Discover the most talked about and latest scientific content & concepts.

Concept: Articular cartilage damage


Untreated articular cartilage defects may lead to chronic joint degeneration and functional disability. In the past decade, several cartilage repair techniques have emerged for the treatment of cartilage lesions. Among these techniques, mosaicplasty was introduced by the senior author into the clinical practice in 1992. This article does not intend to give a review or a comparison of currently existing surgical techniques which aim to repair symptomatic focal defects; however, it focuses on the procedures used in the everyday practice in the authors' institute, namely microfracture, mosaicplasty, autologous chondrocyte implantation (ACI), osteochondral allograft transplantation and biodegradable osteochondral scaffolds. It gives a brief summary of these well-described techniques, summarizes the authors' clinical experience and available data on the clinical outcome, and the rehabilitation protocol following different procedures, with a special emphasis on mosaicplasty.

Concepts: Cartilage, Knee, Organ transplant, Knee cartilage replacement therapy, Autologous chondrocyte implantation, Chondrocyte, Articular cartilage damage, Articular cartilage repair


Osteoarthritis (OA) is a debilitating disease that reflects a complex interplay of biochemical, biomechanical, metabolic and genetic factors, which are often triggered by injury, and mediated by inflammation, catabolic cytokines and enzymes. An unmet clinical need is the lack of reliable methods that are able to probe the pathogenesis of early OA when disease-rectifying therapies may be most effective. Non-invasive quantitative magnetic resonance imaging (qMRI) techniques have shown potential for characterizing the structural, biochemical and mechanical changes that occur with cartilage degeneration. In this paper, we review the background in articular cartilage and OA as it pertains to conventional MRI and qMRI techniques. We then discuss how conventional MRI and qMRI techniques are used in clinical and research environments to evaluate biochemical and mechanical changes associated with degeneration. Some qMRI techniques allow for the use of relaxometry values as indirect biomarkers for cartilage components. Direct characterization of mechanical behaviour of cartilage is possible via other specialized qMRI techniques. The combination of these qMRI techniques has the potential to fully characterize the biochemical and biomechanical states that represent the initial changes associated with cartilage degeneration. Additionally, knowledge of in vivo cartilage biochemistry and mechanical behaviour in healthy subjects and across a spectrum of osteoarthritic patients could lead to improvements in the detection, management and treatment of OA.

Concepts: Metabolism, Nuclear magnetic resonance, Cartilage, Osteoarthritis, Magnetic resonance imaging, Biomechanics, Metabolic pathway, Articular cartilage damage


Articular cartilage defects of the knee are commonly encountered during arthroscopic examination and are believed to be a precursor to osteoarthritis. While a variety of surgical treatments exist, the defect size, specifically the cross-sectional area, has historically been used as a critical element in choosing one procedure over another. The purpose of this study was to characterize the variability associated with arthroscopic techniques that are used to determine the cross-sectional area of distal femoral articular cartilage defects.

Concepts: Chondroitin sulfate, Cartilage, Osteoarthritis, Knee, Articular cartilage damage, Critical graph


Articular cartilage repair remains challenging, because most clinical failures are due to the lack of subchondral bone regeneration. We report an innovative approach improving cartilage repair by regenerating a robust subchondral bone, supporting articular cartilage.

Concepts: Bone, Bone marrow, Skeletal system, Regeneration, Cartilage, Articular cartilage damage, Articular cartilage repair


Osteochondral allografting is an option for successful treatment of large articular cartilage defects. Use of osteochondral allografting is limited by graft availability, often because of loss of chondrocyte viability during storage.

Concepts: Skeletal system, Cartilage, Knee, Autologous chondrocyte implantation, Chondrocyte, Articular cartilage damage, Articular cartilage repair


Symptomatic articular cartilage and osteochondral lesions in the knee are an important source of pain and disability, and may lead to osteoarthritis. There are several surgical treatments for the condition, with emerging data evaluating their clinical effectiveness and longer-term clinical outcome. Health care providers have challenged the indications for the use of expensive techniques and have been reluctant to authorize funding or reimbursement.

Concepts: Health care, Medicine, Clinical trial, Chondroitin sulfate, Cartilage, Osteoarthritis, Knee, Articular cartilage damage


To perform a systematic review of cartilage repair in athletes' knees to (1) determine which (if any) of the most commonly implemented surgical techniques help athletes return to competition, (2) identify which patient- or defect-specific characteristics significantly affect return to sport, and (3) evaluate the methodologic quality of available literature.

Concepts: Skeletal system, Cartilage, Osteoarthritis, Knee, Articular cartilage damage, Articular cartilage repair, Microfracture surgery


Knee injuries, including articular cartilage damage, are common in football players and are potentially career threatening. The rate of return to play (RTP) as well as the factors affecting return after arthroscopic chondroplasty of the knee is performed in National Football League (NFL) athletes are not known.

Concepts: Cartilage, Knee, Texas, American football, Articular cartilage damage, Articular cartilage repair, National Football League, Glossary of American football


Enzyme-induced articular cartilage degeneration resembling osteoarthritis was evaluated using a newly defined acoustic parameter, the “averaged magnitude ratio” (AMR), which has been suggested as an indicator of articular cartilage degeneration. In vitro experiments were conducted on porcine cartilage samples digested with trypsin for 2 h (n = 10) and 4 h (n = 13) and healthy control samples (n = 13). AMR was determined with 15- and 25-MHz ultrasound, and the integrated reflection coefficient (IRC) and apparent integrated backscattering coefficient (AIB) were also calculated for comparison. The Young’s modulus of superficial cartilage was measured using atomic force microscopy. Performance of the AMR differs between 15 and 25 MHz, possibly because of frequency-related attenuation and resolution of ultrasound. At the proper settings, AMR exhibited a competence similar to that of IRC and AIB in detecting cartilage degeneration and could also detect differences in deeper positions. Furthermore, AMR has the advantages of being easy to measure and requiring no reference material.

Concepts: Chondroitin sulfate, Measurement, Cartilage, Osteoarthritis, Knee, Acoustics, Young's modulus, Articular cartilage damage


Due to limited self-healing capacity in cartilages, there is a rising demand for an innovative therapy that promotes chondrocyte proliferation while maintaining its biofunctionality for transplantation. Chondrocyte transplantation has received notable attention; however, the tendencies of cell de-differentiation and de-activation of biofunctionality have been major hurdles in its development, delaying this therapy from reaching the clinic. We believe it is due to the non-stimulative environment in the injured cartilage, which is unable to provide sustainable physical and biological supports to the newly grafted chondrocytes. Therefore, we evaluated whether providing an appropriate matrix to the transplanted chondrocytes could manipulate cell fate and recovery outcomes. Here, we proposed the development of electrosprayed nanoparticles composed of cartilage specific proteins, namely collagen type II and hyaluronic acid, for implantation with pre-seeded chondrocytes into articular cartilage defects. The fabricated nanoparticles were pre-cultured with chondrocytes before implantation into injured articular cartilage. The study revealed a significant potential for nanoparticles to support pre-seeded chondrocytes in cartilage repair, serving as a protein delivery system while improving the survival and biofunctionality of transplanted chondrocytes for prolonged period of time.

Concepts: Protein, Bone, Collagen, Cartilage, Autologous chondrocyte implantation, Chondrocyte, Articular cartilage damage, Articular cartilage repair