Prospective randomized study: early weight bearing after conservative treatment of stable ankle fractures.

Ankle fractures are among the most common fractures of the lower extremities.
With 9% of all fractures, they account for an important part of the traumatic
injuries. A consideration between an operative vs. conservative treatment has
to be made. A distinction must be made between stable and unstable ankle
fractures. The fracture is stable if there is a dislocation of less than 3
millimetres at the *medial clear space* (the jointspace between the medial
malleolus and the talus) with a symmetrical ankle fork on the Mortise X-ray.
Classifications are used to describe the mechanism behind the ankle fracture
and thus to make a statement about the (in)stability of the ankle joint. A
common type of injury is the Weber B fracture or according to the Lauge-Hansen
classification the supination-eversion type, that can be stable (SE type 2
without rupture of the deltoid ligament) and also possibly unstable (SE type 4
with rupture of the deltoid ligament). This ligament has a superficial and a
deep layer. The superficial layer resists plantar flexion and external rotation
of the talus relative to the tibia. The deep layer has anterior and posterior
components, the anterior and posterior talo-tibial ligaments (ATTL and PTTL),
of which the posterior ligament is the strongest. The PTTL is tight when the
foot is plantigrade and loose when the foot is plantar flexed. If however, the
foot is plantigrade, as on an anteroposterior weight-bearing radiograph, the
intact PTTL will prevent lateral translation of the talus and the ankle fork
appears congruent. Therefore, Gougoulias N. et al. (2017) proposed that a
(ligamentous) SE type 4 ankle fracture, one without a medial malleolar
fracture, with a ruptured superficial and/or ATTL, but an intact PTTL, be
classified as a *SE type 4A* fracture. This is a stable fracture, as long as
the foot is in a plantigrade position. With a complete rupture of the
superficial and deep components (both ATTL and PTTL) of the deltoid ligament,
the medial clear space will open in all positions of the foot, thus also on
weight-bearing radiographs. This type of fracture can be classified as SE type
4B, which is always an unstable fracture.

There is controversy about the optimal conservative treatment of common stable
ankle fractures. This is confirmed by the presence of a large number of
treatment protocols with great variability in weight bearing recommendations.
The current international guideline describes non-weight bearing and
immobilization with a plaster cast for 6 weeks. However, a prolonged period of
immobilization causes various negative effects regarding recovery:
- Patient compliance: The noncompliance rate with the postoperative weight
bearing restriction is almost 30% and they start with weight bearing despite
explicit instructions. However, this rarely leads to displacement of the
fracture. The advice currently being applied may therefore be too cautious.
- Physiological cost: Non-weight bearing with 2 elbow crutches and only 1 leg
on the ground costs 4 times more energy than walking with 2 legs on the ground
and 2 crutches for support or stabilization.
- Homeostasis: Weight bearing ensures the preservation of bone and muscle mass.
A few weeks of non-weight bearing results in a significant decrease in bone
mass in the affected extremity even a year later.
- Risk of thrombosis: Posttraumatic immobilization with a plaster cast is a
risk factor for developing a deep venous thrombosis or a pulmonary embolism. At
Zuyderland Medical Center, patients receive thromboprophylaxis during long term
immobilization, according to protocol.
Therefore, advising non-weight bearing out of caution or uncertainty can cause
harmful effects on the health of patients. However, the literature provides no
substantiation for this period of non-weightbearing. When transmitting anxiety
to patients, this can make them insecure, which does not contribute to
rehabilitation.

Primary Objective: What are the 6-week and 12-week effects on the functional
outcome scores of the ankle in early weight bearing (mobilization with Walker)
compared to 6 weeks non-weight bearing and immobilization in conservatively
treated stable ankle fractures (Weber B or Lauge Hansen supination-eversion
stage 2-4A)?

Secondary Objective: What is the 6-week effect on dislocation of the fracture
in early weight bearing (mobilization with Walker) compared to 6 weeks
non-weight bearing and immobilization in conservatively treated stable ankle
fractures (Weber B or Lauge Hansen supination-eversion stage 2-4A)?

Other Objectives: Other outcome measures include range of motion (ROM) of the
ankle circumference of the calf, return to work, mental health outcome scores
and rates of other complications.

Hypothesis 1: We expect earlier functional outcomes in the intervention group
than in the control group.
Hypothesis 2: We expect the number of complications not to be higher in the
intervention group than in the control group.
Hypothesis 3: We expect the long-term recovery function (3 months) in the
intervention group not to be worse than in the control group.

Null hypothesis 1: The treatment in the intervention group is not as effective
as the treatment in the control group, because there are worse functional
outcomes in the intervention group than in the control group.
Null hypothesis 2: The treatment in the intervention group is not as safe as
the treatment in the control group, because there are more dislocations of the
fractures reported in the intervention group than in the control group.

A prospective randomized controlled trial at the Zuyderland Medical Center. We
will include patients at both locations, Heerlen and Sittard/Geleen.
All patients with ankle fractures at the emergency department of both locations
of the Zuyderland Medical Center are treated with a dorsal lower limb cast. 7
to 10 days posttraumatic, they are seen again at the traumatology department,
according to protocol.
During this visit (= t1), radiographs of the ankle joint are obtained at 3
different views (anteroposterior (AP), lateral and Mortise) and a
weight-bearing radiograph (AP). When it*s a stable fracture according to the
surgeon, present at that time, the patients will be approached to participate
in this randomized study. If written informed consent is obtained, the patients
get included.

Intervention group
The dorsal lower limb cast will be removed by the plaster technician. Patients
will get a Walker by which they can start with permissive weight bearing.
According to protocol, they receive daily thromboprophylaxis (Fragmin 5000IE
s.c.). After 6 weeks posttraumatic, the Walker will be removed at the
traumatology department. The patients may then extend the weight bearing to
functional.

Control group
The dorsal lower limb cast will be removed by the plaster technician and a
circular lower limb plaster cast will be applied. Patients get explicit
instruction of non-weight bearing and immobilization till the next visit.
According to protocol, they receive daily thromboprophylaxis (Fragmin 5000IE
s.c.). After 6 weeks posttraumatic, the plaster cast will be removed at the
traumatology department. The patients may then start weight bearing to their
own abilities.

3 site visits during 12 weeks with physical examinations and 2 questionnaires
which have to be filled in during each visit. Risks of the investigational
treatment are myalgia and dislocation of the fracture.