RESUMEN
OBJECTIVE: To investigate the occurrence of meniscal calcifications in individuals with and without knee osteoarthritis (OA). Additionally, we aim to identify the specific types of calcifications: basic calcium phosphate (BCP) and calcium pyrophosphate dihydrate (CPP). METHOD: We analyzed 82 meniscal posterior horn samples (medial and lateral) collected from 41 human subjects. Among them, 20 individuals underwent total knee replacement due to medial compartment OA, while 21 deceased donors had no known knee OA. The assessment of meniscal calcifications and Pauli's histopathological scoring was conducted using histological sections. Furthermore, adjacent sections underwent measurement using Raman spectroscopy to characterize BCP and CPP calcifications based on their distinct spectral fingerprints. RESULTS: All OA individuals exhibited calcifications in at least one meniscus, compared to 9.5% (95%CI 1%, 30%) of donors. Among 35 OA menisci with calcifications, 28(80%) had BCP, 5(14%) had CPP and 2(6%) had both types. In 4 donor menisci, 3(75%) had CPP while 1(25%) had both types. We estimated the association between Pauli score and presence of BCP in OA individuals, yielding an odds ratio of 2.1 (95%CI 0.8, 5.3) per 1 Pauli score. The association between Pauli score and presence of CPP (in whole study sample) seemed weaker, with odds ratio of 1.3 (95%CI 1.1, 1.7). CONCLUSION: The presence of BCP was predominant in menisci of OA individuals, whereas CPP exhibited similar prevalence in individuals with and without OA. The formation of BCP crystals in menisci may represent an important and specific characteristic of OA disease process that warrants further attention.
RESUMEN
Meniscal lesions in vascularized regions are known to regenerate while lack of vascular supply leads to poor healing. Here, we developed and validated a novel methodology for three-dimensional structural analysis of meniscal vascular structures with high-resolution microcomputed tomography (µCT). We collected porcine medial menisci from 10 neonatal (not-developed meniscus, n-) and 10 adults (fully developed meniscus, a-). The menisci were cut into anatomical regions (anterior horn (n-AH and a-AH), central body (n-CB and a-CB), and posterior horn (n-PH and a-PH). Specimens were cut in half, fixed, and one specimen underwent critical point drying and µCT imaging, while other specimen underwent immunohistochemistry and vascularity biomarker CD31 staining for validation of µCT. Parameters describing vascular structures were calculated from µCT. The vascular network in neonatal spread throughout meniscus, while in adult was limited to a few vessels in outer region, mostly on femoral side. n-AH, n-CB, and n-PH had 20, 17, and 11 times greater vascular volume fraction than adult, respectively. Moreover, thickness of blood vessels, in three regions, was six times higher in adults than in neonatal. a-PH appeared to have higher vascular fraction, longer and thicker blood vessels than both a-AH and a-CB. Overall, neonatal regions had a higher number of blood vessels, more branching, and higher tortuosity compared to adult regions. For the first time, critical point drying-based µCT imaging allowed detailed three-dimensional visualization and quantitative analysis of vascularized meniscal structures. We showed more vascularity in neonatal menisci, while adult menisci had fewer and thicker vascularity especially limited to the femoral surface.