Observer variation in the detection of acetabular bone deficiencies

 To determine observer variation in the detection of acetabular bone deficiencies, 42 pairs of frontal (AP) and lateral hip radiographs and CT studies for total hip arthroplasty patients obtained within an average of 4 weeks of each other were reviewed separately by five radiologists and one orthopedic surgeon. Interobserver variations were calculated for each individual reading the films using kappa values. The individual film readings were then compared with a consensus reading of the CT data. When separate observers were analyzed, agreement on plain film readings was slight to fair (av. kappa=0.1440±0.1047). The individual observers were not able to give readings which were very consistent with the CT consensus reading, resulting in a low sensitivity (65%) and specificity (74%) for acetabular defect classification with plain radiographs. The identification of acetabular bone defects from the AP and lateral views of the hip is highly subjective and variable from observer to observer.     

Arthrography of painful hips following arthroplasty: digital versus plain film subtraction

Digital and manual subtraction images obtained during the arthrographic evaluation of 78 painful hip prostheses were reviewed retrospectively. Revision arthroplasty was performed in 53 of these cases, and the arthrographic and surgical findings were correlated. The digital and manual subtraction images were evaluated without knowledge of the surgical results using established criteria for component loosening. Digital subtraction arthrography of the femoral component demonstrated a 96% sensitivity and 100% specificity for the diagnosis of component loosening. Sensitivity and specificity for acetabular component loosening were 83% and 80%, respectively. Plain film subtraction of the femoral component demonstrated a 79% sensitivity and 100% specificity; the sensitivity and specificity for the acetabular component were 75% and 80%, respectively. The difference between detection of femoral component loosening on digital as opposed to manual subtraction images was statistically significant (P<0.05). This study demonstrates that digital subtraction improves the evaluation of femoral component loosening in painful hip prostheses.     

Radiological evaluation of painful total hip replacement

Ninety-four cases of clinically failed, cemented, total hip prostheses requiring surgery were reviewed to determine the accuracy of preoperative plain radiography, culture of aspirated fluid, arthrography, and bone scanning. When radiopaque cement had been used to embed the prosthesis, plain radiography was highly accurate in detecting a loose femoral component, less so in detecting a loose acetabular component. Culture of aspirated fluid was accurate in diagnosing infection. A positive arthrogram identified loosening with good accuracy; however, a negative arthrogram did not reliably exclude loosening. 99mTc bone scans frequently differentiated loosening from loosening with infection. The suggested sequence of diagnostic tests is plain radiography followed by bone scanning. If the bone scan shows diffuse augmented uptake, culture of aspirated fluid followed by arthrography is indicated.     

Diagnostic accuracy of magnetic resonance imaging and magnetic resonance arthrography of the hip is dependent on specialist training of the radiologist

Objective

Significant differences between magnetic resonance imaging reports and intraoperative findings at the time of hip arthroscopy were documented in our practice. We sought to examine the accuracy of radiological reporting of hip pathology based on the training level of the reporting radiologist.

Materials and methods

A retrospective review of hip arthroscopies carried out between July 2008 and June 2009 identified 61 cases where original MRI scans had been reported by general community radiologists. These scans were then reviewed by musculoskeletal specialist radiologists who were blinded to both the original report and the surgical findings. Accuracy of both subsets of radiologists was compared to arthroscopic findings with regard to labral, acetabular, femoral and impingement lesions.

Results

Musculoskeletal radiologists performed better than community radiologists in terms of overall accuracy. Accuracy rates for MSK radiologists were 85, 79, 59, and 82% for labral, acetabular chondrosis, and femoral chondrosis and impingement lesions, respectively. Whereas accuracy rates for community radiologists were 70, 28, 52, and 59% (p values?=?0.08, <0.001, 0.59, <0.001). Accuracy was significantly improved for both groups of radiologists when MR arthrograms were reviewed rather than conventional MRIs.

Conclusions

This study establishes the relationship between accuracy of reporting and the training level of the performing radiologists.     

