With use and time, body joints deteriorate, mainly as an effect of aging and shocks on the cartilage layer cushioning between bones. The consequences of this deterioration can be serious and cause problems to the regular functioning of the joint. Cases of hip and knee beginning to lose cartilage are very frequent.

 
One effective way of dealing with joint deterioration is by surgical replacement. Hip replacement (Total Hip Arthroplasty or THA) and knee replacement (Total Knee Arthroplasty or TKA) are frequent surgical interventions, which are rigorously planned in advance: accurate measurements are taken and the intervention is planned in all its details. A Computer Tomography (CT) image of the interested area is taken and a patient-specific model of the patient’s bones is prepared out of it. The artificial joint is built upon this model, taking into account the required size and many other patient-specific parameters, the accuracy of which is key to ensure that the new joint fits the patient anatomy.

Computer-Assisted Joint Replacement Software

RSIP Vision has developed a software package based on sophisticated computer vision algorithms and the most advanced image processing techniques to build models having a very high anatomic precision, up to 0.3 mm RMSE, so that our model is very close to be as precise as the resolution of the CT allows. This software performs a segmentation of the bones using the CT volume. The main challenge of this segmentation is given by the difficulty to identify the border between bone and cartilage: local values are very close. We solve this difficulty by looking at the gradient structure and applying optimization algorithms to trace the edges between soft tissue, cartilage and bones. Our software is able in a few minutes to delimit edges and complete the segmentation which would take hours for an expert physician.

Besides optimization techniques and as an addition to the segmentation, RSIP Vision’s computer-assisted joint replacement software package is able to accurately identify anatomical landmarks, which are used in the fitting process.