The WOW! Study, Weight-bearing or Non-Weight bearing. A prospective randomised multicenter comparison of three different care regimens after operatively fixed ankle fractures.

Fractures of the ankle occur frequently with an overall estimated incidence of
approximately 100-150 fractures per 100.000 person-years. The most common
causes of ankle fractures are twisting injuries and falls, followed by sports
injuries. The peak incidence is seen in young men and older women.

Surgical treatment, generally open reduction and internal fixation, is
indicated when congruity of the ankle joint has been compromised [3]. Important
goals of the postoperative care regimes are early functional recovery and quick
resumption of work for the young and active patient population.

Postoperative care regimes vary widely. Results from plaster casts, removable
casts, functional bracing, walking boots, unprotected non-weight-bearing
exercises and unprotected weight-bearing are described. The two most commonly
used postoperative care regimens after ankle fractures in the Netherlands are
weight-bearing with a conventional cast and non-weight-bearing functional
mobilisation with active exercises. The studies of both Finsen (1989) and van
Laarhoven (1996) described a temporary benefit at 6 weeks post-operatively for
those patients treated with a below-knee walking plaster in comparison to
unprotected non-functional treatment (Appendix 1). At one year follow-up, no
significant differences were found between these two types of treatment and an
individual based decision was advised.

Early weight-bearing and the avoidance of complete immobilization have been
shown to decrease the development of soft-tissue atrophy and to prevent the
development of osteoporosis. In the unprotected treatment a comparison is made
between non-functional and functional aftercare. In this latter group, daily
exercises were advised. In the Cochrane review all ten studies demonstrated
significant improved outcome for the functional treatment group, which
facilitates the restoration of the range of motion of the injured joint, less
pain and higher quality of life scores. This treatment is described as a safe
and experimental treatment.

A functional brace has the theoretical advantage of both weight-bearing and the
possibility to exercise. However, no clinical significant difference was found
in four studies included in the Cochrane review. This could be partially due to
the rather complicated use of these orthesis and thereby diminished patient
compliance.

The Cochrane review ends with the following statement: *Priority should perhaps
be first directed towards investigating the effectiveness and safety of
interventions that are in common use, such as the effects of exercise and
weight-bearing if started during the period of immobilisation.* In concordance
to this statement, 3 authors published their results on immediate mobilisation
and unprotected weight bearing in relatively stable ankle fractures. Simanski
et al, Gul et al and Partenheimer et al showed that there were even no
disadvantages and demonstrated high patient satisfaction scores. Treatment
without cast would result in earlier full weight bearing toleration and thereby
faster rehabilitation with full walking ability within 5 weeks.

Essential for safe early full weight bearing is selection of suitable patients.
The Lauge Hansen classification for ankle fractures describes best the
intrinsic stability of the ankle joint, as it demonstrates the trauma mechanism
and thereby incorporates the ligament injuries. The Weber classification only
describes the lateral malleolus. The AO classification only describes fracture
patterns and does not implement ligament injuries. Thus the classification best
suitable for selecting the correct patient and fracture type in the present
study is the Lauge Hansen classification. Fractures which are relatively stable
and therefore suitable for immediate post-operative full weight-bearing are
Lauge-Hansen supination-eversion type 2, 3 and 4. Indications for surgical
treatment of ankle fractures are clear, however controversy exists with regard
to the optimal postoperative care regime. This trial is designed and powered to
strengthen current evidence about the effectiveness of postoperative care
regimes after ankle fractures and analyse a new post-operative care regime, as
was suggested in the Cochrane review.

A novelty in analyzing patient rehabilitation is the SensiStep. This is a
pressure chip, which can be implanted in a cast or sole of a shoe. This device
is developed by the medical innovation organization Pontes Medical and marketed
by Evalan. In patients in the weight bearing groups, the insole sensor will be
applied in a standardized shoe (sandal) for examination of the loading pattern
of the operatively fixed ankle during revalidation. The chipresults can be used
in the future to correct, if necessary, the loading pattern of patients during
rehabilitation after operative fixation of ankle fractures.

The primary objective of this prospective randomised multicenter study is to
compare functional outcome after three different postoperative care regimens:

A) unprotected non-weight-bearing mobilisation with active exercises and
crutches
B) protected weight-bearing with a conventional walking cast
C) unprotected weight-bearing mobilisation with active exercises

The primary outcome will be measured by the Olerud Molander score. This scoring
system is a well known measurement instrument in scientific research, which can
separate even minor differences in disability in daily activities. A difference
in 5-10 points is defined as a significant result. The period of resumption to
work and sport activities will also be analysed during this research and
correlated to the SF-36 questionnaire. By this multicenter trial, and its
corresponding sample size, it is thereby expected that a difference of 7 points
in the Olerud Molander will represent a complete analysis of the recovery
process of the patients, including sport and work activities.

