Anterior joint capsule of the normal hip and in children with transient synovitis: US study with anatomic and histologic correlation

PURPOSE: To study the anatomic components of the anterior joint capsule of the normal hip and in children with transient synovitis. MATERIALS AND METHODS: Six cadaveric specimens were imaged with ultrasonography (US) with special attention to the anterior joint capsule. Subsequently, two specimens were analyzed histologically. These anatomic findings were correlated with the US findings in 58 healthy children and 105 children with unilateral transient synovitis. RESULTS: The anterior joint capsule comprises an anterior and posterior layer, mainly composed of fibrous tissue, lined by only a minute synovial membrane. Both fibrous layers were identified separately at US in 98 of 116 (84%) hips of healthy subjects and in all hips with transient synovitis. Overall, the anterior layer was thicker than the posterior layer. In transient synovitis compared with normal hips, no significant thickening of both layers was present (P = .24 and .57 for the anterior and posterior layers, respectively). Normal variants include plicae, local thickening of the capsule, and pseudodiverticula. CONCLUSION: Increased thickness of the anterior joint capsule in transient synovitis is caused entirely by effusion. There is no US evidence for additional capsule swelling or synovial hypertrophy.     

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.     

Transient synovitis of the hip in children: role of US

Transient synovitis of the hip remains a common diagnostic problem for the clinician. The physical signs are not pathognomonic of the condition, and the classic technical examinations are of little help. Therefore, the authors retrospectively studied the value of hip arthrosonography in 46 children with clinical symptoms suggesting pathologic hip conditions. In 20 of the 21 patients with a final diagnosis of transient synovitis, articular effusion was detected on ultrasound (US). Conventional radiography showed an increased medial joint space in only eight of these patients. Increased echogenicity of the articular fluid was found in both transient synovitis and septic arthritis. The high sensitivity of US in detecting intraarticular fluid was demonstrated by cadaver studies.     

Conventional radiography in transient synovitis of the hip in children

Conventional radiography was performed at diagnosis and at follow-up 5 to 9 months later in 70 children with transient synovitis of the hip. Twenty-four of the patients also had CT examination at diagnosis. The cartilaginous and osseous reaction in the conventional antero-posterior radiographs was studied as was the relation between the radiographic and CT findings concerning fat planes, joint effusion, and position of the hip joint. At diagnosis there was significant increase in the medial joint space and at follow-up examination there was significant increase in medial and cranial joint space, metaphyseal width and acetabular roof width. There was a correlation of a bulging lateral 'capsular fat plane' to the position of abduction in the affected hip which explains the asymmetry in the lateral fat plane observed in these patients.     

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.     

Limited effectiveness of sonography in revealing hip joint effusion: preliminary results in 21 adult patients with native and postoperative hips

OBJECTIVE: The object of this study was to determine the effectiveness of sonography in the detection of hip joint effusions in both native and postoperative adult hips using arthrocentesis as a gold standard. MATERIALS AND METHODS: Twenty-one consecutive patients with clinical suspicion of hip joint effusion were examined on sonography by one of five musculoskeletal radiologists with experience in musculoskeletal sonography. All 21 patients underwent diagnostic arthrocentesis (fluoroscopic in 16, sonographic in five) to confirm the presence or absence of joint effusion. A retrospective analysis of the sonograms was made to assess the size of the distention of the anterior joint recess (anteroposterior dimension) and the echogenicity (anechoic or other relative to muscle), and correlation was made to the presence or absence of joint effusion. RESULTS: Joint effusion was seen on diagnostic arthrocentesis in 10 (48%) of the 21 patients. Seven of the 21 patients had native hips and 14 had prior hip surgery. Retrospectively, no significant difference was found with regard to the size of the anterior recess distention (p = 0.34) or echogenicity (p = 0.2) when comparing the patients with and without joint effusion. CONCLUSION: Anterior recess distention and echogenicity could not reliably be used as an indicator of adult hip joint effusion, either in native or postoperative hips. Diagnostic arthrocentesis was necessary to establish or exclude the presence of hip joint effusion.     

Standards for ultrasonographic measurements of the hip joint in Indian adults

Synovitis in the hip joint, in contrast to that in other limb joints, is extremely difficult to evaluate clinically. In the hip joint synovitis manifests as an increase in the distance between the iliofemoral ligament and the femoral neck. The present ultrasonographic study was undertaken in 110 healthy Indian adults to establish standards for the depth of the normal hip joint space in the normal Indian adult population. The shortest distance was 4 mm, the longest was 9 mm. The mean distance was 6.4 (S.D. 1.1) mm. The mean difference between the right and left hips was 0.42 (S.D. 0.49) mm. An age-specific reference curve with 95% confidence limits was constructed. No correlation was found between hip joint space and the subjects' height, weight, age or sex. It is concluded that a distance between the iliofemoral ligament and the femoral neck of more than 9 mm or a difference in measurement between the hips of 1 mm or more suggests an intracapsular effusion or active synovitis. These figures are at variance with the measurements obtained in studies on Western white populations.     

