| Avascular necrosis of the femoral head(ANFH)is a common orthopaedic disease,which can be divided into traumatic ANFH and non-traumatic ANFH.Non-traumatic ANFH is much more common than traumatic ANFH,however,its exact pathogenesis is not completely clear.Various pathogenic factors might reduce the the blood supply of the femoral head.If these factors persistent,it will eventually lead to ischemic necrosis of the femoral head in the corresponding area,and result in the corresponding clinical manifestations.The patients have to accept total hip replacement without effective treatment in early stage of ANFH.Because the life of the prosthesis is limited,young patients may have to receive revision operations several times,which will bring heavy medical burden.Therefore,most orthopaedic surgeons recommend hip-preserving surgeries as the first choice for ANFH.The principle of the hip-preserving surgery is to improve the blood supply of the femoral head and promote the repair of the necrotic area.Therefore,it is the important to know the blood supply system of the femoral head.The extraarticular network of vessels plays an important role in the arterial supply of femoral head.This network includes the lateral femoral circumflex artery,superior and inferior gluteal arteries and also the obturator artery.Microcirculation in the bone of the femoral head is like a coralline.Sinus space capillaries are commonly seen in the red bone marrow,and the arterial and venous capillaries are mainly seen in yellow marrow.The blood flow of red bone marrow is faster than that of the yellow bone marrow,and the density of blood vessels is higher too.The volume of the venous vascular system is significantly larger than that of the arterial vascular system.Because there are no effective methods to show the venous reflux of the femoral head,few studies report the venous blood drainage pattern of the femoral head.In addition,the changes of microcirculation and blood vessel density after ANFH have been rarely reported in the literature.The design concept of hip-preserving surgery for ANFH includes removing necrotic tissue,improving blood supply,transplanting bone,and promoting bone repair in necrotic area,as well as strengthening and restore biomechanical properties of femoral head.The decompression and bone graft procedure of the femoral head fully conforms to the idea of this design,but there are significant differences in the therapeutic effect according to different studies.This might due to the lack of methods to evaluate the operative range and the blood supply of the femoral head,the prognosis of this procedure is mainly dependent on the experience of the surgeons.Although intra-operative CT scanning,arthroscopy,and laser Doppler flowmetry are effective tools to evaluate operative range and the blood supply of the femoral head,these methods cannot be applied widely in clinic because of requiring special equipment and instruments.In this study,the amall and micro vascular distribution in a ANFH was observed.Then,the intraosseous cavity-venography(ICVG)method was proposed and its effectiveness was verified in an animal experiment.In further clinical experiment,the roles in evaluating operative range and blood supply of femoral head were compared between ICVG and ordinary radiographic test.In the end,a new pattern of femoral head venous drainage was described.Part?Pathological study of microvascular distribution in ANFHObjective: The present study was to clarify the boundary of the normal and abnormal blood supply area in ANFH in order to provide histological evidence for hip-preserving surgery.Methods: This study reviewed the non-traumatic ANFH patients who presented at the Department of orthopedics of the Third Hospital of Hebei Medical University between January and December 2016.A total of 20 cases were included.There were 16 male and 4 female with median age of 52 years old(range from 35 years to 56 years).According to the Ficat staging criteria for ANFH,all 20 patients were in stage V.The patients underwent total hip replacement after admission and femoral head specimens were included in the present study.The femoral head specimens were separated from the coronal plane by a pendulum sawing,and the samples were obtained in the necrotic area,the repair area and the healthy area.Decalcification,slicing,and HE staining were carried out step by step.The gross and histological changes of ANFH were observed.5 high magnificent vision(200 times)were taken at random in the necrotic area,repair area and healthy area.The number of blood vessels in each field of vision was counted,and the average number was obtained by 5 times.The results were compared using the Kruskal-Wallis H rank sum test among the necrotic area,the repair area and the healthy area.The difference was considered significantly when P < 0.05.Results:1.The gross appearance of ANFH was the flat-or mushroom-shape.The neck of the femur was shorter,bone hyperplasia was at the junction of the femoral head and neck,the articular surface of the femoral head was rough and uneven,and the cartilage was damaged in different degrees.In coronal section,the femoral head