Evaluation of the Tibial Tubercle to Posterior Cruciate Ligament Distance in a Pediatric Patient Population.

BACKGROUND: Evaluation of distal extensor mechanism alignment continues to evolve in children with patella instability. Prior studies support the use of the tibial tubercle to trochlear groove (TT-TG) distance but limitations exist for this measurement including: changes in the TT-TG distance with knee flexion, difficulty with finding the deepest part of a dysplastic trochlea, and limitations regarding identification of the site of the anatomic abnormality. The tibial tubercle-posterior cruciate ligament (TT-PCL) distance has been introduced as an alternative measure to address the shortcomings in the TT-TG distance by quantifying the position of the TT independent of the trochlea and with respect to the tibia only. The objectives of this study were to (1) confirm that TT-PCL measurements in the pediatric population are reliable and reproducible; (2) determine whether normal TT-PCL distance changes with age; and (3) compare TT-PCL distances in patients with and without patellar instability to assess its utility in the workup of pediatric patellar instability. METHODS: All knee magnetic resonance imaging performed for patients from birth to 15.9 years of age at our institution between December 2004 and February 2012 were retrospectively collected (total 566). Eighty-two patients had patellar instability and 484 patients did not have patellar instability. Two magnetic resonance imaging reviewers measured TT-PCL distance on T2-weighted axial images in a blinded manner. Intraobserver and interobserver agreement was measured. Correlation between TT-PCL distance and age as well as group differences between mean TT-PCL distances was evaluated. RESULTS: Intraobserver and interobserver agreement was excellent (0.93) and very good (0.80), respectively. The mean TT-PCL distance was 20.1 mm with a range of 5.8 to 32.1 mm. The mean age was 12.6 years with a range of 0.8 to 15.9 years. The average TT-PCL distance was 21 mm for the instability group and 19.9 mm for the control group. TT-PCL distance increased significantly as subject age increased; however, there was no significant measurement difference shown between the patellar instability group and the control group. CONCLUSIONS: TT-PCL distance increased with age in the pediatric population but did not correlate with recurrent patella instability in this pediatric cohort. LEVEL OF EVIDENCE: Level III-diagnostic.

Tibial tubercle-trochlear groove distance: defining normal in a pediatric population.

BACKGROUND: The tibial tubercle-trochlear groove (TT-TG) distance is a useful tool in guiding surgical management for patients with recurrent lateral patellar instability. Current recommendations for tibial tubercle transfer are based on TT-TG distance thresholds derived from adult populations. Recurrent patellar instability, however, frequently affects children, but normal and pathological TT-TG values have not been established for pediatric patients. The objectives of this study were to (1) confirm that magnetic resonance imaging (MRI) measurements for TT-TG distance in a pediatric population are reliable and reproducible, (2) determine whether the TT-TG distance changes with age, (3) define normal TT-TG distances in a pediatric population, and (4) confirm that a subgroup of pediatric patients with patellar instability have higher TT-TG distances. METHODS: Six hundred and eighteen MRIs were retrospectively collected for patients who were nine months to sixteen years old. Each MRI was measured twice in a blinded, randomized manner by each reviewer. Patient age, sex, knee laterality, magnet strength, underlying diagnosis, and pertinent previous surgical treatments were all recorded separately from the measurements. MRIs that were unreadable and those of patients who had previous extensor mechanism surgery, preexisting deformity, or destructive neoplasms were excluded. RESULTS: There was excellent intraobserver and interobserver reliability of TT-TG distance measurements. TT-TG distance was associated with the natural logarithm of age (p < 0.001). A percentile-based growth chart was created to demonstrate this relationship. The median TT-TG distance for patients without patellar instability in this pediatric population was 8.5 mm (mean and 95% confidence interval, 8.6 ± 0.3 mm). Patients with patellar instability had higher TT-TG distances (median, 12.1 mm; p < 0.001). TT-TG distance measured nearly 2 mm less on MRIs performed with a 3-T magnet than on those acquired with a 1.5-T magnet (p < 0.001). CONCLUSIONS: TT-TG distance changes with chronologic age in the pediatric population. As such, we developed a percentile-based growth chart in order to better depict normal TT-TG distances in the pediatric population. Like many issues in pediatric orthopaedics, an age-based approach for directing surgical treatment may be more appropriate for skeletally immature individuals with recurrent lateral patellar instability.

Efficacy of alendronate in the treatment of low bone density in the pediatric and young adult population.

