Antegrade Fixation of Distal Metaphyseal Ulnar Shortening Osteotomy.

The ulnar shortening osteotomy (USO) is a common procedure used to treat ulnar impaction syndrome secondary to static or dynamic ulnar-positive variance. There are many described techniques for the USO. The distal metaphyseal ulnar shortening osteotomy (DMUSO) with retrograde cannulated screw fixation was described to reduce complications seen with other techniques. Biomechanical analysis of fixation constructs demonstrates 2-screw constructs are significantly stiffer than 1 screw and antegrade constructs have similar or greater stiffness when compared with retrograde constructs. Here, we describe a technique of antegrade cannulated screw fixation for DMUSO that obviates the need for the disruption of the distal radioulnar joint for intra-articular exposure of the ulnar head. Similar to the traditional retrograde DMUSO technique, this construct may also decrease the risk of delayed union, symptomatic implants associated with diaphyseal osteotomies, and disruption of triangular fibrocartilaginous complex in wafer procedures.

Distal Metaphyseal Ulnar Shortening Osteotomy Fixation: A Biomechanical Analysis.

PURPOSE: Ulnar shortening osteotomy can be used to treat ulnar impaction syndrome and other causes of ulnar wrist pain. Distal metaphyseal ulnar shortening osteotomy (DMUSO) is one technique that has been proposed to reduce the complications seen with a diaphyseal USO or a wafer resection. However, to our knowledge, the optimal fixation construct for DMUSO has not been studied. We sought to characterize the biomechanical stiffness and rotational stability of different DMUSO constructs. METHODS: A DMUSO was performed on 40 human cadaveric ulnas using 4 different fixation constructs (10 specimens per group): one 3.0 mm antegrade screw; two 2.2 mm antegrade screws; one 3.0 mm retrograde screw; and two 2.2 mm retrograde screws. Biaxial testing using axial load and cyclical axial torque was performed until failure, defined as 10° of rotation or 2 mm displacement. Specimens were assessed for stiffness at failure. Bone density was assessed using the second metacarpal cortical percentage. RESULTS: Bone density was similar between all 4 testing groups. Of the 4 groups, the 2 antegrade screw group exhibited the highest rotational stiffness of 232 ± 102 Nm/deg. In paired analysis, this was significantly greater than 1 retrograde screw constructs. In multivariable analysis, 2-screw constructs were significantly stiffer than 1 screw and antegrade constructs were significantly stiffer than retrograde. Maximum failure torque did not differ with orientation, but 2 screws failed at significantly higher torques. CONCLUSION: Using 2 screws for DMUSO fixation constructs may provide higher stiffness and maximum failure torque, and antegrade screw constructs may provide more stiffness than retrograde constructs. CLINICAL RELEVANCE: Antegrade screw fixation using 2 screws may provide the strongest construct for DMUSO. Antegrade fixation may be preferred because it avoids violating the distal radioulnar joint capsule and articular surface of the ulna.

Orthobiologic Techniques for Surgical Augmentation.

General awareness and clinical utilization of orthobiologic therapy has increased sharply in the recent years. Orthobiologics can be defined as "biological materials and substrates that promote bone, ligament, muscle, and tendon healing." There are 3 major strategies by which orthobiologics are thought to augment tissue repair or native biologic potential: factor-based, cell-based, and biomechanical augmentation. The purpose of this review is to synthesize the recent literature on orthobiologic techniques for surgical augmentation, with focus on several key areas including meniscus repair, osteochondral grafting, and rotator cuff repair.

Anatomic relationship of extensor indicis propius and extensor digitorum communis: Implications for tendon transfer.

