The value of pre-operative aspiration in the diagnosis of an infected prosthetic knee: a retrospective study and review of literature

The purpose of this study was to compare the results of cultures of preoperative aspiration samples with those of swabs taken intra-operatively. The records of 70 revision arthroplasties of the knee from 69 patients, 49 females and 20 males, were reviewed. The mean age of the patients at time of revision arthroplasty was 67 years (range: 34 to 89). Sixty-eight knees from 67 patients were included. There were 32 true positives, 17 true negatives, 6 false positives and 13 false negatives. This led to a specificity, sensitivity and accuracy of 57%, 84% and 72%, respectively. Based on these findings, pre-operative aspiration has a positive predictive value of 71% and a negative predictive value of 74%. When the aspiration sample yields a positive culture, the chances are high that the prosthetic knee is infected. When aspiration is negative, infection cannot be ruled out. Our study suggests that, in such cases, a coagulase negative Staphylococcus (CNS) infection has to be considered.     

Evaluation of preoperative ProstaScint scans in the prediction of nodal disease

Diagnostic methods are limited for detecting microscopic soft tissue metastases in patients with prostate cancer. Previous studies using (111)Indium Capromab Pendetide (ProstaScint scan) analyzed patients with extensive localized tumor (prostate specific antigen (PSA) >20 ng/ml) not optimal for surgical therapy. We evaluated the role of the ProstaScint trade mark scan in a preoperative population to provide histological documentation and to assess its utility in a surgical population. A total of 22 preoperative patients, underwent a ProstaScint scan. The mean preoperative PSA was 16.0 ng/ml (range 3.9-33 ng/ml). The mean Gleason score at biopsy was 6.9 (range 6-9). Each patient underwent a radical retropubic prostatectomy and bilateral pelvic lymph node dissection, which included resection of both obturator and common iliac lymph nodes. Histologic analysis of the resected lymph nodes provided the standard of comparison with the ProstaScint scan. The results of the scan and pathology for all 22 patients were compared with the bilateral obturator and iliac nodes, creating 88 data points. Nine areas (10%) were positive on the scan. One of these (11%) was a true positive while the other eight (89%) were false positives. Seventy-nine areas (90%) were negative on scan results. Of these, five areas (6%) were false negatives and 74 areas (94%) were true negatives. The scan yielded a sensitivity of 17%, specificity of 90%, negative predictive value (NPV) of 94% and a positive predictive value (PPV) of 11%. The high false positive rate and low PPV of ProstaScint scans overestimates metastatic lymph nodes disease, and is not useful when used preoperatively.     

Endoscopic and histological criteria for preoperative evaluation of the depth of infiltration of gastric carcinoma

Because the therapeutic approach to gastric carcinoma differs according to the stage of development, a study was carried out to investigate whether there are any factors which would allow the depth of infiltration of a gastric carcinoma to be evaluated preoperatively. The criteria used were endoscopic and histological. The first provide information on size and macroscopic aspect; the second reveal the relationship between bioptic specimens that are positive for carcinoma and those that are negative. On the basis of these standards, small, benign-looking neoplasias with bioptic positivity for carcinoma lower than 30% were classified as probably early. Of the 200 gastric carcinomas investigated, 55 were considered probably early and 145 probably advanced. Surgical fragment findings confirmed the diagnosis in 169 cases (37 true negatives and 132 true positives) and failed to confirm it in the other 31 cases (13 false positives and 18 false negatives). The specificity, sensitivity, negative predictive value, positive predictive value, and total diagnostic accuracy indices were 74.00%, 88.00%, 67.27%, 91.03%, and 84.50%.     

Reliability of MRI Findings of Peroneal Tendinopathy in Patients with Lateral Chronic Ankle Instability

Background

Patients with chronic lateral ankle instability also have peroneal tendinopathy often. However, preoperative MRIs of these patients are vague in many cases. Our study was performed to see the reliability of MRI findings of peroneal tendinopathy in patients with chronic lateral ankle instability.

