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Osteochondral Biopsy Analysis Demonstrates That BST-CarGel Treatment Improves Structural and Cellular Characteristics of Cartilage Repair Tissue Compared With Microfracture.

ABSTRACT: The efficacy and safety of BST-CarGel, a chitosan-based medical device for cartilage repair, was compared with microfracture alone at 1 year during a multicenter randomized controlled trial (RCT) in the knee. The quality of repair tissue of osteochondral biopsies collected from a subset of patients was compared using blinded histological assessments.The international RCT evaluated repair tissue quantity and quality by 3-dimensional quantitative magnetic resonance imaging as co-primary endpoints at 12 months. At an average of 13 months posttreatment, 21/41 BST-CarGel and 17/39 microfracture patients underwent elective second look arthroscopies as a tertiary endpoint, during which ICRS (International Cartilage Repair Society) macroscopic scoring was carried out, and osteochondral biopsies were collected. Stained histological sections were evaluated by blinded readers using ICRS I and II histological scoring systems. Collagen organization was evaluated using a polarized light microscopy score.BST-CarGel treatment resulted in significantly better ICRS macroscopic scores (P = 0.0002) compared with microfracture alone, indicating better filling, integration, and tissue appearance. Histologically, BST-CarGel resulted in a significant improvement of structural parameters-Surface Architecture (P = 0.007) and Surface/Superficial Assessment (P = 0.042)-as well as cellular parameters-Cell Viability (P = 0.006) and Cell Distribution (P = 0.032). No histological parameters were significantly better for the microfracture group. BST-CarGel treatment also resulted in a more organized repair tissue with collagen stratification more similar to native hyaline cartilage, as measured by polarized light microscopy scoring (P = 0.0003).Multiple and independent analyses in this biopsy substudy demonstrated that BST-CarGel treatment results in improved structural and cellular characteristics of repair tissue at 1 year posttreatment compared with microfracture alone, supporting previously reported results by quantitative magnetic resonance imaging.

SUBMITTER: Methot S

PROVIDER: S-EPMC4749746 | biostudies-literature | 2016 Jan

REPOSITORIES: biostudies-literature

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Project description:ObjectiveThe efficacy and safety of BST-CarGel®, a chitosan scaffold for cartilage repair was compared with microfracture alone at 1 year during a multicenter randomized controlled trial in the knee. This report was undertaken to investigate 5-year structural and clinical outcomes.DesignThe international randomized controlled trial enrolled 80 patients, aged 18 to 55 years, with grade III or IV focal lesions on the femoral condyles. Patients were randomized to receive BST-CarGel® treatment or microfracture alone, and followed standardized 12-week rehabilitation. Co-primary endpoints of repair tissue quantity and quality were evaluated by 3-dimensional MRI quantification of the degree of lesion filling (%) and T2 relaxation times. Secondary endpoints were clinical benefit measured with WOMAC (Western Ontario and McMaster Universities Osteoarthritis Index) questionnaires and safety. General estimating equations were used for longitudinal statistical analysis of repeated measures.ResultsBlinded MRI analysis demonstrated that BST-CarGel®-treated patients showed a significantly greater treatment effect for lesion filling (P = 0.017) over 5 years compared with microfracture alone. A significantly greater treatment effect for BST-CarGel® was also found for repair tissue T2 relaxation times (P = 0.026), which were closer to native cartilage compared to the microfracture group. BST-CarGel® and microfracture groups showed highly significant improvement at 5 years from pretreatment baseline for each WOMAC subscale (P < 0.0001), and there were no differences between the treatment groups. Safety was comparable for both groups.ConclusionsBST-CarGel® was shown to be an effective mid-term cartilage repair treatment. At 5 years, BST-CarGel® treatment resulted in sustained and significantly superior repair tissue quantity and quality over microfracture alone. Clinical benefit following BST-CarGel® and microfracture treatment were highly significant over baseline levels.

