A Biomechanical Comparison of the Effect of Baseplate Design and Bone Marrow Fat Infiltration on Tibial Baseplate Pullout Strength.

BACKGROUND: Early clinical results of a new total knee arthroplasty (TKA) implant design show promise for improved outcomes and patellofemoral function scores. However, reports of early tibial component-cement interface debonding requiring revision have been published. This study investigated the biomechanical properties of three different tibial baseplates to understand potential causes of failure. METHODS: PFC Sigma (control), Attune (1st generation) and Attune S+ (2nd generation) tibial baseplates were implanted into 4th generation sawbone tibia models using a standardized technique. Three of each baseplate were cemented with and without additional bovine bone marrow fat. All models were tested to failure with measured axial distraction force. Implant type, presence or absence of bovine marrow and load to failure were all recorded and compared. Two-way ANOVA followed by post-hoc pairwise comparisons were used to determine statistical significance, which was set to P < .05. RESULTS: The 2nd generation tibial baseplates required significantly more force to failure. The presence of bovine marrow significantly reduced the pullout force of the implant designs overall. No significant difference was detected between the 1st generation and control baseplates. Failure mode for each model was also noted to be different irrespective of the presence or absence of bone marrow fat. CONCLUSION: The 2nd generation baseplates required significantly more force to failure compared with older designs. The presence of bone marrow during cementation of a tibial base plate significantly decreased axial pullout strength of a tibial baseplate in this laboratory model. All 1st generation baseplates exhibited debonding at the cement-implant interface.

Arthroscopic Versus Open Rotator Cuff Repair: Fellowship-Trained Orthopaedic Surgeons Prefer Arthroscopy and Self-Report a Lower Complication Rate.

PURPOSE: To evaluate whether fellowship training had an effect on the practice pattern and complication rates among Part II examinees of the American Board of Orthopaedic Surgery (ABOS) for rotator cuff repair (RCR) from 2007-2017. METHODS: The ABOS database was queried for arthroscopic (Current Procedural Terminology [CPT] code 29827) and open/mini-open (CPT codes: 23410, 23412) RCR performed from 2007-2017. Excluded were procedures that did not included CPT codes 29827, 23410, 23412. A comparison between arthroscopic and open/mini-open use as well as self-reported complications were assessed based on recorded fellowship training. RESULTS: A total of 31,907 RCR were reported over the past 10 years (2007-2017). The percentage of RCR procedures performed using arthroscopic technique vs open/mini-open varied among surgeons who completed one fellowship: Sports Medicine (92.5 % arthroscopy; 7.5 % mini/open), Shoulder & Elbow (91.3 % arthroscopy; 8.7% mini/open), and Hand & Upper Extremity (69.6 % arthroscopy; 30.4 % open). Total complication rates varied among surgeons who completed one fellowship: Sports Medicine (11.5 %), Shoulder & Elbow (13.5 %), and Hand & Upper Extremity (13.4 %). Surgeons completing one fellowship in either Sports Medicine, Shoulder & Elbow, Hand & Upper Extremity all reported significantly lower complication rates using arthroscopic over mini/open technique (P < .001). CONCLUSIONS: Among ABOS Part II examinees completing a Sports Medicine, Shoulder and Elbow or Hand and Upper Extremity fellowship, Sports Medicine trained surgeons had significantly greater rates of performing arthroscopic over open RCR and significantly lower self-reported intraoperative complication rates. CLINICAL RELEVANCE: Understanding the effects of fellowship training may guide mentors and future trainees.

Arthroscopic and Open or Mini-Open Rotator Cuff Repair Trends and Complication Rates Among American Board of Orthopaedic Surgeons Part II Examinees (2007-2017).

