Hip ultrasound

Sonography has been widely utilized for several decades in the diagnosis and follow-up of developmental dysplasia of the hip due to its ability to visualize the nonossified femoral head and portions of the acetabulum in neonates, dynamic capabilities, accuracy, and lack of nonionizing radiation. Furthermore, hip sonography is also used throughout parts of the world to diagnose and guide intervention for both children and adults. The hip joint, tendons, and periarticular structures can be delineated with sonography in a variety of congenital, developmental, infectious, inflammatory, arthritic, traumatic, and neoplastic disorders. The following discussion focuses on the sonographic technique and imaging characteristics of congenital and developmental anomalies of the hip in children, as well as the sonographic evaluation of the hip joint and tendons.     

Assessment of congenital hip dislocation with real-time ultrasound: a pictorial essay

Real-time ultrasound (US) is the imaging method of choice for diagnosis and follow-up of congenital dislocation of the infant hip (CDH). Clinical aspects and the role of imaging are reviewed. Technique and anatomy, both normal and abnormal, are illustrated, as well as, the use of sonography during treatment with Pavlik harness and spica cast. Correlation of ultrasound findings with clinical examination, other available imaging studies and long-term patient follow-up shows 100% sensitivity and 100% specificity for real-time US diagnosis of CDH.     

Reliability of ultrasonography in the follow-up of hip dysplasia in children above 2 years of age

PURPOSE: The aim of the present study was to assess whether ultrasonography (US) was reliable in the follow-up of children above 2 years of age who had previously been treated for congenital or developmental hip dislocation or dysplasia (HD). MATERIAL AND METHODS: As part of the routine follow-up, we examined 53 children (106 hips), aged 2-12 years (mean 6 years). Using US, the coverage of the femoral head was assessed by the distance from the lateral tangent of the ossified femoral head to the lateral bony acetabular rim (lateral head distance, LHD). The corresponding distance was measured on radiographs (LHDR). The radiographic femoral head coverage was assessed by the migration percentage (MP) and the center-edge (CE) angle. RESULTS: We found a good accordance between sonographic LHD and the radiographic parameters MP and CE in all age groups, indicating that femoral head coverage was reliably assessed by US. There was also a high correlation between LHD and LHDR (r=0.85). All hips with subluxation were detected by US. In 11 hips that appeared normal on US, but with dysplasia or uncertain findings by radiography, the condition spontaneously normalized in 9 out of 9 examined hips with further follow-up. CONCLUSION: Because a reliable assessment of the hip is obtained, we recommend that US should be used as the primary imaging technique in the routine follow-up of children above 2 years of age with previous HD. Radiography should be omitted when US shows normal findings and is only needed when the US LHD is above the upper normal limit or the hip looks abnormal or suspicious by subjective evaluation.     

Echography in hip dysplasia in neonates and infants. Echographic anatomy, technic and case material

The value of hip joint sonography in newborns and unweaned infants is the latest development in the diagnosis of hip dysplasia. Knowledge of the sonographic anatomy makes accurate examination and staging according to Graf's tables possible. Since sonography is non-invasive it can be used for screening and check-up, thus reducing the use of radiography. A personal series of 250 patients is presented.     

超声在小儿发育性髋关节异常筛查及吊带治疗中的应用

目的探讨超声筛查小儿发育性髋关节异常(DDH)和在吊带治疗疗效评估方面的应用价值。方法选取本院收治的DDH患儿68例为研究组,患儿初诊及吊带治疗后均行超声检查,另纳入同期疑似DDH经超声检查的正常小儿68例为对照组;对比初诊时2组骨顶角(α)、软骨顶角(β)的大小,统计研究组患儿的Graf分型结果,对比研究组吊带前后α、β角及左右股骨头内侧缘与耻骨联合中点间隔长度的差值(d),分析研究组患儿吊带的疗效情况。结果研究组患儿的α角比对照组小儿更小,β角则更大,差异有统计学意义(P<0.05);研究组68例患儿共计患髋75个,Ⅱa型22个、Ⅱb型30个、Ⅱc型9个、Ⅱd型12个Ⅲ和Ⅳ型各1个。与治疗前相比,研究组患儿吊带后α角明显变大,β角明显变小,d值也明显变小,差异有统计学意义(P<0.05)。研究组患儿经吊带治疗后,69个患髋转为Ⅰ型,治愈率为92%。结论超声不仅对小儿发育性髋关节异常筛查有重要作用,在经吊带治疗后患儿的随访监测中也有较高的临床意义。     

