| Part one Experimental study of the effect of breech presentationand breech release on femoral trochlea morphology inneonatal ratsObjective: It is established that the breech presentation is one of the risk factors for femoral trochlea dysplasia.However,the pathophysiological process of trochlea dysplasia associated with breech presentation is not known.The purpose of this study was to establish an animal experimental model simulating breech presentation and investigate whether the breech presentation and its release affect the morphological changes of femoral trochlea in neonatal rats.Methods: 240 neonatal rats were randomly divided into two groups(control group and experimental group).The experimental group establis hed the breech presentation model of newborn rats(using medical breathable tape),kept the knees completely straight and the hips extremely flexed to simulate the breech presentation of intrauterine fetus.Neonatal rats were kept in the breech presentation for 10 days and then released from the breech presentation.The experimental animals were euthanized at 10 days,3 weeks,4 weeks and 6 weeks after birth in both groups,and the tissue of the distal femur was subsequently collected.Gross andcross-sectional observations as well as histological observations and measurements of the femoral trochlea were performed at each time point inboth groups to evaluate the anatomical and morphological alterations of the femoral trochlea.Results: There was significant difference in trochlear groove angle between experimental group(139.6° ± 2.2°)and control group(130.2° ± 2.0°)at 10 days after birth(P < 0.05).The depth of trochlear groove in the experimental group(0.33 mm ± 0.02mm)was statistically different from that in the control group(0.42 mm ± 0.02mm)(P < 0.05).The incidence of femoral trochlear dysplasia was higher in the experimental group(83.3%).The incidence of trochlear dysplasia decreased with the duration of breech release(from 83.3% to 60.0% after 3 weeks,to 33.3% after 4 weeks,and to 0 after 6 weeks).Histological measurements showed that there were statistical differences in the angle and depth of the trochlear groove between the two groups at 10 days,3 and 4 weeks after birth(P < 0.05).However,at 6weeks after birth,there was no significant difference between the experimental group(124.3° ± 1.4°)and the control group(124.7° ± 1.4°)(P =0.086).There was no statistical difference between the experimental group(0.65 mm ± 0.02mm)and the control group(0.64 mm ± 0.02mm)in the depth of trochlear groove(P = 0.119).Conclusions: In this model,the breech presentation status has an adverse effect on the femoral trochlea in neonatal rats and may induce femoral trochlea dysplasia.In addition,this study also shows that the time of breech release is negatively correlated with the incidence of trochlear dysplasia,and the anatomical shape of femoral trochlea will gradually return to normal after breech release.Part two Correlation analysis between timing and duration ofbreech presentation during pregnancy and thedevelopment of femoral trochlea dysplasiaObjective: Breech presentation has been proved to be related to trochlea dysplasia.However,the influence of timing and duration of breech presentation on the development of femoral trochlea is still unclear.The purpose of this study is to analyze the correlation between timing and duration of breech presentation and trochlea dysplasia.Methods: This study included 252 pregnant women and newborns in our hospital as the research objects.We examined the knee joints of 504 newborns with ultrasonic technology.The measurement site was femoral trochlear groove,and the measurement index was trochlear groove angle.Neonatal indicators such as sex,height,weight,gestational age,gestational order,delivery mode,family history of trochlear dysplasia,amniotic fluid volume,the appearance time and duration of breech presentation before birth were recorded respectively.All neonatal clinical data were collected and statistically processed,and the correlation between timing and duration of breech presentation and trochlea dysplasia was analyzed.Results: There were statistically significant differences in gender and family history of trochlear dysplasia between well-developed femoraltrochlear and trochlear dysplasia(P < 0.05),while there were no statistically significant differences in height,weight,gestational age,gestational age,parity,rescue history and amniotic fluid volume(P > 0.05).The ultrasonic measurement showed that there were significant differences in the appearance time and duration of breech presentation in newborns with well-developed femoral trochlear and trochlear dysplasia(P < 0.05).Newborns whose breech presentation occurred between 35 weeks gestation and birth had a 3.009-fold increased risk of trochlear dysplasia.Duration of breech presentation >4 weeks,the risk of neonatal trochlear dysplasia increased 6.491-fold.Conclusions: The timing and duration of breech presentation,female and family history were associated with trochlear dysplasia.The timing and duration of breech presentation as well as female and familyhistory are risk factors for trochlear dysplasia.Part three Ultrasound study of the effect of the breech presentationof the newborn on the development of the femoraltrochleaObjective: The anatomy of the femoral trochlea is critical to the stability of the patellofemoral joint.When considering risk factors for patellofemoral instability,it is useful to understand the characteristics of the femoral trochlea in infants and children.The purpose of this study was to investigate the effect of intrauterine breech presentation on the development of the femoral trochlea in newborns.Methods: A total of 60 neonates with normal intrauterine environment and intrauterine breech presentation were selected and divided into 2 groups,namely,normal group(normal intrauterine environment)and breech group(breech presentation),with 30 cases in each group(60 knees).Ultrasound examination of bilateral knee joints was performed in each newborn,and the measurement indexes were trochlea sulcus angle,and trochlea sulcus depth.The measurement time points were at birth,1 month after birth 3 months after birth,6 monthsafter birth and 12 months after birth.All the measured data of trochlear groove angle and trochlear groove depth were statistically processed.When P < 0.05,the difference was defined as statistically significant.Results: There were no significant differences in height and weight between the two groups at different time periods(P > 0.05).The ultrasonic measurement of newborns at birth showed that there was a statistically significant difference in the trochlear groove angle between the breech group(156.3°±4.5°)and the normal group(149.8°±2.7°)(P < 0.05).At 1 month after birth,there was a statistically significant difference between the breech group(156.3°±4.5°)and the normal group(149.8°±2.7°)(P < 0.05).At 3months after birth,the difference of trochlear groove angle between the two groups(breech group: 154.6°±4.4°,normal group: 148.8°±2.9°)was statistically significant(P < 0.05).At 6 months after birth,the trochlear groove angle(breech group: 154.4°±3.7°,normal group: 149.3°±3.0°)was significantly different between the two groups(P < 0.05).At 12 months after birth,there was significant difference in trochlear groove angle between the two groups(breech group: 153.7°±4.3°,normal group: 149.6°±3.2°)(P <0.05).There was statistical significance in the trochlear groove depth between the two groups at each time point(P < 0.05).The incidence of trochlear dysplasia in the breech group ranged from 31.7% at birth,to 26.7% at 1 month,to 23.3% at 3 months,to 16.7% at 6 months,and to 13.3% at 12 months.Conclusions: The breech status has an effect on the growth and development of the femoral trochlea in newborns,which may lead to a shallow trochlear groove.The incidence of trochlear dysplasia in infants and children may gradually decrease as the breech state is released for a longer period of time. |
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