Project description:Acetabular cartilage lesions are a common abnormality found in patients undergoing hip arthroscopic surgery and may cause pain and functional limitations. Several strategies have been developed to treat chondral defects, with no overwhelming success. Recently, BST-CarGel has gained interest as a scaffolding material that can be injected into the microfracture site to stabilize the clot and facilitate cartilage repair.To perform a retrospective analysis of prospectively collected data to evaluate the safety profile and short-term clinical and radiographic outcomes of patients treated arthroscopically with BST-CarGel for acetabular chondral defects in conjunction with microfracture.Case series; Level of evidence, 4.A retrospective chart review was performed on all patients who underwent hip arthroscopic surgery by the senior surgeon to identify those who had BST-CarGel applied to their hip from November 2014 to July 2016, and basic demographic information for those patients was obtained. Operative reports and patient charts were reviewed to assess intraoperative and postoperative complications as well as to obtain the details of surgery, including lesion size and treatment method of the labrum (repair vs reconstruction). All patients filled out self-reported questionnaires, including the international Hip Outcome Tool (iHOT), Hip Outcome Score-Activities of Daily Living (HOS-ADL), and Hip Outcome Score-Sports Profile (HOS-SP) at the time of consultation and at 1 year postoperatively, and results were used to assess the clinical outcomes of surgery.Thirty-seven patients (37 hips) with a mean age of 36.19 years at the time of the index procedure were evaluated. There were 30 male patients, and 20 procedures were performed on the right hip. The minimum follow-up was 1 year, with a mean follow-up of 12.72 months. There were no major adverse events of deep vein thrombosis, blood vessel or nerve damage, hemarthrosis, arthralgia, or device-related adverse events. Two patients (5.4%) were readmitted because of pain, probably resulting from an inflammatory reaction to BST-CarGel. At 1 year postoperatively, there were statistically significant improvements in the iHOT (40.4 to 59.1; P < .001), HOS-ADL (60.6 to 71.4; P = .02), and HOS-SP (36.9 to 51.6; P = .01) scores. When the patients were subdivided based on the chondral defect size, the iHOT score improved for all chondral defect sizes, and the HOS-SP score improved in patients with medium (2-4 cm2) and very large (>6 cm2) chondral defects. In addition, the iHOT score improved whether the patients had their labrum repaired or reconstructed (P < .001 and P = .02, respectively).The arthroscopic treatment of chondral acetabular defects with BST-CarGel demonstrates a satisfactory safety profile, with statistically significant improvement in patient-reported clinical outcome scores, even for those with very large chondral defect sizes.

Project description:BackgroundMicrofracture of focal chondral defects often produces fibrocartilage, which inconsistently integrates with the surrounding native tissue and possesses inferior mechanical properties compared with hyaline cartilage. Mechanical loading modulates cartilage during development, but it remains unclear how loads produced in the course of postoperative rehabilitation affect the formation of the new fibrocartilaginous tissue.PurposeTo assess the influence of different mechanical loading regimens, including dynamic compressive stress or rotational shear stress, on an in vitro model of microfracture repair based on fibrin gel scaffolds encapsulating connective tissue progenitor cells.Study designControlled laboratory study.MethodsCylindrical cores were made in bovine hyaline cartilage explants and filled with either (1) cartilage plug returned to original location (positive control), (2) fibrin gel (negative control), or (3) fibrin gel with encapsulated connective tissue progenitor cells (microfracture mimic). Constructs were then subjected to 1 of 3 loading regimens: (1) no loading (ie, unloaded), (2) dynamic compressive loading, or (3) rotational shear loading. On days 0, 7, 14, and 21, the integration strength between the outer chondral ring and the central insert was measured with an electroforce mechanical tester. The central core component, mimicking microfracture neotissue, was also analyzed for gene expression by real-time reverse-transcription polymerase chain reaction, glycosaminoglycan, and double-stranded DNA contents, and tissue morphology was analyzed histologically.ResultsIntegration strengths between the outer chondral ring and central neotissue of the cartilage plug and fibrin + cells groups significantly increased upon exposure to compressive loading compared with day 0 controls (P = .007). Compressive loading upregulated expression of chondrogenesis-associated genes (SRY-related HGMG box-containing gene 9 [SOX9], collagen type II α1 [COL2A1], and increased ratio of COL2A1 to collagen type I α1 [COL1A1], an indicator of more hyaline phenotype) in the neotissue of the fibrin + cells group compared with the unloaded group at day 21 (SOX9, P = .0032; COL2A1, P < .0001; COL2A1:COL1A1, P = .0308). Fibrin + cells constructs exposed to shear loading expressed higher levels of chondrogenic genes compared with the unloaded condition, but the levels were not as high as those for the compressive loading condition. Furthermore, catabolic markers (MMP3 and ADAMTS 5) were significantly upregulated by shear loading (P = .0234 and P < .0001, respectively) at day 21 compared with day 0.ConclusionDynamic compressive loading enhanced neotissue chondrogenesis and maturation in a simulated in vitro model of microfracture, with generation of more hyaline-like cartilage and improved integration with the surrounding tissue.Clinical relevanceControlled loading after microfracture may be beneficial in promoting the formation of more hyaline-like cartilage repair tissue; however, the loading regimens applied in this in vitro model do not yet fully reproduce the complex loading patterns created during clinical rehabilitation. Further optimization of in vitro models of cartilage repair may ultimately inform rehabilitation protocols.

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Osteochondral Biopsy Analysis Demonstrates That BST-CarGel Treatment Improves Structural and Cellular Characteristics of Cartilage Repair Tissue Compared With Microfracture.

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