Search

Background: Thread delamination associated with cannulated screws have been reported but likely represent an under-recognized complication in the orthopaedic literature. The purpose of this study is to report the occurrence of repeated hardware failures through thread delamination in the setting of a commonly used orthopaedic cannulated screw implant in a small cohort involving pediatric fracture care at a single academic level I trauma center., Methods: Between August 2015 and December 2020, 9 cases of hardware failure associated with 4.5 mm arbeitsgemeinschaft für osteosynthesefragen cannulated stainless-steel screws were identified within a pediatric orthopaedic division at a single academic level I trauma center. Three cases were excluded, and 6 cases of thread delamination were retrospectively reviewed., Results: Six cases of thread delamination comprised a cohort of patients with a mean age of 13.7 years (range: 12 to 15 y). All cases involved 4.5 mm arbeitsgemeinschaft für osteosynthesefragen cannulated screws, including 5 partially threaded and 1 fully threaded screw. Five cases involved open reduction and internal fixation of incarcerated medial humeral epicondylar fragments and the other case was an open reduction and internal fixation of a displaced medial malleolar fracture. Five of these occurred within a recent 18-month period of time. There were 4 cases of partial, distal thread delamination, 1 case of partial proximal thread delamination and another case of complete thread delamination which had unwound into the tibiotalar joint and required an anterior ankle arthrotomy to retrieve the thread. None of the 5 patients in this series who currently harbor a retained thread have experienced symptoms because of this issue., Conclusions: Thread delamination associated with cannulated screw implantation likely represents an under-reported phenomenon in orthopaedic surgery. In cases where retained, delaminated threads exist, these do not appear to cause short-term concern., Level of Evidence: Level IV-case series., Competing Interests: The authors declare no conflicts of interest., (Copyright © 2022 The Author(s). Published by Wolters Kluwer Health, Inc.)

Study Design: Prospective cohort study., Objectives: The objective of this study was to examine intermediate-term progression for a large series of patients with adolescent idiopathic scoliosis (AIS) with curves 40° or greater., Background: Curve progression in AIS has been well documented for smaller curves in adolescence up to skeletal maturity; however, the data on curve progression past 40° or into adulthood are limited. With many surgeons recommending surgical correction when patients reach this threshold, it is important to understand the radiographic progression of curves into adulthood., Methods: A database of all patients seen by a single surgeon from 1984 through 2018 with AIS curves progressing to at least 40° entered prospectively was utilized for this study. This included a total of 738 patients. Curve progression was analyzed overall and stratified by length of follow-up, curve location, and Risser stage at the time of presentation among other variables. Curve magnitude and Risser stage designations in this study were validated by performing a separate inter- and intrarater agreement study using four independent reviewers reading 50 patients' Cobb angle and Risser stage blinded in triplicate to examine the reliability of the study measurements., Results: Annualized curve progression (ACP) averaged 6.3 ± 10.4°. ACP varied with length of follow-up: patients with up to 1 year of follow-up had an average ACP of 11.5 ± 17.0°, while those with 1-2 years had 8.2 ± 8.8°, and 2-5 years had 3.7 ± 4.1°, tapering off further from there. Risser stage 0 or 1 was associated with the highest ACP as compared to Risser stage 2-3 or 4-5. Intraclass correlation (ICC) values for Cobb angle measurement and Risser stage designations from four raters measuring 50 patients' measures, blinded and in triplicate, were all > 0.80, signifying a high degree of reliability within and between readers., Conclusions: Annualized curve progression for 40° and greater curves was not linear over time; it was greatest immediately after a curve reaches 40° and tapered off over the next decade. Immature Risser stage at presentation was strongly associated with increasing ACP at all time frames., Level of Evidence: Prognostic Level I.