Methods

MRI images for 82 patients who had chronic lateral ankle instability, and had received surgical treatment between March 2006 and November 2009 were compared with impressions from operating rooms. The mean age of patients was 36.4 years (range, 15 to 64 years), 82 ankles were studied, and patients with rheumatoid diseases were excluded from the study.

Results

Of the 82 cases, 26 were true positives, 38 true negatives, 13 false positives and 5 false negatives. Of 39 cases of peroneal tendinopathy diagnosed from MRI, 14 had peroneal tendon partial tears, 15 tenosynovitis, 3 dislocations, 17 low-lying muscle bellies, and 6 peroneus quartus muscles. Of 31 cases of peroneal tendinopathy observed in surgery 11 had peroneal tendon partial tears, 4 tenosynovitis, 5 dislocations, 12 low-lying muscle belliess, and 1 peroneus quartus muscle. Sensitivity and specificity of peroneal tendinopathy were 83.9% and 74.5%, respectively. Positive predictive value was 66.7%. Negative predictive value was 88.4%. Accuracy rate was 78.0%.

Conclusions

MRI is a useful diagnostic tool for detecting peroneal tendinopathy in patients with chronic lateral ankle instability. However, MRI is vague in many cases. Therefore, a thorough delicate physical examination and careful observation is needed.     

Myxoid liposarcoma of the ankle: a case report

Myxoid liposarcoma occurs predominantly in the deep soft tissues of the extremities, and tends to metastasize to a wide range of soft tissue or bone locations. We report a case of myxoid liposarcoma arising in the ankle of a 19-year-old man. A diagnosis of myxoid liposarcoma was made by open biopsy, and a wide resection requiring plastic surgical reconstruction was performed. Cytogenetic analysis of the resected tumor exhibited a reciprocal translocation t(12;16)(q13;p11) as the sole anomaly, which is found in more than 90% of myxoid liposarcoma cases. The patient had no evidence of local recurrence or metastasis within 7 years of follow-up. Although myxoid liposarcoma is rare in the ankle, it should be considered in the differential diagnosis of a painless soft tissue mass in this region.     

Surgical management of primary hyperparathyroidism: the case for giving up quick intraoperative PTH assay in favor of routine PTH measurement the morning after

OBJECTIVE: To analyze the utility of quick intraoperative parathyroid hormone (PTH) measurement in the surgical management of primary hyperparathyroidism. BACKGROUND DATA: The use of intraoperative PTH monitoring is well established in the surgery of primary hyperparathyroidism. However, some false-negative predictions lead to unnecessary explorations; furthermore, surgeons are becoming increasingly dependent on hormone measurement for intraoperative decisions, which raises concerns about the cost-effectiveness of the method. METHODS: A retrospective analysis of 268 neck explorations performed for primary hyperparathyroidism using intraoperative PTH monitoring from April 2001 to February 2003 was done. We used the criterion of "biologic recovery" of hyperfunctioning tissue, defined as a more than 50% decrease in PTH level from baseline value at 5 minutes after excision to predict the outcome of successful parathyroidectomy documented by normal postoperative serum calcium level. Additionally, we also sampled PTH at 10 minutes, 30 minutes, and the morning after surgery to compare the predictive value of delayed sampling. Patients were classified according to the prediction being concordant or discordant with the outcome. The data were analyzed using a 2 x 2 table construct for each of the sampling times, therefore providing sequential sensitivity, specificity, positive and negative predictive values, and overall accuracy of the predictions. RESULTS: Concordance or overall accuracy of prediction (true positives and negatives) was obtained in 229 cases (85.4%), and discordance or failure of prediction (false positives and negatives) was obtained in 34 cases (12.7%) at T5. On analyzing the iPTH prediction at T10, T30, and D1 among the group of 33 false negatives, we found that 28 (10.4%) patients reached the concordance at 30 minutes, while by the first day 32 patients (12.3%) had achieved concordance. Thus, there was a progressive increase in sensitivity and overall accuracy, but more importantly, in the negative predictive value reaching 88.9% on the day after surgery. CONCLUSIONS: The method of sampling PTH intraoperatively at 5 minutes has a high positive predictive value (99.5%) but a low negative predictive value (19.5%), which can lead to unnecessary explorations and a delay in the operative procedure. The negative predictive value increases substantially at 30 minutes and is best on the day after surgery. We suggest giving up the intraoperative measurement of PTH to adopt the first day postoperative measurement of PTH as a predictor of successful parathyroidectomy.     

