Establishment and evaluation of rabbit model of closed tibial fracture / 中国骨伤

OBJECTIVE@#To explore the effect of a modified three-point bending fracture device for establishing a rabbit model of closed tibial fracture.@*METHODS@#The model of closed tibial fracture was established in 40 6-month-old male New Zealand white rabbits with a body weight of 2.5 to 3.0 kg, and the model was verified at 6 weeks after operation. Five rabbits underwent pre modeling without temporary external fixation before modeling, and then were fractured with a modified three-point bending fracture device;35 rabbits underwent formal modeling. Before modeling, needles were inserted, and splints were fixed externally, and then the fracture was performed with a modified three-point bending fracture device. The fracture model and healing process were evaluated by imaging and histopathology at 2 hours, 4 weeks, and 6 weeks after operation.@*RESULTS@#Two hours after modeling, the prefabricated module showed oblique fracture in varying degrees and the broken end shifted significantly;Except for 1 comminuted fracture, 2 curved butterfly fractures and 2 without obvious fracture line, the rest were simple transverse and oblique fractures without obvious displacement in formal modeling group. According to the judgment criteria, the success rate of the model was 85.71%. Four weeks after modeling, the fixed needle and splint of the experimental rabbits were in good position, the fracture alignment was good, the fracture line was blurred, many continuous callus growths could be seen around the fracture end, and the callus density was high. Six weeks after modeling, many thick new bone trabeculae at the fracture, marginal osteoblasts attached, and a small number of macrophages were seen under the microscope. The intramembrane osteogenesis area was in the preparation bone stage, the medullary cavity at the fracture had been partially reopened, the callus was in the absorption plastic stage, and many osteoclasts were visible. The X-ray showed that the fracture line almost disappeared, part of the medullary cavity had been opened, the external callus was reduced around, the callus was in the plastic stage, and the bone cortex was continuous. It suggests that the fracture model showed secondary healing.@*CONCLUSION@#The improved three-point bending fracture device can establish a stable rabbit model of closed tibial fracture, and the operation is simple, which meets the requirements of closed fracture model in basic research related to fracture healing.

Analysis of the axial stretching force of the small splint fixation system / 中国骨伤

<p><b>OBJECTIVE</b>To measure the axial stretching force produced by the small splint fixation system in the treatment of the fracture.</p><p><b>METHODS</b>Dumbbell shaped plexiglass was machined to model the bone shaft with expanded two ends. Force transducer was set at the model fracture site to measure the stretching force produced by fracture fixation of the small splint with cloth aqueous bag that simulated the muscles and other soft tissue underneath.</p><p><b>RESULTS</b>There was positive relationship between the axial stretching force produced at the model fracture site and the transverse pressing force exerted by the external plates. The ratio of which was 1/10.</p><p><b>CONCLUSIONS</b>Muscle enwrapped with fascia is similar to the cloth aqueous bag system in mechanical structure. From this article, axial stretching force exists at the bone shaft fracture site when fixed by small splint which exerts the force transversely from the outside of the extrimity.</p>

Regeneration and functional recovery of rabbit knee joint after osteotomy under control of external artificial joint / 医用生物力学

