G. Zanotto (Fort Collins, US)
Colorado State UniversityPresenter Of 1 Presentation
23.3.9 - Microfracture Augmentation with Enzymatic Pretreatment And Growth Factor Functionalized Self-Assembling Peptide Hydrogel Scaffold
Abstract
Purpose
To evaluate the use of trypsin enzymatic pretreatment of the surrounding cartilage combined with a self-assembling KLD hydrogel scaffold functionalized with growth factors for microfracture augmentation in an equine model.
Methods and Materials
Bilateral, 15 mm diameter cartilage defects were created on the medial trochlear ridge of the femoropatelar joints in eight adult horses (A, B, C). One defect was randomly assigned to receive microfracture plus treatment, while the other received microfracture only. Treatment consists of enzymatic exposure of the surrounding cartilage to trypsin for 2 minutes, followed by inactivation with fetal bovine serum (D). Standard subchondral bone microfracture was performed (E) and the defect was filled with self-assembling KLD hydrogel pre-mixed with growth factors (platelet-derived growth factor BB and heparin-binding insulin-like growth factor 1)(F). After surgery, all horses were submitted to standardized controlled exercises on a high-speed treadmill. Clinical evaluation and radiographic exams were conducted at multiple time points during the study period. After 12 months, all animals were euthanized and MRI, arthroscopy, gross pathologic evaluation of the joint, histology, immunohistochemistry and biomechanical analysis were performed. Generalized linear mixed models with horse as random effect were utilized to assess outcome parameters. When p-value<0.05, pairwise comparisons were made using least square means.
Results
Treatment resulted in improved functional outcome parameters (lameness and flexion test), even though mildly increased joint effusion and subchondral bone sclerosis was noticed on imaging. Microscopically, treatment resulted in overall improved histology scores and proteoglycan content in the proximal aspect of the reparative tissue, which is subjected to higher load. Further, dynamic compressive force and shear stiffness were increased in the cartilage adjacent to the treated defects.
Conclusion
Trypsin enzymatic pretreatment combined with a functionalized self-assembling KLD hydrogel resulted in improved cartilage healing and better functional outcomes compared to microfracture alone.