FACTS study: Functional outcome assessment after Calcaneal Trauma Surgery

In the Netherlands the number of patients that are treated in the emergency
room with an ankle- or foot injury is valued on approximately 190,000. The
fractures of the calcaneus comprise 60% of the tarsal fractures, but only 4% of
all foot-ankle fractures. The most common mechanism of injury is a high energy
axial load: fall from height.
The fractures can be treated conservatively or with ORIF (open reduction and
internal fixation). Functional outcome after conservative or ORIF is frequently
tampered. Improved understanding of biomechanical changes after calcaneal
fractures and surgery for calcaneal fractures may alter the functional outcome.

The aim of this study is to assess biomechanical properties after a calcaneal
fracture, and compare these data tot the radiological and functional outcome
parameters. Hereby comparing healthy subjects to patients who were treated with
ORIF (open reduction internal fixation), with arthrodesis of the talar joint or
arthrodesis of the subtalar joint. The methods used for the assessment are the
VICON-system with the *Oxford foot model*, radiological characteristics
(computed tomography) and questionnaires. The VICON-system comprises of six
cameras and markers. The markers are placed on specific points on the subjects
with tape. The camera system then makes a recording and calculates specific
changes/vectors of the markers. By using this system the gait of the subject
can be analyzed and a comparison can be made between healthy and treated
subjects. The outcome of this part of the investigation is to assess the
biomechanical changes of the ankle-joint and to determine the *subtalar
joint-axis* (STJ-axis).
The VICON system is validated for the testing of the lower extremity in
combination with other programs, the oxford foot model has been validated by
other authors. This system has been used in multiple trials by the department
of movement sciences of Maastricht University, but previsously not regarding
the STJ-axis. Recently, the department of movement sciences has validated with
the VICON-system the Oxford foot model.
Earlier investigations have given us more insight in the relationship between
the function of the ankle-joint and the STJ-axis. It is known that this axis,
between the calcaneal bone and the talus bone, has great influence on the
function of the ankle.
The aim of this study is to determine the influence of deviations in the
STJ-axis on the (postoperative) outcome.
Also there will be a footprint-analysis to get an impression of the pressure
partitioning.
The outcomes of the biomechanical analyses are compared in the patients group
with the radiological findings on CT (Böhler, Ghislaine angle, subtalar joint
congruency). Furthermore the patients* satisfaction is analyzed by health
questionnaires (The foot and ankle disability score (FADI), Visual Analog Scale
of Hildebrand and RAND-36).
By analyzing these outcomes there can be overall, objective, assessment of the
postoperative outcome after the trauma ankle-surgery. At present there is no
evidence comparing biomechanical analyses of the VICON-system with radiological
and patient reported outcome scores. The outcome of this study can contribute
in the knowledge about the foot biomechanics and the decision for the treatment
of a calcaneal fracture. Intra-operative pedobarography has been shown to
improve outcome in patients undergoing ankle arthrodesis and may be also
applicable in acute fracture surgery.

The experimental design of the study is a prospective observational study
comparing healthy and operated patients regarding foot biomechanical and
anatomical abnormalities, and outcome satisfaction.

There will be no benefits or extra risks for the participants during this
study.