9-Phenanthrol modulates postinhibitory rebound and afterhyperpolarizing potentials in an excitatory motor neuron of the medicinal leech.

Postinhibitory rebound (PIR) responses in leech dorsal excitatory motor neurons (cell DE-3) are eliminated by Ca2+ channel blockers but also exhibit a strong dependence on extracellular Na+. These features could be explained by a voltage-gated Ca2+ current acting in concert with a Ca2+-activated nonspecific current (ICAN). In vertebrates, ICAN is associated with TRPM4 channels which are blocked selectively by 9-phenanthrol. Here, we show that 9-phenanthrol selectively inhibits a late phase of PIR and simultaneously enhances afterhyperpolarizing potentials (AHPs). Bath application of NNC 55-0396 or Cd2+ combined with ion substitution experiments indicate that a low-voltage-activated Ca2+ current plays a key role in generating PIR and that Ca2+ influx through low- or high-voltage-activated Ca2+ channels can trigger AHPs via activation of a Ca2+-dependent K+ current. We also demonstrate modulation of rebound responses by other ICAN blockers such as gadolinium and flufenamic acid, as well as the calmodulin antagonist W-7. We discuss how these results provide additional insights into the specific types of ionic currents underlying rebound responses of motor neuron DE-3 in the medicinal leech.

Is Immediate Postoperative Radiograph Necessary Following Robotic-Assisted Total Knee Arthroplasty?

The necessity of immediate postoperative radiographs following total knee arthroplasty (TKA) has long been debated. With the increasing use of robotic-assisted TKA (RTKA), and thus more precise implant placement, the need for immediate postoperative radiographs to determine implant positioning may be unnecessary. We sought to evaluate implant position on the immediate postoperative radiographs following RTKA to determine their necessity. A retrospective review of 150 RTKAs was performed. The posterior slopes for all TKAs were recorded based on the preoperative three-dimensional template. Additionally, two independent trained researchers (J.G./L.B.) each measured the posterior slope of the postoperative day 0 (POD0) radiograph and postoperative week 2 radiograph. The difference in posterior slope measurement between template and POD0, between template and postoperative week 2, and between POD0 and postoperative week 2 was calculated. Of the 150 TKAs performed, there were no periprosthetic fractures found on the POD0 radiograph. The mean difference between the templated posterior slope and measured posterior slope on POD0 was 0.04 degrees (standard deviation [SD], 1.01; p = 0.615). There was a weak correlation between the two values (rs [95% confidence interval (CI)], 0.38 [0.21, 0.53]). When comparing the template to the postoperative week 2 radiographs, there was a mean difference of 0.02 degrees (SD, 0.48; p = 0.556).  However, a moderate to strong correlation was noted (rs [95% CI], 0.71 [0.61, 0.79]). Comparison of the mean posterior slope from POD0 radiograph to that of postoperative week 2 radiograph showed a mean difference of 0.06 degrees (SD, 1.0; p = 0.427). A weak correlation was found between these two values (rs [95% CI], 0.43 [0.26, 0.56]). Given the accuracy and precision of RTKA, along with the ability to decrease cost and radiation, immediate postoperative radiograph may be unnecessary, when pertaining to the uncomplicated RTKA. However, if there is concern for intraoperative fracture, long stems placed in a revision arthroplasty, or other intraoperative complications, then postoperative radiographs are encouraged.

A review of chronic pectoralis major tears: what options are available?

Rupture of the pectoralis major muscle typically occurs in the young, active male. Acute management of these injuries is recommended; however, what if the patient presents with a chronic tear of the pectoralis major? Physical exams and magnetic resonance imaging can help identify the injury and guide the physician with a plan for management. Nonoperative management is feasible, but is recommended for elderly, low-demand patients whose functional goals are minimal. Repair of chronic tears should be reserved for younger, healthier patients with high functional demands. Although operative management provides better functional outcomes, operative treatment of chronic pectoralis tears can be challenging. Tendon retraction, poor tendinous substance and quality of tissue, muscle atrophy, scar formation, and altered anatomy make direct repairs complicated, often necessitating auto- or allograft use. We review the various graft options and fixation methods that can be used when treating patients with chronic pectoralis major tears.

