Ankle fractures constitute 9% of all fractures and have an incidence of approximately 187 per
100,000 persons per year in Norway. Weber B fractures are the most common type of fracture of
the fibula. A posterior malleolar fragment (PMF) is present in up to 46% of Weber B and Weber
C fractures. Patients with a PMF were recently shown to have significantly lower
patient-reported outcome measures (PROM) than the general population. Clinical outcome for
ankle fractures with a PMF is known to be poor from several studies. For this reason, the
indication and choice of intervention for these fractures have been the object of increased
interest over the recent years. It is one of the most debated areas within ankle fracture
surgery. Traditionally, PMFs have been treated with closed reduction, without direct
manipulation of the PMF, and anteroposterior screw fixation, or even no-fixation of the
smaller fragments. A more novel posterior approach to the ankle for open reduction and
internal fixation is increasingly popular and has led to fixation of smaller and medium-sized
PMFs.
The reason for focusing on the posterior approach is new knowledge that intraarticular
step-off in the tibiotalar joint and malreduced syndesmosis is associated with poor outcomes.
Studies suggest fracture reduction is better with a posterior approach. However, there is no
consensus as to what the best treatment is. Pilskog et. al. published a retrospective study
in Nov. 2020 where patients without fixation reported similar PROM to patients with fixation.
Most studies are retrospective and with a variable number of patients without a reasonable
conclusion as to what is best practice. A few prospective studies are published. But there
are no available randomized controlled studies examining PROM in patients after surgery with
fixation versus no fixation for the PMF.
Through a multicenter, prospective, randomized controlled trial initiated from Haukeland
University Hospital, patients with Weber B fracture and associated PMF (with or without a
medial malleolus fracture) will be recruited and randomized to receive treatment with or
without fixation of the PMF. Patients will be recruited at seven study hospitals from all
Regional Health Trusts in Norway.
Mason and Molly type 2A and 2B fractures will be included in the study. Type 2 fractures are
medium-sized fractures of the posterior malleolus which involve the fibular incisura. The
fractures are classified as type 2A if only the posterior malleolus is fractured and as type
2B if there are two posterior fragments of the tibia in which the medial fragment extends to
and involves the medial malleolus.
The lack of consensus on best practice is of great concern as patients of all ages are
affected. In a retrospective study examining the patient-reported outcome of 130 patients
with a PMF, 75% were aged 67 or younger. Such an injury, therefore, affects patients with
many active years left in both their working life and daily activities. Interviews with the
patient representative and with patients at the outpatient clinic reveal a long time for
rehabilitation, over 16-18 months until 100% working ability. The patients also talk about
the need to change working tasks due to reduced range of motion and pain. The study will not
only answer the best way to treat the PMFs, but also give insights into the impact on the
patient's life through the use of sick leave, treatment of the ankle syndesmosis, and
complication rates. The aim is to give the patients the best possible treatment for better
recovery and function.
The main aim of the study is to compare PROM in patients who had fixation of the PMF with
patients without PMF fixation with the intention to define what is the best surgical approach
and treatment of the fractures in question.
The null hypothesis (H0): There is no difference in mean patient-reported outcome
(Self-reported Foot and Ankle Score, SEFAS) in patients treated with fixation of the PMF and
patients treated without fixation of the PMF.
The intention is to deliver treatment recommendations based on the study results. The results
will thus have direct consequences for both patients and orthopedic surgeons.
Additional aims:
Publish treatment recommendations for ankle fractures including a PMF
Sub-analysis of patients with and without syndesmotic injury
Publish complication rates in the different treatment groups
Health economic impact of ankle fractures
Report rate of posttraumatic osteoarthritis after 2 and 5 years
The primary outcome is the summary score of Self-reported Foot and Ankle Score (SEFAS) at 2
years.
Project methodology:
Patients will be prospectively recruited from all six participating hospitals. An estimated
275 patients with ankle fractures per year will be eligible for inclusion. The investigators
aim to include 208 patients over two years. Data are collected and stored by using Viedoc as
the electronic case report form (eCRF). Patients will be treated according to randomization
and data will be collected at each study site, stored via Viedoc, and sent to Haukeland
University Hospital for analysis. Randomization is performed using Viedoc without
interference from the surgeon on call. The last follow-up will be 5 years postoperative.
Local coordinators at each hospital will manage inclusion and ensure correct treatment
according to protocol.
The primary outcome of the mean difference between groups will be analyzed with an analysis
of covariance (ANCOVA) with SEFAS at two years with baseline as covariate. Change in SEFAS
over time (3 months - 1 year - 2 years - 5 years) will be analyzed with linear mixed effect
models. The use of ANCOVA with adjusting for PROM at baseline (inclusion) is unique in
orthopedic trauma studies as most studies report solely 1- or 2- year results with
differences in mean values between groups. Adjusting for baseline will strengthen the
analysis.
The Student t-test for continuous variables and chi-squared test for categorical variables
will be used.
A power of 90% with a priori significance level of 0.05 requires 86 patients in each arm of
randomization. A difference between groups of five points is considered to be a clinically
relevant difference. Accounting for 20% lost to follow-up or dropout, 104 patients will be
included in each group. The total number of patients will be 208.
NorCRIN will be used as a national monitoring service via Viedoc and Anne Mathilde Henden
Kvamme.
Helse Bergen HF, Haukeland University Hospital, will be the coordinator of the project. All
four regional health trusts in Norway are involved in this project. There will be responsible
local coordinators for the study at the seven sites represented. The local coordinators are
responsible for developing and coordinating the study and communicating with the project
leaders and main coordinators.
Ethical considerations None of the surgical methods can be considered experimental as they
are in conventional use at the study clinics and several other level 1 trauma centers.
Participation in the study will not cause any delay in treatment compared to conventional
care, nor will patients have any extra expenses related to follow-up evaluation. Patients
having any concerns throughout the study period will be offered an extra follow-up by one of
the participating surgeons.
As there is no clear evidence supporting the choice to fixate, or not fixate, the posterior
malleolus fracture, the study can contribute new knowledge thereby contributing to a more
evidence-based approach to treating these patients.
The project is approved by the Helse Bergen Data Protection Officer and Regional Committees
for Medical and Health Research Ethics (REC). REC ref.nr: 255548. Patients will have to give
their written, informed consent prior to inclusion in the study.