BACKGROUND: Pediatric osteoporosis is uncommon but can result in painful and debilitating insufficiency fractures. Treatment options for osteoporosis in children are few. Bisphosphonate therapy for children has not been approved by the Food and Drug Administration (FDA) in the United States, but its use in that population has been increasing. Randomized controlled studies have not been done because of the small subject pool and the difficulty in randomizing a child with an insufficiency fracture to a placebo arm of a study. This retrospective case-control study of a population of children with primarily neuromuscular disease was done to review changes in bone mineral density as reflected by dual x-ray absorptiometry (DXA) scanning. METHODS: Medical records and DXA scans were screened to identify children with low bone density who had been treated with alendronate as well as similar control subjects with low bone density for their age who had not received alendronate. Medication acquisition was confirmed by refill records, and cumulative exposure was calculated. Interval DXA scans were reviewed to correlate bone mineral density change in grams per square centimeter as well as the percent change and percent change over time for both alendronate-treated and control subjects. RESULTS: Twenty-eight alendronate-treated subjects and thirty control subjects met the inclusion criteria. No significant improvement in bone mineral density was seen in the alendronate-treated subjects as compared with the control subjects. Some patients in both groups exhibited marked improvement, with improvement of >31% seen only in the alendronate-treated subjects. CONCLUSIONS: Alendronate does not reliably improve bone density in children and young adults with primarily neuromuscular disease and without osteogenesis imperfecta. Individual patients treated with bisphosphonates must be carefully followed to ensure medication compliance and appropriate response.

Adolescents with idiopathic scoliosis are not osteoporotic.

STUDY DESIGN: Case controlled study. OBJECTIVE: To explore the relative effects of body mass index (BMI) and the presence or absence of adolescent idiopathic scoliosis (AIS) on bone mineral density (BMD) as evidenced by Z-scores in adolescents. SUMMARY OF BACKGROUND DATA: Prior studies have identified adolescents with idiopathic scoliosis as having "osteoporosis" or "osteopenia," when only a small percentage of subjects in these studies actually had bone density that was clinically abnormal. The terms osteoporosis and osteopenia as used in adults cannot be applied to adolescents and children, as fracture risk has not been well correlated to Z-scores. As we had noted that our scoliosis patients of normal and heavy weight had normal Z-scores, this study was undertaken to explore the relationship of bone mineral density to body mass index in adolescents with and without scoliosis. METHODS: Dual energy x-ray absorptiometry (DXA) scans of 49 adolescents with adolescent idiopathic scoliosis were compared to 40 normal control adolescents. Z-scores were compared to reduce variability when comparing subjects of varying age and genders. Student t test or simple linear regression was used to explore relationships between Z-scores and clinical and demographic variables. RESULTS: In both groups of subjects, Z-score was most strongly correlated with BMI (P < 0.001). The presence of scoliosis had the effect of lowering the Z-score as if the individual had "lost" 3.4 BMI units. CONCLUSION: Z-scores in subjects with and without scoliosis were most strongly correlated to BMI: thin patients had lower bone density, heavy patients had higher. The presence of scoliosis had an effect similar to subtracting 3.4 "BMI units," lowering the Z-score from what might otherwise be predicted. The "scoliosis effect" may be noticeable in thin individuals, pushing them to the "low for age" level, whereas in heavier individuals, the effect is negligible. No subjects in either group met the ISCD definition for osteoporosis.

The prehospital 12-lead electrocardiogram's effect on time to initiation of reperfusion therapy: a systematic review and meta-analysis of existing literature.

The prehospital electrocardiogram (ECG) is becoming the standard of care of suspected cardiac chest pain. We evaluated the evidence regarding the prehospital ECG and sought to quantify the reduction in time to reperfusion therapy attributable to the prehospital ECG. We conducted a systematic review and analyzed studies that were conducted in emergency medical systems relevant to providers in the United States. The papers were limited to studies that reported original data that compared prehospital ECG to no prehospital ECG groups. Four studies containing 99 patients met the inclusion criteria. A meta-analysis of these studies revealed a difference of 24.7 (95% confidence interval, 16.7-32.7) minutes. Providers now have a quantified value of the prehospital ECG based on the best published evidence. In addition, this search showed a relatively low quality and quantity of research on the prehospital ECG.

Do poison center guidelines adversely affect patient outcomes as triage referral values increase?

BACKGROUND: The purpose of this study was to determine whether patient outcomes were adversely affected as healthcare referral values increased for two common poisonings: acute, unintentional acetaminophen (APAP) poisonings and acute, unintentional iron (Fe) poisonings. We hypothesized that symptom rates would increase with high referral values. METHODS: Qualifying 1997 exposures were separated by substance (APAP or Fe) and then further stratified into three healthcare referral value ranges. Symptomatic and asymptomatic patients were totaled for each stratum. Expected vs. observed distributions of symptomatic and asymptomatic patients across triage referral strata for a given substance and treatment location were compared using chi-square test for independence. The Wilcoxon-Mann-Whitney test was used to compare the distribution of patients across referral strata for home vs. healthcare facility locations for a specific substance. RESULTS: There were no statistically significant differences in the distribution of symptomatic patients within referral value strata for APAP or for Fe. There was also no difference in distribution of symptomatic patients across strata when comparing home vs. healthcare facility for APAP and Fe. CONCLUSION: Referral values as high as 201 mg/kg for APAP and 61 mg/kg for Fe do not appear to adversely affect patient outcomes.