Coronal radiographs and videofluoroscopy improve the diagnostic quality of temporomandibular joint arthrography

Detection of mediolateral displacement of the temporomandibular joint (TMJ) meniscus and evaluation of the reducibility of this displacement are necessary because surgery is indicated when the displacement is irreducible. During TMJ arthrography, the routine sagittal study does not allow detection of this type of meniscal displacement. In a prospective study of 158 TMJ arthrograms in 83 patients, coronal radiographs were obtained and videofluoroscopy was performed (in addition to routine sagittal films and fluoroscopy) to detect mediolateral shift of the meniscus and to evaluate the reducibility of this displacement. Both upper and lower joint spaces were opacified. Coronal and lateral radiographs were obtained with the mouth open and closed. On coronal images, in 79 cases (50%) the meniscus was shifted medially, in 22 cases (14%) laterally, and in 57 cases (36%) it was in the normal position. In 90 (89%) of the 101 abnormal cases, anterior displacement was associated with a mediolateral shift. In 59 cases (58%), the mediolateral shift was irreducible. Coronal and lateral views and fluoroscopy were reviewed separately by two observers, whose conclusions were identical for all cases. In 32 (54%) of the 59 joints with irreducible mediolateral displacement, surgery was performed. For all of these, comparison of radiologic data with surgical findings indicated that coronal views and videofluoroscopy were diagnostic, whereas mediolateral displacements were not detectable on routine sagittal studies.     

Digital subtraction arthrography in preoperative evaluation of painful total hip arthroplasty

 Objective. The objective of this clinical study was to define the diagnostic value of plain radiography, digital subtraction arthrography and two-phase bone scintigraphy in patients with clinically loose or infected hip prostheses. Design. Digital subtraction arthrograms, scintigrams and plain radiographs of 70 consecutive patients who underwent revision hip arthroplasty were scored individually and in masked fashion for the presence or absence of features indicating loosening of femoral and/or acetabular components. The operative findings acted as the gold standard. Results. Digital subtraction arthrography was best (P<0.001) for predicting a loose acetabular component, while no significant additional predictive value was found for plain radiographs (P=0.24) and scintigraphy (P=0.27). Digital subtraction arthrography was also the most important modality for predicting a loose femoral component (P=0.001), while the plain radiograph was of significant (P=0.04) additional value and scintigraphy was of no additional value (P=0.13) on multivariate analysis. Conclusion. Digital subtraction arthrography gives the best results in the prediction of loosening of acetabular and femoral components. Plain radiographs give additional information on loosening of the femoral component, but scintigraphy offers no additional advantage.     

Iliopsoas impingement on the acetabular component: radiologic and computed tomography findings of a rare hip prosthesis complication in eight cases

OBJECTIVE: To describe the radiographic and computed tomography (CT) scan features of iliopsoas impingement on the acetabular component (IPI) in total hip arthroplasty. METHOD: Eight cases of iliopsoas impingement were diagnosed and confirmed by surgical revision. The plain film radiograph findings and CT scan findings were compared with those of two control populations (8 patients with painless total hip prosthesis and 16 patients with other complications confirmed by surgical revision). RESULTS: An oversized cup was found in four hips with IPI (50%) and in one hip with another complication (6%). Coronal inclination of the acetabular cup was normal in the IPI group and in the two control groups, with a similar mean cup size. All patients with IPI had an acetabular cup overhang of more than 12 mm. Conversely, in the two control groups, the overhang, present in three and two cases, respectively, was always less than 8 mm. Iliopsoas bursal effusion was present in four hips with IPI and three hips with other complications and was never present in normal prostheses. CONCLUSION: More than a 12-mm overhang of the acetabular cup is a sensitive and specific parameter for diagnosing IPI.     

Sacrococcygeal chordoma

Sixty patients with sacrococcygeal chordoma, who were seen at this center between 1946 and 1985, were studied with particular attention to the radiographic findings. This study was undertaken because of the large number of these cases and comparison was made between the plain films available in 39 patients and the computed tomography CT studies in 22. Bone destruction was found in 78% on plain films but in 90% on CT. A soft tissue mass was identified in plain films in 60% but in 90% on CT. Calcific debris was found in plain films in 44% but in 87% on CT. Mostly the debris consisted of coarse irregular fragments and probably represented sequestrated necrotic bone. Myelography was performed in only 15 patients. Angiography was studied in 10 cases. Of the 60 patients 88% underwent surgical resection. The tumor recurred in 80% and in only 20% was there no evidence of recurrence. Distant metastases occurred in 24% of patients. Fifty percent survived 5 years; 28% survived 10 years; mean survival 7.5 years.     