Study Design: Prognostic study and validation using prospective clinical trial data., Objective: To derive and validate a model predicting curve progression to ≥45° before skeletal maturity in untreated patients with adolescent idiopathic scoliosis (AIS)., Summary of Background Data: Studies have linked the natural history of AIS with characteristics such as sex, skeletal maturity, curve magnitude, and pattern. The Simplified Skeletal Maturity Scoring System may be of particular prognostic utility for the study of curve progression. The reliability of the system has been addressed; however, its value as a prognostic marker for the outcomes of AIS has not. The BrAIST trial followed a sample of untreated AIS patients from enrollment to skeletal maturity, providing a rare source of prospective data for prognostic modeling., Methods: The development sample included 115 untreated BrAIST participants. Logistic regression was used to predict curve progression to ≥45° (or surgery) before skeletal maturity. Predictors included the Cobb angle, age, sex, curve type, triradiate cartilage, and skeletal maturity stage (SMS). Internal and external validity was evaluated using jackknifed samples of the BrAIST data set and an independent cohort (n = 152). Indices of discrimination and calibration were estimated. A risk classification was created and the accuracy evaluated via the positive (PPV) and negative predictive values (NPV)., Results: The final model included the SMS, Cobb angle, and curve type. The model demonstrated strong discrimination (c-statistics 0.89-0.91) and calibration in all data sets. The classification system resulted in PPVs of 0.71-0.72 and NPVs of 0.85-0.93., Conclusions: This study provides the first rigorously validated model predicting a short-term outcome of untreated AIS. The resultant estimates can serve two important functions: 1) setting benchmarks for comparative effectiveness studies and 2) most importantly, providing clinicians and families with individual risk estimates to guide treatment decisions., Level of Evidence: Level 1, prognostic., (Copyright © 2019 Scoliosis Research Society. Published by Elsevier Inc. All rights reserved.)

Background: Performance on the Orthopaedic In-training Examination (OITE) has been correlated with performance on the written portion of the American Board of Orthopaedic Surgery examination. Herein we sought to discover whether adding a regular pediatric didactic lecture improved residents' performance on the OITE's pediatric domain., Methods: In 2012, a didactic lecture series was started in the University of Pittsburgh Medical Center (UPMC) Hamot Orthopaedic Residency Program (Hamot). This includes all topics in pediatric orthopaedic surgery and has teaching faculty present, and occurs weekly with all residents attending. A neighboring program [UMPC Pittsburgh (Pitt)] shares in these conferences, but only during their pediatric rotation. We sought to determine the effectiveness of the conference by comparing the historic scores from each program on the pediatric domain of the OITE examination to scores after the institution of the conference, and by comparing the 2 programs' scores., Results: Both programs demonstrated improvement in OITE scores. In 2008, the mean examination score was 19.6±4.3 (11.0 to 30.0), and the mean percentile was 57.7±12.6 (32.0 to 88.0); in 2014, the mean examination score was 23.5±4.2 (14.0 to 33.0) and the mean percentile was 67.1±12.1 (40.0 to 94.0). OITE scores and percentiles improved with post graduate year (P<0.0001). Compared with the preconference years, Hamot residents answered 3.99 more questions correctly (P<0.0001) and Pitt residents answered 2.93 more questions correctly (P<0.0001). Before the conference, site was not a predictor of OITE score (P=0.06) or percentile (P=0.08); there was no significant difference found between the mean scores per program. However, in the postconference years, site did predict OITE scores. Controlling for year in training, Hamot residents scored higher on the OITE (2.3 points higher, P=0.003) and had higher percentiles (0.07 higher, P=0.004) than Pitt residents during the postconference years., Conclusions: This study suggests that adding a didactic pediatric lecture improved residents' scores on the OITE and indirectly suggests that more frequent attendance is associated with better scores., Level of Evidence: Level III-retrospective case-control study.

