The treatment of stable ankle fractures: Brace versus Cast immobilization

Ankle fractures are commonly seen on emergency departments of hospitals. They
represent about 10% of all fractures and the incidence is expected to increase
in the following years.
In the case of an ankle fracture, the fibula (lateral malleolus) and/or the
tibia (medial and/or posterior malleolus) can be injured. Furthermore, there
can be ligament injury (mainly the syndesmosis between tibia and fibula en the
deltoid ligament are of important value). The degree of osseous and/or ligament
injury determines if the fracture is stable or unstable. In general, stable
fractures are treated non-operatively (conservatively) and unstable fractures
are treated operatively.

Ankle fractures can be subdivided according to different classification
systems. A system that is practical in use divides ankle fractures in
unimalleolar ( fibular fracture solely or medial malleolar fracture solely),
bimalleolar ( fibular fracture and medial malleolar fracture) or trimalleolar
fracture (fibular fracture, medial malleolar fracture and posterior malleolar
fracture). The most commonly used classification system is the AO-Weber system,
which classifies the fracture based upon the level of the fibular fracture.
Weber-A fractures are located distal to the syndesmosis, Weber-B fractures are
located at the level of the syndesmosis and Weber-C fractures are located
proximal to the syndesmosis.

Weber-A fractures are stable fractures and are therefore treated as ankle
sprains (usually 1 week cast immobilization, followed by tape). In general,
Weber-C fractures are stable for which they are treated operatively. In case of
a Weber-B fracture, the presence of osseous and/or ligament injury additional
to the fibular fracture is relevant in deciding how to treat the fracture. Bi-
and trimalleolar fractures are practically always unstable and are treated
operatively. Weber-B fractures without signs of medial ligament injury (deltoid
ligament) are stable and do not need to be treated operatively. This group
represents about 50% of all ankle fractures.

The current treatment of stable ankle fractures in the Netherlands and most
other Western European countries consist of 6 weeks cast immobilization: a
below-the-knee plaster cast for 1-2 weeks non-weight bearing, followed by a
fiberglass short leg walking cast for the next 4-5 weeks, bearing weight within
the limits of pain. Disadvantages of this treatment are that after cast
immobilization some stiffness in the ankle joint may develop, atrophy of the
calf muscle occurs and there might be an increased risk of developing
osteoporosis.

In some countries, including Switzerland, stable ankle fractures are often
treated with a functional brace. Some previous studies indicate that this
functional treatment prevents fracture dislocation as well as cast
immobilization does, although it results in better clinical outcome and more
comfort. In 1989 Stuart examined the treatment of stable ankle fractures with a
functional brace compared to 6 weeks cast immobilization6. He reported a more
rapid decrease of swelling because of use of the calf muscle and more comfort
in the functional treated group and no significant difference in functional
outcome between both groups. Pitfalls of this study are the small sample sizes,
poorly defined endpoints and the fact that no standardized Outcome Scores were
used. In addition, the outcome measures were assessed at one point and not
evaluated for a period of time. Brink published a study which compared two
different ankle braces as treatment for stable ankle fractures3. Both braces
provided accurate fracture healing with good results; there were no significant
differences between the braces. However, this does not indicate whether a
functional brace or cast immobilization provides the best result. Furthermore,
there have been studies in the past that compare these two types of treatment,
although in these studies the ankle fractures were treated operatively after
which they were treated with a brace or cast.
In general they showed that the group treated with a functional brace reported
less pain, better function and a greater range of motion on short term. As for
long term, no significant differences were found.

A well designed randomized controlled trial performed by Lehtonen (2003)
comparing the two types of treatment in operatively treated ankle fractures
showed more wound infection in the group treated with a functional brace, due
to the movement of the ankle. Vioreanu (2007) ruled this out by starting with
the functional treatment after wound healing, 2 weeks postoperatively. He found
a significantly better outcome at 6 weeks postoperatively in the functional
brace group compared to the cast immobilization group. This difference was not
significant at long-term follow up.

A recent Cochrane Review (2009) described that there is limited evidence that
the use of a removable type of immobilization and performing exercises during
the immobilization period result in a better outcome. They also indicate that
more clinical studies are necessary to support the current evidence. Future
trials need to be adequately designed, outcome measures and endpoints need to
be clear and they need to be adequately powered so that the results can be
conclusive.

To examine if a functional brace in the treatment of Unimalleolar Weber-B
fracture results in a higher Olerud and Molander Score, less pain, better
comfort, greater range of motion.

Multicenter, prospective clinical trial in Medical Center Haaglanden (The
Hague) and Bronovo Hospital (The Hague). All patients presenting at the
emergency department with a stable ankle fracture will initially be treated
with cast immobilization, the current treatment. Patients that meet the
inclusion criteria will be informed about the study at the emergency department
and they get an information letter. They will be asked by telephone to
participate in the trial, a few days after their visit to the emergency
department. By telephone they will be asked for any questions about the study
and the procedures. One week after visit to the emergency department there will
be a check by the trauma-surgeon of the fracture by an ankle X-ray. If the
fracture shows to be stable, they will be included in the study and
randomization takes place under patients who are willing to participate in the
trial. Group 1 will receive the current treatment with cast immobilization for
a period of 5 weeks (non-weight bearing for 2 weeks and 3 weeks bearing weight
within the limits of pain).

Patients will be reviewed at 1 week, 3 weeks, 6 weeks, 12 weeks, 26 weeks and
52 weeks to assess some parameters (see section 5 Assessment). After which
these parameters will be analyzed between both groups.

At 1 week post fracture the patient will return to the clinic. If he/she is
willing to participate in the trial the randomization will take place.
Group 1 consists of patients treated with cast immobilization for a period of 5
weeks.
Group 2 consists of patients treated with a functional ankle brace for a period
of 5 weeks.

Week 1:
Olerud & Molander Ankle Score
Pain level using a Visual Analogue Scale
Patient comfort using a Visual Analogue Scale
Dislocation of the fracture using radiographs
Euroqol-5D questionnaire

Week 3:
Olerud & Molander Ankle Score
Pain level using a Visual Analogue Scale
Patient comfort using a Visual Analogue Scale
Dislocation of the fracture using radiographs
Euroqol-5D questionnaire

Week 6:
Olerud & Molander Ankle Score
Pain level using a Visual Analogue Scale
Patient comfort using a Visual Analogue Scale
Range of Motion
Dislocation of the fracture using radiographs
Euroqol-5D questionnaire

Week 12:
Olerud & Molander Ankle Score
Pain level using a Visual Analogue Scale
Range of Motion
Euroqol-5D questionnaire

Week 26:
Olerud & Molander Ankle Score
Pain level using a Visual Analogue Scale
Range of motion
Euroqol-5D questionnaire
AAOS-score

Week 52:
Olerud & Molander Ankle Score
Pain level using a Visual Analogue Scale
Range of motion
Euroqol-5D questionnaire
AAOS-score
The presence of arthrosis using radiographs (Ankle Osteoarthritis Scale)

The treatment will not differ from regular treatment, the number of outpatient
visits and the number of X-rays will be the same. Extra is that the patient
will be asked to fill in a questionnaire. During the review visits the function
of the ankle will be examined and an X-ray will be made. In addition, the group
of patients who are treated with an ankle brace will be asked to perform a
number of daily exercises with the ankle.