High-Density Mineralized Protrusions and Central Osteophytes: Associated Osteochondral Junction Abnormalities in Osteoarthritis.

Alecio F Lombardi,Saeed Jerban,Eric Y Chang,Hyungseok Jang,Jonathan H Wong,Qingbo Tang,Judith L Williams,Jiang Du,Yajun Ma

doi:10.3390/diagnostics10121051

Alecio F Lombardi, Saeed Jerban + Show 7 more

Open Access

https://doi.org/10.3390/diagnostics10121051

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Abstract

The aim of this study was to determine the association between high-density mineralized protrusions (HDMPs) and central osteophytes (COs), and describe the varying appearance of these lesions using advanced clinical imaging and a novel histological protocol. Seventeen consecutive patients with clinically advanced knee osteoarthritis undergoing knee arthroplasty were included. Surgical tissues containing the osteochondral region were investigated using computed tomography (CT); a subset was evaluated using confocal microscopy with fluorescence. Tissues from seven subjects (41.2%) contained HDMPs, and tissues from seven subjects (41.2%) contained COs. A significant association between HDMPs and COs was present (p = 0.003), with 6 subjects (35.2%) demonstrating both lesions. In total, 30 HDMPs were found, most commonly at the posterior medial femoral condyle (13/30, 43%), and 19 COs were found, most commonly at the trochlea (5/19, 26.3%). The HDMPs had high vascularity at their bases in cartilaginous areas (14/20, 70%), while the surrounding areas had elevated levels of long vascular channels penetrating beyond the zone of calcified cartilage (p = 0.012) compared to HDMP-free areas. Both COs and HDMPs had noticeable bone-resorbing osteoclasts amassing at the osteochondral junction and in vascular channels entering cartilage. In conclusion, HDMPs and COs are associated lesions in patients with advanced knee osteoarthritis, sharing similar histologic features, including increased vascularization and metabolic bone activity at the osteochondral junction. Future studies are needed to determine the relationship of these lesions with osteoarthritis progression and symptomatology.

Highlights

Osteoarthritis (OA) is the most common form of arthritis and is a leading cause of disability worldwide [1]
OA has been considered a primary disorder of articular cartilage, but it is well-known that OA is, a multi-faceted disease with various etiologies
We found that high-density mineralized protrusions (HDMPs) and central osteophytes (COs) are associated lesions and concurrently present in43. 5D%iscoufsssuiobnjects with advanced knee osteoarthritis

Summary

Introduction

Osteoarthritis (OA) is the most common form of arthritis and is a leading cause of disability worldwide [1]. Abnormalities at the OCJ include loss of integrity and increasing degrees of plasticity [9]. Plasticity is a more gradual, cellular process where upregulation of growth factors results in channels formed by osteoclasts and chondroclasts leading to potential neurovascular invasion [11]. These abnormalities may not be mutually exclusive processes since micro-cracks associated with integrity loss may trigger cellular processes [12], and plasticity in the OCJ may be associated with focal cartilage degeneration [13,14,15]

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