Magnetic Resonance Imaging of Diabetic Foot Osteomyelitis: Imaging Accuracy in Biopsy-Proven Disease

Magnetic resonance imaging (MRI) is the recommended diagnostic imaging technique for diabetic foot osteomyelitis (DFO). The gold standard to diagnose osteomyelitis is bone biopsy with a positive culture and/or histopathology finding consistent with osteomyelitis. The purpose of this study is to assess the accuracy of MRI readings in biopsy-proven diabetic foot osteomyelitis with a second read done by a blinded, expert musculoskeletal radiologist. A retrospective chart review of 166 patients who received a bone biopsy to confirm the diagnosis of a suspected DFO at a large county hospital between 2010 and 2014. A second, blinded musculoskeletal radiologist reviewed the images for accuracy, once the official reading was recorded. Imaging results were correlated with the final diagnosis of osteomyelitis determined by bone biopsy. In 17 of 58 patients (29.3%), the diagnosis of DFO by MRI was not confirmed by bone biopsy. There were 12 false positives and 5 false negatives. After the second expert read, there were 5 false positives and 4 false negatives. The overall accuracy was 84% for the second read. Our study demonstrated results comparable to the previously reported meta-analysis findings. There is a clear variation on the read of MRI that could lead to an incorrect diagnosis of DFO. An integrated approach with evaluation of clinical findings, communication with radiologist about the MRI results when indicated, and bone biopsy is warranted for accurate diagnosis management of DFO.     

Computed tomography in the evaluation of the aorta in patients sustaining blunt chest trauma

Computed tomography is used with increasing frequency to evaluate blunt chest trauma. Since traumatic aortic rupture (TAR) is a rapidly lethal condition, unnecessary CT scanning may not be justified. To determine the accuracy of chest CT scanning for TAR, we reviewed 17 patients who underwent both chest CT scanning and aortography. Five patients had TAR by aortography. CT scanning yielded three true positives and two false negatives. In 12 patients with a negative aortogram, CT scanning recorded four false positives and eight true negatives. The specificity was 23% and the sensitivity was 83% compared with aortography. The overall accuracy for CT scanning was 53%. From these data we conclude that in the presence of an unstable patient or where there is a strong clinical suspicion of TAR the patient should proceed directly to aortography.     

Validity of acoustic quantification colour kinesis for detection of left ventricular regional wall motion abnormalities: a transoesophageal echocardiographic study

Transoesophageal echocardiography is a sensitive monitor for intraoperative myocardial ischaemia. Colour kinesis is a new technology for echocardiographic assessment of regional wall motion based on acoustic quantification. We have examined the feasibility and accuracy of quantitative segmental analysis of colour kinesis images to provide objective evaluation of systolic regional wall motion during the perioperative period using transoesophageal echocardiography (TOE). Two- dimensional echocardiograms were obtained in the transgastric short- axis and long-axis views in 60 patients with coronary artery disease undergoing noncardiac surgery. End-systolic colour overlays superimposed on the grey scale images were obtained with colour kinesis to colour encode left ventricular endocardial motion throughout systole. These colour-encoded images were divided into segments and compared with corresponding conventional two-dimensional images. Six hundred of a potential 720 left ventricular wall segments were of sufficient resolution for grading by experts; they diagnosed wall motion abnormalities in 61 of these segments by a conventional method. In comparing the conventional TOE method with colour kinesis, there were 60 true positives, 482 true negatives, 57 false positives and 1 false negative result. This yielded a sensitivity of 98%, specificity of 89%, positive predictive value of 51% and negative predictive value of 100%. Translational and rotational movement of the heart and papillary muscle interference were common problems accounting for false positive diagnoses. We conclude that colour kinesis provides a basis for objective and on-line evaluation of left ventricular regional wall motion which is a sensitive but non-specific method. It may be a useful aid for the less experienced because it can potentially direct the anaesthetist's attention towards specific segments.      

