Jan Rongen, Ph.D., M.D.

Jan Rongen left the ORL June 1st 2016. Jan graduated December 12th 2016. Click his LinkedIn tag.
To Thesis: An Evidence Based Evaluation of the Treatment of Meniscus Tears.


Jan Rongen, M.Sc., Orthopaedic Research Laboratory (ORL) Nijmegen, RUN MC Jan.RongenAapje……..
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About Me
Research Impression
Publications

About Me

I started to study medicine in 2002 at the Radboud University Nijmegen Medical Centre. Motivated by a high affinity with human movement and its related sciences I followed an additional master program in Biomedical Health Sciences (major in Human Movement Sciences), which I graduated cum laude. After finishing medical school I worked as a resident at the department of orthopedics in the Elkerliek hospital in Helmond and in the St Maartenskliniek in Nijmegen. Aiming for a more scientific career I seized the opportunity to follow a STW funded Ph. D. program within the Orthopedic Research Laboratory (ORL) of the Radboud University Nijmegen Medical Centre, which started July 2013. My research is embedded into the ORL research line ‘Tissue Engineering of a Meniscus’, supervised by Prof. Pieter Buma and funded by the STW-project ‘A Functional Tissue-Regenerating Meniscus Implant’.
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Research Impression

Menisci are C-shaped fibro-cartilage structures, located in pairs in the knee joint. The menisci perfectly fill the space between the two femoral condyles and the tibial plateau. They have an important function in load-bearing and load-distribution in the knee joint. Traumatic injuries of the meniscus occur particularly frequently in young sportsmen or -woman. Most meniscus tears occur in the inner avascular part of the meniscus. This avascularity strongly reduces the intrinsic tissue repair capacity. These injuries can result in severe functional knee problems, pain, and in overloading of the articular cartilage. Although the direct post-traumatic symptoms can be relieved by a partial or total meniscectomy, both treatments will cause overloading of articular cartilage and osteoarthritis. Many patients that have undergone a total meniscectomy in the past are now confronted with severe knee problems and most of them, although still relatively young, need a very expensive total knee arthroplasty. However, these prostheses can fail. A very traumatic event for the patient. Currently there are no suitable clinical solutions for patients with a damaged meniscus.

meniscus fig.1A: 1[mm] scanning electron micrograph of porous structure with diamond pore network; Jan Rongen, Orthopaedic Research Laboratory Nijmegen, Radboud umc meniscus fig.1B: 100[micron] scanning electron micrograph of porous structure with diamond pore network; Jan Rongen, Orthopaedic Research Laboratory Nijmegen, Radboud umc meniscus fig.1C: Micro-CT visualization of porous structure with diamond pore network; Jan Rongen, Orthopaedic Research Laboratory Nijmegen, Radboud umc

Figure 1: Scanning electron micrographs of mathematically designed flexible and elastic porous structures with diamond pore network architecture prepared by stereolithography. A) Overview, scale bar is 1 mm; B) Detail, scale bar is 200 µm; C) Micro-CT visualization. Click on Image to Enlarge

A functional meniscus implant that slowly resorbs and simultaneous allows the formation of new tissue would be of enormous benefit for patients faced with an injured meniscus. Synthetic biodegradable polymers are the materials of choice to create such implants. Such implant will act as a temporary replacement of the lost meniscus. After tissue ingrowth and resorption of the polymer, complete restoration of meniscus functionality is achieved and osteoarthritic degeneration will be prevented. We identified a number of properties that are of critical importance for the success of a functional meniscus implant: The anatomical shape of the implant and its mechanical properties should resemble those of the native meniscus as closely as possible. The structure of the internal pore network of the implant should enable the direct differentiation of ingrowing tissue into the typical meniscus tissue. For this, the pores should be highly anisotropic and oriented in a similar way as the orientation of the collagen bundles in the native meniscus. Furthermore, the implant surface should have excellent tribological properties to minimize friction in the joint. So far it has not been possible to produce such an implant with conventional technologies.

meniscus fig.2A: porous structure; Jan Rongen, Orthopaedic Research Laboratory Nijmegen, Radboud umc meniscus fig.2B: histological image of canine meniscus tissue;
 Jan Rongen, Orthopaedic Research Laboratory Nijmegen, Radboud umc meniscus fig.2C: drawing of meniscus part depicting bundle components; Jan Rongen, Orthopaedic Research Laboratory Nijmegen, Radboud umc meniscus fig.2D: scheme of a meniscus scaffolding structure;
 Jan Rongen, Orthopaedic Research Laboratory Nijmegen, Radboud umc

Figure 2: Meniscus implant structures. A) Porous structure with homogenous pore network architecture. B) Histological section after six months implantation in a canine model. Note the orientation of the collagen bundles in the channels connecting the isotropic pores. C) Part of the meniscus showing the various bundle components: 1) superficial bundle network, 2) tie fibres, 3) circumferentially oriented fibre bundles. D) Simplified scheme showing circumferential orientation of the pores in a designed meniscus scaffolding structure. Click on Image to Enlarge

In this project we will develop a functional tissue regenerating implant for the replacement of an entire meniscus using high resolution stereolithography (SLA). This advanced processing technology allows the generating of anatomically shaped implants from graphical computer data based on CT or MRI images. The technique also allows the creation of a predesigned anisotropic internal pore architecture, optimized for the direct differentiation of ingrowing tissue into meniscus tissue. For this, resins that cure into biodegradable flexible networks upon illumination with light, will be developed. The suitability of the materials and implants will be evaluated in vitro by cell culturing and mechanical testing, and in vivo in a clinically relevant animal model.
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Publications

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