Physician attitudes about prehospital 12-lead ECGs in chest pain patients.

INTRODUCTION: The prehospital 12-lead electrocardiogram (ECG) has become a standard of care. For the prehospital 12-lead ECG to be useful clinically, however, cardiologists and emergency physicians (EP) must view the test as useful. This study measured physician attitudes about the prehospital 12-lead ECG. HYPOTHESIS: This study tested the hypothesis that physicians had "no opinion" regarding the prehospital 12-lead ECG. METHODS: An anonymous survey was conducted to measure EP and cardiologist attitudes toward prehospital 12-lead ECGs. Hypothesis tests against "no opinion" (VAS = 50 mm) were made with 95% confidence intervals (CIs), and intergroup comparisons were made with the Student's t-test. RESULTS: Seventy-one of 87 (81.6%) surveys were returned. Twenty-five (67.6%) cardiologists responded and 45 (90%) EPs responded. Both groups of physicians viewed prehospital 12-lead ECGs as beneficial (mean = 69 mm; 95% CI = 65-74 mm). All physicians perceived that ECGs positively influence preparation of staff (mean = 63 mm; 95% CI = 60-72 mm) and that ECGs transmitted to hospitals would be beneficial (mean = 66 mm; 95% CI = 60-72 mm). Cardiologists had more favorable opinions than did EPs. The ability of paramedics to interpret ECGs was not seen as important (mean = 50 mm; 95% CI = 43-56 mm). The justifiable increase in field time was perceived to be 3.2 minutes (95% CI = 2.7-3.8 minutes), with 23 (32.8%) preferring that it be done on scene, 46 (65.7%) during transport, and one (1.4%) not at all. CONCLUSIONS: Prehospital 12-lead ECGs generally are perceived as worthwhile by cardiologists and EPs. Cardiologists have a higher opinion of the value and utility of field ECGs. Since the reduction in mortality from the 12-lead ECG is small, it is likely that positive physician attitudes are attributable to other factors.

Nightmare frequency in sexual assault survivors with PTSD.

Sexual assault survivors with post-traumatic stress disorder (PTSD) were assessed for frequency of nightmares, measured retrospectively on the Nightmare Frequency Questionnaire (NFQ) and prospectively on nightmare dream logs (NLOG). Retrospective frequency was extremely high, averaging occurrences every other night and an estimated number of nightmares greater than five per week. Test-retest reliability data on the NFQ yielded weighted kappa coefficients of .85 (95% CI, .74-.95) for nights and .90 (95% CI, .83-.97) for nightmares. Correlations between retrospective and prospective nightmare frequencies ranged between .53 (P = .001) for nights and .63 (P = .001) for nightmares. Correlations between frequency and distress measures (anxiety, depression, post-traumatic stress) yielded coefficients ranging from (r = .28-.53). Compared with intrusive, cumbersome and time-consuming prospective measurements, the NFQ appears reliable, convenient, and equally useful in assessing nightmare frequency in a group of sexual assault survivors. Nightmare frequency, prevalence, distress and impairment are discussed.

Low prevalence of Chlamydia trachomatis by urinary ligase chain reaction in women patients in the emergency department.

UNLABELLED: Recent studies suggest that women with acute urethral syndrome or abdominal pain, presenting to emergency departments (EDs), have a high prevalence of Chlamydia trachomatis. OBJECTIVES: To estimate the prevalence of C. trachomatis in women presenting to an ED and to see whether those with dysuria or abdominal pain have a higher prevalence of C. trachomatis. METHODS: The authors conducted a prospective cross-sectional study of C. trachomatis in the urine of women aged 18 to 50 years who had a urinalysis performed at a university/county ED from February through May 1998. Urine specimens were labeled for the presence of symptoms and analyzed for C. trachomatis by ligase chain reaction (LCR). Polymerase chain reaction (PCR) testing of cervical swabs for C. trachomatis was done for usual clinical indications. Difference in proportions of positive LCR tests among patients was tested with Fisher's exact test. Agreement between PCR and LCR was measured using Cohen's kappa statistic. RESULTS: Of 397 women whose urine was tested, 280 had symptoms of dysuria, abdominal pain, or both, and 117 had no symptoms. The overall prevalence of C. trachomatis by LCR was 3.8% (95% CI = 2.1% to 6.2%); and the combined PCR-LCR prevalence was 4.3% (95% CI = 2.5% to 6.8%). The presence of symptoms was not associated with a positive LCR test for C. trachomatis (p = 0.26, power = 0.8, alpha = 0.05, difference 3% vs. 12%). In the 172 patients who had both a PCR cervical swab and urine LCR, agreement was excellent (kappa = 0.67, 95% CI = 0.45 to 0.90). CONCLUSIONS: This ED had a surprisingly low prevalence of C. trachomatis. Women with symptoms were not more likely to test positive than those without.