BACKGROUND: The extensor indicis proprius (EIP) tendon is a frequently used donor for a variety of tendon transfers, most commonly for reconstruction of the extensor pollicis longus (EPL). EIP is known to have frequent anatomic variants including split tendons and variations in tendon arrangement. AIM: To characterize the anatomy of the EIP at the level of the extensor retinaculum, where tendon harvest is often performed, and share our preferred technique for EIP to EPL transfer. METHODS: Twenty-nine fresh-frozen cadaveric forearms without history of forearm or hand injury or surgery were dissected. Tendon circumference and relationship of the EIP and extensor digitorum communis to the index (EDCI) at the metacarpophalangeal (MCP) joint and the distal extensor retinaculum were recorded. Distance from the distal extensor retinaculum to the EIP myotendinous junction was measured. RESULTS: EIP was ulnar to the EDCI in 96.5% of specimens (28/29) at the distal edge of the extensor retinaculum. In the remaining specimen, EIP was volar to EDCI. Tendon circumference at the distal extensor retinaculum averaged (9.3 mm ± 1.7 mm) for EDCI and 11.1 mm (± 2.7 mm) for EIP (P = 0.0010). The tendon circumference at the index MCP joint averaged 11.0 mm (± 1.7 mm) for EDCI and 10.6 mm (± 2.1 mm) for EIP (P = 0.33). EIP had a greater circumference in 76% (22/29) of specimens at the distal extensor retinaculum whereas EIP had a greater circumference in only 31% (9/29) of specimens at the MCP joint. CONCLUSION: The EIP tendon is frequently ulnar to and greater in circumference than the EDCI at the distal extensor retinaculum, which can be taken into consideration for tendon transfers involving EIP.

Deconstructing adolescent ethnicity: A longitudinal analysis of ethnic-racial identity development and self-categorization.

BACKGROUND: The study of adolescent perceptions of their ethnicity/race has been investigated from an ethnic-racial identity (measurement) perspective or through an ethnic-racial classification lens. AIMS: This study examines both, as it explores change in adolescents' ethnic-racial self-categorization; change in strength of ethnic-racial identity (ERI); and the relationship between change in self-categorization and strength of ERI. In so doing, it contributes to theorizing about the content and process of ERI formation. MATERIALS AND METHODS: The longitudinal and mixed-methods study followed 732 middle and high school students biannually in a semi-rural, ethnically diverse school district. All students completed the Multigroup Ethnic Identity Measure (MEIM) in fall and spring each year and interviewed annually for qualitative inquiry. RESULTS: The four waves of data demonstrated that: (1) 22% of students changed their ethnic-racial classification at least once; (2) Multiracial youth, boys, and 8th graders were significantly more likely to change self-classification compared to White youth, girls, and 10 th graders; (3) strength of ERI did not change over time, however, African American and Hispanic youth had the strongest ERI over time compared to the others; (4) change in self-classification was significantly related to change in strength of ERI, however, its direction varied by race of students. DISCUSSION: While adolescent ethnic-racial identity development (ERI) appears to be related to ethnic-racial categorization, the direction of the relationship varies depending on ethnic self-categorization. CONCLUSION: Results contribute to theory building of ERI in relation to: content and process, group consciousness, certainty and clarity, and public regard.

Metastatic Pattern of Truncal and Extremity Leiomyosarcoma: Retrospective Analysis of Predictors, Outcomes, and Detection.

Leiomyosarcomas (LMS) are a heterogenous group of malignant mesenchymal neoplasms with smooth muscle origin and are classified as either non-uterine (NULMS) or uterine (ULMS). Metastatic pattern, prognostic factors, and ideal staging/surveillance studies for truncal and extremity LMS have not been defined. A retrospective analysis of patients diagnosed with histopathology-confirmed truncal or extremity LMS between 2009 and 2019 was conducted. Data collected included demographics, tumor characteristics, staging, surveillance, and survival endpoints. The primary site was defined as: (1) extremity, (2) flank/Pelvis, or (3) chest wall/Spine. We identified 73 patients, 23.3% of which had metastatic LMS at primary diagnosis, while 68.5% developed metastatic disease at any point. The mean metastatic-free survival from primary diagnosis of localized LMS was 3.0 ± 2.8 years. Analysis of prognostic factors revealed that greater age (≥50 years) at initial diagnosis (OR = 3.74, p = 0.0003), higher tumor differentiation scores (OR = 12.09, p = 0.002), and higher tumor necrosis scores (OR = 3.65, p = 0.026) were significantly associated with metastases. Older patients (≥50 years, OR = 4.76, p = 0.017), patients with larger tumors (≥5 cm or ≥10 cm, OR = 2.12, p = 0.02, OR = 1.92, p = 0.029, respectively), higher differentiation scores (OR = 15.92, p = 0.013), and higher necrosis scores (OR = 4.68, p = 0.044) show worse survival outcomes. Analysis of imaging modality during initial staging and during surveillance showed greater tumor detection frequency when PET imaging was employed, compared to CT imaging (p < 0.0001). In conclusion, truncal and peripheral extremity LMS is an aggressive tumor with high metastatic potential and mortality. While there is a significant risk of metastases to lungs, extra-pulmonary tumors are relatively frequent, and broad surveillance may be warranted.

