Articulis is a pre-operative planning system that simulates the bone-determined range of motion of a joint. This allows surgeons to pre-operatively assess the joint they are going to operate on.

The program was showcased in the Dutch television series Intensive Care and has won two awards; a Best Paper award at SimVis 2006 in Magdeburg, Germany and the 1st prize of the Young Investigator Award (Dutch Biomedical Engineering 2007).

Technique

Articulis offers automatic and manual planning functionality and aims to replace traditional templating. The planning system uses 3D bone models that are extracted directly from CT or MRI. The automatic planning functionality of Articulis is based on landmarks that are automatically located on the surface of the 3D bone models.

Articulis is more than just a pre-operative planning station. Articulis continuously determines the bone-determined range of motion of the joint and visualises this using a unique visualisation that has been specifically designed for this purpose. When a user adjusts the pre-operative plan, the range of motion is redetermined and updated on the screen. In this way the clinician receives interactive feedback on the effects of adjustments.

Articulis is currently being used for the following conditions and procedures:

Proximal humerus fractures

In a large study conducted with Imperial College London and the orthopaedics clinic of NHS St Mary’s Hospital Articulis was used to determine the range of motion of proximal humerus fractures. The varying appearance of these fractures leads to unpredictable surgical outcome. Simulation of the range of motion before and after surgery supports clinicians in the difficult decision-making process involved in treating these fractures.

Femoroacetabular impingement (FAI)

In collaboration with HagaZiekenhuis, Reinier de Graaf Gasthuis and the Leiden University Medical Center, Articulis is being used for the analysis of femoroacetabular impingement. Articulis allows users to compare a hip joint with its contralateral side, pinpointing changes in shape morphology and range of motion. An accurate analysis of the bone models allows surgeons to zoom in on ossifications and visualise the possible gain with regards to range of motion.

Joint replacement / arthroplasty

Articulis was initially designed for the placement of prothesis components and for the prevention of impingement complications. The joint replacement is planned using CT data that is converted to bone models. When a virtual prosthesis has been selected from a list of manufacturers, it is inserted into the scene and automatically aligned with the joint.

Articulis simulates and visualises the range of motion of the pre-operative plan. This information is constantly updated while the clinician adjusts the plan.