PURPOSE: To ascertain trends and reported complication rates of arthroscopic and open or mini-open rotator cuff repairs (RCRs) reported by American Board of Orthopaedic Surgery (ABOS) Part II examinees between 2007-2017. METHODS: The ABOS database was queried for both arthroscopic RCR (International Classification of Diseases code 29827) and open or mini-open RCR (International Classification of Diseases codes 23410 and 23412) performed by Part II examinees from 2007-2017. A comparison between overall procedure rates, as well as reported complications (anesthetic, medical, surgical, reoperations, and readmissions) associated with the respective repair technique, was performed. RESULTS: From 2007-2017, a total of 31,907 RCRs were reported by Part II examinees. Of those, 85.2% (n = 27,189) were arthroscopic whereas 14.8% (n = 4,718) were open or mini-open. The rate of arthroscopic RCR increased from 73% (n = 2,138) in 2007 to 90% (n = 2,031) in 2017, whereas the rate of open or mini-open RCR decreased from 27% (n = 771) to 10% (n = 234) during the same period. Rates of reported annual complications were significantly lower for arthroscopic RCR (7.4%-16.2%) than for open or mini-open RCR (12.9%-30.3%) for each of the past 6 years (2012-2017) (P < .001). Arthroscopic RCR had an overall lower cumulative occurrence of complications than open or mini-open RCR over the past decade (2007-2017) (P < .001). The relative risk of complications for arthroscopic RCR compared with open RCR was 0.71 (95% confidence interval, 0.66-0.77). CONCLUSIONS: ABOS Part II examinees reported an increased practice of arthroscopic RCR in comparison with open or mini-open RCR over the past 10 years. Reported annual complication rates have been significantly lower for arthroscopic RCR over the past 6 years, with an overall lower cumulative rate from 2007-2017. LEVEL OF EVIDENCE: Level III, retrospective cohort study.

Capnocytophaga canimorsus Periprosthetic Joint Infection in an Immunocompetent Patient: A Case Report.

INTRODUCTION: A periprosthetic joint infection (PJI) is a potentially devastating complication following an arthroplasty procedure. There are many organisms that commonly cause this complication; in this case report, we will discuss a PJI caused by an unusual bacteria found in the mouths of domestic pets. OBJECTIVE: To present a case report of a patient with a periprosthetic hip infection from Capnocytophaga canimorsus and review the literature. METHODS: We present a case of C canimorsus PJI in an immunocompetent woman who had undergone a total hip arthroplasty. The patient was doing well postoperatively for many years until she was bitten on the foot by a domestic canine. Patient diagnosed using Musculoskeletal Infection Society criteria, then treated with explant of the hip prosthesis, irrigation and debridement, placement of an antibiotic cement spacer, and a 6-week course of intravenous antibiotics. RESULTS: Unfortunately, while awaiting replant, this patient had a massive myocardial infarction and died. DISCUSSION: Current literature suggests treating canine bites with amoxicillinas well as a discussion with patients pre-/postoperatively from a lower extremity arthroplasty specialist. CONCLUSION: Capnocytophaga canimorsus is a rare cause of infection, even more unusual in an immunocompetent patient. This study highlights the importance of considering C canimorsus as a cause of PJI, regardless of the immunologic status of the patient.

Digital mammography: observer performance study of the effects of pixel size on the characterization of malignant and benign microcalcifications.

RATIONALE AND OBJECTIVES: The authors performed this study to evaluate the effects of pixel size on the characterization of mammographic microcalcifications by radiologists. MATERIALS AND METHODS: Two-view mammograms of 112 microcalcification clusters were digitized with a laser scanner at a pixel size of 35 microm. Images with pixel sizes of 70, 105, and 140 microm were derived from the 35-microm-pixel size images by averaging neighboring pixels. The malignancy or benignity of the microcalcifications had been determined with findings at biopsy or 2-year follow-up. Region-of-interest images containing the microcalcifications were printed with a laser imager. Seven radiologists participated in a receiver operating characteristic (ROC) study to estimate the likelihood of malignancy. The classification accuracy was quantified with the area under the ROC curve (Az). The statistical significance of the differences in the Az values for different pixel sizes was estimated with the Dorfman-Berbaum-Metz method and the Student paired t test. The variance components were analyzed with a bootstrap method. RESULTS: The higher-resolution images did not result in better classification; the average Az with a pixel size of 35 microm was lower than that with pixel sizes of 70 and 105 microm. The differences in Az between different pixel sizes did not achieve statistical significance. CONCLUSION: Pixel sizes in the range studied do not have a strong effect on radiologists' accuracy in the characterization of microcalcifications. The low specificity of the image features of microcalcifications and the large interobserver and intraobserver variabilities may have prevented small advantages in image resolution from being observed.

Journal publications in radiologic education: a review of the literature, 1987-1997.