Objective To discuss the possibility for regeneration of knee joint with normal function under bionics biomechanical environment. Methods Seven normal rabbits with two metal frames respectively mounted on their femur and tibia of single (right) side leg by two threading pins of 1.5 mm diameter were used. Then the external artificial joints, containing two four-bar-linkage inside and outside of the knee to simulate motion trajectory of the joint in sagital plane were connected with the two preset fixed frames before osteotomy. The arthro-cartilage of the knee joint, crucial ligaments, semi-lunar fibro-cartilages, and partial under-cartilage-osseous intra articular capsule were cut off during osteotomy, with the patella, sesamoid bones remained intact. Insertion sites of muscle tendons were not invaded as far as possible, and capsules with ligaments outside were kept complete when the incision wound was closed by suture. The rabbits could move freely after osteotomy. The range of motion (ROM) of the knees in sagital plane and bony gap between the femur and tibia were measured by X-Ray films during the fracture healing after osteotomy. Results External artificial knee joints were successfully installed on right legs of 6 rabbits among the seven. The rabbits moved freely after osteotomy under the control of minimal invasive external artificial joint in bionics trajectory. The average angles between femoral shaft and tibial shaft at the 1st week after osteotomy were from (144.7±15.62)° in extremely flexed position to (44.2±25.77)° in extremely extended position, with ROM of (100.5±29.03)°. At the 12th week, the average angles were from (139.4 ± 12.92)° in extremely flexed position to (40.4±22.04)° in extremely extended position, with ROM of (99.0±23.39)°. No significant differences were displayed in flexed/extended position and ROM between the 1st and 12th week, with the bony gaps of the knees still existed but decreased significantly from (4.03±1.84) mm at the 1st week to (2.32±1.05) mm at the 12th week. In contrast, bony gaps of the opposite knees were not changed significantly, which were (1.27±0.22) mm on average. At the end of 16th week after osteotomy, the external artificial joints were removed. Newly born cartilage, with white color and smooth surface, were covered at lower end of the femur and upper end of the tibia. Typical trochlear surface appeared at the front side of regenerated cartilage corresponding to the posterior surface of the patella. And the regenerated fibro-bundle linkage similar with ligament, which started from bony structure of regenerated lower end of the femur and inserted into regenerated upper end of the tibia, was observed in each rabbit. At the 25th week, the average angles between femoral shaft and tibial shaft were from (148.3 ± 4.75)° in extremely flexed position to (48.30±17.57)° in extremely extended position, with ROM of (100.0±20.80)°. In the opposite (left) leg, the average angles between femoral shaft and tibial shaft were from (148.3±7.5)° in extremely flexed position to (21.6±9.09)° in extremely extended position, with ROM of (126.7±6.88)°, and the average bony gap of the knees after osteotomy was (1.4±0.59) mm, while that of the opposite (left) knees was (0.92±0.35) mm. Conclusions The external artificial joint with bionics trajectory could reserve the space for regeneration of rabbit knee joint by providing motion modeling environment, and proved the stress adaption during fracture healing. The present results indicated that regeneration of the knee joint after intra-capsular osteotomy in bionics biomechanical environment was possible.

Biomechanical test in vivo on reduction fixator for treating distal radius fractures / 医用生物力学

Objective To investigate the regular pattern of traction forces during the treatment of distal radius fracture by reduction fixator with pins. Methods A self-designed pin-lock style force transducer instead of two original pin locks in the distal of reduction fixator was adopted to conduct continuous testing on six cases of unstable distal radius fracture of forearms treated by reduction fixator in vivo. The value of static traction force and the added value of traction force in fist clenching at the postoperative 1st, 5th, 14th, 21st, 28th, 35th, 42nd, 49th day, was recorded respectively. Results The maximum and minimum static traction force was 9.93 kg and 2.26 kg, respectively, with mean value of (4.93±1.79) kg. The maximum and minimum traction force increment in fist clenching was 10.40 kg and 0.13 kg, respectively, with mean value of (3.17±2.42) kg. Conclusions Larger axial forces can be generated in muscles of the forearm, by both static tension and dynamic contraction, which might be a serious negative factor in healing unstable distal radius fractures.

Using radiographs to analyze equivalent weakest transverse interface of fracture healing / 医用生物力学

