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Biological aspects of early osteoarthritis



Early OA primarily affects articular cartilage and involves the entire joint, including the subchondral bone, synovial membrane, menisci and periarticular structures. The aim of this review is to highlight the molecular basis and histopathological features of early OA.


Selective review of literature.


Risk factors for developing early OA include, but are not limited to, a genetic predisposition, mechanical factors such as axial malalignment, and aging. In early OA, the articular cartilage surface is progressively becoming discontinuous, showing fibrillation and vertical fissures that extend not deeper than into the mid-zone of the articular cartilage, reflective of OARSI grades 1.0–3.0. Early changes in the subchondral bone comprise a progressive increase in subchondral plate and subarticular spongiosa thickness. Early OA affects not only the articular cartilage and the subchondral bone but also other structures of the joint, such as the menisci, the synovial membrane, the joint capsule, ligaments, muscles and the infrapatellar fat pad. Genetic markers or marker combinations may become useful in the future to identify early OA and patients at risk.


The high socioeconomic impact of OA suggests that a better insight into the mechanisms of early OA may be a key to develop more targeted reconstructive therapies at this first stage of the disease.

Level of evidence

Systematic review, Level II.

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Henning Madry received funding for OA research from the German Osteoarthritis Foundation (Deutsche Arthrose-Hilfe). Frank Luyten is supported and received some funding for OA research from the seventh framework program TREAT-OA network (www.treatoa.eu). Andrea Facchini received funding from the Regione Emilia Romagna, Italy (PRRU 2007-2009 “Regenerative medicine in osteo-articular diseases”), Fondazione Monte dei Paschi di Siena, Fondazione CARISBO, Italy, FIRB and MIUR, Italy.

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Madry, H., Luyten, F.P. & Facchini, A. Biological aspects of early osteoarthritis. Knee Surg Sports Traumatol Arthrosc 20, 407–422 (2012). https://doi.org/10.1007/s00167-011-1705-8

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  • Articular chondrocytes
  • Articular cartilage
  • Early OA