The ultrasound screen for penetrating truncal trauma

A prospective blinded pilot study was performed at an urban level 1 trauma center to evaluate the efficacy of ultrasound in ruling out penetrating visceral truncal injury. For 8 months, 49 nonconsecutive patients who presented with truncal gunshot and stab wounds were evaluated by a 10-MHz ultrasound tranducer probe. The deepest muscle bundle and the fascia enveloping it was examined by ultrasound. These images were compared to the equivalent contralateral unaffected side of the patient. All the patients then underwent standard testing to evaluate for potential intracavitary injury. Forty-nine patients with a mean age of 28 years (SD, 8.8) were evaluated by ultrasound. A total of 58 injuries were evaluated of which 37 were stab wounds and 21 were gunshot wounds. Thoracoabdominal and back and flank injuries were the most commonly evaluated injuries. There were 20 true positives, 20 false positives, and 18 true negatives, each with approximately twice as many stab as gunshot wounds. There were no false negatives. The sensitivity and negative predictive value of ultrasound in determining clinically significant truncal visceral injury in penetrating truncal trauma is 100 per cent. The specificity and positive predictive value are both approximately 50 per cent. Ultrasonic examination of the injured abdominal wall layers in truncal penetrating trauma is an excellent screening tool. Simple comparative assessment with the unaffected contralateral side allows a highly sensitive method of decreasing the number of potentially morbid, time consuming, and expensive tests that are currently employed to rule out visceral injury.     

Selective use of ultrasonography for acute appendicitis in children

BACKGROUND: To evaluate the role of ultrasonography in children with equivocal signs of acute appendicitis, and correlate with initial clinical impression and pathological findings. METHODS: This is a prospective evaluation of all children presenting with a possible diagnosis of appendicitis during a 14-month study period. Patients with unequivocal clinical signs of appendicitis underwent appendectomy without ultrasonography. Patients with equivocal signs had documentation of the clinical impression and subsequent abdominal ultrasound. Statistical analysis of results was performed using the chi-square test (P <0.05 significant). RESULTS: Two hundred fifteen consecutive children were enrolled. Signs were unequivocal in 116 and equivocal in 99. Seven patients in the first group had a normal appendix at operation. Of the 99 patients with equivocal signs, there were 28 true positives, 3 false positives, 64 true negatives, and 4 false negatives. In equivocal cases, sensitivity of the initial clinical impression versus ultrasound was 50% and 88%, respectively (P <0.05). Specificity was 85% and 96%, respectively. The positive and negative predictive values improved from 63% to 90% and 78% to 94%, respectively, with the use of ultrasonography. CONCLUSIONS: The low false positive rate (6%) in clinically obvious cases of appendicitis does not, in our opinion, warrant ultrasonography. In clinically equivocal cases, ultrasonography is a fast, sensitive, and specific diagnostic modality to diagnose or rule out appendicitis, avoiding the need for prolonged observation and/or hospitalization.     

Negative MRI findings in knee injury: clinical implications

Magnetic resonance imaging (MRI) is now commonly used to diagnose knee pathology. Based on results in a study conducted in a private practice setting, the diagnostic value of MRI for all articular cartilage surfaces, menisci, ligaments, and soft tissue structures of the knee was determined. Subjects included 102 consecutive patients undergoing arthroscopic knee surgery for whom MRI findings also were available. Sensitivity, specificity, accuracy, positive predictive value (PPV), and negative predictive value (NPV) of MRI were calculated. Sensitivity was highest for meniscus tears: 73.2% for medial tears and 63.3% for lateral tears. Sensitivity for other pathologies was poor, ranging from 26.2% for chondromalacia of the patella to 11.1% for loose bodies. Negative predictive values were variable, ranging from 84.3% for lateral meniscus tears to 39.2% for chondromalacia of the patella. MRI for most pathologies had an NPV between 50 and 75%. Results indicate a high rate of false negative MRI findings.     

