In Vitro Microstructural and Mechanical Analysis of Waste Material From Total Knee Arthroplasty for the Study of Innovative Solutions in the Treatment of Joint and Ligament Pathologies

In orthopedic surgical practice, there is an increasing incidence of degenerative joint diseases, due to the rising average age of the population, as well as ligament injuries resulting from the growing participation in sports activities. The knee joint, in particular, is the most affected by these conditions, which, given their heterogeneous nature, impact patients across a wide age range.

Knee pathologies, often interconnected (with a higher incidence of degenerative diseases following ligamentous and/or meniscal injuries), are particularly debilitating for patients and entail high costs for the national healthcare system, which are expected to increase over time.

Scientific efforts in the field of knee surgery are therefore focused on achieving an increasingly detailed understanding of pathological conditions, as well as on the development of innovative technologies to support surgical and clinical practice.

Carrying out such analyses and developing new technologies inevitably involves experimental laboratory studies of joint tissues. The study of waste material obtained from surgical procedures represents a fundamental resource in this context and has always been used safely, with no additional invasiveness for the patient. A vast amount of information derived from laboratory analyses of discarded tissue has contributed to improving clinical practice and has led to the development of solutions that are now part of routine surgical use.

Recent technologies allow increasingly accurate evaluation of both the structure and mechanical properties of discarded tissue explanted during surgery. For example, structural assessment using micro-CT enables visualization and analysis of the interface between bone tissue, ligamentous structures, and surgical implants with micrometric precision. This makes it possible to determine tissue density, orientation, and material quality, distinguishing between different boundary conditions and physiopathological states of the tissues. Such analyses can also be performed under conditions close to those characterizing the joint in vivo, both in terms of tissue immersed in fluid and with respect to mechanical loads applied to deform the tissue. Furthermore, it is possible to reconstruct the structural interaction between human tissue and external materials used in surgery, such as screws, plates, anchoring devices, etc.

These instruments therefore make it possible to surpass the level of detail achievable with conventional diagnostic and research equipment used over the years, and to investigate with increasing accuracy the onset and progression of a pathology, the condition of the involved tissues, and to predict functional recovery of the treated site following the application of anchoring devices in the operating room. These new analyses also enable the study of innovative solutions for tissue repair and reconstruction, such as patient-specific customized devices and/or new materials produced using 3D printing technology, without posing any risk to the patient during surgery.