Low bone mineral density is not a predictive factor for subchondral insufficiency fracture of the knee, based on the analysis of QCT studies

Purpose The association between subchondral insufficiency fracture of knee (SIFK) and potential lower bone mineral density (BMD) were not clear and multifactorial. We tried to investigate their relevance by using the phantom-less quantitative computed tomography (QCT). Methods We collected bone mineral density (BMD) measurements from 32 cases diagnosed with SIFK and 28 control cases with osteoarthritis of the knee(KOA). All SIFK cases were gathered within two months of symptom onset and met the diagnostic criteria for magnetic resonance imaging. BMD measurements were conducted at the femoral neck and knee compartments. The medial-to-lateral (M-L) BMD ratios for the femoral and tibial medial compartments were compared between the two groups. Results The mean BMD values for the femoral neck and medial femoral regions showed no statistically significant difference between the SIFK cases and the KOA group. However, the mean tibial medial-to-lateral (M-L) ratios were statistically higher in the KOA group compared to those in the SIFK group, while the femoral M-L ratios remained statistically consistent between the two groups. The mean BMD in the osteonecrotic area was measured at 63.9 mg/cm³, with all instances located within the femoral condyle. Conclusion Our findings do not support the hypothesis that SIFK are based on low bone mineral density, which was regard as a predictive factor in previous studies.