Abstract
Purpose: Osteoarthritis (OA) is a complex disease process affecting both articular cartilage and underlying bone. An emphasis has been placed on understanding changes in articular cartilage that occur with disease progression, but comparatively little work has been done to understand changes in subchondral bone. The purpose of this study was to evaluate the architectural changes that occur in underlying osteoarthritic bone and to determine their relation to the stages of arthroscopic disease progression.
Methods: Three cadaver knees were evaluated and graded arthroscopically using the Marshall grading system. Representative bone plugs were then extracted from each compartment. Twenty-eight plugs were extracted and imaged using microcomputed tomography (microCT) scanner developed at the Robart’s Research Institute. Volumetric data for each plug biopsy was obtained in 20 minutes of scan time at an isotropic resolution of 68 μm voxels. The data acquired was analyzed using the GE Health Care Scan Control software and reconstruction utility. Subchondral bone thickness bone mineral density (BMD), trabecular thickness (TT), trabecular separation (TS), and structure model index (SMI) were collected and compared in the medial, lateral and patellofemoral compartments of the knees.
Results: No statistical difference was found in any of the parameters when compared with advancing arthroscopic disease progression. When the data was pooled into normal and osteoarthritic specimens, BMD was found to be significantly decreased (p < 0.05) in osteoarthritic bone. A decrease in BVF and an increase in SMI approached significance in osteoarthritic bone.
Conclusions: Further investigation is required for a complete understanding of the architectural changes that occur in subchondral bone with disease progression. A better understanding of OA would have clinical implications in primary and secondary disease prevention. Funding: Other Education Grant
Correspondence should be addressed to Cynthia Vezina, Communications Manager, COA, 4150-360 Ste. Catherine St. West, Westmount, QC H3Z 2Y5, Canada
