[Correlation analysis of degenerative cartilage injury and bone marrow edema with osteoporosis in knee osteoarthritis based on quantitative CT].

Abstract

Objective: To investigate the correlation between cartilage injury, bone marrow edema and osteoporosis in patients with knee osteoarthritis (KOA) using quantitative computed tomography (QCT).

Methods: A retrospective analysis was performed on chest CT and clinical data of 86 patients with LOA between January 2020 and December 2022. The patients included 23 males and 63 females, aged from 42 to 74 years with a mean age of(57.72±7.97) years. Bone mineral density (BMD) of T₁₂ and L₁ vertebrae was measured using QCT. According to Outerbridge classification, patients were graded into grade 2, grade 3, and grade 4 cartilage injury. Bone marrow edema was evaluated on knee MRI. The differences in BMD among different grades of cartilage injury were compared, and correlation analysis and partial correlation analysis were performed. The incidence of osteoporosis was compared between groups with and without bone marrow edema, and the correlation between BMD values and bone marrow edema was analyzed.

Results: There were statistically significant differences in age, T₁₂ and L₁ BMD, and the incidence of osteoporosis among different cartilage injury grades (P<0.001). Statistically significant differences were observed in BMD between grade 2 and grade 3, and between grade 2 and grade 4(P<0.001), while no significant difference was found between grade 3 and grade 4(P>0.05). The severity of cartilage injury was inversely correlated with T₁₂, T₁₂^*, L₁ BMD, and M-BMD, with r values of -0.377, -0.382, -0.437, and -0.407, respectively(all P< 0.001). After adjusting for confounding factors including age, BMI, and gender using partial correlation analysis, the severity of cartilage injury still showed a certain inverse correlation with M-BMD(r=-0.210, P=0.033). The incidence of osteoporosis was higher in patients with bone marrow edema than in those without bone marrow edema. Bone marrow edema was inversely correlated with T₁₂, T₁₂^* BMD, and M-BMD, with r values of -0.242, -0.246, -0.208, and -0.227, respectively (all P<0.05).

Conclusion: In patients with KOA, T₁₂ and L₁ BMD gradually decreased and the incidence of osteoporosis gradually increased with the worsening of cartilage injury. T₁₂ and L₁ BMD were lower in KOA patients with bone marrow edema than in those without bone marrow edema.