Objective An effective but simple method for quantifying the fracture healing progress was provided to obtain more information on fracture healing mechanics from plain X-ray film. Method Twelve rabbits were used for experimentally osteotomy at the middle tibiae, each of which was fixed by the sliding fixator with four pins of 1.5 mm diameter, with mini transducer of displacement measuring the sliding micro movement between the fractured bone fragments, denoted as ΔL. The bending rigidity, denoted as K=P/ ΔL, of the rabbits’ tibia (with sliding fixator together) were recorded by computer data assembling system once a week, where P was the load on the fracture site from anterior of the tibia by manual operation of a loading transducer. The anterior posterior and lateral radiographs were also taken every week by digitally upgraded X-ray radioscope. The effective weakest transverse curved interfaces were found, and the equivalent bending moments of inertia were calculated from the radiographs automatically, by gray scan along the longitudinal axis of the tibia upon the image programs edited in Delphi programming environment. And they were used for quantitative description of the rigidity of the healing bone. Results The sliding fixators were removed in 29~41 days after the osteotomy. Ratios of the minimum to the maximum of equivalent bending moments of inertia for each fracture bone were calculated. And they were found to increase via the healing time. The means of the ratios of all twelve rabbits calculated from lateral radiographs were (0.31±0.17) for the first week, (0.34±0.13) for the second week，(0.43±0.20) for the third week, and (0.56±0.23) for the fourth week after the osteotomy, respectively. From anterior posterior radiographs, the means of the ratios were (0.40±0.19), (0.47±0.16)， (0.56±0.20), and (0.66±0.11), respectively. These ratios were significantly correlated with the bending rigidity K of the fracture tibia of the rabbits. The means of K value was （3.976±4.986）N•μm-1 before the operation，and （0.679±1.026）N•μm-1 for the first week，（2.115±3.233）N•μm-1 for the second week，（3.459±4.723）N•μm-1 for the third week and （4.788±4.831）N•μm-1 for the fourth week after the operation, respectively. Conclusions The growth of external callus has its own rules. It can be distinguished from plain radiographs easily, and it grows from either side of the fracture site and meets together gradually, filling up the gap at the fracture site at last. The methods described in this paper could reflect the feeling when reading the radiographs.

Effects of tension relaxation by small needle knife on muscle tension and nerve endings after compression of gracilis muscle in rats / 中国骨伤

<p><b>OBJECTIVE</b>To determine the effect of tension relaxation by small needle knife on the muscle tension and morphology changes of nerve terminals when sustained pressure was applied to muscular tissue.</p><p><b>METHODS</b>Rat gracilis muscles were exposed to pressure in vivo at 70 kPa for 2 hours. Sixty rats were divided into three groups: normal, control and experiment group respectively. In all rats except the six normal ones, the lower legs were considered as the control group, and the right left as experiment group. At day 1, 2 and 3, 9 rats from the two groups were randomly selected and sacrificed in order to determine the muscle tension change. At the same time, muscle histology and morphology changes of nerve terminals were observed.</p><p><b>RESULTS</b>Abnormal tension increased in muscles under compression of 70 kPa. At the 1st and 2nd days, there were no significant differences between the two groups. Compared with control group, the tension was lower in experiment group, and there was statistically significant difference (P < 0.01) between the two groups. Exposure of striated muscle tissue to intensive and prolonged compression may pathologically alter its microstructure. Histological evaluation showed that this stiffening accompanied extensive necrotic damage. The changes could not be found in the nerve terminals.</p><p><b>CONCLUSION</b>Deep muscle tissue that undergoes prolonged compression may significantly increase its stiffness during acute injury. Tension relaxation applied by small needle knife can effectively reduce the mechanical load which is harmful to the whole tissue.</p>

Effects of small needle knife on the substance P in the dorsal root ganglion and spinal cord of rats / 中国骨伤

<p><b>OBJECTIVE</b>To study the mechanism of synthesis of substance P (SP) in the dorsal root ganglion (DRG) and the release of it in the dorsal horn of the spinal cord of rats after compression of skeletal muscle, and to observe the influence of small needle knife.</p><p><b>METHODS</b>Sustained pressure of 70 kPa was applied to rats, muscular tissues for 2 hours. The rats were divided into three groups: normal, control and experiment group respectively. In all rats except the six normal ones, the lower legs were compressed once one day. The left leg was considered as the control group, the right left was experiment group, which were divided into the 1st day, the 2nd day and the 3rd day within the two groups. Experiment group was treated with small needle knife after the muscular tissue was compressed. After completing the stimulation, the DRG related to the muscle and part of spinal cord were removed for the qualification of SP-like immunoreactivity using immunohistochemistry. The dark brown stains on the DRG and on the REXed laminae I and II in the dorsal horn of the spinal cord were counted by Image-Pro Plus software.</p><p><b>RESULTS</b>SP-like immunoreactivity in the side treated by the small needle knife was enhanced comparing with the counterpart in DRG in normal group (P < 0.01). The integrated optical density of SP like immunoreactivity of the DRG in the experiment group were significantly reduced compared with the control group (P < 0.05). However, the release of SP from spinal cord in experiment group was lower than that in the control group at the 1st day and the 3rd day (P < 0.01), with the opposite result of the 2nd day.</p><p><b>CONCLUSION</b>Based on the fact that SP is a nociceptive neurotransmitter, the present study suggests that tension relaxation by small needle knife reduces expression of SP in the DRG, and shows no effects on the release of SP from the spinal cord in short-term (3 days).</p>