Clearing the cervical spine in victims of blunt trauma

Cervical spine injuries occur in 2.3% to 6.4% of victims of blunt trauma. The difficulty of identifying the minority of patients with cervical spine injuries continues to challenge those who triage and treat the acutely injured. We retrospectively reviewed our practice for cervical spine clearance, which consists of three-view plain radiographs supplemented by focused further studies, such as computed or plain film tomography and flexion/extension views, as needed. Fifty-four patients with cervical spine injuries were identified during a 39-month period, which represented approximately 1% of the patients evaluated. Eighty cervical spine injuries were found, of which nine were missed. Review of the six patients in whom the nine cervical spine injuries were missed demonstrated error in the interpretation of radiographic studies in five patients, only two of whom were felt to have technically adequate films in hindsight. We conclude that a protocol based on three-view plain film radiographs supplemented by focused additional studies will allow the visualization of virtually all cervical spine injuries and that the main cause of missed injuries is errors of interpretation.     

Diagnosis of bowel infarction: a comparison of plain films and CT scans in 23 cases

We retrospectively reviewed abdominal CT and plain film findings in 23 proved cases of mesenteric infarction to compare the value of the two techniques. Criteria considered specific for infarction on CT were identified in nine (39%) of 23 patients and comprised pneumatosis in seven patients (30%), mesenteric or portal venous gas in three patients (13%), and focally thick-walled bowel in two patients (9%). Criteria considered specific for bowel infarction on plain films were identified in seven (30%) of 23 patients and comprised focally edematous bowel in six patients (26%) and pneumatosis intestinalis in one patient (4%). Only one patient had specific changes on both CT and plain films, but 15 (65%) of the 23 showed specific changes on at least one study. The results indicate that plain films remain an important tool in patients suspected of mesenteric infarction and can provide information that is complementary to CT. Also, as both studies were nonspecific in eight (35%) of our patients, negative or nonspecific findings should not deter further diagnostic or interventional procedures in patients in whom the clinical suspicion of bowel infarction is high.     

Diagnosis of pelvic fractures in patients with acute pelvic trauma: efficacy of plain radiographs.

Although CT is widely recognized as an important adjunct to plain films in the evaluation of patients with acute pelvic trauma, accurate diagnosis of orthopedic injuries with plain films alone is often important to determine if immediate external fixation is necessary. The purpose of this study was to determine the efficacy of plain radiographs in the detection of pelvic fractures and dislocations in patients with acute pelvic trauma by using CT as the gold standard. CT scans and plain films collected prospectively in 50 patients with acute pelvic injuries were evaluated independently, and fractures and dislocations were identified and tabulated. Of a total of 162 fractures and dislocations seen on CT, only 14 (9%) were misdiagnosed on plain films. None of these misdiagnoses altered patients' management. Sixteen (80%) of 20 cases of intraarticular fragments in the hip joint associated with acetabular fractures were not identified on plain films. We conclude that plain film examination of the patient with pelvic trauma is sufficient to identify virtually all clinically important fractures and dislocations. Plain radiographs alone are not accurate in detecting fracture fragments within the hip joint.     

Tibial stress phenomena and fractures: imaging evaluation

This study aims to evaluate the various imaging modalities used to diagnose tibial stress–fractures/phenomena and determine which of these are most useful and definitive. The plain film, computed tomography (CT), magnetic resonance (MR), and nuclear medicine findings in a 20-patient cohort, ranging from ages 10 to 21 years with an average of 16 years, were reviewed. The male to female ratio was recorded as was the incidence of right or left, or bilateral extremity involvement. Thereafter, each imaging modality was evaluated for positive findings. Twelve of the patients had pretibial swelling on plain films, 10 a thickened cortex, to a visible fracture on plain films and 13 had increased short-tau inversion recovery (STIR) signal in the post tibial (marrow) and pretibial (subperiosteum) areas on MR imaging. No CT studies were performed. One positive nuclear medicine study was available. Although there are a number of imaging modalities which can be used to evaluate the tibial stress/fracture phenomena problem, it would appear that plain films and MR studies are most useful. If plain films do not show a fracture and further information is required, an MR study is most appropriate.     