was almost round.The thickness of the articular cartilage in the outer layer was varied,the articular cartilage collapses in the weight bearing area,and the subchondral area can be seen as cystic degeneration.The inner parts of the femoral head were repare and sclerotic areas in yellowish white color.The trabecular bone density was relatively higher than that in healthy area which was in grey yellow color.2.Under microscope,the necrotic area of femoral head has a destructive structure.The thickness of trabecular bone reduces and number was less.The articular cartilage was fractured and shedding.Empty osteocyte lacunaes were seen in area.The bone marrow tissue was necrosis and be instead with fibrous.The number of capillaries was less and its density decreased.The repair area has a proliferating structure.The structure of the trabecular bone was relatively normal but some become thick,and the osteocyte was living with normal shape.The bone marrow was normal,fibrous tissue proliferates for repairing.The number of capillaries was more,and its density increased The healthy area had a normal structure.Bone trabeculas were neatly arranged and normal bone marrow cells and adipocytes were found among the trabeculaes.The number of capillaries was normal and distributed evenly.3.The number of blood vessels in femoral head dereased from repair area(54.9 vessels,range: 47.8~60.4 vessels),healthy area(21.3 vessels,range: 19.8~23.8 vessels),and necrotic area(3.3vessels,range: 1.0~4.4 vessels).The number differences of blood vessels among 3 areas were compared using Kruskal-Wallis H rank sum test,and considered significantly(Z=-5.417,P<0.001).The number differences of blood vessels between each two areas were compared using Kruskal-Wallis H rank sum test,and considered significantly(P<0.001).Summary: The blood vessels in the necrotic area of the femoral head decreased,and the blood supply was insufficient.On the contrary,that in the repair area increased,and the blood supply was insufficient due to the unbalance distribution.Blood vessels in the healthy area were more than those in necrotic area,and distributed balance.This study provided an important hisological evidence for the surgical management of ANFH that the blood vascular distribution was normal in the health area,while those in necrotic and repair areas were abnormal in either number or function,which should be surgically removed.Part Experimental ? study of intraosseous cavity-venography to evaluate the operative extent in the swain distal femurObjective: The aime of this study is to determine the effect of intraosseous cavity-venography(ICVG)in evaluating the operative bone cavity in the distal swine femur.Methods: 20 fresh swine femur bones were collected and examined by gross and X rays to excluded the pathological abnormalities such as the serious osteoporosis and the destruction of the bone tissue.Soft tissues were removed carefully to keep the integrity of the bones.A window was made in the distal femur and an intraosseous cavity was made by curettage through it.Frontal and lateral images of distal femurs were taken using C-arm X-ray Machine.The contrast agent,Compound Meglumine Diatrizoate(CMD)injection,was slowly injected into the operative cavity to the level of the bone window without leakage.Frontal and lateral images were taken again.The swain femur was split along the sagittal plane by an electric swing saw and photograph of the operative cavity were taken.The features of the cavity were observed and compared between plain X-ray images and ICVG images.The boundaries and shapes in detail in above methods were compared with those in gross observation as the gold standard.Results:1.There was an enough density contrast between the CMD and the bone tissue,which can make the intraosseous cavity recognizable.The cavity was the lowest density,surrounding cancellous bone was the moderate high density and the cortical bone was the highest density in frontal and lateral X-ray images.Because the density of the cavity was lower than that of the surrounding cancellous bone,the cavity can be recognized.It was easier to be identified in the lateral images than in the frontals.After ICVG performed,the cavity was the highest density,the surrounding cancellous bone was the lowest density and the cortical bone was the moderate density in the frontal and the lateral X-ray images.Because the density of the cavity was much higher than its surrounding bone,the cavity can be identified easily.2.The ICVG had an advantage to the plain X-ray fluoroscopy in evaluating the boundaries and the shape of operative bone cavity.The density of bone cavity was the lowest in plain X-ray images and can be recognized.However,its boundaries were vague and its shape cannot be identified.The density of the cavity was the highest in ICVG images and its boundaries and shape can be identified easily.The details of the bone marks were clearly discernible.3.The boundaries,shape and details were highly consistent between the ICVG images and the gross specimens.The boundaries of the operative bone cavity were sharp and irregular,the bone marks were recognizable in the ICVG images.The