RATIONALE AND OBJECTIVES: This study was designed to analyze articles on radiologic education quantitatively and qualitatively, comparing those published in 1987-1997 with those published in 1966-1986. MATERIALS AND METHODS: An initial literature search used four major databases to identify and retrieve articles related to radiologic education. Additional articles were identified through manual cross-checking of references from the original articles. All articles were reviewed by two radiologists as to type of article (editorial, expository, survey, correlational, or experimental, including preexperimental, quasi-experimental, or true experimental), statistics used (inferential or descriptive), educational emphasis (medical student, resident, postgraduate, or other), and topic of article (philosophical or political, technology, program evaluation, program description, examinations, or career decisions). Interrater agreement was estimated by means of the kappa statistic. A chi2 test for independence was used to assess whether the relative distribution of articles was similar for the two periods. RESULTS: More articles per year were published in 1987-1997 (n = 12.6, P < .01) compared with 1966-1986 (n = 9.2). Articles pertinent to radiologic resident education predominated (50.7% vs 29.9% in the prior study, P < .01). In both periods, most articles were expository (37.7% vs 49.5%), and the most common topic was program description (34% vs 35%). Editorials decreased from 35.5% to 18.1%. Experimental studies accounted for 12.3%, increased from 8.7%. The fastest-growing topic of study was technology (30.4% vs 17.5%, P < .01). CONCLUSION: The increased number of articles addressing radiologic education is encouraging. Although the percentage of experimental studies increased slightly in this period, there is still little empirical research in radiologic education.

Continuous quality improvement process to track lost radiographs and reduce losses.

OBJECTIVE: To describe a quality improvement process that was initiated in a Department of Radiology to reduce the number of incomplete or "lost" imaging studies and decrease the time from the initiation of an imaging study to printing of the final report. METHODS: Incomplete cases were defined as those imaging studies that did not have a signed final report more than 3 days and less than 90 days after imaging. A computer program was written to generate a monthly incomplete case list from the radiology information system database; each step in the process, from patient arrival to final report printing, was analyzed and a list of root causes (for the incomplete cases) was developed. Short- and long-term interventions were introduced and the effects were monitored from 1992-1999. RESULTS: Problems were identified at each step in the process. Although some of the root causes originated outside the authority of the Department of Radiology, interventions we implemented within the department reduced the incomplete list by 72%, from a high of 2.8% of all imaging examinations to less than 0.8%. Continual monitoring of the problem is necessary to maintain this level. CONCLUSION: The number of incomplete or "lost" imaging studies can be decreased using a continuous quality improvement process. This leads to improved patient care and increased revenue.

Congenital cystic adenomatoid malformation: impact of prenatal diagnosis and changing strategies in the treatment of the asymptomatic patient.

OBJECTIVE: This study was designed to assess the effect of prenatal sonographic diagnosis on the treatment of congenital cystic adenomatoid malformation of the lung. MATERIALS AND METHODS: The medical records of 27 patients with pathologically proven congenital cystic adenomatoid malformations were retrospectively reviewed. Patients were divided into four groups based on mode of presentation: with or without abnormal findings on prenatal sonography and with or without symptoms at birth. Age at diagnosis, age at surgical intervention, complications, and length of hospital stay were recorded for each group. RESULTS: Twenty-seven patients with 31 proven congenital cystic adenomatoid malformations were included. Eleven patients underwent prenatal sonography establishing the diagnosis (6 asymptomatic at birth, 5 symptomatic), and 16 did not have a prenatal diagnosis (10 asymptomatic at birth, 6 symptomatic). In the symptomatic populations, prenatal diagnosis had no impact on age at surgery, length of stay, or surgical complication rate (p = 0.78-0.83). In the asymptomatic population, prenatal diagnosis allowed early diagnosis (p < 0.001) and resection in the asymptomatic period. It was also associated with a shorter length of stay at the time of surgical resection (mean time, 4.2 days for patients with prenatal diagnosis versus 12.9 days for those without it;p < 0.001) and with a trend toward lower serious complication rate (3 patients without prenatal diagnosis versus 1 patient with it). CONCLUSION: Prenatal sonography provides the radiologist a means to identify congenital cystic adenomatoid malformations in a population of infants who are asymptomatic at birth. Surgical intervention in the asymptomatic infant is associated with a shorter length of stay, a trend toward fewer complications, and decreased medical cost compared with intervening after symptoms develop.

