Preparation of difluoromethylthioethers through difluoromethylation of disulfides using TMS-CF2H

We report an operationally simple, metal-free approach for the late-stage introduction of the important lipophilic hydrogen-bond donor motif, SCF2H. This reaction converts diaryl- and dialkyl-disulfides into the corresponding aryl/alkyl–SCF2H through the nucleophilic transfer of a difluoromethyl group with good functional group tolerance. This method is notable for its use of commercially available TMSCF2H, and does not rely on the need for handling of sensitive metal complexes

Novel Cemented Technique for Trochanteric Fixation and Reconstruction of the Abductor Mechanism in Proximal and Total Femoral Arthroplasty: An Observational Study

Background: Little evidence exists regarding the clinical outcomes of cemented trochanteric fixation for abductor mechanism reconstruction in proximal or total femoral replacements. Clinical outcomes were assessed for a novel cemented technique for trochanteric fixation in femoral megaprostheses. Methods: A descriptive series of 13 patients who underwent proximal or total femoral arthroplasty from 2016 to 2019 were reviewed. Radiographic trochanteric displacement \u3e 1 cm defined construct failure. A Kaplan-Meier survival analysis was performed to determine survival rates for these cemented constructs. Demographic information was obtained to better characterize the patient population in whom this technique was used. Results: Eleven patients were included (age = 63.6 years; 45.4% females; body mass index = 31.7). Mean time to final radiographic follow-up was 73.8 weeks. Three of 11 (27.2%) patients had construct failure. Overall, survival at 1 year was 81.8%. At 2 years, survival of cemented constructs was 65.5%. More construct failures occurred in patients who sustained a postoperative dislocation than in those who did not (P = .05). Conclusions: This novel cemented trochanteric fixation technique for reconstruction of the abductor mechanism in femoral megaprostheses had 81.8% survival at 1 year postoperatively. While longitudinal comparative studies with larger samples are needed, the cemented technique may provide a viable alternative to traditional cementless methods of trochanteric fixation. Increased construct failure rates after postoperative dislocation highlight the importance of robust abductor reconstruction in these implants

Drawing Trees with Perfect Angular Resolution and Polynomial Area

We study methods for drawing trees with perfect angular resolution, i.e., with angles at each node v equal to 2{\pi}/d(v). We show: 1. Any unordered tree has a crossing-free straight-line drawing with perfect angular resolution and polynomial area. 2. There are ordered trees that require exponential area for any crossing-free straight-line drawing having perfect angular resolution. 3. Any ordered tree has a crossing-free Lombardi-style drawing (where each edge is represented by a circular arc) with perfect angular resolution and polynomial area. Thus, our results explore what is achievable with straight-line drawings and what more is achievable with Lombardi-style drawings, with respect to drawings of trees with perfect angular resolution.Comment: 30 pages, 17 figure

Femoroacetabular Impingement as a Complication of Acetabular Fracture Fixation

Case We present the case of a thirteen-year-old female who sustained a posterior wall acetabular fracture dislocation. She underwent urgent closed reduction and subsequent uncomplicated open reduction and internal fixation. Post reduction computed tomography demonstrated a concentrically reduced hip joint with no evidence of femoroacetabular impingement (FAI). She subsequently healed her fracture and returned to running activities; however, one year later presented with aching pain in her thigh. Radiographs demonstrated the development of a large osseous prominence on her anterolateral femoral neck consistent with femoroacetabular impingement. Based on these findings she was evaluated by a hip preservation specialist. She subsequently underwent successful hip arthroscopy for labral repair and femoral osteochondroplasty. She was eventually able to return to running sports with little pain. Summary We present a case of FAI presenting as a complication of acetabular fracture fixation. This should be discussed with patients presenting with traumatic hip dislocations as a possible complication of surgical fixation or possibly of the injury itself

Is Cooled Radiofrequency Genicular Nerve Block and Ablation a Viable Option for the Treatment of Knee Osteoarthritis?

