Towards better methods for knee repair
On June 23, Janne Spierings defended her PhD thesis at the Department of Biomedical Engineering, in which she investigated why anterior cruciate ligament (ACL) reconstructions often lead to complications, and how decellularized grafts could contribute to improved knee recovery.
Every year, thousands of people, primarily young, athletic, and active individuals, tear their ACL, with significant consequences for mobility and quality of life. The standard treatment, surgical reconstruction using a tendon graft, does not always result in full recovery. Many patients experience recurring knee instability, difficulty returning to sports, or develop osteoarthritis over the long term.
explored the underlying causes of these complications. Using computer models, cell culture experiments, and bioreactors, she mapped how the body responds to a transplanted tendon and why this response is often suboptimal. She discovered that postoperative changes in the graft, such as inflammation and a loss of mechanical strength, play a major role in the development of complications.
To address these issues, Spierings studied decellularized ACL grafts as a promising alternative. Unlike traditional tendon grafts, decellularized grafts retain the structure and strength of a healthy ACL while triggering a reduced immune response. Her findings suggest that these grafts not only cause less inflammation, but also support cell infiltration under realistic knee movement conditions: an important step in the healing process.
Simulations and Mechanical Changes
Spierings used computational models to examine how graft weakening affects knee movement. The results showed that as the graft weakens, knee instability increases, which can lead to changes in cartilage loading and ultimately to osteoarthritis. This highlights the critical role of postoperative changes in graft properties in the development of long-term complications.
Another key finding from her research was that decellularized grafts release fewer inflammatory factors compared to traditional tendon grafts, potentially contributing to a more stable healing process. Furthermore, cell infiltration studies in a bioreactor confirmed that cells can effectively adhere to and penetrate decellularized grafts, even under dynamic loading, further supporting their surgical applicability.
The future of ACL surgery
This dissertation provides valuable insights into the causes of complications in ACL reconstruction and demonstrates that decellularized grafts could be a promising alternative solution. While further research is needed before these grafts can be applied clinically, the findings suggest they may help prevent knee instability and reduce the risk of early-onset osteoarthritis. With continued investigation, this approach could improve outcomes in ACL reconstruction and more effectively support the recovery of athletes and active individuals following injury.
Title of PhD thesis: 鈥�鈥�
Supervisors: Keita Ito and Jasper Foolen
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