Bone and Cartilage Interfaces With Orthopedic Implants: A Literature Review

Abstract

The interface between a surgical implant and tissue consists of a complex and dynamic environment characterized by mechanical and biological interactions between the implant and surrounding tissue. The implantation process leads to injury which needs to heal over time and the rapidity of this process as well as the property of restored tissue impact directly the strength of the interface. Bleeding is the first and most relevant step of the healing process because blood provides growth factors and cellular material necessary for tissue repair. Integration of the implants placed in poorly vascularized tissue such as articular cartilage is, therefore, more challenging than compared with the implants placed in well-vascularized tissues such as bone. Bleeding is followed by the establishment of a provisional matrix that is gradually transformed into the native tissue. The ultimate goal of implantation is to obtain a complete integration between the implant and tissue resulting in long-term stability. The stability of the implant has been defined as primary (mechanical) and secondary (biological integration) stability. Successful integration of an implant within the tissue depends on both stabilities and is vital for short- and long-term surgical outcomes. Advances in research aim to improve implant integration resulting in enhanced implant and tissue interface. Numerous methods have been employed to improve the process of modifying both stability types. This review provides a comprehensive discussion of current knowledge regarding implant-tissue interfaces within bone and cartilage as well as novel approaches to strengthen the implant-tissue interface. Furthermore, it gives an insight into the current state-of-art biomechanical testing of the stability of the implants. Current knowledge reveals that the design of the implants closely mimicking the native structure is more likely to become well integrated. The literature provides however several other techniques such as coating with a bioactive compound that will stimulate the integration and successful outcome for the patient.

A Simple Cerium Coating Strategy for Titanium Oxide Nanotubes’ Bioactivity Enhancement

“…Poor osseointegration is the basis of both phenomena. As a bio-inert material, Ti is not able to actively interact with the surrounding environment and to favor a satisfactory cell adhesion, which are instead key points for the formation of the structural and functional direct connection between the living bone and the implant surface needed to ensure long-term stability [3]. Great efforts have been paid to improve bone-implant contact, such as changing the substrate surface topography [4,5], chemically modifying the surface layer [6,7], and coating the implant with bioactive materials [8,9].…”

Temporal Changes in Reverse Torque of Locking-Head Screws Used in the Locking Plate in Segmental Tibial Defect in Goat Model

“…Based on pre-assigned study endpoints, PRT measurements were obtained from 16 goats 3 months after the surgery, 24 goats at 6 months, 23 goats at 9 months, and 20 goats 12 months after surgery. The length of the screws used 23 IBM SPSS v. 26, New York, NY. 24 PS power and sample size analysis software v. 3.0, 2009.…”

“…The statistical analysis was conducted using the SPSS software 23 and the power of the study was calculated with the PS software 24 . Descriptive statistics, including the mean, standard deviation, and percentage were calculated and presented.…”

“…Complications associated with locking plate fixation are not uncommon. Locking plates are known to provide a stable, stiff fixation (23,32,33). These constructs create single beam constructs which are defined with no motion between the single elements of the beam, including plate, screws and bone (15,16).…”

“…This provides an indirect measurement of the screw-plate-bone interface integrity and it has been positively correlated with implant primary and secondary stability (10,18,22). Several factors have been described to significantly influence the primary and secondary implant stability, from which implant micromotion is most relevant (23). Cyclic axial compressive loading of the tibia defect model was recently shown under ex-vivo conditions to significantly reduce peak reverse torque of the screw implants placed within the locking plate (22).…”