Residency Match Rates in Orthopaedic Surgery Based on Sex, Under-Represented in Medicine Status, and Degree Type.

Orthopaedic surgery is well recognized as one of the most competitive and least diverse medical specialties. Despite efforts toward improving diversity, studies have shown that gender and racial/ethnic disparities continue to persist in orthopaedic graduate medical education. Therefore, we sought to identify the match rates of traditionally under-represented groups within orthopaedic surgery-female candidates, racial and ethnic minorities under-represented in medicine (URiM), and osteopathic physicians-compared with their application rates. Methods: A retrospective review of the Electronic Residency Application Service (ERAS) application data from the 2017 to 2021 application cycles was performed, and the total number of applicants, sex, race/ethnicity, and degree type of all students applying for orthopaedic surgery were recorded. A separate database, the Orthopaedic Residency Information Network (ORIN), which is a database self-reported by residency programs to provide information to applicants, was also queried to identify the total number of residents, sex, race/ethnicity, and degree type of all current residents in June 2022, corresponding to those residents who matched in 2017 to 2021. Results: From the ERAS application data, a total of 7,903 applicants applied to orthopaedic surgery during the study period. A total of 1,448 applicants (18%) were female, 1,307 (18%) were URiM, and 1,022 (15%) were from an osteopathic medical school. Based on the ORIN database, 688 of 3,574 residents (19%) were female, 1,131 of 7,374 (19%) were URiM, and 1,022 of US medical school graduates (12%) had a DO degree. The application and match rates were not significantly different for female (p = 0.249) and URiM (0.187) applicants; however, there was a significant difference in the application and match rates (15% vs 12%; p = 0.035) for US medical graduates with a DO degree. Conclusion: In recent years, there has been a significant and necessary push to increase diversity in the field of orthopaedic surgery. From 2017 to 2021, match rates of female and URiM candidates are reflective of their application rates. Osteopathic applicants in orthopaedic surgery have a lower match rate than their allopathic counterparts. Level of Evidence: III.

Publication Rates of Abstracts Presented at American Orthopaedic Society for Sports Medicine Annual Meetings From 2016 to 2019.

Background: Research in the form of poster and podium abstracts is disseminated at subspecialty society meetings. The quality of this research can be defined by exploring the ultimate publication rate of the presented abstracts. Purpose: To investigate (1) the manuscript publication rate of abstracts presented at the American Orthopaedic Society for Sports Medicine (AOSSM) annual meeting; (2) whether abstract format (poster vs podium) influences overall or 2-year publication rates and time to publication; (3) the abstract factors that are associated with increased publication rate; and (4) whether publication quality as measured by journal of publication, level of evidence (LOE), and number of citations differs between posters and podiums. Study Design: Cross-sectional study. Methods: Poster and podium abstracts that were presented at the AOSSM annual meetings between January 1, 2016, and December 31, 2019, were included. The PubMed and GoogleScholar databases were searched by abstract title and authors to determine whether the related manuscript had been published. For published manuscripts, the journal, journal impact factor (IF), time to publication, authors, and LOE were recorded. Results: The manuscripts of 664 abstracts (341 poster, 323 podium presentations) were published during the study period. The overall publication rate was 52.4%. Publication within 2 years of the meeting was found to be higher in podium abstracts (45.8%) compared with poster abstracts (37.8%) (P = .0366). Podium abstracts had a shorter time to publication (P < .001), higher LOE (P = .0166), more citations (P < .0001), and were published in higher IF journals (P = .0028). Poster presentations were more likely to undergo a change in first author between the time of the conference and future publication (P = .0300). The most common journal of publication was the American Journal of Sports Medicine (36.8%). Conclusion: Abstracts presented at the AOSSM annual meeting had a high rate of publication within 2 years. There was no difference in publication rates between podium and poster abstracts, but podium abstracts had a shorter time to publication and more future citations and were published in journals with higher IFs.