduce the fracture in our patient because the
anteriorly dislocated tendons were applying a lateral force on the tibia and
wedging the talus between the tibia and fibula. Only with use of a medial
approach to identify and release these tendons with a retractor while
simultaneously levering the talus inferiorly and anteriorly from the lateral
side was it possible to reduce the fracture-dislocation. After reduction, the
tendency was for the tibia and fibula to diverge; hence, we chose to stabilize
the fibula to the tibia with two syndesmosis screws as well as to fix the
posterior malleolar fragment percutaneously.
Early reduction and evacuation of the tense hematoma was possible within
two hours after the injury and relieved the pressure on the compromised skin.
The prompt reduction and decompression probably minimized postoperative
complications, such as swelling and blistering, that would have been expected
from what was definitely a high-energy injury.
In retrospect, a closed reduction of this injury was never likely to
succeed. The presence of the posterior malleolar fragment on the original
anteroposterior radiograph perhaps should have alerted us to this possibility.
A computed tomographic scan may have helped identify this fragment and its
position, whereas a magnetic resonance imaging scan would have identified the
position of the displaced soft tissues. However, the performance of either of
these investigations might have delayed the definitive treatment of this
injury and increased the risk of postoperative soft-tissue complications. The
posterolateral incision permitted easy access to the fibula and the back of
the talus and allowed us to lever the talus forward while retracting the
dislocated tendons through the medial incision. We recommend immediate
surgical reduction and fixation of this type of injury pattern with use of a
two-incision approach.