Study of Relationship between Bone Mineral Density in Ipsilateral Proximal Femur and Severity of Osteoarthritis of Knee

Introduction: Osteoarthritis (OA) of the knee is the most common rheumatic disease that is characterized by degradation of articular cartilage, subchondral bone alteration, meniscal degeneration, synovial inflammatory response, and overgrowth of bone and cartilage. In severe OA, the reduced mobility caused by pain can increase bone loss and reduction of bone mineral density leading to osteoporosis.

Objective: To examine the possible relationship between severity of osteoarthritis (OA) and bone mineral density (BMD) by evaluating the bone mineral density in ipsilateral proximal femur and radiographic grading of knee OA in the Indian population.

Methods: In this cross-sectional observational study, 100 subjects diagnosed with OA knee using ACR criteria were enrolled. Severity of OA knee was assessed using Kellgren-Lawrence scale (1 to 4) on weight-bearing radiographs. The BMD, T-score, and Z-score of the ipsilateral proximal femur was measured by dual-energy X-ray absorptiometry. Pearson's correlation coefficient was used to test the association of severity of OA knee with BMD.

Results: Among 100 subjects, there were 51 females and 49 males with mean age 59.94 ± 6.67. Maximum patients were with K-L grade 2 (42%) followed by grade 3 (30%) and grade 4 (22%). There was statistically significant (p < 0.0001) association between BMD and severity of OA knee. BMD decreased as the K-L grade of OA knee increased from 1 to 4. Similar statistically significant association was observed in T-score and Z-score.

Conclusion: The study concluded that BMD of ipsilateral proximal femur decreases with severity of OA knee. These data support the fact that the two conditions may be related to each other and primary care physicians must look for these two conditions in coexistence. Primary prevention of either of the two conditions should be advised, if the other condition coexists in the same patient.