To study the characteristics of bone density and bone turnover markers in different parts of adult patients with non-traumatic osteonecrosis of the femoral head(ONFH).

A total of 150 patients with non-traumatic ONFH who were admitted to Department of Third Orthopaedics, First Affiliated Hospital of Guangzhou University of Chinese Medicine from September 2017 to March 2019 were diagnosed as non-traumatic ONFH (necrosis group ). There were 92 males and 58 females, aged (40.9±9.5) years old. Among them, 43 were alcoholic ONFH, 23 were idiopathic ONFH and 84 were hormonal ONFH. Association Research Circulation Osseous (ARCO) stage Ⅱ 84 cases, ARCO Ⅲ period in 66 cases. During the same period, a total of 101 healthy people (control group) underwent bone mineral density examination in First Affiliated Hospital of Guangzhou University of Chinese Medicine including 61 males and 40 females, aged (41.9±10.7) years old.The bone mineral density values of lumbar spine (L1-L4), femoral neck and hip joint (greater trochanter, intertrochanter line and lesser trochanter) of the two groups were measured by dual-energy X-ray bone density meter. Blood detection of two groups with serum collagen type Ⅰ amino terminal extension of the peptide (P1NP), collagen type Ⅰ degradation products (beta CTx) and alkaline phosphatase (ALP) and so on the levels of bone turnover markers. Independent sample t test and single factor analysis of variance were used for data statistics.

(1) The femoral neck bone mineral density [(0.97± 0.15) g/cm²] in the necrosis group was higher than that in the control group [(0.91± 0.14) g/cm²], with statistically significant differences (t=3.148, P=0.002). The hip joint [(0.94± 0.12) g/cm²] and lumbar spine bone density[(1.11± 0.14) g/cm²] in the necrosis group were compared with the hip joint[(0.96± 0.14) g/cm²]and lumbar spine bone density [(1.12± 0.15) g/cm²]in the control group. The differences were not statistically significant (t=-0.548, -1.461; P=0.584, 0.145). The serum levels of P1NP[(65.44±28.64) ng/mL] and ALP [(68.89±19.15) U/L] in the necrotic group were both higher than those in the control group[(56.82±23.49) ng/mL], [ (59.64±23.72) U/L], while the serum levels of β-CTx [ (0.54±0.27) ng/mL] were lower than those in the control group[ (0.62±0.29) ng/mL], the differences were statistically significant (t=2.608, 3.404, -2.095; P=0.010, 0.001, 0.037). (2) In the necrosis group, bone mineral density of femoral neck of alcoholic ONFH [(1.02± 0.15) g/cm²] was higher than that of hormone ONFH[(0.96± 0.14) g/cm²] and idiopathic ONFH[ (0.93± 0.14 g/cm²], and the difference was statistically significant (F=3.954, P=0.021). There were no statistically significant differences in bone mineral density, serum P1NP, and serum -ctx levels between the lumbar spine and the hip joint among the three types of necrosis (P> 0.05), and serum ALP[(76.09±18.36 ) U/L] of alcoholic ONFH was higher than that of hormone ONFH [(65.49±18.82) U/L], the difference was statistically significant (P< 0.05). (3) The necrosis of ARCO Ⅱ period in patients with femoral neck bone mineral density[(0.95±0.15) g/cm²)]below the ARCO Ⅲ period[(1.00±0.14) g/cm²], the difference was statistically significant (t=2.346, P=0.020), the lumbar spine and hip bone mineral density values were no statistical difference (P> 0.05); ARCO Ⅱperiod patients serum level of P1NP [(70.24±32.11) ng/mL] and β-CTx [ (0.60± 0.27) ng/mL] were higher than ARCO Ⅲ period [ (59.33±22.26) ng/mL], [ (0.47 ±0.25) ng/mL] patients, and the difference was statistically significant (t= 2.454, 2.985; P= 0.015, 0.003), there was no statistical difference in serum ALP level between the two stage patients (P> 0.05).

In adult patients with non-traumatic ONFH, bone mineral density in the area surrounding necrosis may increase, and with the progression of the disease and the repair of the necrotic site, bone mineral density in the area surrounding necrosis tends to increase. Among the different types of necrosis, the increase of bone density in the area around alcoholic ONFH is the most obvious.