Pitfalls in ultrasonography of hip joint synovitis in the child

The normal and abnormal anatomy of the hip joint in childhood was evaluated by ultrasonography (US) with reference to examination technique and errors. When compared with computed tomography (CT), it was confirmed that the two sonographic echoes from the hip joint represent the femoral neck and the external surface of the capsule and that the thickness of the echo received from the capsule depends on the frequency of the transducer. Partial volume effects may simulate or increase the sonographic appearance of hip joint effusion. The normal relationship between joint capsule and femoral neck was established.     

Morphological analysis of the knee joint in patients with hip dysplasia

Purpose

The purpose of this study was to investigate the morphological changes of the knee in patients with untreated developmental dysplasia of the hip.

Methods

Morphological analysis of 150 knee joints in 75 patients with developmental dysplasia of the hip was performed by examining computed tomographic (CT) images. Of these patients, 36 had unilateral developmental dysplasia of the hip and 39 had bilateral developmental dysplasia of the hip. Therefore, 36 hips were normal, and 114 hips were dislocated. CT images ranged from the iliac crest to 2 cm inferior to the tibial tuberosity.

Results

Compared with the knees in patients with normal hips, the femoral condyles in patients with dislocated hips were smaller and exhibited greater medial and lateral condylar asymmetry. The anterior femoral condylar angle of the femur was increased, as was the groove angle, while the trochlear groove was shallower in patients with dislocated hips. Furthermore, the lateral patella shift was reduced and the patellar tilt angle was increased in patients with dislocated hips compared with patients with normal hips. The extent of changes in these variables differed with the degree of dislocation. However, the posterior condylar angle of the femur was not affected by the degree of dislocation.

Conclusion

These findings suggest that developmental dysplasia of the hip is associated with morphological changes in the knee joint. These changes should be considered during hip and knee surgery.

Level of evidence

Prospective study, Level II.     

Femoral anteversion in infants: a method using ultrasound

Objective To design a reproducible method to measure femoral anteversion in children under 1 year old.Design and patients We conducted a prospective, observational study to determine intra- and inter-observer reproducibility of the sonographic measurement of femoral anteversion in infants. The method involves imaging of the proximal femur using a vertical transducer with the infant in the lateral position. Anterior femoral anteversion is measured using a vertical baseline and a line tangential to the anterior femoral head and the trochanter (anterior anteversion). We similarly measured true femoral anteversion using a line passing through the centre of the femoral head and the femoral neck (true anteversion). Anteversion measurements were taken at the time of routine ultrasound screening for developmental dysplasia of the hip when infants were an average of 10.4 weeks old. Anteversion measurements were made in 74 hips (37 infants).Results Our results showed that for the anterior anteversion measurements intra-observer repeatability was ±6.2° and inter-observer repeatability was ±7.8°. For true anteversion measurements intra-observer repeatability was ±9.5°, but inter-observer repeatability was ±23.5°.Conclusions Our results have shown that our method for measuring "anterior femoral anteversion" has an acceptable level of inter- and intra-observer agreement. The method used to determine "true anteversion", however, proved to have an unacceptable level of inter-observer variability.     

Coxitis fugax. The sonographic and radiologic picture in 65 cases

Sonography is a valuable technique for the detection of hip joint effusion in children with transient synovitis. In a retrospective study of 65 patients distension of the anterior recess was found to be increased by 2 mm or more in all patients investigated. A sonographic follow-up examination was carried out in 30 patients. These patients showed complete regression of hip effusion after 4 weeks. The importance of attention to sonographic changes of the adjacent bony outline and femoral head deformity in connection with other hip diseases is emphasized. In 45 patients in this study (62% of the cases) conventional radiography showed one or more indirect signs such as displacement, blurring or even obliteration of the fatty intermuscular planes or an increased joint space. In uncomplicated cases with clear sonographic and clinical findings a pelvic radiogram is unnecessary.     