Gluteus Minimus Debridement During Acetabular Fracture Surgery Does Not Prevent Heterotopic Ossification-A Comparative Study.

OBJECTIVES: To compare rates of heterotopic ossification (HO) after acetabular fracture surgery, through a posterior approach, with and without gluteus minimus muscle (GMM) debridement. DESIGN: Retrospective comparative study. SETTING: Single academic Level I trauma center. PATIENTS: Ninety-four patients in the GMM preserved group and 42 patients in the GMM debrided group met inclusion criteria. INTERVENTION: GMM preservation or debridement during acetabular fracture surgery through a single-posterior approach. MAIN OUTCOME MEASUREMENTS: Primary outcomes were incidence and severity of HO. Reoperation for HO excision was assessed. Other risk factors for severe HO (Brooker class III-IV) were secondarily assessed using multivariable logistic regression analyses. Odds ratios (ORs) with 95% confidence intervals were calculated. The significance was set at P-value ≤ 0.05. RESULTS: There was no difference in the incidence or severity of HO between the debrided and preserved groups. Rates of reoperation for HO excision were comparable. American Society of Anesthesiologists physical status class (OR = 3.3), head injury (OR = 4.6), and abdominal injury (OR = 4.5) were associated with severe HO. CONCLUSION: GMM debridement was not associated with a decreased incidence of HO after acetabular fracture surgery. American Society of Anesthesiologists class is a novel risk factor associated with severe HO formation. LEVEL OF EVIDENCE: Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Low profile fragment specific plate fixation of lateral tibial plateau fractures - A technical note.

PURPOSE: Precontoured plates used to stabilize lateral tibial plateau (LTP) fractures are limited in their ability to raft particular areas of the reconstructed articular surface. These implants also do not fit every individual's bony anatomy and can lead to soft tissue irritation. The purpose of this study was to evaluate fragment specific plate fixation of LTP fractures using generic small and mini fragment constructs. METHODS: This was a retrospective case series of LTP fractures treated with small fragment tubular and/or mini fragment plate constructs at a single Level I trauma center. Postoperative complications were recorded. Final radiographs were analyzed to determine union and interval subsidence of the articular surface and/or loss of reduction. RESULTS: All 19 LTP fractures healed without loss of reduction or implant failure. There was minimal interval subsidence of the LTP in all patients. There were no complications or reoperations for symptomatic implant removal within the given follow-up period. CONCLUSION: Fragment specific fixation of LTP fractures using small and mini fragment plates creates a lower profile construct that reliably maintains fracture reduction to union.

Trochanteric osteotomy for acetabular fracture fixation: a case series and literature review.

