Femoral-Sided Avulsion Fracture of the Anterior Cruciate Ligament in a Skeletally Immature Patient: A Case Report.

CASE: A 10-year-old boy presented to the clinic with sharp left knee pain after sustaining an injury while hiking. The patient was unable to bear weight. Physical examination demonstrated a moderate effusion and lateral joint line tenderness. Imaging studies revealed a femoral-sided avulsion of the anterior cruciate ligament. Arthroscopic suture fixation of the avulsed fragment resulted in good radiographic and clinical results at the 13-month follow-up. CONCLUSION: Physeal-sparing suture-fixation of femoral-sided anterior cruciate ligament avulsion injuries can be performed using an all-arthroscopic approach and may be a viable treatment option.

Brown Carbon Production by Aqueous-Phase Interactions of Glyoxal and SO2.

Oxalic acid and sulfate salts are major components of aerosol particles. Here, we explore the potential for their respective precursor species, glyoxal and SO2, to form atmospheric brown carbon via aqueous-phase reactions in a series of bulk aqueous and flow chamber aerosol experiments. In bulk aqueous solutions, UV- and visible-light-absorbing products are observed at pH 3-4 and 5-6, respectively, with small but detectable yields of hydroxyquinone and polyketone products formed, especially at pH 6. Hydroxymethanesulfonate (HMS), C2, and C3 sulfonates are major products detected by electrospray ionization mass spectrometry (ESI-MS) at pH 5. Past studies have assumed that the reaction of formaldehyde and sulfite was the only atmospheric source of HMS. In flow chamber experiments involving sulfite aerosol and gas-phase glyoxal with only 1 min residence times, significant aerosol growth is observed. Rapid brown carbon formation is seen with aqueous aerosol particles at >80% relative humidity (RH). Brown carbon formation slows at 50-60% RH and when the aerosol particles are acidified with sulfuric acid but stops entirely only under dry conditions. This chemistry may therefore contribute to brown carbon production in cloud-processed pollution plumes as oxidizing volatile organic compounds (VOCs) interact with SO2 and water.