Objective To study the expression difference of Sclerostin in the medial and lateral subchondral bone of the varus osteoarthritic knee plateau. Methods The tibial plateau was obtained from 20 patients with varus knee osteoarthritis receiving total knee arthroplasty from March to October 2015. There were 8 males and 12 females with an average age of 67.8 years (range, 61-78 years). The mean course of osteoarthritis was 3.2 years (range, 2-5 years). Before operation, the varus angle was 12.0-25.5° (mean, 17.6°) on the X-ray film. Five cases were rated as grade III and 15 cases as grade IV according to Kellgren-Lawrance classification. Micro-CT scan was performed on the medial and lateral subchondral bone to compare the changes of bone structure; bone volume/total volume (BV/TV), trabecular number (Tb.N), trabecular thickness (Tb.Th), structure model index (SMI), and the trabecular separation (Tb.Sp) were measured. Immunohistochemistry and real-time fluorescent quantitative PCR were used to test the expressions of Sclerostin protein and sost gene. Results Micro-CT showed that BV/TV, Tb.N, and Tb.Th significantly increased in the medial subchondral bone when compared with the lateral part (P<0.05), but SMI and Tb.Sp significantly reduced (P<0.05). Real-time fluorescent quantitative PCR detection showed that sost gene expression level in the medial subchondral bone (1.000) was significantly lower than that in the lateral part (4.157±2.790) (t=2.371,P=0.040). The percentage of Sclerostin positive cells in the lateral subchondral bone (52.00%±0.19%) was significantly higher than that in the medial subchondral bone (7.20%±0.04%) (t=5.094,P=0.005). Conclusion Sclerostin plays an important role in the subchondral bone remodeling of the varus osteoarthritic knee. And the low expression of Sclerostin may be an important factor to promote bone remodeling and aggravate knee deformity.
Objective To investigate the correlation of elderly knee osteoarthritis with bone marrow edema and osteoprotegerin, DKK-1 (dickkopf-1), sclerostin. Methods A total of 100 elderly patients with knee osteoarthritis in Sichuan Province Orthopedic Hospital from September 2017 to December 2018 were selected and divided into bone marrow edema group (50 cases) and non-bone marrow edema group (50 cases). The patients’ basic data, Western Ontario and McMaster University Osteoarthritis Index (WOMAC) scores and Visual Analogue Scale scores were collected. The patients’ serum osteoprotegerin, DKK-1, sclerostin, C-reactive protein, and erythrocyte sedimentation rate were tested, and the differences between the two groups were compared. The correlation of the detection indicators and bone marrow edema and its clinical indicators was explored. Results There was no significant difference in age, gender, course of disease, C-reactive protein and erythrocyte sedimentation rate between the two groups (P>0.05). WOMAC scores (76.1±5.4 vs. 67.5±6.6), Visual Analogue Scale scores (8.4±1.1 vs. 5.5±0.9), proportion of synovitis (84.0% vs. 52.0%), osteoprotegerin [(1.3±1.1) vs. (0.6±0.5) μg/L], DKK-1 [(18.4±16.9) vs. (6.9±6.0) μg/L] and sclerostin [(147.3±119.4) vs. (99.7±70.7) pg/mL] in the bone marrow edema group were higher than those in the non-bone marrow edema group (P<0.05). There was no statistically significant correlation of the bone marrow edema volume score and degree score and serum osteoprotegerin of patients in the bone marrow edema group (P>0.05). The bone marrow edema volume score and degree score of patients in the bone marrow edema group were positively correlated with serum DKK-1 (volume score rs=0.464, P=0.001; degree score rs=0.379, P=0.007) and sclerostin (volume score rs=0.316, P=0.025; degree score rs=0.461, P=0.003). Conclusion In elderly patients with knee osteoarthritis and bone marrow edema, the local bone metabolism indicators of osteoprotegerin, DKK-1 and sclerostin are up-regulated, especially DKK-1 and sclerostin are related to the severity of bone marrow edema.