Development of a diagnostic protocol to aid the investigation and management of posterior malleolus ankle fractures.

Ankle fractures account for 10% of all adult fractures presented to the emergency department.  In the researchers’ NHS Lothian unit, covering a population of 800,000 people, they see over 900 ankle fractures per year, 450 of which are unstable and require an operation., Around 250 patients with unstable ankle fractures have a fracture at the back of the ankle (posterior malleolus fractures). A simple calculation of the incidence of ankle fractures in the NHS Lothian unit, relative to the 67 million United Kingdom population, reveals that almost 21,000 posterior malleolus fractures occur per year countrywide.

A recent systematic review concluded that no classification system has established itself in the literature and they do not help in predicting outcomes post injury.

Data published on posterior malleolus fractures has increased over the last decade, with a debate surrounding appropriate imaging modalities to determine the optimal surgical management and improve patient outcomes. One theory is ankle fractures can be assessed sufficiently using standard x-rays (2D images).

Current British Orthopaedic Association Standards for Orthopaedics and Trauma (BOAST guidelines) advise that complex patterns, particularly involving posterior malleolus, should undergo pre-operative computed tomography (CT) scan to gain a 3D image of the ankle fracture. This has become standard practice in the United Kingdom, and the researchers have noted a large rise in the number of pre-operative CT scans in their centre.

CT scans can lead to delays in surgery and unnecessary radiation. Acquisition of CT scans pre-operatively have also shown to change surgical planning to a more aggressive, larger, less practiced approach into the posterior ankle joint, associated with overtreatment and an increased risk of complications (23% complication rate), including posterior ankle pain, stiffness and nerve injury.

The main aims and objectives of the research study.

Primary Objective: The aim of this study is to develop and validate an imaging protocol that identifies which posterior malleolus fractures, based on plain film x-rays, require CT scanning pre-operatively.

Secondary Objectives:

• To understand the risk factors for osteoarthritis between different types of posterior malleolus fracture.
• To understand the functional impact of patients with posterior malleolus fractures.
• Assessment of a patients’ return to pre-injury work and sport after a posterior malleolus ankle fracture.
• Assess whether the ‘Normal Ankle Score’ is a good representation of the already validated foot and ankle functional outcome scores.
• Assessment of the complication and re-operation rates following operative management of posterior malleolus ankle fractures.
• Assess whether better utilisation of CT scanning of posterior malleolus ankle fractures allows for reduced costs per patient.

How this research is going to help address MSK health.

The project aims to improve patient outcomes and reduce the cost of investigating and treating these fractures by developing a diagnostic protocol to help surgeons manage such a complex ankle fracture.

The researchers’ protocol would safely decrease the number of CT scans by around 90%, with the grounds that only one specific ankle fracture type requires a CT scan (this would be around 25 of 250 patients in their unit). This would reduce the cost of CT scans from around £5.2M to £0.5M per year (at £250 per CT scan).

The main research methods, or datasets being used.

Study Design

The project is a prospective, single study centre cohort study. Recruitment will be over a one-year period. Patients will be followed up at the Royal Infirmary of Edinburgh, a tertiary orthopaedic centre. The Royal Infirmary of Edinburgh surgically operates on around 300 ankle fractures per year. It is likely that the researchers will see and recruit between 120 and 140 patients to the study, as 40-50% of unstable ankle fractures will have a posterior malleolus fracture.

There will be no changes to a patients’ routine investigation and management plan. However, prospective clinical data and Patient Reported Outcome Measures (PROMs) will be collected over the follow-up period. Routine pre-operative and post-operative images will be analysed where carried out.

Study Population

The study will include adult patients (≥16 years) presenting to a single centre, with an unstable ankle fracture involving the posterior malleolus requiring surgical intervention. The study has received favourable outcomes from the NHS Research Ethics Committee (REC) and the NHS Research and Development Management. Approximately 125 participants are expected to be enrolled in the study over a one-year recruitment period.

All patients will be treated as per the standard practice of the receiving on-call Trauma and Orthopaedic Consultant from presentation to surgical intervention. The research team will then be able to carry out clinical reviews as well as carry out study questionnaires to validate a pre-determined imaging protocol.

Research results generated.

So far 97 patients have been recruited. Results are yet to be collated and analysed.

Next steps of this research project.

Complete enrolment in September 2024 (1 year after study commenced). Complete data collection over the next year (study completion data is September 2025).

Researcher: Mr Nicholas Heinz. 

Supervisors: Mr Andrew Duckworth and Mr Time White.

Trust: Lothian Health Board.

Award stream: Inspiration Fund.

Award duration: 2 years.

Amount rewarded: £23,000.

Collaborations/ partners: Mr Anish Amin. The University of Edinburgh and NHS Lothian Research and Development department.