Clinic Value Of High-frequency Ultrasound In Diagnosis Of Developmental Dysplasia Of The Hip In Infant

Objective1.To study the feasibility and diagnostic value of ultrasound in diagnosis of developmental dysplasia of the hip in infant.2.To screen the available index in diagnosis of developmental dysplasia of the hip in infant at present.3.To observe the morphological changes of the cartilage and the ossification center of the femoral head.Materials and methodsPatients:A total of 60 hips of 30 either in-patients or out-patients visiting The ShengJing hospital of CMU between 6 months and 36 months who were suspected of developmental dysplasia of the hip were included in this study.The exclusion criteria comprised patients with deformed developmental dysplasia of the hip and that who have been treated before visiting our hospital.Ultrasound examination:The studies were performed using Logic 9 color Doppler ultrasound machine produced by GE Company with 5～7MHz and 9～14MHz linear array probes and diagnostic software for diagnosing developmental dysplasia of the hip.All patients were examined by ultrasonography and 3D CT1.Measurements of the hip:On the standard coronal section of hip,the Graf'sαangle andβangle and the Terjesen's bone rim percentage and lateral head distance were measured,and whether the bone margin of acetabulum was sharp or not was observed too.2.Measurements of the femoral head:We obtain the maximum section of the neck and head of femur with the sound beam through the greater trochanter.After measuring the maximum width(W)which parallels the top of the shaft of femur and the distance (H)between the top of the head of femur and "W",H/W was calculated to estimate whether the head of femur was colplanate.3.Measurements of the ossification center of the femoral head:Measure the length of the ossification center of the femoral head in the maximum section of femoral head and neck.Rotate the probe 90°,then measure the anteroposterior diameter of the ossification center of the femoral head.To measure the transverse diameter of the center of ossification of the femoral head in maximum transverse section obtained from inguinal region.Statistical analysis:3D CT examination for golden standard,we evaluate the availability of ultrasound in diagnosing developmental dysplasia of hip in infant with the evaluating index of sensitivity,specificity,accuracy,positive predictive value and negative predictive value.The result of 3D CT classified the hips as DDH group and normal group.The significant differences of H,W,H/W of the femoral head between the two groups were analyzed with t test using SPSS12.0 software.The significant differences of the longitude,transverse and anteroposterior diameter of the ossification center of the femoral head between the two groups were analyzed with t test too.Result1.A total of 60 hips of 30 infants and young children suspected with developmental dysplasia of the hip by pediatric Orthopedic surgeon were examined with ultrasound and 3D CT scan 23 normal hips(8 left hips,15 right hips),4 dysplasia hips(4 right hips),9 subdislocation hips(6 left hips,3 right hips)and 24 dislocation hip(16 left hips,8 right hips)were diagnosed with 3D CT.2.Theαangle,βangle,bone rim percentage,lateral head distance were measured and whether the bone margin of acetabulum is dull or defect was observed,the sensitivity,specificity,accuracy,positive predictive value and negative predictive value in diagnosis of DDH were:αangle:94.6%94.6%,100%,96.7%,100%,92%;βangle: 78.4%,100%,86.7%,100%,74.2%;LHD:68.6%,100%,81%,100%,67.6%; BRP:70.3%,100%,81.7%,100%,67.6%;the bone margin of acetabulum is dull or defect:89.2%,95.7%,91.7%,97.1%,84.6%.The sensitivity,specificity,accuracy were 95.7%,97.30%,96.7%when we diagnosed DDH with abnomalities of any one ofαangle,bone rim percentage or the bone margin of acetabulum.3.The cartilage of the femoral head with DDH is smaller than that of the normal hips,but not colplanate obviously.4.The ossification center of the femoral head with DDH is smaller than that of normal hips.Diminishing of length and transverse diameter is more obvious in DDH, but anteroposterior diameter is not obvious.Conclusion1.High-frequency ultrasound scan is a valuable method in diagnosing the developmental dysplasia of the hip in infants and children so that it can be used as a routine examinating method.2.The cartilage of the femoral head with DDH is smaller than that of the normal hips,but not colplanate obviously.3.The ossification center of the femoral head with DDH is smaller than that of normal hips.The shortening of length and transverse diameter is more obvious in DDH, but not obvious in anteroposterior diameter.