Randomized control clinical study on third lumbar transverse process syndrome treated by knife needle / 中国骨伤

<p><b>OBJECTIVE</b>To evaluate the therapeutic effects of knife needle on third lumbar transverse process syndrome.</p><p><b>METHODS</b>From 2007.3 to 2007.12, patients were divided into treatment group and control group according to the random digits table, 34 and 35 patients respectively. Patients in both groups were separately treated for 3 weeks, with knife needle in treatment group and electroacupuncture in control group. In treatment group, 12 patients were male and 22 patients were female, the average age was (42.33 +/- 7.86) years. In control group, 16 patients were male and 19 patients were female, the average age was (44.73 +/- 10.34) years. The changes of biomechanics, local tension and tenderness index were observed and recorded respectively before and after the therapy, and the results obtained from two groups were then compared with each other. The JOA score was used to evaluate the clinical effect.</p><p><b>RESULTS</b>Sixty patients finished the clinical observation. The treatment efficacy was evaluated according to the JOA score in 60 cases. The soft tissue tension in treatment group was lower than that in the control group (P=0.00004). Excellent result was found in 18 cases, good in 9 cases, fair in 3 cases and poor in 0 case.</p><p><b>CONCLUSION</b>Tension relaxation by needle knife can effectively improve the clinical symptoms and signs of third lumbar transverse process syndrome.</p>

Relationship between the gray level of X-ray photograph and the cortical thickness / 中国骨伤

<p><b>OBJECTIVE</b>In order to get three dimensional measurements simply an plain X-ray photographs.</p><p><b>METHODS</b>The multi-layers of bone pieces were made by use of bone saw, and piled up to spiral ladder, which was used as a calibrating module for to living bone in clinics. The relationship between the cortical thickness and gray level of the X-ray photographs was obtained.</p><p><b>RESULTS</b>The correlation can be described with a cubic regression curve, and it can be simplified to a linear regression equation when cortical thickness is small than 3.8 mm.</p><p><b>CONCLUSION</b>It can be realized to get three dimensional measures of the bone on plain X-ray photographs, by use of the bony spiral ladder described here.</p>

Revealing mechanical property of intact rabbit tibia in three-point bending test / 中国骨伤

<p><b>OBJECTIVE</b>To explore the mechanical property of intact long bone through three-point bending test of rabbit tibia according to mechanics of materials.</p><p><b>METHODS</b>Ten pairs of normal rabbits tibia were treated on three-point bending test with 80 mm supporting distance in order to corroborate the virtual loading test on bone model.</p><p><b>RESULTS</b>Bending stiffness and strength of 10 pairs of normal rabbit tibia were obtained. The maximum flexibility of the right and the left tibia was (2.737 +/- 0.262) mm and (2.739 +/- 0.233) mm respectively. The maximum load, which indicated the bending strength, of the right and the left tibia was (17.803 +/- 2.675) kg and (18.366 +/- 2.653) kg respectively. The area under the load-flexibility curve before fail of the right and the left tibia was (23.829 +/- 4.413) kg/mm and (24.725 +/- 4.101) kg x mm respectively. The slope of the load-flexibility curve which indicate the stiffness of the right and the left tibia was (7.545 +/- 1.310) kg/mm and (7.631 +/- 1.174) kg x mm respectively.</p><p><b>CONCLUSION</b>The discrepancy between different animal body is larger than conventionally required. It's suggested for performing three-point bending test of long bone of the body both sides in pair.</p>

Evaluation of diagnosing cervical vertigo with computerized static posturography / 中国骨伤