Limitations of student evaluations of curriculum.

RATIONALE AND OBJECTIVES: Medical student surveys are used extensively in the development and modification of curriculum. The purpose of this study was to look at medical student surveys of a radiology lecture series, evaluating the accuracy of student perceptions of learning and factors affecting them. MATERIALS AND METHODS: After a "Case of the Week" lecture series, 156 3rd-year medical students returned a survey evaluating the experience with 10 questions on a four-point scale (1 = disagree, 4 = agree very much) and took a clinical competency assessment (CCA) examination with a radiology substation. Survey responses were compared with actual examination performance, analyzed for how overall learning was characterized in specific educational objectives, and evaluated for factors affecting perceived learning. RESULTS: The mean response for perceived CCA examination preparedness was 1.83. The mean radiology station test score was 90.43%. Correlations between student perception of learning and the scoring of focused learning objectives ranged from 0.33 to 0.48 (P < .01). Students responding 1 to items assessing perceived lecture organization, stimulation to read, and interest in the field of radiology had mean scores for perception of overall learning of 2.09-2.44 and mean scores for recommendation of course continuation of 1.68-2.46. Students responding 4 had means of 3.25-3.81 and 3.06-4.0, respectively. CONCLUSION: Student perceptions of the value of curriculum were inaccurate compared with external measures of performance, and students poorly related their general impressions to specific learning objectives. Perceived lecture organization, stimulation to read, and interest in radiology as a specialty affected perceived overall learning and perceived value of the lecture series.

Current prognosis in necrotizing enterocolitis with portal vein gas.

OBJECTIVE: To investigate anecdotal reports that portal vein gas in necrotizing enterocolitis is no longer associated with a poor prognosis. PATIENTS AND METHODS: Twelve cases of neonatal necrotizing enterocolitis with portal vein gas from 1988 to 1994 were identified retrospectively from the radiology dictation system in a large university hospital. RESULTS: Two distinct groups of patients with portal vein gas in necrotizing enterocolitis were identified. In 3 of the 12 children, portal vein gas was identified on abdominal films after the diagnosis of necrotizing enterocolitis. These infants had no serious sequelae. By contrast, in 8 of the 9 infants with portal vein gas seen on the initial film at presentation, emergent surgery was required. Four of these infants died from complications of necrotizing enterocolitis and 2 died from sepsis related to total parenteral nutrition. The remaining 2 children have short bowel syndrome, 1 is dependent on total parenteral nutrition and 1 requires continuous gastrostomy tube feedings. CONCLUSION: The children with portal vein gas on the initial abdominal film continue to have a guarded prognosis.

Value of case-of-the-week presentations on the radiology component of the Comprehensive Clinical Assessment examination.

RATIONALE AND OBJECTIVES: The Comprehensive Clinical Assessment (CCA) examination at the University of Michigan Medical School is a series of test stations through which the mastery of clinical skills is evaluated. The purpose of this study was to determine whether student performance on the radiology station improved in years when radiology faculty presented case-of-the-week unknowns to the 3rd-year students. MATERIALS AND METHODS: The authors compared four separate classes of medical students in examination years 1993, 1994, 1995, and 1996 by using the total CCA examination score, the radiology station score, and radiology station pass/fail rates. Radiology case-of-the-week presentations were given by the radiology faculty only in academic years 1993-1994 and 1994-1995 (examination years 1994 and 1995). RESULTS: The means and standard deviations of the radiology station scores for the examination years when case-of-the-week presentations were not given, 1993 and 1996, were 78.92 +/- 13.62 and 79.76 +/- 13.62, respectively. In the years case-of-the-week presentations were given, 1994 and 1995, the radiology station scores averaged 90.83 +/- 8.58 and 89.97 +/- 9.66, respectively (P < .001, global alpha = .05). Total CCA percentage correct scores were similar for all years studied. In 1993 and 1996, 7.6% and 5.3% of students, respectively, failed the radiology station. In 1994 and 1995, 0.4% and 0% of students, respectively, failed (P < .0001). CONCLUSION: Case-of-the-week presentations by radiology faculty increased 3rd-year students' basic radiologic knowledge as evidenced by increased scores on the radiology station of the CCA examination.