发育性髋关节发育不良的外科治疗分析

目的：探讨发育性髋关节发育不良的治疗方法及疗效。方法：对26例发育性髋关节发育不良的治疗效果进行回顾性分析,治疗方法包括Pavlik吊带、蛙式石膏、Salter截骨、Pemberton截骨、Steel截骨、Chairi截骨及复合股骨近端截骨治疗。结果：Pavlik吊带2例为优。蛙式石膏4例,优1例,良1例,差2例。Salter截骨14髋,优5例,良4例,可4例,差1例。Pemberton截骨8髋,优5例,良3例。Steel截骨1例可。Chairi截骨2例优。结论：根据病情采用不同的治疗方法是提高发育性髋关节发育不良治疗效果的重要手段。     

Sonography of the painful hip in children: 500 consecutive cases

Five hundred children with a painful hip or a limp were evaluated prospectively by plain films and sonography. The clinical, radiographic, and sonographic findings were correlated with the final diagnoses. Sonography disclosed hip effusion in 235 patients, and plain films were abnormal in 58 of these 235 patients and in four others. Both sonography and plain films were normal in 261 patients. No sonographic signs served to differentiate sterile, purulent, or hemorrhagic effusion. Follow-up sonograms were performed in 202 patients. Sonography showed that 73% of patients with presumed transient synovitis had no effusion 2 weeks after diagnosis. Patients with hip disorders other than transient synovitis had persistent effusion for more than 2 weeks; however, that was also observed in 27% of patients with presumed transient synovitis. Sonography was more sensitive than plain films for detecting hip effusion. However, sonographic detection of effusion changed the therapeutic approach in only six patients.     

Femoral anteversion is correlated with acetabular version and coverage in Asian women with anterior and global deficient subgroups of hip dysplasia: a CT study

Objective

Morphological correlation between the acetabulum and femur at the hip joint is still controversial. We tested the hypothesis that femoral anteversion correlates with acetabular version and coverage in patients with developmental dysplasia of the hip (DDH).

Materials and methods

Using pelvic computed tomography (CT) images of 79 hips in 49 Asian women with DDH and 49 normal hips, we measured femoral anteversion, the axial and vertical acetabular version and the acetabular sector angle (ASA) to demarcate femoral head coverage. Depending on the location of the acetabular bone defect, dysplastic hips were divided into three subgroups: the anterior, global and posterior deficiency groups. We performed a comparative analysis between dysplastic and normal hips using the Wilcoxon rank sum test, and a relative analysis between femoral anteversion and acetabular measurements in dysplastic hips using Pearson’s correlation coefficient.

Results

The amount of femoral anteversion in dysplastic hips was greater and more variable than in normal hips (p?p?=?0.0277 respectively). Femoral anteversion in dysplastic hips correlated significantly with acetabular anteversion in the groups with anterior and global deficiency subgroups (p?p?Conclusions Our results showed significantly greater and more variable femoral anteversion in DDH, and a significant correlation between femoral anteversion and acetabular version and coverage in DDH with anterior and global acetabular bone deficiency.     

Radiographic measurements of dysplastic adult hips

 Hip dysplasia is a not uncommon feature in adults and can vary from subtle acetabular dysplasia to complex sequelae of developmental dysplasia of the hip. This review article describes the most useful radiographic measurements used to evaluate the adult hip. The frontal projection of the pelvis permits measurement of the center-edge angle (CE angle) and ”horizontal toit externe” angle (HTE angle), both of which assess the superior coverage of the acetabulum. The femoral neck-shaft angle (NSA) is also measured on this view. The false profile radiograph of the pelvis is described. It allows measurement of the vertical-center-anterior angle (VCA angle), which determines the anterior acetabular coverage and detects early degenerative hip joint disease. When surgery is contemplated, computed tomography (CT) is useful to better determine the anterior acetabular coverage by use of the anterior acetabular sector angle (AASA), and the posterior acetabular coverage by use of the posterior acetabular sector angle (PASA). CT also permits measurement of femoral anteversion. These measurements are particularly useful in the evaluation of acetabular dysplasia and for the preoperative assessment of the dysplastic hip.     