Background The purpose of this study was to determine demographic and psychosocial factors that influence the effectiveness of cooled radiofrequency genicular nerve ablation (C-RFA) and block in patients with chronic knee pain secondary to osteoarthritis (OA). Methods A retrospective review was completed including patients with knee OA who underwent genicular nerve ablation or block or both. Patient information collected included opioid use, psychological comorbidities, smoking history, body mass index, and medical comorbidities. Success was defined using the Osteoarthritis Research Society International criterion of greater than or equal to 50% reported pain relief from the procedure. Patients without a diagnosis of knee OA and patients with ipsilateral total knee arthroplasty were excluded. Patient factors were compared between (1) those that did or did not respond to the initial block and (2) those that did or did not respond to C-RFA. Results Of the 176 subjects that underwent genicular nerve block, 31.8% failed to respond to the procedure. Subjects that failed the initial block were significantly more likely to have psychological comorbidities, smoking history, and diabetes. Of the subjects that proceeded to genicular nerve ablation, 53.7% reported less than 50% pain relief, and 46.3% reported pain relief greater than or equal to 50% at the first follow-up visit. While the presence of psychological comorbidities, smoking, and diabetes were associated with first-stage block failures, these patient factors were not associated with second-stage ablation failures. Conclusions C-RFA may be an effective adjunct therapy as part of a multimodal pain regimen; however, individual patient characteristics must be considered

Making Sense of Hip Preservation Procedural Coding--Getting Paid for Your Work!

Hip preservation and peri-trochanteric procedures are becoming more commonplace for the arthroplasty surgeon. Understanding the reimbursement for these procedures remains a challenge for those looking to expand this portion of their practice. In order to financially maximize the surgeon’s efforts, we present recommendations for hip preservation procedural coding

How Has COVID-19 Affected Our Orthopedic Implant Industry Partners? Implications for the Surgeon-Industry Relationship in 2020 and Beyond

This article is made available for unrestricted research re-use and secondary analysis in any form or by any means with acknowledgement of the original source. These permissions are granted for the duration of the World Health Organization (WHO) declaration of COVID-19 as a global pandemic.Background The COVID-19 pandemic has had far-reaching societal and financial consequences. The purpose of this study was to evaluate how COVID-19 has affected AAHKS industry partners and the surgeon-industry relationship, emphasizing education, resource allocation, and strategic direction for the 2nd half of 2020. Methods AAHKS industry partners were contacted to participate in a blinded survey and optional interview with the AAHKS Industry Relations Committee. Based on the results, a group of AAHKS member surgeons with disparate practice types were asked to postulate on how the COVID-19 pandemic has and will affect their practice and relationship with Industry. Results AAHKS industry partner responses indicated decreased resource allocation for regional, “other national,” and AAHKS annual meetings (67%, 55%, and 30%, respectively). Web-based educational content was expected to increase in 2020 and will likely remain a point of emphasis in 2021 (100% and 70% of responders). For Q3/Q4 2020, a significant emphasis was placed on site of service/outpatient TJA and COVID-19-related safety measures (70% and 90% of responders), as well as increased availability of instrumentation and implants (40% and 60%, respectively). Conclusion The COVID-19 pandemic has altered the orthopedic landscape for the foreseeable future. Survey responses by AAHKS industry partners demonstrate a continued commitment to surgeon education with and increasing shift to a web-based platform. Increased resource allocation for outpatient TJA and COVID-19-related safety measures were significant. Articulating optimal mechanisms to aid industry in supporting surgeons with different practice models to meet demand during the second half of fiscal year 2020 will be critical

Latent regulatory potential of human-specific repetitive elements

At least half of the human genome is derived from repetitive elements, which are often lineage specific and silenced by a variety of genetic and epigenetic mechanisms. Using a transchromosomic mouse strain that transmits an almost complete single copy of human chromosome 21 via the female germline, we show that a heterologous regulatory environment can transcriptionally activate transposon-derived human regulatory regions. In the mouse nucleus, hundreds of locations on human chromosome 21 newly associate with activating histone modifications in both somatic and germline tissues, and influence the gene expression of nearby transcripts. These regions are enriched with primate and human lineage-specific transposable elements, and their activation corresponds to changes in DNA methylation at CpG dinucleotides. This study reveals the latent regulatory potential of the repetitive human genome and illustrates the species specificity of mechanisms that control it