Magnetic resonance and cadaveric findings of the incidence of plantaris tendon

A retrospective review of 63 Magnetic Resonance Image studies (yielding 86 ankles) was conducted to find the incidence of the plantaris tendon. Radiographically, the plantaris tendon was visualized 62.8% of the time. Surgical confirmation of this tendon during 18 achilles surgeries yielded 13 "true positives" and 4 "true negatives". Sensitivity was 92.8%; specificity and positive predictive value was 100%, respectively. As a comparison, forty cadaveric specimens were evaluated as well, with the incidence of the plantaris found to be 97.5%. These findings may be useful when considering MRIs as a screening tool for the presence of plantaris tendon. When axial images were 4 mm or less, the plantaris tendon was more easily visualized. A Chi-squared test examining for differences of axial sections greater than 4 mm was not significant. (P=0.2). This is important if one is to use MRI to screen for the plantaris (for graft purposes).     

MRI在急性肩袖间隙损伤中的诊断价值

目的:对比分析1.5 T 磁共振在急性肩袖间隙损伤中的临床应用价值.方法:回顾性分析自2016 年3 月至2019 年2 月经临床诊断并分别行MRI、关节镜检查的急性肩袖撕裂患者160 例,男122 例,女38 例,年龄22～71(42.35±3.48)岁.以关节镜检查结果为金标准,通过MRI 轴位、斜冠状位、斜矢状位...     

THE VALUE OF TECHNETIUM-99M RENOGRAPHY FOR THE DETECTION OF RENAL ARTERY STENOSIS IN PATIENTS WITH AORTIC AND LOWER LIMB VASCULAR DISEASE

The results of technetium renography were compared with arteriography to determine whether this is a satisfactory screening test for renal artery stenosis (RAS). Sixty-three patients were studied before aortic surgery. All were investigated by aortography and isotope renography. These tests were assessed blind and all arteriograms were graded by a single independent radiologist. Renal artery stenosis was detected by arteriography in 34 (54%) patients. Twenty-three (37%) had mild (< 50%) stenosis, seven (11%) had moderate (50–80%) stenosis and four (6%) had severe (> 80%) stenosis. Of these 34 patients, only 6 (18%) were correctly diagnosed by isotope renography. None of the four with severe stenosis were identified. Isotope renography resulted in six true positives, six false positives, 23 true negatives and 28 false negatives. It was concluded that isotope renography did not fulfil the criteria for a screening test for the detection of RAS and appeared to be of no value in those patients undergoing aortic surgery in whom arteriography was not indicated.     

The value of technetium-99M renography for the detection of renal artery stenosis in patients with aortic and lower limb vascular disease.

The results of technetium renography were compared with arteriography to determine whether this is a satisfactory screening test for renal artery stenosis (RAS). Sixty-three patients were studied before aortic surgery. All were investigated by aortography and isotope renography. These tests were assessed blind and all arteriograms were graded by a single independent radiologist. Renal artery stenosis was detected by arteriography in 34 (54%) patients. Twenty-three (37%) had mild (less than 50%) stenosis, seven (11%) had moderate (50-80%) stenosis and four (6%) had severe (greater than 80%) stenosis. Of these 34 patients, only 6 (18%) were correctly diagnosed by isotope renography. None of the four with severe stenosis were identified. Isotope renography resulted in six true positives, six false positives, 23 true negatives and 28 false negatives. It was concluded that isotope renography did not fulfil the criteria for a screening test for the detection of RAS and appeared to be of no value in those patients undergoing aortic surgery in whom arteriography was not indicated.     