Ultrasound examination of tendons

This article reviews the type of equipment used in sonography of the tendons, the method of approach in viewing normal tendon anatomy, and the sonographic appearance in pathologic conditions of the tendons. The role of ultrasound in follow-up studies is also emphasized because of its noninvasive nature.     

Neonatal hip: from anatomy to cost-effective sonography

Therapeutic success in treating congenital dysplasia of the hip is associated with early diagnosis, but the specific neonatal anatomy makes screening difficult. The purpose of this study was to determine whether this specific neonatal anatomy is taken into account by current ultrasound (US) techniques. Anatomic studies were performed on 22 hips, US examinations on 7750 neonatal hips; 2370 untreated hips were reexamined at 1 month by US and at 3 months by X-ray. The transformation of the neonatal cartilaginous acetabulum into an osseous cavity is dependent on harmonious metaphyseal growth and a properly seated femoral head. Defects in the acetabular roof, together with displacement of the femoral head, cause an abnormal anatomical relationship which leads to further deformities. The described sonographic techniques give only partial information on these specific abnormalities. The sonographic monoplanar methods as used in Graf's technique, which relies largely on acetabular development, lead to difficulties in assessing posterior coverage of the femoral head and difficulties in assessing alignment of the metaphyseal weight-bearing surface with the femoral head. Combining Graf's morphological analysis with Novick's dynamic technique enables one to more accurately define the relationship of the femoral head and the acetabulum and increases the reliability and predictive value of the examination, while reducing the number of doubtful cases. This makes screening cost effective. Received: 20 February 1997; Revision received: 28 August 1997; Accepted: 7 January 1998     

Diseases of the musculoskeletal system in children: imaging with CT, sonography, and MR.

We reviewed the applications of CT, sonography, and MR imaging in diseases of the musculoskeletal system in children. Unique advantages of each technique are discussed, and common disease entities and practical applications of the three imaging methods are stressed. Evaluation of congenital dysplasia of the hip, hip effusion, and soft-tissue foreign bodies with sonography are emphasized. The role of CT in imaging patients with congenital dysplasia of the hip, tarsal coalition, osteomyelitis, and benign and malignant bone tumors is stressed. Common applications of MR that are emphasized include imaging of osteomyelitis, musculoskeletal tumors, normal bone marrow, and avascular necrosis. Innovations are briefly discussed, including evaluation of dermatomyositis with MR and imaging sternoclavicular dislocation, congenital vertical talus, and fractures and dislocations with sonography.     

Central aponeurosis tears of the rectus femoris: sonographic findings

OBJECTIVE: The purpose of this study was to review the normal and sonographic (US) anatomy of the central aponeurosis of the rectus femoris muscle, describe the sonographic appearance of its tears and correlate it with the MR findings. DESIGN AND PATIENTS: The rectus femoris internal architecture was evaluated by cadaveric dissection. To correlate the sonographic normal findings with cadaveric data, axial sections were compared with the corresponding US images. The normal in vivo sonographic appearance of rectus femoris was assessed in 20 healthy subjects (40 thighs). To evaluate the US findings in central aponeurosis tears we performed a retrospective review of 17 examinations of 17 patients suffering from acute injuries. Follow-up examinations were available in five patients. Sonographic findings were correlated with MR findings in eight patients. RESULTS: Anatomical dissection of the rectus femoris confirmed the presence of the central aponeurosis, a sagittally oriented fibrous band located within the proximal two-thirds of the muscle belly. In vitro US showed the central aponeurosis as a curvilinear hyperechoic structure whose shape correlated well with the cadaveric data, and in vivo US demonstrated it in all healthy subjects. In the retrospective analysis of the patient group, we classified the lesions into three groups according to the size at sonography: group 1 ( n=9), hyperechoic band surrounding an intact central aponeurosis; group 2 ( n=7), mixed hypo- and hyperechoic bands surrounding an intact central aponeurosis but associated with globular enlargement of the rectus femoris; group 3 ( n=1), complete discontinuity of the rectus femoris. These findings can reflect small partial tears, larger partial tears and complete musculotendonous junction tears respectively. In patients evaluated with both techniques, MRI confirmed the US findings. In five patients follow-up studies showed an irregular hyperechoic ill-defined area centred on the central aponeurosis that was compatible with a central scar. CONCLUSIONS: Sonography can demonstrate the normal internal anatomy of the rectus femoris and post-traumatic changes at the myotendinous junction of the central aponeurosis. Sonographic data correlate well with MR findings, and the low cost and wide availability of sonography make it the first-line technique in the evaluation of injuries of the rectus femoris.     

