Development of a preclinical natural porcine knee simulation model for the tribological assessment of osteochondral grafts in vitro

P Bowland,E Ingham,J Fisher,L.M Jennings

doi:10.1016/j.jbiomech.2018.06.014

Abstract

In order to pre-clinically evaluate the performance and efficacy of novel osteochondral interventions, physiological and clinically relevant whole joint simulation models, capable of reproducing the complex loading and motions experienced in the natural knee environment are required. The aim of this study was to develop a method for the assessment of tribological performance of osteochondral grafts within an in vitro whole natural joint simulation model.The study assessed the effects of osteochondral allograft implantation (existing surgical intervention for the repair of osteochondral defects) on the wear, deformation and damage of the opposing articular surfaces. Tribological performance of osteochondral grafts was compared to the natural joint (negative control), an injury model (focal cartilage defects) and stainless steel pins (positive controls). A recently developed method using an optical profiler (Alicona Infinite Focus G5, Alicona Imaging GmbH, Austria) was used to quantify and characterise the wear, deformation and damage occurring on the opposing articular surfaces. Allografts inserted flush with the cartilage surface had the lowest levels of wear, deformation and damage following the 2 h test; increased levels of wear, deformation and damage were observed when allografts and stainless steel pins were inserted proud of the articular surface. The method developed will be applied in future studies to assess the tribological performance of novel early stage osteochondral interventions prior to in vivo studies, investigate variation in surgical precision and aid in the development of stratified interventions for the patient population.

Highlights

There is an increasing clinical need for effective early intervention osteochondral therapies that can restore the structure and function of cartilage and bone tissue
The volume extending below the meniscal surface (Fig. 3) was measured for all experimental groups; this value was used as a measure of the level of wear, deformation and damage occurring during simulator testing due to the presence of focal cartilage defects, allografts and stainless
It is important to determine the changes that occur in the tissues of the natural joint in the presence of cartilage defects and osteochondral allografts and how these compare to novel interventions such as regenerative scaffolds and constructs

Summary

Introduction

There is an increasing clinical need for effective early intervention osteochondral therapies that can restore the structure and function of cartilage and bone tissue. Tissue engineered osteochondral scaffolds and constructs have the potential to regenerate cartilage and bone tissues that possess the structural, biological, mechanical and tribological properties of native cartilage and bone (Bowland et al, 2015). The development of such early stage repair interventions in the knee, requires an understanding of how the range of variables in the natural knee environment interact with the design and material properties of the intervention to determine mechanical and tribological performance (Liu et al, 2015). Whole joint experimental simulation models, capable of reproducing the complex physiological loading, motions and interactions in the natural knee, can play a key role in the preclinical testing of early osteochondral interventions in order to determine mechanical and tribological performance prior to in vivo studies

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Conclusion