Is there a correlation between distal femur anatomy and bone mineral density measurements?

Purpose

This study aimed to investigate the relationship between the Citak classification of distal femoral morphology and bone mineral density (BMD) measured by dual-energy X-ray absorptiometry (DEXA). We hypothesized that Type C morphology, characterized by a wider femoral canal, would correlate with lower BMD and a higher prevalence of osteoporosis.

Materials and methods

This retrospective study included 150 patients (51 males, 99 females) who underwent DEXA for BMD evaluation and had knee radiographs available for Citak classification. Radiographs were analyzed to classify femoral morphology into Types A, B, and C based on the Citak index. BMD values were categorized as normal, osteopenic, or osteoporotic. Statistical analyses included correlation and group comparisons, with p-values < 0.05 considered significant.

Results

The study revealed a significant association between the Citak classification and BMD (p = 0.013). Type C morphology was strongly linked to osteoporosis, with a higher prevalence of low BMD compared to Types A and B. A weak but significant negative correlation was observed between the Citak index and BMD T-scores in both males (r = − 0.345, p = 0.013) and females (r = − 0.208, p = 0.039). Males exhibited a significantly higher Citak index and Type C morphology prevalence than females (p = 0.001).

Conclusions

This study is the first to establish a direct correlation between the Citak classification and BMD, demonstrating that Type C morphology serves as a marker for poor bone quality. Integrating the Citak classification with preoperative evaluations can help identify high-risk patients, optimize surgical planning, and improve outcomes in total knee arthroplasty.

Level of evidence

Level IV, retrospective study.