PURPOSE: This study examined osteotomy union and heterotopic ossification (HO) after performing digastric trochanteric osteotomies during open reduction and internal fixation (ORIF) of acetabular and combined femoral head fractures. Femoral head osteonecrosis and trochanteric screw removal were secondarily assessed. METHODS: Twenty-six patients treated at a Level I trauma center, from years 2003 to 2019, who received a digastric trochanteric osteotomy during acetabular and combined femoral head fracture ORIF through a posterior surgical approach were retrospectively identified. Osteotomies were fixed with two 3.5 mm cortical lag screws. Rates of osteotomy union, HO, femoral head osteonecrosis, and trochanteric screw removal were determined. RESULTS: All osteotomies went onto union without displacement or failure of fixation. Only three (12%) patients developed severe HO (modified-Brooker class III-IV). There were no instances of femoral head osteonecrosis and only one (7%) patient required trochanteric screw removal. CONCLUSIONS: The digastric trochanteric osteotomy heals reliably with low rates of severe HO, femoral head osteonecrosis, and screw removal for soft-tissue irritation. A review of the literature is presented and found comparable findings.

Lateral Distractor Use During Internal Fixation of Tibial Plateau Fractures Has a Minimal Risk of Iatrogenic Peroneal Nerve Palsy.

OBJECTIVES: To determine the incidence of iatrogenic peroneal nerve palsy after application of an intraoperative lateral distractor during open reduction and internal fixation of tibial plateau fractures. DESIGN: Retrospective review. SETTING: Single academic Level I trauma center. PATIENTS: One hundred forty-seven patients met criteria and were included in the study. INTERVENTION: Patients with unicondylar and bicondylar tibial plateau fractures underwent open reduction and internal fixation and received application of an intraoperative lateral distractor to aid in visualization and reduction of the impacted lateral plateau. MAIN OUTCOME MEASUREMENTS: Incidence of iatrogenic peroneal nerve palsy. RESULTS: There was a 2.0% incidence of iatrogenic peroneal nerve symptoms (3 of 147 patients), most of which were incomplete sensory deficits. There was no association with staged external fixation, regional anesthesia, or tourniquet use. CONCLUSION: Use of an intraoperative lateral distractor is safe and has a low incidence of iatrogenic peroneal nerve palsy if applied carefully. LEVEL OF EVIDENCE: Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Effects of Antiplatelet and Nonsteroidal Anti-inflammatory Medications on Platelet-Rich Plasma: A Systematic Review.

BACKGROUND: Platelet-rich plasma (PRP) has wide applications in orthopaedic care. Its beneficial effects are attributed to the growth factor profile from the platelet secretome. In theory, these effects would be diminished by medications that inhibit platelet activation and/or the subsequent release of growth factors. PURPOSE: To determine whether commonly used antiplatelets, nonsteroidal anti-inflammatory drugs (NSAIDs), or anticoagulant medications affect platelet growth factor release in PRP. STUDY DESIGN: Systematic review; Level of evidence, 2. METHOD: A systematic review of the literature related to antiplatelet, anti-inflammatory, and anticoagulant drugs was performed following the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. We used the Downs and Black objective quality scoring system. The literature search consisted of PubMed and Cochrane Library databases. Search terms consisted of 1 item selected from "platelet-rich plasma," "platelet-derived growth factor," and "platelet-rich plasma AND growth factor" combined with 1 item from "antiplatelet," "aspirin," "anticoagulant," and "NSAID." Only studies published within the past 25 years were included. RESULTS: A total of 15 studies met the inclusion criteria: 7 studies detected no significant decrease in growth factors or mitogenesis, whereas 6 detected a decrease with antiplatelet agents, 1 detected mixed results with an antiplatelet agent, and 1 had mixed results with an antiplatelet agent/vasodilator. In terms of PRP activation, all 3 studies assessing collagen, the 2 studies analyzing adenosine diphosphate alone, and the 1 study investigating arachidonic acid found a decrease in growth factor concentration. CONCLUSION: Antiplatelet medications may decrease the growth factor release profile in a cyclooxygenase 1- and cyclooxygenase 2-dependent manner. Eight of 15 studies found a decrease in growth factors or mitogenesis. However, more studies are needed to comprehensively understand antiplatelet effects on the PRP secretome.

Promoter Cre-Specific Genotyping Assays for Authentication of Cre-Driver Mouse Lines.