above features were consistent with the gross specimen.The boundaries of the operative bone cavity were vague and the shape was unrecognizable.Therefore,it cannot be compared with the gross specimen.Summary: The CMD can increase density of the operative bone cavity.The effect of ICVG in evaluating the boundaries and shape of the intraosseous cavity was superior to that of the plain X ray images.The features of boundaries and shape were consistent with the gross specimen.The present study demonstrated the effictiveness of CMD in visualizing the operative bone cavity,which provided an important experimental evidence for the clinical application of the ICVG.Part ?Clincial study of intraosseous cavity-venography to evaluate the operative extent and blood circulation in the femoral headObjective: This study is to determine the effectiveness and safety of intraosseous cavity-venography(ICVG)in evaluating the operative extent and blood circulation in the femoral head.Methods: The present study retrospectively reviewed 33 adult patients with non-traumatic avascular necrosis of the femoral head(ANFH)from January 2010 to September 2013 at the Department of orthopedics in the Third Hospital of Hebei Medical University.A total of 45 hips were diagnosed as non-traumatic ANFH.There were 24 males and 9 females,with the median age of 29 years(range from 27 years to 46 years).According to the Ficat staging criteria for nontraumatic ANFH,3 hips were in stage I,29 hips in stage ?,and 13 hips in stage ?.42 hips of ANFH in stage ?and ?were treated with decompression through the junction of the femoral head and neck and bone grafting procedure.3 hips of stage I ANFH were treated with core decompression procedure.All patients had iodine allergy tests before the sugeries and the results were negative.ICVG was performed during the decompression and bone grafting procedure.The ICVG was performed as follow steps.The hip joint was flexed in order to keep the bone window on the top of the operative bone cavity of the femoral head.The contrast,Compound Meglumine Diatrizoate(CMD),was injected into the cavity.The bone window was sealed with the bone wax suppository in aseptic plastic film.The operative bone cavity was evaluated by the C-arm X-ray machine immediately and at a 5 to 8 minutes interval within 40 minutes.A senior and a junior orthopaedic surgeons independently evaluated the boundaries and shapes of the operative bone cavities in the plain X-ray images and the ICVG images of 42 hips,respectively.A positive result was marked when the boundaries were recognized more than 2/3.On the contrary,a negative result was marked.The blood circulation of operative bone cavity was further evaluated according to the evacuation mode of the contrast agent.The difference of evaluation of the boundaries of the bone cavity between the senior and the junior surgeons were analyzed using Chi-square test.The difference was considered significantly when P<0.05.The time cost of the ICVG were recorded.The patients were followed up within 2 weeks after the ICVG performed,and the early complications were observed.Results:1.The ICVG had advantages to plain X-ray fluoroscopy in evaluating the boundaries and shapes of operative bone cavity.In the plain X-ray images,the structure of the hip joint was clear.The density of the operative bone cavity in the femoral head was slightly less than that of the surrounding bone.Because the bone cavity showd a low contrast,it was not recognizable.In ICVG images,the density of the bone cavity increased dramatically.The boundaries of the bone cavity were easily recognized due to the high contrast to the surrounding bone.The bone cavity can be clearly identified when repeating the ICVG procedure.2.There was no clinical experience requirement to evaluate the boundaries and shape of the bone cavity in the ICVG images.When recognizing the boundaries of operative bone cavity in plain X-ray images,the positive rate of the junior surgeon was 31%,while that of the senior surgeon was 78.6%.The differences in the positive rate of between two surgeons were statistically significant(?2=19.222,P < 0.001).When recognizing the boundaries of the operative bone cavity in the ICVG images,both the junior and the senior surgeons had the same 100% positive results.3.The ICVG can be used to evaluate the blood circulation of femoral head.The operative bone cavity in ICVG images was a high density.If the blood circulation of ischemic area in femoral head improved,the contrast agent may be taken away,and the density of the cavity reduced with the evacuation of contrast until bacasming the same as the surrounding bone.The reduction of the density of the bone cavity occured at the boundaries near the femoral neck,then extended to the cartilage of the femoral head.When parts of the necrotic and repair area in the femoral head were surgically removed,no or delay contrast evacuation might be observed in the bone cavity.When all of the necrotic and repair area has been removed,evacuation of the contrast agent can be seen mostly or totally.4.An additional 30 minutes to 90 minutes was required for performing the ICVG in one side of femoral