Prof. Dr. med. Marcus Jäger // St. Marien-Hospital Mülheim an der Ruhr

Quantifying wear in total hip arthroplasties with RayMatch

Challenge

Traditional methods for measuring prosthetic wear in total hip arthroplasties can be subjective and imprecise.

Solution

RayMatch uses CAD implant data to automatically quantify wear behavior and cup positioning in total hip arthroplasties.

Outcome

The precision of RayMatch is assisting Prof. Dr. Jäger in developing biomaterials for hip prostheses that result in lower levels of wear.

Excerpt

Wear is a key factor affecting the lifespan of orthopedic prostheses. Univ.-Prof. Dr. med. Marcus Jäger, Chair of Orthopedics at the Marienhospital at the University of Duisburg-Essen, uses RAYLYTIC’s RayMatch method to automatically and noninvasively measure prosthetic wear in total hip arthroplasties (THA) with remarkable precision.

Measuring prosthetic wear in THA

In Dr. Jäger’s research, every micrometer counts. As part of the “VITAS” study initiated by Aesculap AG, which is exploring how acetabular liner material in THA affects wear, Jäger required a highly precise method for quantifying wear behavior and cup positioning.  

These two factors are linked to the production of microparticulate debris–a central factor in aseptic loosening of prosthetic joints. Aseptic loosening can cause severe complications for patients, necessitating corrective surgeries or even leading to total failure of the prosthesis.  

RayMatch’s automation and validation

RAYLYTIC’s RayMatch method represented a scientifically validated, minimally invasive way for Jäger to observe wear behavior in hip prostheses. After uploading imaging data from his hospital’s PACS (picture archiving and communication system) directly and in compliance with data protection standards to RAYLYTIC’s cloud-based platform, he could rely on “automated processes that cannot be influenced by researchers” to ensure his results were free from bias down to the finest detail.  

With this precision, Jäger is aiding in the development of biomaterials which result in lower levels of wear and better implant performance.  

Jäger also emphasized how RAYLYTIC’s subject-specific expertise and approachability allow him to swiftly resolve challenges as they arose, saving him and his team time.

RayMatch’s edge over conventional X-ray analysis techniques

The RayMatch method utilizes CAD data of the implant components provided by the manufacturer to automatically determine the position and orientation (anteversion and inclination) of the prosthesis with the help of artificial intelligence. In this case, anteroposterior pelvic radiographs were analyzed one and five years post-operatively for femoral head penetration and cup positioning.¹ 

Other methods proved to be too unreliable for Jäger because of their subjective measurement procedures. He stressed that software programs that volumetrically determine wear rates result in too much variance, especially when multiple users evaluate the medical imaging data.

Other methods require that anatomical landmarks are manually placed by radiologists. “These procedures are too error-prone,” said Jäger. X-ray projection of the images depends heavily on the positioning of the patient, which can negatively influence the subjective placement of anatomical markers. In addition to being unreliable, measuring wear volumetrically with a vector solution requires additional invasive procedures.

¹ Baghdadi J, Alkhateeb S, Roth A; VITAS-Group, Jäger M. Cup positioning and its effect on polyethylene wear of vitamin E- and non-vitamin E-supplemented liners in total hip arthroplasty: radiographic outcome at 5-year follow-up. Arch Orthop Trauma Surg. 2022 Apr 10. 

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