US assessment of hip joint synovitis in rheumatic diseases. A comparison with MR imaging

PURPOSE: To assess the significance of ultrasonography (US) in detecting hip joint synovitis in patients with rheumatic diseases. MATERIAL AND METHODS: Forty patients with rheumatic disease and suspected hip joint synovitis underwent MRI and US of the hip joint. In addition to the throughout MRI evaluation, the anterior collum-capsule distance (CCD) was determined by both MRI and US. Thirteen healthy volunteers were examined with MRI to establish the criteria for normal findings in MRI when classifying hip joints to those with synovitis and those without. MRI was used as a gold standard. RESULTS: Synovitis was found using MRI in 31 hips of 22 patients (9 patients had bilateral synovitis). The intraclass correlation was 0.61 between MRI and US in measuring CCD. In classifying hip joint synovitis with US, the sensitivity of the method was 87% and specificity 42%, when the CCD criterion for synovitis was determined to be > or = 7 mm. If the cut-off point was raised to 9 mm, the sensitivity decreased to 61% while specificity increased to 94%. A difference in CCD of > or = 1 mm between the hips as an additional criterion for synovitis increased the number of false-positive findings. CONCLUSION: Measurement of CCD with US proved to be a rather inaccurate method to point out synovitis in rheumatic patients when using MRI as a reference. The main reason for this result was the thickened capsule, which US could not differentiate from a thickened synovium.     

小儿髋关节一过性滑膜炎的超声诊断及中医治疗

目的:探讨B超检查在小儿髋关节一过性滑膜炎的诊断和中医疗效观察中的价值。方法:对53例髋关节一过性滑膜炎病例,在中医手法治疗与中药湿热敷治疗过程中,采用超声检查了解股骨颈颈前间隙的变化。结果:治疗一周后,有15例患儿股骨颈颈前间隙<6mm,两周后复查,仅3例患儿股骨颈颈前间隙>6mm,四周后所有病例恢复正常。讨论:通过超声检查,能准确测量股骨颈颈前间隙的宽度,直观评价中医疗法在少儿髋关节一过性滑膜炎治疗中的疗效。     

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.     

Concentric joint space narrowing of the hip associated with hemosiderotic synovitis (HS) including pigmented villonodular synovitis (PVNS)

Concentric joint space narrowing of the hip is an expected radiographic finding in cases of inflammatory arthritis such as rheumatoid arthritis or sepsis. However, similar joint space narrowing is associated with chronic hemorrhagic conditions that produce hemosiderotic synovitis. Hemosiderotic synovitis results from chronic intraarticular bleeding such as occurs in pigmented villonodular synovitis, generalized bleeding diathesis, synovial hemangioma, and chronic trauma. Five hips in five patients with concentric joint space narrowing not associated with inflammatory arthritis or with hemophilia were reviewed clinically, radiographically, and pathologically. All patients had a hemosiderotic synovitis. The definitive diagnosis of pigmented villonodular synovitis was made pathologically in two cases that demonstrated nodular areas of giant cell proliferation, collagen production, and lipid-laden histiocytes on histologic samples.     

Pigmented villonodular synovitis of the hip: review of radiographic features in 58 patients

Clinical and radiographic findings were retrospectively reviewed in a multicentric survey of 58 patients with histologically proven pigmented villonodular synovitis (PVNS) of the hip. The most common clinical features were mechanical pain (47 cases) and limitation of joint motion (47 cases). On plain films, a classic form with large and multiple lucencies was found in 36 cases, followed by an osteoarthritis-like form (9 cases), an arthritis-like form (8 cases), normal radiographic appearance (3 cases), osteonecrosis of the femoral head (one case) and joint destruction with acetabular protrusion (one case). Bilateral involvement of the hips was probable in two patients. In contrast to the knee, the hip showed a high prevalence of bony lesions and joint space narrowing. Although an uncommon disease, PVNS of the hip has to be considered when arthritis is associated with uncharacteristic clinical or radiographic findings.     

Arthrography in the diagnosis of unexplained chronic hip pain with regional osteopenia.

