Microfractures and hydrogel scaffolds in the treatment of osteochondral knee defects: A clinical and histological evaluation

Abstract

Background: Osteochondral knee defects (OCD) are often symptomatic, causing pain and functional impairment even in young and active patients. Regenerative surgical options, aiming to stimulate natural cartilage healing, have been recently used as a first line treatment. In this study, a new hydrogel is investigated in its capacity to regenerate the ultra-structural quality of hyaline cartilage when combined with a classical microfracture technique. Material and methods: Forty-six patients, affected by grade III and IV knee chondropathies, were consecutively treated between 2013 and 2015 with microfractures followed by application of a modern hydrogel in the lesion site. All patients underwent clinical evaluation (WOMAC) pre-operatively, at 6,12 and at 24 months postoperatively: the results were compared with a subsequent, consecutive, matched, control group of 23 patients treated with microfractures alone. In a parallel and separate in-vitro histological study, adipose derived mesenchymal stem cells (ADMSCs) were encapsulated in the hydrogel scaffold, induced to differentiation into chondrocytes, and observed for a 3 weeks period. Results: The initial WOMAC score of 58.6 AE 11.0 in the study group was reduced by 88% at 6 months (7.1 AE 9.2) and 95% at 24 months (2.9 AE 5.9). The "in-vitro" study revealed a histological characterization typical of hyaline cartilage in study group. Separate biopsies performed at 12 months post-op in the study group also revealed type 2 collagen and hyaline-like cartilage in the regenerated tissue. Conclusion: Our study demonstrated high patient satisfaction rates after microfractures combined with a modern hydrogel scaffold; histologic evaluation supported the hypothesis of creating an enhanced chondrogenic environment. Microfracture "augmentation" using modern acellular biomaterials, like hydrogels, might improve the clinical outcomes of this classical bone marrow stimulating procedure.

Microfracture and Hydrogel Scaffolds for the Treatment of Osteochondral Injuries of the Knee: Clinical Results at 4 Years Follow-Up

“…The thin superficial zone forming the gliding surface in contact with the synovial fluid was characterized by small, flattened chondrocytes with poor matrix; deeper layers showed larger and rounder chondrocytes rounded by abundant extracellular matrix. Immunohistochemistry assay for human type II collagen confirmed the restoration of the hyaline cartilage, which was observed in the extracellular matrix of hyaline cartilage, whereas collagen type II was not detected in sub-chondral bone [8].…”

“…The preliminary result of the treatment of osteochodral knee defects with microfractures and injectable Polyglucosamine/Glucosamine Carbonate (PG/GC) have been recently reported. This is a hydrogel scaffold which is applied onto cartilage defect, and rapidly solidifies at body temperature providing support for Bone-Marrow (BM)-MSCs following microfracture [8]. In this study, we investigated a methodology to create a simple and reproducible cartilage repair procedure, using biomaterials to guide endogenous healing and new cartilage formation.…”

Microfracture Technique for Chronic Unstable Osteochondral Defect of Knee: Case Report

“…They reported improvement in WOMAC score of 58.6 ± 11.0 in the study group to 7.1 ± 9.2 at six months and 2.9 ± 5.9 at 24 months. They concluded that microfracture “augmentation” might improve the clinical outcomes in osteochondral defects [ 13 ].…”

Extracellular matrix grafts: From preparation to application (Review)

“…In parallel, previous findings have shown that Avance ® Nerve Graft (AxoGen Inc.) has been used to repair human sciatic nerve defect and achieve positive axon regrowth and motor functional recovery ( 99 ). Besides, a biocompatible hydrogel scaffold (Geistlich Pharma AG) isolated from the decellularized and demineralized bone has confirmed promising outcomes for repairing early and mid-term clinical osteochondral knee defects ( 100 ). The common features of these ECM-P for extensive applications of regenerative medicine can be categorized as follows: i) Preserving meshwork of native architecture and biologically active molecules; ii) excellent mechanical and structural profiles; iii) biodegradation and temperature-sensitive property; and iv) easily integrating with the native tissue by filling the irregular defects.…”