Histopathological Correlation of Subchondral Bone Changes in Early Knee Osteoarthritis and Their Clinical Implications

Background: Knee osteoarthritis (OA) is one of the leading causes of disability worldwide. Increasing evidence suggests that subchondral bone plays a pivotal role in the initiation and progression of OA, with early changes such as trabecular thickening, sclerosis, and marrow fibrosis contributing significantly to pain and functional impairment. However, limited data are available on histopathological alterations in early OA, particularly in the Indian population. Aim: To evaluate histopathological changes in subchondral bone in patients with early knee osteoarthritis and correlate these findings with clinical outcomes. Methods: This cross-sectional study was conducted over one year at a tertiary care centre in Amravati, Madhya Pradesh. A total of 100 patients with early knee OA (Kellgren–Lawrence Grade I and II) undergoing surgical procedures were included. Subchondral bone samples were collected and examined histologically for trabecular thickening, sclerosis, microfractures, osteoid deposition, marrow fibrosis, and vascular changes. Clinical severity was assessed using VAS for pain, WOMAC score, and Knee Society Score (KSS). Data were analyzed using chi-square test and correlation analysis, with p < 0.05 considered significant. Results: The mean age of patients was 54.6 ± 8.2 years, with females comprising 62% of the study group. The mean VAS, WOMAC, and KSS were 6.8 ± 1.1, 58.4 ± 9.6, and 48.6 ± 7.5, respectively. Histopathological findings included trabecular thickening/sclerosis (64%), microfractures (42%), marrow fibrosis (38%), and osteoid deposition with vascularity (26%). Patients with moderate-to-severe histological changes had significantly higher VAS and WOMAC scores and lower KSS compared to those with mild changes (p < 0.01). Conclusion: Histopathological changes in subchondral bone are evident in the early stages of knee OA and correlate strongly with pain and functional disability. These findings emphasize the role of subchondral bone pathology in early OA and suggest that targeting bone remodeling may offer novel strategies for diagnosis and early intervention.