Study Design: Comparing thoracic pedicle screw trajectories, screw lengths, and starting points by examining osteologic specimens., Objective: Describe a medial screw trajectory (MST) compared to a screw trajectory along the anatomic pedicle angle (APA) in terms of trajectory, screw length, and starting point., Summary of Background Data: Although thoracic pedicle screw insertion is commonly used for posterior fusion and instrumentation, there is little data to quantify an MST that avoids the great vessels and allows for greater screw purchase., Methods: Thirty adult female skeleton thoracic vertebral columns from the University of New Mexico Maxwell Museum of Anthropology Osteology Collection were photographed from axial and right and left lateral views from T1 to T12. Axial plane measurements included APA and MST (both measured from the midline), screw lengths, and APA/MST intersection on the superior articular facet (SAF). The MST was defined as an insertion angle through the midpoint of the pedicle isthmus intersecting the anterior midpoint of the vertebral body. The intersection of each trajectory with the SAF was measured in relation to the lateral base of the SAF, reported as a percentage of the SAF base width from the lateral SAF border., Results: At every vertebral level, the APA was different from the MST for angle, screw length, and SAF intersection (p < .0001), with the largest difference at T12. The T12 differences were APA versus MST angles (-25.5°, 95% CI -22.7° to -28.4°), screw lengths (11.0 mm, 95% CI 9.2 mm to 12.9 mm), and percentage of SAF width from the lateral border of the SAF base (38.6%, 95% CI 29.1% to 48.1%)., Conclusions: The MST was approximately 8° to 10° greater at T1-T10 (19° at T11 and 25° at T12) than the traditional APA insertion angle. This resulted in a much more lateral starting point on the SAF and longer screw length, greatest at T12., (Copyright © 2016 Scoliosis Research Society. Published by Elsevier Inc. All rights reserved.)

Case: The subscapular space is a clinically concealed anatomic space where soft-tissue abscesses can form. To our knowledge, five cases of a subscapular abscess have been reported in the past thirty-four years, so there is little evidence available to guide treatment. We present a unique case of a spontaneous, subscapular abscess due to methicillin-resistant Staphylococcus aureus in a pediatric host, and we describe a surgical approach for adequate debridement., Conclusion: The effective treatment of a subscapular abscess depends on an accurate, rapid diagnosis and effective surgical debridement. A modified Judet approach provides adequate access to the subscapular space for debridement.

Background: Nonoperative management of clubfoot with the Ponseti method has proven to be effective, and it is the accepted initial form of treatment. Although several studies have shown that problems with compliance with the brace protocol are principally responsible for recurrence, no distinction has been made with regard to whether the distance from the site of care affects the early recurrence rate. We compared early recurrence after Ponseti treatment between rural and urban ethnically diverse North American populations to analyze whether distance from the site of care affects compliance and whether certain patient demographic characteristics predict recurrence., Methods: One hundred consecutive infants with a total of 138 clubfeet treated with the Ponseti method were followed prospectively for at least two years from the beginning of treatment. Early recurrence, defined as the need for subsequent cast treatment or surgical treatment, and compliance, defined as strict adherence to the brace protocol described by Ponseti, were analyzed with respect to the distance from the site of care, age at presentation, number of casts needed for the initial correction, need for tenotomy, and family demographic variables., Results: Of eighteen infants from a rural area who had early recurrence, fourteen were Native American. The families of these children, like those of all of the children with early recurrence, discontinued orthotic use earlier than was recommended by the physician. Discontinuation of orthotic use was related to recurrence, with an odds ratio of 120 (p < 0.0001), in patients living in a rural area. Native American ethnicity, unmarried parents, public or no insurance, parental education at the high-school level or less, and a family income of less than $20,000 were also significant risk factors for recurrence in patients living in a rural area. Intrinsic factors of the clubfoot deformity were not correlated with recurrence or discontinuation of bracing., Conclusions: Compliance with the orthotic regimen after cast treatment is imperative for the Ponseti method to succeed. The striking difference in outcome in rural Native American patients as compared with the outcomes in urban Native American patients and children of other ethnicities suggests particular problems in communicating to families in this subpopulation the importance of bracing to maintain correction. An examination of communication styles suggested that these communication failures may be culturally related.