The Cre-LoxP system gene knockout (KO) technology provides cell- and time-specificity of gene ablation to investigate cell-autonomous gene function in vivo, and is paramount for understanding the function of genes involved in bone development, remodeling, and repair. This approach permits gene ablation in a cell- or tissue-specific, differentiation stage-specific, and inducible manner, thanks to the use of well-chosen promoters that drive expression of the Cre recombinase in selected cells/tissues. The generation of these powerful tools has led to the expansion of Cre mouse lines available to the research community, which are often shared within and between laboratories. Although convenient and commonly used, genotyping these Cre lines with a generic set of primers that amplifies the Cre transgene does not distinguish between various Cre-deleter lines. This practice poses the significant risk of mistakenly swapping Cre lineages, as laboratories often host and handle several lines at a time and utilize multiple lines per project. In line with the NIH-led effort to promote authentication of biological reagents and increase scientific rigor, we report here strategies for designing appropriate sets of primers able to discriminate some of most widely used Cre-deleter mouse lines in the field of bone biology, and the validation of 24 of them.

Impact of dental clearance on total joint arthroplasty: A systematic review.

Many orthopedic surgeons require that their patients obtain dental clearance before elective total joint arthroplasty (TJA). However, there is no consensus substantiating the practice. To this end, a systematic review on the prevalence of dental pathology in TJA patients, risk factors for failing dental screening, and impact of dental evaluations was performed. Literature was sourced from PubMed and Scopus databases. Six papers were sourced from the initial search, one study was extracted from the references of the original six manuscripts, and one new publication was retrieved from a second search conducted after the first. The prevalence of dental pathology ranged from 8.8% to 29.4% across studies. Two of four papers reported lower than average or improvements in post-operative infection with pre-operative dental evaluations while two found no such association. There is insufficient evidence to support universal dental clearance before TJA.

Acute Cardiac Events in Patients With Severe Limb Infection.

Recent studies have shown an association between infections, such as influenza, pneumonia, or bacteremia, and acute cardiac events. We studied the association between foot infection and myocardial infarction, arrhythmia, and/or congestive heart failure. We analyzed the records of 318 consecutive episodes of deep soft tissue infection, gangrene, and/or osteomyelitis in 274 patients referred to a vascular surgery service at a tertiary center. We identified 24 acute cardiac events in 21 of 318 (6.6%) episodes of foot infection or foot gangrene. These 24 events included 11 new myocardial infarctions (3.5%), 8 episodes of new onset or worsening congestive heart failure (2.5%), and 5 new arrhythmias (1.6%). Tachycardia and systemic inflammatory response syndrome were associated with acute cardiac events ( P < .05 for each). The 1-year survival of patients with acute cardiac events was 50.4%, significantly lower than the 91.7% 1-year survival of patients without acute cardiac events ( P < .0015). Acute cardiac complications are not uncommon among patients presenting with severe foot infection and are associated with a high 1-year mortality. Primary care physicians, cardiologists, and vascular and orthopedic surgeons must keep a high index of suspicion for the occurrence of an acute cardiac event.

Clinical Results of Direct Anterior Approach THA with Minimal Fluoroscopic Exposure Optimization Techniques.

