Fietsen verstandig?


Bij hardlopen wordt de knie belast met 6x uw lichaamsgewicht bij elke stap

Máxima Medisch Centrum

Value-Based Health Care

ESSKA Accredited Teacher

Orthopedie Groot Eindhoven

Goede uitleg is essentieel voor juiste keuze behandeling


Voorste kruisbandreconstructie

Achterste kruisbandletsel

Zorg op maat

YouTube kanaal dr RPA Janssen

Internationaal wetenschappelijk onderzoek

Kruisbandoperaties knie

RPA Janssen MD PhD


Waardegedreven zorg

Last van knie-artrose?

Spreekuur / Policlinique / Outpatient clinic

Nederlandse Vereniging voor Arthroscopie

Máxima Medisch Centrum

Kruisbandoperaties bij kinderen

Veel pijn bij ernstige knie-artrose?

Samen met uw arts gekozen voor een knie-operatie?

Eenzijdige knie-artrose knie en actief leven?

Máxima Medisch Centrum Eindhoven-Veldhoven

Kwaliteit van leven

Samen kiezen voor de beste behandeling

Sporten met plezier

Oplossingen voor de lange termijn

Associate Professor Knee Reconstruction


Kneecap pain is a regular occurrence in fitness knee rehabilitation

Knee osteoarthritis

Cycling wise?


When running, the knee is loaded with 6x your body weight with each step

Steigerung der Evidenz zur optimalen Behandlung kindlicher VKB-Verletzungen: Die Initiative zur Erfassung von Verletzungen des vorderen Kreuzbandes bei Kindern und Jugendlichen (Paediatric Anterior Cruciate Ligament Monitoring Initiative, PAMI)

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Mouton, C., Magosh, A., Moksnes, H., Janssen, R. P. A., Fink, C., Zaffagnini, S., Monllau, J. C., Ekås, G., Engebretsen, L., Nührenbörger , C., & Seil, R
Sports Orthopaedics and Traumatology. 2022, Published Online Nov 30
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A patient-specific microtissue platform to compare biological properties in vitro with patient outcome for anterior cruciate ligament reconstruction

M. van Vijven, J. Kimenai, B. van Groningen, M.C. van der Steen, R.P.A. Janssen, K. Ito, J. Foolen
Orthopaedic Proceedings VOLUME 103-B, ISSUE SUPP_4 / MARCH 2021 (a supplement to the Bone and Joint Journal

After anterior cruciate ligament (ACL) rupture, reconstructive surgery with a hamstring tendon autograft is often performed. Despite overall good results, ACL re-rupture occurs in up to 10% of the patient population, increasing to 30% of the cases for patients aged under 20 years. This can be related to tissue remodelling in the first months to years after surgery, which compromises the graft's mechanical strength. Resident graft fibroblasts secrete matrix metalloproteinases (MMPs), which break down the collagen I extracellular matrix. After necrosis of these fibroblasts, myofibroblasts repopulate the graft, and deposit more collagen III rather than collagen I. Eventually, the cellular and matrix properties converge towards those of the native ACL, but full restoration of the ACL properties is not achieved. It is unknown how inter-patient differences in tissue remodelling capacity contribute to ACL graft rupture risk. This research measured patient-specific tissue remodelling-related properties of human hamstring tendon-derived cells in an in vitro micro-tissue platform, in order to identify potential biological predictors for graft rupture.

Human hamstring tendon-derived cells were obtained from remnant autograft tissue after ACL reconstructions. These cells were seeded in collagen I gels on a micro-tissue platform to assess inter-patient cellular differences in tissue remodelling capacity. Remodelling was induced by removing the outermost micro-posts, and micro-tissue compaction over time was assessed using transmitted light microscopy. Protein expression of tendon marker tenomodulin and myofibroblast marker α-smooth muscle actin (αSMA) were measured using Western blot. Expression and activity of remodelling marker MMP2 were determined using gelatin zymography.

Cells were obtained from 12 patients (aged 12–51 years). Patient-specific variations in micro-tissue compaction speed or magnitude were observed. Up to 50-fold differences in αSMA expression were found between patients, although these did not correlate with faster or stronger compaction. Surprisingly, tenomodulin was only detected in samples obtained from two patients. Total MMP2 expression varied between patients, but no large differences in active fractions were found. No correlation of patient age with any of the remodelling-related factors was detected.

Remodelling-related biological differences between patient tendon-derived cells could be assessed with the presented micro-tissue platform, and did not correlate with age. This demonstrates the need to compare this biological variation in vitro – especially cells with extreme properties – to clinical outcome. Sample size is currently increased, and patient outcome will be determined. Combined with results obtained from the in vitro platform, this could lead to a predictive tool to identify patients at risk for graft rupture.