Three cases of chronic hip pain with radiographic periarticular osteopenia and normal joint spaces are reported. The articular nature of symptomatology, periarticular demineralization, and radionuclide localization suggested intraarticular disease. Computed tomography did not disclose the cause of hip pain when utilized in two instances. Positive contrast hip arthrography was the only diagnostic modality which demonstrated the chondromatosis or adhesive capsulitis responsible for pain. Differential diagnosis and pathophysiologic mechanisms are briefly reviewed.     

Ultrasonography of hip joint effusions

In order to evaluate ultrasonography in patients with suspected hip joint effusions, 123 consecutive patients were examined prospectively. Twenty healthy subjects were used as a control group. The normal sonoanatomy, the recommended scanning approach, and the diagnostic features of intra-articular joint effusions are presented. Even minor fluid collections of 1 or 2 ml could be accurately detected. Transient synovitis and fresh hemorrhagic effusions proved to be echofree, whereas clotted hemorrhagic collections or septic arthritis showed non-echofree effusions. Based on intraoperative and computed tomography (CT) data, ultrasonography is clearly superior to X-ray films in detecting joint effusions. A negative sonogram will exclude a fluid collection; the depiction of an echofree effusion with virtually rule out septic arthritis. The use of additional imaging techniques can be reduced greatly, as ultrasonography seems to be an improved method for the early diagnosis of septic arthritis.     

强直性脊柱炎髋关节改变的X线、CT和MRI对比研究

目的 探讨强直性脊柱炎(AS)髋关节受累的影像表现,比较X线平片、CT和MRI显示AS髋关节受累的敏感度.方法 对55例AS患者行骨盆X线平片和MR检查,其中29例行髋关节CT检查.MR平扫均包括冠状面T1WI、T2WI、STIR、附加水激励的三维稳态快速梯度回波序列(3D-BTFE-WATS),其中24例同时行脂肪抑制T1WI增强检查.分析患者的影像资料,应用x2检验对X线平片、CT和MRI显示AS髋关节受累改变的敏感度进行分析.结果 55例AS患者110侧髋关节中,X线平片和MRI显示异常分别为13侧和85侧;X线平片改变包括关节面下骨侵蚀破坏13侧、关节间隙变窄4侧、韧带骨赘5侧;MRI显示关节面下骨侵蚀破坏31侧、关节间隙变窄4侧、关节少量积液80侧、骨髓水肿32侧、脂肪沉积28侧、韧带附着点炎21侧,24例行MR增强检查患者中19例见双侧滑膜异常强化.CT检查29例共58侧髋关节,CT在显示X线平片和MRI所显示的骨破坏同时,发现X线平片未能显示的10侧骨破坏和MRI未显示的1侧骨破坏.X线平片、CT、MRI显示异常分别为10.3％ (6/58)、27.6％ (16/58)和77.6％ (45/58),MRI显示髋关节受累的敏感度优于X线平片和CT(x2值分别为53.22和29.08,P值均＜0.05).MRI除显示X线平片和CT所能显示的慢性骨结构改变外,还发现X线平片和CT未能显示的急性炎症改变.结论 MRI能显示X线平片和CT不能显示的AS髋关节受累的急性炎症改变,滑膜炎所致的少量积液和滑膜异常强化是髋关节受累最常见的MRI表现.     

MR imaging of bone marrow edema and joint effusion in patients with osteonecrosis of the femoral head: relationship to pain

OBJECTIVE: Our aim was to determine the occurrence of bone marrow edema and joint effusion and their relationship to pain in patients with osteonecrosis of the femoral head on the basis of MR imaging. MATERIALS AND METHODS: There were 71 patients with osteonecrosis of the femoral head based on characteristic radiographic and MR imaging findings. All patients had surgical confirmation of the disease. Both hips were affected with osteonecrosis in 39 patients, whereas only one hip was involved in 31 patients. The last patient underwent an arthroplasty of one hip during the study and had only one hip imaged. We evaluated a total of 110 hips in this study, of which 98 were painful. We staged osteonecrosis of the femoral head, using the classification of Steinberg et al. The 31 unaffected hips served as controls. Bone marrow edema and joint fluid were evaluated on MR images. Bone marrow edema was defined as an ill-defined area of low signal intensity on T1-weighted images with corresponding high signal intensity on T2-weighted or inversion recovery images localizing to the femoral head, neck, and intertrochanteric region. The amount of joint fluid was graded from 0 to 3. RESULTS: The peak of bone marrow edema occurred in stage III disease (72%); its odds ratio was seven times greater than that for stage I osteonecrotic hips. Effusions of a grade greater than or equal to 2 were seen most often in stage III disease (92%), compared with 10% in the control hips. With an effusion, bone marrow edema was 12.6 times greater when the hip was painful than when it was not. CONCLUSION: Both bone marrow edema and joint effusions existed with a peak occurrence in stage III disease. Bone marrow edema seems to have a stronger association with pain than does joint effusion in osteonecrosis of the femoral head.     