Combined [<Superscript>18</Superscript>F]Fluorodeoxyglucose Positron Emission Tomography and Computed Tomography (FDG-PET/CT) for Detection of Recurrent, <Superscript>131</Superscript>I-Negative Thyroid Cancer

Background Whole-body ¹³¹I scintigraphy (WBS) and serial thyroglobulin measurement (Tg) are standard methods for detecting thyroid cancer recurrence after total/near total thyroidectomy and ¹³¹I ablation. Some patients develop elevated Tg (Tg-positive) or there is clinical suspicion of recurrence, but WBS are negative (WBS-negative). This may reflect non-iodine-avid recurrence or metastasis. In 2002, the Centers for Medicare and Medicaid Services (CMS) approved positron emission tomography with [¹⁸F]fluorodeoxyglucose (FDG-PET) for Tg-positive/WBS-negative patients with follicular-cell-origin thyroid cancer. Limited data are available regarding the performance of combined FDG-PET/computed tomography (FDG-PET/CT) for detecting recurrent thyroid cancer in WBS-neg patients. Methods This retrospective review of prospectively collected data analyzed 65 patients who had FDG-PET/CT for suspected thyroid cancer recurrence (April 1998–August 2006). Patients were WBS-negative but were suspected to have recurrence based on Tg levels or clinical grounds. Suspected FDG-PET/CT abnormalities were reported as benign or malignant. Lesions were ultimately declared benign or malignant by surgical pathology or clinical outcome (disease progression). Results Of 65 patients who underwent FDG-PET/CT, 47 had positive FDG-PET/CT. Of the positive FDG-PET/CT, 43 studies were true positives, with 21 (49%) confirmed pathologically by surgical resection. The four false positives (3/4 confirmed pathologically) included an infundibular cyst, an inflamed supraclavicular cyst, pneumonitis, and degenerative disc disease. Of the 18 FDG-PET/CT studies that were negative, 17 were true negatives and one was a false negative (metastatic papillary carcinoma). Thus, FDG-PET/CT demonstrated a patient-based sensitivity of 98%, specificity of 81%, positive predictive value of 91%, and negative predictive value of 94%. Conclusions FDG-PET/CT is useful for detecting thyroid cancer recurrence in WBS-negative patients, and can assist decision making.     

THE CLINICAL ROLE OF SHOULDER ULTRASOUND

Background : Rotator cuff surgery is facilitated by accurate pre-operative information regarding the presence and size of cuff tears, and the extent of any cuff retraction or lamination. Methods : A total of 117 consecutive patients who underwent shoulder ultrasound followed by surgical management were assessed, and the pre-operative ultrasound diagnoses were correlated with the operative findings. Results : Ultrasound was found to be reliable for the detection of full-thickness cuff tears (positive predictive value 96%). In the assessment of partial thickness tears, ultrasound produced few false positives, but failed to diagnose a significant proportion of these lesions. Lamination and other interstitial cuff pathology were not reliably detected by ultrasound. In the diagnosis of subacromial impingement, ultrasound produced few false positives (positive predictive value 95%), but did produce a significant number of false negative results (negative predictive value 66%). Conclusions : Ultrasound is cheaper than MRI and arthrography, and is both non-invasive and ‘dynamic’. It is reliable in the diagnosis of full-thickness cuff tears and is a useful adjunct in the diagnosis of cuff impingement and partial thickness tears, but is very much operator-dependent.     

A crossover comparison of four peripheral bone-site measurements to identify central osteopenia and osteoporosis in women

The objective of this study was to assess the ability of four peripheral bone measurement sites to predict low bone mineral density of the lumbar spine, femoral neck, and total hip as defined by the WHO classification, and to evaluate their role as a screening procedure for central dual-energy X-ray absorptiometry (DXA). One thousand three hundred white women patients aged 58.3+/-13.9 years were enrolled. Correlations between the peripheral and central sites were moderate, varying between 0.51 and 0.67. In receiver-operating characteristic (ROC) analysis, the areas under the curve for the peripheral sites revealed a few small, but significant, differences between sites. The optimal cut-point was derived from the ROC data for each site to assess its value as a screening parameter. These proved to be unsatisfactory, because the average number of false positives and false negatives were 18% and 24%, respectively. A proposal is made which entails two cut-points, one for an acceptable percentage of false negatives and the other for an acceptable number of false positives. Patients with t-scores between these cut-points would be referred for central DXA for classification. The result is a substantial decrease in the number of false negatives, i.e., patients who would be candidates for treatment. The contentious issue is what proportion of supplemental DXAs is considered logistically and economically acceptable for any of the peripheral site measurements to be useful.