PURPOSE: To determine if low-level intraoperative fluoroscopy usage is associated with increased complications during an initial series for an experienced surgeon transitioning to direct anterior approach (DAA) for total hip arthroplasty (THA). MATERIALS AND METHODS: Subjects who underwent DAA were eligible for analysis. Inclusion criteria included the first 50 subjects who underwent DA hip arthroplasty by a single surgeon (January 2013 to December 2014). Total operating room (OR) time, fluoroscopy absorbed dose, flouoroscopy time, procedure time, and complications were collected and analyzed. Subject demographics were also collected with subjects divided by date of surgery to one of two possible groups. Simple linear regression analysis was performed to determine the relation between case number and both radiation dose and fluoroscopy time. RESULTS: Subjects underwent DAA total hip arthroplasty (n=45). Total OR time ranged from 1.1hrs up to 2.5 hours. Surgeries required an average fluoroscopic time of 7.8 seconds, with improvement over the series of 3.7 seconds. The average radiation dose or fluoroscopy was 2.6 mrem per case. This resulted in a total estimated exposure of 127 mrem over a 23-month period. No patients suffered intraoperative or postoperative fractures or revisions. No significant difference was found for the groups by weight, age, height, and body mass index. Regression analysis yielded a statistically significant (p<0.05) decrease in fluoroscopy time of 0.36 seconds per case over the 45 cases studied. CONCLUSION: An experienced single surgeon's learning curve in DAA THA can be accelerated, with proper training and technique, within a lifetime case experience less than 50 procedures. Surgeons should be aware that with proper techniques and sufficiently-experienced teams, a flattened learning curve is attainable while minimizing fluoroscopy exposure and maintaining clinical outcomes.

Ethnic Identity, Gender, and Adolescent Attitude toward School: Adaptive Perspectives in Diverse Settings.

The relationships between adolescent ethnic identity and attitudes toward school and school climate are investigated in a small, multiracial/multiethnic city in the Great Lakes region with ethnically diverse adolescents taught by primarily White teachers. The mixed methods investigation of 986 eighth through eleventh grade students during the 2010-2011 academic year suggests that the relationship between ethnic identity and attitude toward school is a complex interaction among individual characteristics of ethnicity/race, ethnic identity, gender, and ecological context. Quantitative results reveal that White female and Hispanic and African American male students exhibit strong ethnic identity that correlates positively with school attitude; however, qualitative results indicate very different paths in getting to those outcomes. Hispanic students appear to benefit from a strong ethnic identity that assists with positive relationships at school, while African American male students utilize parental cultural socialization as a protective function in school. The results emphasize the implications of positive school climates for all students.

Staphylococcus aureus primase has higher initiation specificity, interacts with single-stranded DNA stronger, but is less stimulated by its helicase than Escherichia coli primase.

The study of primases from model organisms such as Escherichia coli, phage T7 and phage T4 has demonstrated the essential nature of primase function, which is to generate de novo RNA polymers to prime DNA polymerase. However, little is known about the function of primases from other eubacteria. Their overall low primary sequence homology may result in functional differences. To help understand which primase functions were conserved, primase and its replication partner helicase from the pathogenic Gram-positive bacteria Staphylococcus aureus were compared in detail with that of E. coli primase and helicase. The conserved properties were to primer initiation and elongation and included slow kinetics, low fidelity and poor sugar specificity. The significant differences included S. aureus primase having sixfold higher kinetic affinity for its template than E. coli primase under equivalent conditions. This naturally higher activity was balanced by its fourfold lower stimulation by its replication fork helicase compared with E. coli primase. The most significant difference between the two primases was that S. aureus helicase stimulation did not broaden the S. aureus primase initiation specificity, which has important biological implications.

Evaluation of response time of a portable system for in-use vehicle tailpipe emissions measurement.

The objective of this paper is to quantify and evaluate the effects of response time of a portable emission measurement system (PEMS). The PEMS measures tailpipe emissions and vehicle dynamics on a second-by-second basis. Response times of the PEMS for exhaust concentrations were quantified on the basis of fixed periods of measurement of calibration gases for NO, hydrocarbons (HC), CO, and CO2. The time constant was quantified on the basis of the time to reach 63% of the maximum measured value when calibration gas was continuously administered for a period of typically 20 s or more. The time constant was found to be 6 s for NO and 3 s each for CO, HC, and CO2. Measurement errors associated with the response time of the PEMS were quantified. A first-order dynamic discrete model was developed to simulate the instrument measurements. Simulations showed that correction improves the measurement accuracy. Correction with smoothing better improves the measurement accuracy, especially when the noise is relatively large. On a trip level, the average error of the simulated measurements relative to the simulated signal before correction is -4%, which is deemed to be acceptable. For real-world data, smoothing and correction is recommended for major peaks to improve the measurement accuracy.