Doppler sonography of the anterior ascending cervical arteries of the hip: evaluation of healthy and painful hips in children

OBJECTIVE: We evaluated the Doppler sonography of small feeding arteries to the femoral head in children. SUBJECTS AND METHODS: In a prospective study of 224 hips in 112 patients (mean age, 5 years 11 months), the anterior ascending cervical arteries of the hip were identified with color Doppler sonography. Subsequently, we measured the resistive index (RI) with pulsed Doppler sonography. RESULTS: In 61% (137/224) of hips, a Doppler signal could be obtained. In asymptomatic hips (n = 64), the mean RI was 0.58. In symptomatic hips, the definitive diagnoses and mean values of RI included transient synovitis (n = 31) and 0.92, Perthes' disease (n = 9) and 0.67, and miscellaneous (n = 5) and 0.68. In 28 symptomatic hips, no definite diagnosis could be determined and the complaints spontaneously disappeared during follow-up (mean RI, 0.57). We found no statistically significant difference in the RI of symptomatic versus asymptomatic hips, except in patients with transient synovitis (p < 0.001). In 11 hips with transient synovitis that were reexamined after 4-6 weeks, the RI returned to normal (0.57). The RI in symptomatic hips showed a positive correlation with the amount of effusion (r = 0.69, p < 0.001). In symptomatic and asymptomatic hips, we found no correlation with age (p = 0.9 and 0.1, respectively). CONCLUSION: The deep capsular vessels of the hip joint can be evaluated on Doppler sonography in more than 60% of hips. Also, the RI is age independent and correlates with the amount of effusion.     

Scrotal sonography in infants and children

In this review we will attempt to summarize the use of scrotal sonography in infants and children. The material is gathered from the literature and from our own experience of 197 sonograms performed on 175 pediatric patients. Included will be information on testicular development and descent, normal sonographic anatomy, classification of scrotal disease, and the final diagnoses of the sonograms. Scrotal sonography has proven useful in evaluating undescended testes in the inguinal canal and just inside the inguinal ring. It is of limited value when the testes are in the abdomen. Sonography can often distinguish the various causes of nonpainful scrotal masses such as tumors, hydrocele, and meconium peritonitis. Sonography is highly accurate in distinguishing normal from abnormal scrotal contents and in separating testicular from extratesticular masses. However, sonography does have limitations in distinguishing benign from malignant neoplasms or from some inflammatory lesions.

Sonography can be successfully used in the differential diagnosis of the painful scrotum especially with color flow Doppler. Inflammatory diseases that often involve the epididymis can be distinguished from torsion. Torsion of the appendages has been diagnosed.

In cases of scrotal trauma, management decisions are often based on the sonographic findings. Conditions that require surgical management such as testicular rupture or large testicular hematomas can be recognized. Information is included on a variety of miscellaneous conditions such as hydrocele, varicocele, and ambiguous genitalia in which sonography has proven valuable.     

Acetabular angles and femoral anteversion in dysplastic hips in adults: CT investigation

Transpelvic CT was used to quantify the relationship between the acetabulum and proximal femur in 21 adult patients (33 hips) with congenital hip dysplasia (defined by a center edge angle of less than 20 degrees). The anterior and posterior acetabular sector angles (AASA and PASA) were measured, as well as the degree of acetabular and femoral anteversion. The results demonstrated deficient anterior acetabular support (i.e., decreased AASA) in approximately two-thirds of the dysplastic hips and reduced posterior support (i.e., decreased PASA) in one-third. The acetabular anteversion was normal. The femoral anteversion. however, was greater than normal in most hip. As important additional information is obtained by CT compared with conventional radiography, CT is recommended when operative procedures aimed at preventing or postponing osteoarthrosis are considered.