小儿髋关节暂时性滑膜炎的彩色多普勒超声表现

目的:探讨彩色多普勒超声在小儿髋关节暂时性滑膜炎的临床价值。方法:选取髋关节暂时性滑膜炎患儿38例,应用彩色多普勒超声对患儿治疗前后髋关节滑膜内细小血管的血供情况和频谱多普勒进行血流检测评价。结果:患儿治疗前,肿胀组与积液组滑膜增厚型的病例患侧髋关节滑膜内血流信号较健侧明显丰富;肿胀组血流速度升高,积液组血流速度减低。治疗后1周,肿胀组及积液组患髋滑膜内的血流信号较治疗前有所下降;肿胀组血流速度减低,积液组血流速度升高。治疗后2周,两组患髋滑膜内血流信号基本同健侧。结论:多普勒超声能监测小儿髋关节暂时性滑膜炎髋关节滑膜内的血供改变,对疾病的诊断和疗效观察有重要的应用价值。     

Hip ultrasound

In newborns, US has an established role in the detection and management of developmental dysplasia of the hip. Later in childhood, when the limping child is a major diagnostic dilemma, US is extremely helpful in the identification of the varied disease processes underlying this condition, as transient synovitis, septic arthritis, Perthes disease and slipped femoral capital epiphysis. In adolescent practicing sporting activities, US is an excellent means to identify apophyseal injures about the pelvic ring, especially when avulsions are undisplaced and difficult-to-see radiographically. Later on, in the adulthood, US is an effective modality to diagnose tendon and muscle injuries about the hip and pelvis, identify effusion or synovitis within the hip joint or its adjacent bursae and guide the treatment of these findings. The aim of this article is to provide a comprehensive review of the most common pathologic conditions about the hip, in which the contribution of US is relevant for the diagnostic work-up.     

MRI of joint fluid in the normal and ischemic hip

MR images in 36 hips with documented avascular necrosis and 80 hips without evidence of joint disease were studied to determine the amount and appearance of fluid in the joint. All MRI examinations were done on a 1.5-T machine and included coronal images made with relative T2 weighting (repetition times = 2000-2500 msec, echo delays = 60-100 msec). The amount of joint fluid, which had an intense signal higher than fat, was graded from 0 to 3 and analyzed with respect to the patient's age and radiographic stage of avascular necrosis. Joint fluid was seen in 84% of presumed normal hips. Only four (5%) of 80 had enough fluid to surround the femoral neck (grade 2), and none had sufficient fluid to distend the joint capsule (grade 3). In comparison, 21 (58%) of 36 hips with avascular necrosis had grade-2 or grade-3 effusions (p less than 0.005), and some fluid was seen in all. Grade-3 effusions were seen in seven (50%) of 14 hips with flattening of the femoral head, compared with only one (5%) of 20 in which the femoral contour was normal. It is concluded that small amounts of fluid are present in both normal hips and those with avascular necrosis. In avascular necrosis, increased joint fluid may be present before radiographic abnormalities occur, but it is greatest after there is flattening of the femoral head. MRI is a highly sensitive method for detecting fluid in the hip joint.     

Septic arthritis versus transient synovitis at MR imaging: preliminary assessment with signal intensity alterations in bone marrow

PURPOSE: To find any differential magnetic resonance (MR) imaging findings between septic arthritis and transient synovitis in pediatric patients. MATERIALS AND METHODS: The MR imaging findings in nine pediatric patients with septic arthritis and 14 with transient synovitis were retrospectively studied. The diagnoses were made by means of joint aspiration with bacteriologic study, arthrotomy, and clinical evaluation. MR imaging findings were analyzed with emphasis on the grade of joint effusion and alterations in signal intensity in the soft tissue and bone marrow of the affected hip joint. RESULTS: Signal intensity alterations in bone marrow (i.e., low signal intensity on fat-suppressed gadolinium-enhanced T1-weighted spin-echo images and high signal intensity on fat-suppressed T2-weighted fast spin-echo images) were seen in eight of nine patients with septic arthritis. These signal intensity alterations consisted of mild juxtaarticular changes in six patients without osteomyelitis and extensive changes in the femoral head and neck in two patients with coexistent osteomyelitis. Signal intensity alterations in bone marrow were not seen in the 14 patients with transient synovitis. CONCLUSION: Signal intensity alterations in the bone marrow of the affected hip joint are useful in the differentiation of septic arthritis from transient synovitis.