<p><b>OBJECTIVE</b>To provide a quantitative base for diagnosing cervical vertigo by establishing a biomechanics method.</p><p><b>METHODS</b>From July 2004 to Nov 2005, the static posturography (SPG) of normal 86 health individuals and 75 patients with cervical vertigo were quantitatively measured and qualitative diagnosis respectively in closed and open eyes. There were 40 male and 46 female in health adults, ranging from 20 to 74 years old (mean 30 years). There were 16 male and 59 female in vertigo patients, ranging from 20 to 74 years old (mean 44.5 years). In contrast to current diagnosis method of patients with cervical vertigo, the clinical value was evaluated.</p><p><b>RESULTS</b>Under the state of closed eyes, the sensitivity of SPG diagnosing cervical vertigo was 76%; the specificity was 93%; the Youden index was 69%; the coincidence was 85.1%; the positive predictive value was 90.5%; the negative predictive value was 93%; the positive and negative likelihood ratio were 10.893 and 0.258 respectively. Under the state of open eyes, the sensitivity was 49.3%; the specificity was 87.2%; the Youden index was 38.6%; the coincidence was 69.6%; the positive predictive value was 77.1%; the negative predictive value was 87.2%; the positive likelihood ratio was 3.857; the negative one was 0.581. Regardless of closed or open eyes, foreword-backward type shift orbit was the with cervical vertigo.</p><p><b>CONCLUSION</b>The patients with cervical vertigo and normal individuals can be diagnosed objectively and quantitatively with SPG under the state of closed eyes, which can achieve the basic requirements of diagnosing cervical vertigo with validity, reliability and good clinical application. However, the rate of missed diagnosis with SPG under the state of open eyes is too high to meet the diagnostic needs.</p>

In vivo effects of Qizheng-xiaotong plaster on soft tissue injury of rabbit ears / 中国骨伤

<p><b>OBJECTIVE</b>To explore in vivo effects of Qizheng-xiaotong plaster on soft tissue injury in rabbit ears at different periods and to offer theoretical bases for clinical application.</p><p><b>METHODS</b>The experimental models of soft tissue injury in ears were produced in 10 New Zealand white rabbits, and the ears were divided into three groups at the 1st, 2nd, 3rd week. The normal group and treatment group were given the Qizheng-xiaotong plaster extract, and the model group with normal saline. Microscopic analysis, digital collection system, infrared temperature tester and thickness tester were applied to determine the changes of soft tissue injury in local microcirculation and the temperature change after 0, 0.5, 3 and 5 hours, and swelling change at 1 to 5 days respectively.</p><p><b>RESULTS</b>At the 3rd hour, blood velocity speeded up in normal group and model group, and it lasted for two hours in model group. As compared with model group, it slowed down to original level in treatment group at the 5th hour and the soft tissue swelling decreased from the 3rd to the 5th day as well.</p><p><b>CONCLUSION</b>The application of Qizheng-xiaotong plaster is effective in preventing further soft tissue oedema and haematoma. It can make the soft tissue swelling decreased at chronic stage compared with that at acute stage.</p>

Factors of influence on quality evaluation of adhesive property on cataplasma / 中国中药杂志

<p><b>OBJECTIVE</b>To provide experimental proof for establishing a standard quality evaluation method of adhesive property on Cataplasma by studying the factors of effect on evaluation of adhesive quality on Cataplasma.</p><p><b>METHOD</b>With 180 degrees peel off test, tensile shear and adhesive force test, the influence caused by the square of samples, texture of fabric base and the moisture loss was tested with multifunctional material tester and first stickiness tester.</p><p><b>RESULT</b>The peel off strength of 40 mm wide sample is 26% lower than that of the 20 mm wide sample (P < 0.05), and tensile shear strength had no significant difference. The peel off strength of transverse fabric base was higher than that of lengthways fabric base (P < 0.01). The tensile shear strength of transverse fabric base was lower than that of lengthways fabric base (P < 0.05). The sample with 35% moisture lost had a maximum tensile shear strength and the sample which lost 30% moisture lost had a maximum peel off strength; The sample which lost 20% moisture lost had a maximum first adhesive force.</p><p><b>CONCLUSION</b>The square of samples, the texture of fabric base and the moisture loss of samples can all affect the evaluation of adhesive quality on Cataplasma.</p>