Association between knee alignment, articular cartilage degradation, and subchondral trabecular bone remodeling in patients with knee osteoarthritis

Abstract

Purpose: Knee osteoarthritis (OA) is a common disabling disease involving the entire joint tissue, its onset and progression are affected by many factors. However, the current number of studies investigating the relationship between subchondral trabecular bone (STB), knee alignment and articular cartilage degradation is limited. We aimed to investigate the variation in tibial plateau STB remodeling in knee OA patients and their association with knee alignment (hip-knee-ankle, HKA, angle) and articular cartilage degradation. Methods: Forty-three knee OA patients scheduled for total knee arthroplasty (TKA) underwent preoperative radiography to measure the HKA angle and Kellgren-Lawrence grade. Tibial plate specimens collected from TKA was used for histology, histomorphometric measurements, and immunohistochemistry to assess subchondral bone remodeling and cartilage degradation ((OARSI score). Correlations between HKA angle, OARSI score, and STB remodeling parameters were evaluated. Differences in STB remodeling parameters between varus and valgus groups based on the HKA angle were examined. Results: The HKA angle was significantly correlated with all STB remodeling parameters (p<0.01). The HKA angle was more correlated with the medial-to-lateral ratios of the remodeling parameters than with the medial or lateral tibia plateaus. The HKA angle and all STB remodeling parameters are significantly correlated with OARSI score (p<0.01). Conclusions: The variation of tibial plateau STB structural and remodeling indices is associated with the HKA angle and cartilage degradation. Knee malalignment causes the abnormal STB remodeling and microstructural sclerosis potentially affecting transmission of loading stress from the cartilage to the subchondral bone, and then resulting in accelerated OA progression in patients with knee OA. The results indicate that correction of knee malalignment could affect STB remodeling and then intervene the occurrence and development of OA. In addition, the improvement in subchondral bone with bone-metabolism agents may help mitigate OA progression.