AIM:To investigate the function of macrophage differentiation antigen-1 (Mac-1) in receptor acti-vator of nuclear factor-κB ligand ( RANKL )-induced osteoclast differentiation and the mechanisms .METHODS: The spleen cells were isolated from 4-week-old C57BL/6J mice, and cultured with RANKL, macrophage colony-stimulating fac-tor and CD11b and CD18 antibodies for 1 week.The actin bundles were stained with rhodamine-labeled phalloidin, and nu-clei were stained with DAPI.CD11b and CD18 antibodies, lentivirus with interfering vector plasmid of target gene Itgam (encoding CD11b) and empty virus (control virus) were used to treat osteoclasts for 1 week, and then immunofluorescence staining was performed.CD11b antibody, lentivirus and control virus were used to treat osteoclasts for 1 week, and total protein was taken for Western blot .RESULTS:Lower multinuclear positive rates in the groups treated with CD 11b anti-body were observed than that in the groups treated with CD 18 antibody and control group .Lower immunofluorescence inten-sity of Syk, CD11b and NFATc1 was found in CD11b antibody group than that in control group .Lower Syk, CD11b and NFATc1 immunofluorescence intensity was also observed in lentivirus group than that in control virus group .The results of Western blot analysis showed that the protein levels of CD 11b, Syk, NFATc1, c-Fos and p-ERK/ERK in CD11b antibody group were decreased as compared control group .Compared with control virus group , the protein levels of CD11b, Syk, NFATc1, c-Fos and p-ERK/ERK in lentivirus group were also decreased .CONCLUSION:CD11b subunit of Mac-1 pro-motes osteoclast differentiation by up-regulating c-Fos, ERK activity and NFATc1.

[Objective]To evaluate the unreamed femoral nail with spiral blade (UFN-SB) in the treatment of nonpathologic subtrochanteric femoral fractures.[Method]Twenty-seven patients who suffer subtrochanteric femoral fracture.Those fractures were classified with Seinsheimer’s way.Two cases of typeⅠ,9 cases of typeⅡ(5 of typeⅡ_A,3 of typeⅡ_B,1 of typeⅡ_C),12 cases of typeⅢ(7 of typeⅢ_A,5 of typeⅢ_B),3 cases of typeⅣ,1 case of typeⅤ.[Result]All cases were fellowed-up for 9~42 months,average 15 months.The authordidn't find any severe complications.All these patients could exercise early and bearing weight early.The authordidn't observe broken or loosen or quitted of this kind of internal fixation.[Conclusion]The UFN-SB is a better way for the treatment of subtrochanteric fractures of the femur.It can provide a satisfied restoration,a dependable fixation.It does good use to the concrescence of bone.It prevents short,rotation and varus angulation of femoral.The author get very good curative effect,less trauma,good sciatic function by using this kind of way to heal subtrochanteric femoral fracture.Especially in old people who suffer osteoporosis,this kind of interlocking way decreases the quantity lose of the bone,increases the contact area between bone and internal fixation,provides better angulation stability and rotation stability.

One case of periprosthetic infection after artificial joint replacement caused by Coxiella burnetii was reported. The patient was admitted to hospital due to joint pain and sinus formation after artificial knee replacement. Through medical history, physical examination, imaging examination and gene detection, it was confirmed that the infection around the prosthesis was caused by Coxiella burnetii. The patient was treated with two-stage revision surgery combined with sensitive antibiotics. Through literature review, a total of 9 cases of Coxiella burnetii infection after artificial joint replacement were reported, including 6 cases of hip joint and 3 cases of knee joint; 4 cases had clear pathogen exposure history; only one case was found protheses loosening on imaging; 7 cases with positive IgG antibody against Coxiella burnetii; 7 cases were positive for gene detection; 8 cases were negative in etiological examination, and 1 case was not cultured. All patients were treated with doxycycline and hydroxychloroquine. The serological index of 1 case without Q fever symptom turned negative after treatment. 1 case with multiple system organ dysfunction relieved symptoms after treatment, and serological antibody indicators and nuclear medicine results turned negative. All 7 patients were cured after secondary revision surgery. Coxiella burnetii infection after total joint arthroplasty is rare and lacks typical imaging manifestations and clinical features. The diagnosis of Coxiella burnetii infection after total joint arthroplasty mainly depends on gene detection and serological detection. Two-stage revision surgery combined with sufficient and long-term sensitive antibiotics is the main method of treatment.