全髋置换术后首次X线平片在评估假体稳定性中的临床价值

目的研究全髋置换术后首次X线平片在评估假体稳定性中的临床价值。方法初次全髋置换术患者53例,观测术后首次术侧髋关节正位片中假体周围骨质情况、人工髋臼的前倾角和外展角、假体柄位置;与其后1 a内复查片对比,观察假体的变化。结果术后1 a内发生假体不稳定共6髋,其中脱位3髋,假体周围骨折1髋,假体与骨界面之间出现连续宽度大于等于2 mm的透亮线2髋。术后首次X线平片中的假体周围骨质情况、人工髋臼的前倾角和外展角、假体柄位置均与假体稳定性的判断密切相关,P<0.05。结论全髋关节置换术后首次X线平片能预测短期内发生假体不稳定的风险,具有重要的临床价值。     

Arthrographic study of painful total hip arthroplasty: refined criteria

The criteria for a diagnosis of loosening or infection of hip arthroplasties on arthrographic study were further refined by a retrospective review of 178 arthrograms representing 170 patients. The 97 arthroplasties that were surgically evaluated form the basis of this report. With the refined criteria, subtraction arthrography had a sensitivity of 96% and specificity of 92% for demonstrating loosening of the femoral component and a sensitivity of 97% and a specificity of 68% for demonstrating loosening of the acetabular component. Pseudocapsule size and the presence of bursae were important factors influencing arthrographic interpretation. Arthrographic findings of pseudocapsule irregularity and the presence of nonbursal cavities were suggestive of infection but were not sensitive or specific. Laboratory evaluation of aspirated material was a more reliable predictor of infection, although its sensitivity was only 71%.     

Diagnosis of cruciate ligament injury using single contrast arthrography

To evaluate the accuracy of arthrography for assessing the status of the anterior cruciate ligament (ACL), 212 arthrograms from 212 knees in 205 consecutive patients undergoing single contrast arthrography and subsequent arthroscopy or arthrotomy were reviewed. Criteria for evaluation of the ACL included the clarity of its radiographic appearance as well as the anterior laxity of the knee as seen on manual stress views. Of the 111 knees having intact ACLs at surgery, 98 (88%) were evaluated correctly by arthrography. Of the 101 knees having a damaged ACL, 85 were read as torn or attenuated on the arthrogram. When the torn and attenuated ligaments were considered separately, accuracy was decreased. Of the 87 ligaments actually torn, 68 (78%) were read as torn and 9 (10%) as attenuated. Of the 14 actually attenuated, 5 (36%) were read as attenuated and 3 (21%) as torn. Of 114 arthrograms read as intact, 98 (86%) were correct. Of 77 arthrograms read as torn, 68 (88%), were correct. Of 21 arthrograms read as attenuated, 5 (24%) were correct. Of 114 torn medial menisci, 112 (98%) were correctly diagnosed, as were 38 (69%) of 55 torn lateral menisci. Sixteen of the 17 missed lateral meniscus tears were in knees with torn medial menisci. Single contrast arthrography is, therefore, highly accurate in distinguishing intact from damaged ACLs. The distinction between torn and attenuated ligaments, however, is not valuable.     

