The influence of microfracturing on fixation and degradation of a hydrogel in a horse model

Abstract

Articular cartilage lesions are a commonly encountered problem of the knee joint in humans. Cartilage has a limited ability to repair these lesions and the produced repair tissue is inferior to the original tissue. To overcome these limitations several surgical and non-surgical methods are developed to treat cartilage defects, including microfracturing and implantation of hydrogels. The current pilot study was performed to evaluate the influence of microfracturing on fixation and degradation of a hydrogel in the early stages after surgery in an equine model.

In the experiment 9 mature horses underwent surgery to create two full thickness cartilage defects with microfractures in one stifle and two full thickness cartilage defects without microfractures in the other stifle. In each stifle one defect was used to implant the hydrogel with fibrin glue to fixate the gel. In the other defect only fibrin glue was implanted to serve as a control. 3 different hydrogels were used in this study (hydrogel 1, hydrogel 2 and hydrogel 3). In three horses hydrogel 1 was implanted, in three horses hydrogel 2 was implanted and in three horses hydrogel 3 was implanted. After euthanasia at 1, 2 and 4 weeks post implantation, the harvested samples of the different defects were histological evaluated for 9 parameters (general presence of inflammatory cells, macrophages, neutrophils, eosinophils, collagen, capsule formation, blood vessel formation,presence of gel/fibrin glue and bone erosion).

The current study did not confirm a difference between microfracturing and no microfracturing on fixation and degradation of a hydrogel. However, this conclusion has to be taken with considerably caution. This study was designed as an pilot study to find major differences within the results and to use the information of this study to direct future full-scale research projects. The scope of this project was to obtain information and to make decisions towards the two techniques. Unfortunately, it was not possible to answer the research question with the gathered data. So additional research is recommended to investigate the influence of microfracturing on fixation and degradation of a hydrogel.