ObjectiveTo design and produce a lesser trochanteric reduction fixation system and verify its value and effectiveness. MethodsA lesser trochanteric reduction fixation system was designed and produced according to the anatomical features of the lesser trochanteric fractures. Sixty-six patients with intertrochanteric fractures of Evans type Ⅲ were included between January 2010 and July 2012. Of 66 patients, 32 were treated with dynamic hip screw (DHS) assisted with the lesser trochanteric reduction fixation system (study group), and 34 cases were treated with DHS only (control group). The 2 groups were comparable with no significant difference in gender, age, the reasons, and the types of the fractures (P>0.05). The operation time, intraoperative blood loss, neck-shaft angle, bone healing time, ratio of successful fixations, and the functional evaluation of the hip joint after operation were compared between 2 groups. ResultsThe study group had shorter operation time [(58.4±5.3) minutes] and less intraoperative blood loss [(186.3±6.6) mL] than the control group[(78.5±6.2)minutes and (246.2±8.7) mL], showing significant differences (t=-14.040, P=0.000; t=-31.145, P=0.000). There was no significant difference in neck-shaft angle between study group [(138.6±3.0)°] and control group [(139.4±2.9)°] (t=-1.044, P=0.301). The wounds healed by first intention in both groups. The 30 and 31 patients were followed up 12 to 24 months (mean, 15 months) in the study group, and 13 to 25 months (mean, 16 months) in the control group, respectively. All fractures healed well in 2 groups. The study group had significantly shorter healing time [(8.8±2.0) weeks] than the control group [(10.7±3.4) weeks] (t=-2.871, P=0.006). At 12 months after operation, coxa vara happened in 2 cases of the study group with a successful fixation ratio of 93.3% and in 10 cases of the control group with a successful fixation ratio of 67.7%, showing significant difference (χ2=6.319, P=0.022). According to Harris hip score, the excellent and good rate was 83.3% in the study group (25/30) and was 58.1% in the control group (18/31), showing significant difference (χ2=4.680, P=0.049). ConclusionThe application of the lesser trochanteric reduction fixation system can reduce stripping of the soft tissue around the fracture fragments, shorten the operation time and the healing time, and preserve the function of the hip joint maximumly.
ObjectiveTo evaluate the ectopic osteogenesis of recombinant human bone morphogenetic protein 2 (rhBMP-2) loaded chitosan (CS)/dextran sulfate (DS) by micro-CT. MethodsrhBMP-2/CS/DS microspheres were prepared by the ionic crosslinking and its shape was observed under the scanning electron microscope. The release of rhBMP-2 was determined from resultant microspheres by ELISA assay. Forty-eight Sprague Dawley male rats were randomly divided into 4 groups (n=12), quadriceps muscle bag model was made, gelatin sponge (group A), CS/DS microspheres (group B), rhBMP-2 (group C), and CS/DS/rhBMP-2 microspheres (group D) were implanted into the bags respectively. The tissue samples with heterotopic ossification were harvested for micro-CT scanning at 4, 8, 12, and 16 weeks. The tissue mineral density (TMD), bone volume fraction (BVF), trabecular thickness (Tb.Th), trabecular number (Tb.N), bone mineral density (BMD), and tissue mineral content (TMC) were measured. ResultsThe prepared rhBMP-2/CS/DS microspheres with smooth surfaces were spherical and evenly disperses without obvious agglomeration. At 2 hours, microsphere started a sudden release period in vitro; the release reached a peak at 2 days; and the release cycle lasted about 20 days. The rats survived to the end of the experiment. At each time point after operation, no radiation developed and no osteogenesis was observed by three dimensional reconstruction in groups A and B. However, radioactive strength and reconstructed bone tissue gradually increased in groups C and D, and group D had more radioautography and more bone tissues than group C. At each time point, TMD, BVF, Tb.Th, Tb.N, BMD, and TMC of groups A and B were zero. Ectopic bone formed with time, the other parameters showed an increasing trend except Tb.N in groups C and D, showing significant difference when compared with groups A and B at each time point (P < 0.05). There was no significant difference between groups C and D at 4 weeks (P>0.05); the parameters of group D were significantly higher than those of group C at 8-16 weeks (P < 0.05). ConclusionrhBMP-2/CS/DS microspheres have stronger ability of ectopic bone formation than single rhBMP-2.