发育性髋关节发育不良：影像检查新观点

目前,发育性髋关节发育不良（DDH）的诊断主要依靠超声及X线平片。超声的敏感性虽高,但观察者依赖性强,容易造成过度诊断;X线平片仅能观察骨性髋关节的形态,不能显示软骨部分,然而髋臼软骨对髋关节的稳定具有重要作用。由于MRI软组织分辨力高,可清晰显示髋臼软骨并进行定量测量,还可显示影响髋关节复位的软组织成分,因此MRI在DDH的诊断和治疗的应用越来越广泛。综述影像检查在DDH诊断中的新观点和思路,特别是MRI在评估髋关节发育中的应用价值。     

The use of forced flexion/extension views in the obtunded trauma patient

OBJECTIVE: To determine whether forced flexion/extension (F/E) films for "clearing" the cervical spine in unconscious or semiconscious patients are useful or actually dangerous. DESIGN AND PATIENTS: Of 810 patients admitted for blunt trauma over a 5-year period, 479 patients whose films and charts were available received passive F/E film views of the cervical spine. Of these, 447 were reviewed retrospectively in masked fashion for any exacerbation of neurological changes subsequent to the procedure and with respect to the final neurological status at discharge. RESULTS: Twenty-nine patients (6%) had various abnormalities including fractures and ligamentous injuries seen on the initial films. Following forced F/E films no change was made in the diagnosis of 23 patients. Of the remaining six patients, two required no treatment, two only required the use of a collar but two did have surgical intervention, this decision being based on the findings seen in the initial films. However, 285 films (59%) were judged inadequate due either to inadequate F/E (150 patients, 31%) or poor visualization (194 patients, 40%). There were three false positives all subsequently cleared by other studies and there were no false negatives. From the chart review, there were no complications or deaths attributable to the procedure. CONCLUSION: Although we were unable to find any complication or deaths directly attributable to the procedure, the clinicians abandoned passive F/E views in obtunded patients on the grounds of expense. Our present method of "clearing" a cervical spine in an obtunded patient is a cross-table lateral radiograph followed by a high-resolution thin-slice CT scan with sagittal and coronal reconstruction. We are against the use of routine MRI studies and of a forced F/E view in these patients.     

Obturator externus bursa: prevalence of communication with the hip joint and associated intra-articular findings in 200 consecutive hip MR arthrograms

The purpose of the study was to demonstrate the prevalence of communication between the hip joint and the obturator externus bursa on hip MR arthrography. Following institutional review board approval, 200 hip MR arthrograms in 196 subjects were independently reviewed by two musculoskeletal radiologists. Discrepancies were resolved by adjudication. The presence or absence of communication between the hip joint and the obturator externus bursa was recorded. Associated lesions involving the acetabular labrum and articular cartilage were recorded. The obturator externus bursa was shown to communicate with the hip joint in 11 of the 200 (5.5%) hip MR arthrograms. Of these, six were in men and five were in women. The age range was 15–63 years with a mean age of 34 years. All 11 patients had labral tears. Eight of the 11 had cartilage lesions. The obturator externus bursa can be seen to communicate with the hip joint in 5.5% of hip MR arthrograms. Associated labral and cartilage lesions are common.     

The value of contrast arthrography in assessing loosening of symptomatic uncemented total hip components

Twenty-five patients with symptomatic uncemented total hip components were studied with contrast arthrography prior to surgical exploration. All but one had uncemented femoral stems and 16 had an uncemented acetabular component. As judged by the findings at surgery, on the femoral side the sensitivity, specificity, and accuracy of arthrography were 57%, 60%, and 58% respectively. There was a relatively high incidence of both false positives (17%) and false negatives (25%). On the acetabular side sensitivity, specificity, and accuracy were 29%, 89%, and 62.5%. False negatives were common (31%), while there was only one false positive. The results in this small series show that arthrography has distinct limitations in identifying the fixation status of uncemented total hip components.     

军团菌肺炎的胸部CT表现（附14例分析）

目的：了解军团菌肺炎的ＣＴ表现特点及ＣＴ能否提供较平片更多有利于本病诊断及治疗的信息，材料与方法，收治１４例经临床及血清学证实的军团菌肺炎患者，分析其胸部ＣＴ表现特点，并与平片进行对比分析，结果：ＣＴ扫描示病变呈多叶段受累者１１例，大片及斑片状阴影为最常见的表现，见于本组１０例患者，空洞病变３例，其中１例似金葡萄菌肺炎表现余１列表现双肺弥漫毛玻璃密度及索条影，在本组病例中，１０例伴胸腔积及胸膜肥厚