Susann Junker1, Grit Krumbholz1, Klaus W Frommer1, Stefan Rehart2, Jürgen Steinmeyer3, Markus Rickert4, Georg Schett5, Ulf Müller-Ladner1, Elena Neumann6. 1. Department of Internal Medicine and Rheumatology, Justus-Liebig-University Giessen, Kerckhoff-Klinik Benekestraße 2-8, 61231 Bad Nauheim, Germany. 2. Department of Orthopaedics and Orthopaedic Surgery, Markus Hospital, 60431 Frankfurt am Main, Germany. 3. Department of Orthopedics, Justus-Liebig-University of Giessen, 35390 Giessen, Germany. 4. Department of Orthopedics and Orthopedic Surgery, Justus-Liebig-University of Giessen, 35390 Giessen, Germany. 5. Department of Internal Medicine 3, University of Erlangen-Nuremberg, 91054 Erlangen, Germany. 6. Department of Internal Medicine and Rheumatology, Justus-Liebig-University Giessen, Kerckhoff-Klinik Benekestraße 2-8, 61231 Bad Nauheim, Germany. Electronic address: e.neumann@kerckhoff-klinik.de.
Abstract
OBJECTIVE: Osteoarthritis is not only characterized by cartilage degradation but also involves subchondral bone remodeling and osteophyte formation. Osteophytes are fibrocartilage-capped bony outgrowths originating from the periosteum. The pathophysiology of osteophyte formation is not completely understood. Yet, different research approaches are under way. Therefore, a histological osteophyte classification to achieve comparable results in osteophyte research was established for application to basic science research questions. METHODS: The osteophytes were collected from knee joints of osteoarthritis patients (n=10, 94 osteophytes in total) after joint replacement surgery. Their size and origin in the respective joint were photo-documented. To develop an osteophyte classification, serial tissue sections were evaluated using histological (hematoxylin and eosin, Masson's trichrome, toluidine blue) and immunohistochemical staining (collagen type II). RESULTS: Based on the histological and immunohistochemical evaluation, osteophytes were categorized into four different types depending on the degree of ossification and the percentage of mesenchymal connective tissue. Size and localization of osteophytes were independent from the histological stages. CONCLUSION: This histological classification system of osteoarthritis osteophytes provides a helpful tool for analyzing and monitoring osteophyte development and for characterizing osteophyte types within a single human joint and may therefore contribute to achieve comparable results when analyzing histological findings in osteophytes.
OBJECTIVE:Osteoarthritis is not only characterized by cartilage degradation but also involves subchondral bone remodeling and osteophyte formation. Osteophytes are fibrocartilage-capped bony outgrowths originating from the periosteum. The pathophysiology of osteophyte formation is not completely understood. Yet, different research approaches are under way. Therefore, a histological osteophyte classification to achieve comparable results in osteophyte research was established for application to basic science research questions. METHODS: The osteophytes were collected from knee joints of osteoarthritispatients (n=10, 94 osteophytes in total) after joint replacement surgery. Their size and origin in the respective joint were photo-documented. To develop an osteophyte classification, serial tissue sections were evaluated using histological (hematoxylin and eosin, Masson's trichrome, toluidine blue) and immunohistochemical staining (collagen type II). RESULTS: Based on the histological and immunohistochemical evaluation, osteophytes were categorized into four different types depending on the degree of ossification and the percentage of mesenchymal connective tissue. Size and localization of osteophytes were independent from the histological stages. CONCLUSION: This histological classification system of osteoarthritis osteophytes provides a helpful tool for analyzing and monitoring osteophyte development and for characterizing osteophyte types within a single human joint and may therefore contribute to achieve comparable results when analyzing histological findings in osteophytes.