Vesicoureteral reflux in older children: concordance of US and voiding cystourethrographic findings.

PURPOSE: To determine if a negative renal sonogram is reliably predictive of the absence of vesicoureteral reflux at voiding cystourethrography (VCUG) in children aged 5 years or older. MATERIALS AND METHODS: Imaging studies in 70 children aged 5 years or older who underwent renal ultrasound (US) and VCUG on the same day were reviewed. These children had initially undergone evaluation because of a urinary tract infection. RESULTS: Five of 70 children had abnormal sonograms; two (40%) of the five had reflux at VCUG. One had mild pelvicalyceal dilatation, and one had a small kidney. The other three (without reflux) had a pelvic kidney, a calyceal diverticulum, or a renal stone. Of 65 children with a negative sonogram, 19 (29%) had reflux at VCUG; 46 (71%) did not. Altogether, of the 70 children, 21 had reflux, 19 (90%) of whom had no sonographic abnormality. CONCLUSION: Children with abnormal screening renal sonograms often have vesicoureteral reflux, but a normal sonogram does not reliably exclude the condition even in children aged 5 years or older. Therefore, VCUG must be performed even in older children, regardless of US findings, if clinical decisions are influenced by documentation of the presence of VUR.

Complications after gastric transposition in children.

BACKGROUND AND OBJECTIVE: Esophagogastrostomy with gastric transposition, a procedure for replacement of the esophagus in cases of esophageal atresia, is increasing in popularity among pediatric surgeons. This study was undertaken to document the differences between postoperative complications in children and those reported in adults. PATIENTS AND METHODS: The authors reviewed the medical records and radiologic images for details of complications in 6 children (5 boys and 1 girl) who underwent esophagogastrostomy with gastric transposition for esophageal atresia. Follow-up ranged from 18 months to 12 years. The observations were compared with complications in adults, as reported in the literature. RESULTS: The complications of gastric transposition were classified as early (up to 1 month after surgery) of late (more than 1 month after surgery). They included anastomotic leak (in 1 patient), hernia (in 1) and recurrent structure (in 3). In 1 patient mediastinal abscess developed secondary to esophageal perforation, which occurred during a dilation procedure for stricture. CONCLUSIONS: Postoperative complications of gastric transposition occur less commonly in children than in adults. Benign stricture, which may occur both early and late, is the most common problem.

Medical students' attitudes toward radiology: comparison of matriculating and graduating students.

RATIONALE AND OBJECTIVES: To determine graduating medical students' perceptions of radiology and to document changes in their perceptions since they entered medical school. MATERIALS AND METHODS: A survey questionnaire was distributed to 213 graduating students. Questions were similar to those answered by the same group of students as they entered medical school nearly 4 years earlier. RESULTS: The survey was anonymously completed by 140 students. Seventy percent of students changed their choice of medical specialty since entering medical school. Factors with a major or important influence on specialty choice included intellectual excitement (96%), high patient contact (86%), opportunity for a good family life (72%), and regular hours (57%). Radiology was perceived to be a well-paid (89%), "high-tech" (86%) specialty with a healthy lifestyle (82%), regular hours (99%), and good family life (92%), but it was not perceived to offer high patient contact (1%) and was intellectually exciting to only 33% of students. This perception was unchanged from freshman year. CONCLUSIONS: This 4-year longitudinal study of a medical student class documents surprisingly little change in the perception of radiology throughout medical school. High patient contact and intellectual excitement, both factors of major or important influence on specialty choice, were thought to be lacking in radiology.

Use of abdominal ultrasonography to assess pediatric splenic trauma. Potential pitfalls in the diagnosis.

