Clinical and Pre-operative Assessment of Lower Limb Rotational Profiles in Virtual and Augmented Reality

Context and Research Goal
Rotational abnormalities of the lower extremities are common medical conditions, mostly seen in young adolescent population. These conditions manifest with gait disorders and knee symptoms. In extreme cases, rotational abnormalities can cause repetitive patellar dislocation from the trochlear groove, the notch within the distal femur, which articulates with the patella. Functionally, patients experience chronic symptoms, and in severe cases this can cause abstinence from sports and any strenuous physical activities. Rotational mal-alignment of the lower limb can also cause secondary complications and symptoms following knee arthroplasty. Computed Tomography (CT) is the imaging modality of choice, although interpretation of imaging can be challenging even to the most experienced radiologists and orthopaedic surgeons, given the complex anatomical considerations associated with these conditions. Often, due to the complexity of the condition, visualisation of multi-planar CT imaging on conventional medical 2D picture archiving and communication systems (PACS), can lead to poor understanding of the anatomy and lower limb rotational profile.

Emerging Virtual Reality (VR) and Augmented Reality (AR) technologies have been pivotal in modern medical technological innovations. We suggest the use of VR and AR technologies for an immersive 3D visualisation of CT rotational profile imaging, to aid understanding of complex anatomical abnormalities. This can aid diagnosis and management, including pre-operative planning, for those requiring surgical correction and de-rotational osteotomies.

Project Aims
We will develop a VR platform to enable 3D visualisation of CT imaging data in patients with suspected rotational abnormalities of the lower limbs. During pre-operative planning we aim to employ AR technologies to overlay the imaging data on the patient to (i) re-align osseous structures and (ii) obtain angles and measurements, for a complete and comprehensive understanding of the rotational alignment anatomy.

Methodology
The simulation software will be tested with respect to various clinical aspects. These include, but are not limited to, (i) the capability to render complex 3D anatomy in immersive VR environments, (ii) ability to obtain accurate key angles and measurements which will be further evaluated against state-of-the-art conventional techniques on PACS, and (iii), the functionality to enable real time manipulation of imaging data on a VR and AR platform to improve the assessment of structural abnormalities and aid pre-surgical planning.

We also aim to obtain feedback from orthopaedic surgeons, regarding the experience and impact of using the sof tware in understanding the anatomical abnormalities, clinical decision-making and pre-operative planning in relevant cases.

Summary
Interpretation of medical imaging in rotational abnormalities of lower limbs can be challenging, given that complex 3D anatomy is evaluated on 2D screens, and there exists significant inter-observer variability. The use of VR and AR software could enhance the image viewing experience of clinicians in simulated, real-life like, immersive 3D format, to better understand the complex anatomical abnormalities. We envisage that the use of the proposed technologies in such complex medical conditions can improve clinicians' understanding of structural abnormalities and aid patients' management, for improved clinical outcomes.