To observe the surface micro-topography of multiple femoral heads under different grouping and to extract, analyze and summarize the topographic parameters.

During 2016 to 2017, 43 cases of femoral head specimens for patients with artificial femoral head replacement or total hip arthroplasty in the Department of Orthopedics, First Affiliated Hospital of Kunming Medical University were collected. The inclusion criteria: the patients who have completed bone density examination before surgery, no abnormalities in blood tests and signed informed consent. Exclusion criteria: the patients with old fractures, or with a history of bone metabolic diseases, tumors, local inflammation, tuberculosis, and hereditary diseases. The specimens divided into three groups according to age, sex and bone density: (1)the middle-aged group (42-59 years old, n=7)and the elderly group (60-83 years old, n=36); (2)the male group (n=21) and the female group (n=22); (3)the normal bone mass group (n=9), the bone mass reduction group (n=13), and the osteoporosis group (n=21). The surface microscopic morphology was characterized by scanning electron microscopy and the morphology parameters were extracted by ImageJ software. The data of the microscopic topography parameters (diameter, angle and length) were statistically analyzed by multivariate analysis of variance.

Different bone surface morphology was found in each group. (1)The micro-topography parameters of the three groups were as follows: in the osteoporosis group, the mineralized collagen fiber bundle diameter was (1.57±0.46)μm, the length was (19.14±7.98)μm, angle was (66.67±9.40)°; in the osteopenia group, the diameter of collagen fibril bundle diameter was (2.02±0.71)μm, the length was (23.10±7.89)μm and the angle was (51.66±14.78)°; in the normal bone mass group, the diameter of collagen fibril bundle diameter was (2.22±0.25)μm, the length was (27.02±12.25)μm and the angle was (46.85±7.53)°.Statistical analysis showed significant difference in diameter among the three groups (F =33.687, P<0.01). LSD-t comparison showed significant difference in the diameters between osteoporosis group and normal bone mass group (P<0.05). The differences in angles and lengths of the three groups were statistically significant (F =19.614, P<0.05). (2) Data of collagen fibril bundles in the elderly group vs. the young and middle-aged group: diameter (1.76±0.62) μm and (2.22±0.25)μm(t =-2.896, P<0.01); angle (60.51±13.99) ° and (46.85±7.53)°(t =7.674, P<0.01); length (20.89±8.11) μm and (27.02±12.25)μm(t =-2.653, P<0.05). (3) No statistical difference was found in the data between the two gender groups(P>0.05).

SEM can clearly and completely characterize the microstructure of the bone surface, and the microscopic morphology parameters can be accurately and reliably extracted by using ImageJ software. Different state of bone will lead to the changes of the surface micro-morphology, including mineralize collagen fibers diameter, length, orientation of the different distribution.