Preclinical Testing of New Hydrogel Materials for Cartilage Repair: Overcoming Fixation Issues in a Large Animal Model

International Journal of Biomaterials, 2021 · DOI: https://doi.org/10.1155/2021/5583815 · Published: June 19, 2021

Simple Explanation

This study investigates hydrogels for cartilage repair, focusing on fixation challenges in a minipig model. Different fixation methods were tested in chondral and osteochondral defects using fibrin glue, BioGlue®, suturing, and press-fit techniques. The goal was to find a reliable method for construct retention in cartilage defects. The research compared two hydrogels, starPEG and PAGE, analyzing their integration and impact on bone. Fixation in chondral defects proved difficult, leading to the use of superficial osteochondral defects for better construct stability. The study assessed bone lysis and regeneration tissue formation. Ultimately, press-fit fixation in superficial osteochondral defects showed promise for reinforced hydrogels. Future approaches should focus on multilayered constructs mimicking natural cartilage to avoid bone lysis. The study highlights the importance of construct fixation for cartilage repair success.

Study Duration

12 Weeks

Participants

27 skeletally mature miniature pigs

Evidence Level

Not specified

Key Findings

1
Fixation rates were below 50% for all tested methods in chondral defects.
2
A superficial osteochondral defect of 1 mm depth was necessary for long-term fixation of a PCL-reinforced hydrogel construct.
3
Press-fit fixation in superficial osteochondral defects resulted in a reliable fixation rate of 95%.

Research Summary

The study evaluated various fixation methods for hydrogel constructs in minipig cartilage defects, comparing fibrin glue, BioGlue®, suturing, and press-fit techniques. Results showed that fixation in chondral defects was generally insufficient, leading to construct dislocation. Superficial osteochondral defects with press-fit fixation significantly improved construct retention. Two hydrogels (starPEG and PAGE) were compared, with micro-CT and histological analysis revealing bone lysis, particularly in the starPEG group. The research concludes that press-fit fixation in superficial osteochondral defects is a promising method for reinforced hydrogels. Future strategies should focus on multilayered constructs mimicking zonal cartilage to minimize bone lysis.

Practical Implications

Improved Fixation Techniques

Press-fit fixation in osteochondral defects offers a more reliable method for hydrogel construct retention compared to traditional methods like fibrin glue or suturing.

Construct Design

Future cartilage repair strategies should focus on developing multilayered constructs that mimic the zonal structure of native cartilage to improve integration and reduce bone lysis.

Hydrogel Material Selection

Further research is needed to optimize hydrogel materials, such as starPEG, to minimize bone lysis while promoting cell integration and cartilage regeneration.

Study Limitations

1
The relatively short observation period of <3 months may have been insufficient to show full remodeling of the subchondral bone.
2
The study observed bone lysis, the causes of which could not be definitively isolated.
3
The use of nonzonal constructs did not lead to effective cartilage restoration in our study.

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