The so-called "Kety model" is a two-compartment pharmacokinetic model describing tumor perfusion kinetics. Its parameters, the transendothelial transfer constant (K(trans)), extravascular extracellular volume fraction (upsilon(e)), and microvascular plasma volume fraction (upsilon(p)), can be estimated with dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI). However, the results obtained by current methods show large variation in predictability and reliability. Here, the aim was to examine which experimental conditions have to be fulfilled to avoid large uncertainties and mutual dependencies of the parameters. Using frequency response analysis and simulation, the identifiability of the model was examined. The requirements and influence of contrast enhancement measurements, such as temporal resolution, signal to noise ratio, and contrast injection rate, on the accuracy of the parameters were analyzed. Tissue response characteristics revealed a low-frequency system with a cutoff frequency equal to K(trans)/upsilon(e), which confines the required temporal resolution. For malignant tissue with hyperpermeable vasculature (high K(trans)) a higher sampling frequency is required to accurately estimate K(trans) than for normal tissue. Too low sampling rates or too low injection rates resulted in inaccurate K(trans) values and hereby unreliable classification of malignant tissue.

Telomeres, the ends of chromosomes, shorten with each cell division in human somatic cells, because of the end-replication problem, C-strand processing and oxidative damage. On the other hand, the reverse transcriptase telomerase can add back telomeric repeats at the telomere ends. It has been suggested that once telomeres have reached a critical length, cells cease proliferation, also known as senescence. Evidence is accumulating that telomere shortening and subsequent senescence might play a crucial role in life-threatening diseases. So far, mathematical models described telomere shortening as an autonomous process, where the loss per cell division does not depend on the telomere length itself. In this study, published measurements of telomere distributions in human fibroblasts and human endothelial cells were used to show that telomeres shorten in a length-dependent fashion. Thereafter, a mathematical model of telomere attrition was composed, in which a shortening factor and an autonomous loss were incorporated. It was assumed that the percentage of senescence was related to the percentage of telomeres below a critical length. The model was compared with published data of telomere length and senescence of human endothelial cells using the maximum likelihood method. This enabled the estimation of physiologically important parameters and confirmed the length-dependency of telomere shortening.

Although low-grade cartilage neoplasms typically consist of hyaline-like cartilage, most of them also contain some fibrocartilaginous regions. CD44, a cell surface receptor for hyaluronan, has been identified in cartilage. A family of alternatively spliced mRNA containing the variant 6 (v6) exon sequence of CD44 has been linked to several types of neoplasms. We hypothesized that expressions of v6-containing CD44 species are associated with fibrocartilaginous regions of low-grade cartilage neoplasms. To test this hypothesis we performed reverse transcriptase-polymerase chain reaction (RT-PCR) and immunohistochemical analysis on eight samples: four from normal articular cartilage, one from a synovial chondromatosis, and three chondrosarcomas which were graded as I and I/II. The standard CD44s and a unique v6-containing CD44 species (CD44v6-10) were identified in all tissue samples by RT-PCR analysis. Immunohistochemically, using an antibody that cross-reacted with all CD44 species, CD44 was localized to the cell surface, lacuna wall and intracellular compartment of the chondrocytes in the middle and deep zone of normal cartilage, as well as with cells throughout the neoplastic masses. Utilizing an antibody specific for v6-containing CD44 species, the variant species was identified throughout cells of the middle and deep zone of normal cartilage, and localized selectively to intracellular positions. In neoplastic masses, v6-containing CD44 species were found associated only with cells in the hyaline-like cartilage, but not in the fibrocartilaginous regions. Thus a differential expression of the v6-containing CD44 species in the neoplastic masses containing both hyaline-like cartilage and fibrocartilaginous regions was observed when compared to its homogenous expression in normal hyaline cartilage. An involvement between the lack of the variant CD44 (v6-containing) and altered tissue phenotype (e.g., fibrocartilaginous) is suggested.