head during the operation.The average time was 50 minutes.None of the ICVG related complication was reported.Summary: The boundaries,shape and details were easily recognized in the ICVG images,which required no clinical experience and had a high consistent positive result.It can also be use to evaluate the blood circulation of femoral head.The ICVG was a safe,reliable,and effective technique to evaluate the operative extent and blood circulation in the femoral head.Part ?maging study of the venous drainage pattern in the femoral head?Objective: This study is to explore the venous drainage pattern of femoral head by reviewing intraosseous cavity-venography(ICVG)images.Methods: The patients and ICVG procedure were the same as those described in the Part ?.3 hips of ANFH in stage I were treated with the core decompression procedure and the intraosseous venography were performed during the procedure.Intraosseous venography was performed by quickly injecting 10 ml CMD through the core depression channel.Continuous images were taken every 20 seconds with the C-arm X-ray machine.The contrast agent drainage and the density changes were observed in the femoral head and neck,as well as in the surrounding soft tissues.Results: In 42 hips of ICVG images at beginning,the intraosseous cavity showed a much higher density than surrounding bones,and the boundaries of the cavity and the surrounding bone were sharp and clear.The surrounding bone had the same density as that of the femoral neck,and there was no high density in the soft tissue.After 5 minutes,the contrast in the bone cavity began to be evacuated.the density of the intraosseous cavity reduced but still much higher than surrounding bones.The density of surrounding bone increased and slightly higher than that of femoral neck.there was no high density in the soft tissue,either.The boundaries near the femoral head were still sharp and clear,but those near the femoral neck was blurred.The density of the cavity near the femoral neck reduced but higher than surrounding bones.Continuous observation at intervals of 5 minutes showed that the density of the cavity reduced with the evacuation of the contrast agent.The cavity still showed a higher density than surrounding bone,and can be recognized.The density of surrounding bone slightly increased and higher than femoral neck.Stripes high density can be recognized in soft tissues of the base of femoral neck.The boundaries of the bone cavity and the surrounding bone were still recognizable,but gradually blurred.The density of the bone increased from the femoral head to the femoral neck gradually.In the end,the density of bone cavity was equal to surrounding bone,the cavity became unrecognizable.The density of femoral head was higher than that of the femoral neck base bone.Stripes high density can be recognized in soft tissues in the base of femoral neck,too.In 3 hips of intraosseous venography,at the beginning of the contrast injection through the core decompression channel the density of the entire femoral head showed no change,the channels showed a high density and were recognizable,the veins was filled with contrast agents and showed high density,their number were the most,and small veins were tortuous.With the contrast agent evacuation,the density of the entire femoral head showed no recognizable change,the density of vein reduced starting from small vein until they were not recognizable.The density of core decompression channel reduction happened at the end.Summary: ICVG was an effective method to evaluate small veins drainage in the bone.Through the arteries at the femoral neck and cartilage junction,arterial blood came into the femoral head and flowed to the subchondral bone and returned to the base of the femoral neck.The blood was collected by the vein plexus,and rejoined the venous plexus near the great trochanter of femur.This was a new pattern of femoral head venous drainage,which might explain the mechanism of the femoral head necrosis secondary to the hip injury without fractures or dislocation.Conclusion:1.The number of blood vessels in the necrotic area of the femoral head decreased obviously,the blood flow was insufficient,the number of blood vessels in the repair area increased obviously,the blood flow increased,but the distribution of blood vessels was uneven,although the number of blood vessels in the storage area was less than that of the repair area,but the distribution was uniform.It provided an important pathological basis for surgical treatment of ANFH.2.The effectiveness of ICVG to evaluate the operative extent was determined by injecting contrast agent CMD into the distal end of the fresh swain femur,which provided an important experimental evidence for the clinical application of ICVG.3.The results of ICVG were clear and easy to read,which was superior to plain X-ray images.The effectiveness,safety and reliability of ICVG to evaluate operative extent and blood circulation were confirmed.4.ICVG was an effective method to visualize the intraosseous vein drainage,and a new pattern of vein drainage of femoral head was identified. |
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