Primary Objective:
Compare functional results of the three postoperative care regimens assessed
with the Olerud-Molander ankle score 12 weeks after surgery.

Secondary Objective(s):

1) Compare functional results and patient satisfaction of the three
postoperative care regimens assessed by the Olerud-Molander ankle score, 6
weeks and 6, 12 months after surgery

2) Compare the rate of wound related problems after the three postoperative
care regimens

3) Compare the rate of hardware failure after the three postoperative care
regimens

4) Compare range of motion (plantar-flexion and dorso-flexion) of the ankle
after the three postoperative care regimens after 6 and 12 weeks and 6, 12
months after surgery

5) Compare the amount of weight baring (chip results), calf wasting (determined
by the difference between the injured leg preoperatively and the same leg
postoperatively with respect to the circumference of the leg) and muscle
strength 12 weeks post-operatively

6) Compare the duration to radiologic consolidation after the three
postoperative care regimens 6 and 12 weeks and 1 year after surgery

7) Compare patient satisfaction measured by the visual analogue scale (VAS) and
SF-36 questionnaire 6 and 12 weeks and 6 and 12 months after surgery

8) Compare period of resumption to work after the three postoperative care
regimens

9) Compare period of resumption to sports after the three postoperative care
regimens

Design: Prospective randomised multicenter clinical study

Duration: 4 years

Setting:
Two level 1 trauma center:
- Academic Medical Center Utrecht
- St. Elisabeth Hospital, Tilburg

Four level 2 trauma centers:

- Antonius Hospital, Nieuwegein
- Diakonessenhuis, Utrecht
- Twee Steden Hospital, Tilburg
- Medisch Centrum Haaglanden, 's-Gravenhage

* A) Unprotected non-weight-bearing group:
A compression bandage is placed directly after surgery. The bandage can be
removed 24 hours postoperatively and patients will be allowed to move the ankle
joint. Active exercises, dorso-flexion, plantar-flexion and rotation of the
foot, are recommend three times a day during approximately 5 minutes. Weight
bearing is not allowed for 6 weeks. After 6 and 12 weeks the pressure load will
be measured by scale.

* B) Protected weight-bearing (conventional cast) group:
A below knee non-weight bearing plaster of Paris is placed directly after
surgery. After 2 weeks the cast will be removed, a new below knee walking cast
is applied and full weight bearing is allowed when it can be performed without
pain. A microchip (SensiStep) will be installed in their cast to analyse the
weight distribution of the operatively fixed ankle during revalidation. The
cast will be removed 6 weeks post-operatively. *After 2,6 and 12 weeks the
pressure load will be measured by scale.*

* C) Unprotected weight-bearing group:
Comparable to the non-weight bearing group, a compression bandage will be
placed directly after surgery. The bandage can be removed after 24 hours, which
will allow movement to the ankle joint. Active exercises, Active exercises,
dorso-flexion, plantar-flexion and rotation of the foot, are recommend three
times a day during approximately 5 minutes. After the compression bandage is
removed, full weight bearing of the ankle is allowed when it can be performed
without pain. Patient will be to mobilise with a customised standardised shoe,
with a microchip installed in their sole of their shoe to analyse the weight
distribution of the operatively fixed ankle during revalidation. Results will
be reviewed after 6 weeks. From that moment on, it is not necessary anymore for
patients to mobilise with the standardised shoe. After 2,6 and 12 weeks the
pressure load will be measured by scale.

Due to the development of the Sensistep, the pressure load will be measured
randomly by the Sensistep in group C.

In general, all patients will attend the care of a physiotherapist during the
intervention period.

The indication for surgery is unrelated to the study. Participation is
completely voluntary and can be aborted at any time of the study without
consequences. This study includes in total 5 visits to the outpatient
department, after 2, 6, 12 weeks, 6 months and 1 year. These visits are part of
standard post-operative care regimes. Each visit includes physical examination,
standardized clinical evaluation, registration of possible complications and in
addition completing an Olerud-Molander and SF-36 questionnaire. Participation
in this study does not provide supplementary risks besides the standard
complications of surgery, such as wound infections, damage due to pressure of
the cast, deep venous thrombosis or hardware failure. Insurance is vacant for
every participant in case of unexpected damage due to this study.