内側型変形性膝関節症における骨形態と骨粗鬆症との関係

抄録

Objective: To assess the relationship between bone morphology of medial compartment knee osteoarthritis (OA) and osteoporosis.

Methods: We investigated 43 patients with OA of the knee (12 men and 31 females) who underwent total knee arthroplasty between January 2016 and June 2016, inclusive. The mean age was 74.3 years. Bone mineral density (BMD) was measured in the proximal femur using dual energy X-ray absorptiometry. Osteoporosis was defined as a BMD of less than 70% of peak bone mass according to the criteria of the Japanese Society for Bone and Mineral Research. Knee radiographs were obtained with the patient standing on one leg. The femorotibial angle (FTA), femoral condylar-femoral shaft angle (FC-FS), tibial plateau-tibial shaft angle (TP-TS) were used as parameters of deformity. OA was classified into two types, depression-type and slope-type by the bone morphology of the medial tibial plateau. The depression-type was defined as the bottom of the articular surface being at the same or lower level than the medial tibial condyle. The slope-type was defined as the bottom of the articular surface being higher than the level of the medial tibial condyle.

Results: In patients with OA of the knee, there was no significant association between the presence of osteoporosis and radiographic parameters measured in this study. However, the frequency of the depression-type of OA was significantly higher in the patient group with osteoporosis, compared with the group without osteoporosis.

Conclusion: The presence of osteoporosis had no significant effect on coronal alignment of the knee in patients with OA. However, the frequency of the depression of the medial tibial plateau was shown to be significantly higher in patients with osteoporosis.