With cadavers scarce and their heterogeneity an issue, a team of researchers set out to design, manufacture, and experimentally validate a synthetic knee surgical training model which reproduces the flexion dependent varus‐valgus and anterior‐posterior mechanics of cadaveric knees, while maintaining anatomic accuracy.
Their work, “Development and validation of a biomechanically fidelic surgical training knee model,” appears in the October 2024 edition of the Journal of Orthopaedic Research.
Co-author Mark Taylor, Ph.D., professor of Biomedical Engineering at Flinders University in Australia, told OTW, “This was a collaborative project between Flinders University, Fusetec, and DePuy Synthes, which was funded by a Global Linkages Grant.”
“Fusetec is an innovative company developing surgical training models. They had started to work on models training orthopaedic surgeons and needed to generate models that were not only anatomically correct but also had the same biomechanics. This was important so that the model had the same feel as a real knee during training.”
In formulating the knee models, the authors developed a probabilistic finite element model based on the left knee geometry of an adult male, consisting of five ligament structures—lateral and medial collateral ligaments, anterior cruciate ligament, anterolateral ligament and the posterior cruciate ligament.
The research team then tested seven synthetic models.
As for why they chose to use a probabilistic finite element modeling approach, Dr. Taylor explained to OTW, “The key challenge was finding a suitable way to simulate the ligaments, particularly the medial and lateral collateral ligaments and the anterior and posterior cruciate ligaments.”
“We had to find suitable materials and methods to provide the right tension in the simulated ligaments to replicate the natural ligament behavior.”
“In addition, we know that there will be subtle differences in the manufacture of each knee model, and we had to ensure that within the manufacturing tolerances we were able to produce a repeatable model. The probabilistic modelling helped use ensure that we could achieve this.”
The authors found that “…the synthetic models exhibited cadaver-like varus‐valgus and anterior‐posterior mechanics across a wide range of flexion angles with little variation between models.”
“In the extended position, two models showed increased valgus rotation (<0.5°), and three models showed increased posterior tibial translation (<1.7 mm) when compared to the 95% confidence interval of cadaveric measurements.”
“At full flexion, all models showed varus‐valgus and anterior‐posterior mechanics within the 95% confidence interval of cadaveric measurements. Given the repeatable mechanics exhibited, the knee models developed in this study can be used to reduce the current reliance on cadaveric specimens in surgical training.”
“We were able to experimentally validate the final model and that that it replicated the behavior of the intact knee,” explained Dr. Taylor.
“This is the first step in developing these kinds of models. They have many advantages over using cadaveric specimens for training which include no risk of transfer of disease, they are repeatable, have the potential to develop a series of models of increasing complexity and therefore provide scaffolded learning for surgical residents and also have the potential to be used for surgical planning in very complex cases.”

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