OBJECTIVE: The purpose of this study was to evaluate the accuracy of abdominal ultrasonography (US) for screening and grading pediatric splenic injury. SUMMARY BACKGROUND DATA: The use of abdominal US has increased rapidly as a method of evaluating organ damage after blunt abdominal trauma. Despite US's increasing use, little is known about its accuracy in children with splenic injury. METHODS: Children (N = 32) suffering blunt abdominal trauma who were diagnosed with splenic injury by computerized tomography (CT) scan prospectively were enlisted in this study. Degree of splenic injury was evaluated by both CT and US. The ultrasounds were evaluated by an initial reading as well as by a radiologist who was blinded as to the results of the CT. RESULTS: Twelve (38%) of the 32 splenic injuries found on CT were missed completely on the initial reading of the US. When the ultrasounds were graded in a blinded fashion, 10 (31%) of the splenic lacerations were missed and 17 (53%) were downgraded. Seven (22%) of the 32 splenic fractures were not associated with any free intraperitoneal fluid on the CT scan. CONCLUSIONS: This study has shown that US has a low level of sensitivity (62% to 78%) in detecting splenic injury and downgrades the degree of injury in the majority of cases. Reliance on free intraperitoneal fluid may be inaccurate because not all patients with splenic injury have free intra-abdominal fluid. Based on these findings, US may be of limited use in the initial assessment, management, and follow-up of pediatric splenic trauma.

A multifaceted approach to changing handwashing behavior.

BACKGROUND: Few interventions to influence handwashing have had measurable effects. This prospective quasi-experimental study was designed to address predisposing, enabling, and reinforcing factors to improve frequency of handwashing. METHODS: Over a 12-month time period, a multifaceted intervention including focus group sessions, installation of automated sinks, and feedback to staff on handwashing frequency was implemented in one intensive care unit; a second unit served as a control. Dependent variables observed were handwashing frequency and self-reported practices and opinions about handwashing. Study phases included baseline, three phases of about 2 months each in duration in which sink automation was incrementally increased, and follow-up 2 months after intervention. RESULTS: During 301 hours of observation, 2624 handwashings were recorded. Proportion of times hands were washed varied by indication, ranging from 38% before invasive procedures to 86% for dirty-to-clean procedures (p < 0.00001). Although there were some significant differences between experimental and control units in handwashing during the study, these differences had returned to baseline by the 2-month follow-up. There were no significant differences in self-reported practices and opinions from before to after intervention nor between units. CONCLUSIONS: Intensive intervention, including feedback, education, and increased sink automation, had minimal long-term effect on handwashing frequency.

Performance on the radiology component of a critical clinical skills examination.

RATIONALE AND OBJECTIVES: Clinical competence certification is now required in some specialties in medicine. A Comprehensive Clinical Assessment (CCA) was created to test mastery of critical skills by students at the end of the 3rd year of medical school. METHODS: The CCA is a series of stations that test skills the faculty consider important for all medical students (eg, breast examination, electrocardiogram reading, chest pain assessment, ophthalmology photographs). The radiology station was designed to evaluate imaging skills believed to be taught and learned in the core 3rd-year rotations. RESULTS: External measures (National Board Examinations, grade point average, and overall score) of clinical performance of the 608 medical students who completed the CCA examination between 1991 and 1993 were found to be correlated with the radiology station scores. CONCLUSION: The radiology station in the CCA examination is a reproducible measure of clinical performance.

Assessment of urine collection technique for microbial culture.

Two methods of urine collection-clean catch and midstream only-were compared in 200 samples (100 with each technique). There were no significant differences between the two collection methods with regard to number of positive culture results or types and counts of organisms isolated. There is little if any added benefit to special preparation for urine collection for culture.

Effect of intravascular surveillance and education program on rates of nosocomial bloodstream infections.

BACKGROUND: Because of high proportions of central line-related bloodstream infections (BSIs), an intravascular surveillance and education program (IVSP) was instituted in the study institution in 1987. METHODS: A 6 1/2-year historical prospective study was conducted to evaluate the effects of the IVSP on incidence of nosocomial BSIs. With use of Centers for Disease Control and Prevention criteria, concurrent data on nosocomial BSIs were collected by two infection control professionals before, during, and for 3 years after the IVSP. RESULTS: Hospital-wide BSIs during the 3-year IVSP and for 3 years after were 0.9% and 0.9% (p = 0.58) or 1.4 and 1.2/1000 patient-days (p = 0.24). Central line-related BSIs represented 29%, 24%, and 29% of the total BSIs 6 months before, 3 years during, and 6 months after the intervention, respectively (p = 0.62). CONCLUSIONS: The IVSP resulted neither in a reduction in the total intravascular catheter-related BSIs nor in a change in the proportion of potentially preventable central line-related BSIs. To be successful, an intervention must include the authority to mandate practice changes; education and feedback without such authority were inadequate.