The synaptonemal complex (SC) is a conserved meiotic structure that regulates the repair of double-strand breaks (DSBs) into crossovers or gene conversions. The removal of any central-region SC component, such as the Drosophila melanogaster transverse filament protein C(3)G, causes a complete loss of SC structure and crossovers. To better understand the role of the SC in meiosis, we used CRISPR/Cas9 to construct 3 in-frame deletions within the predicted coiled-coil region of the C(3)G protein. Since these 3 deletion mutations disrupt SC maintenance at different times during pachytene and exhibit distinct defects in key meiotic processes, they allow us to define the stages of pachytene when the SC is necessary for homolog pairing and recombination during pachytene. Our studies demonstrate that the X chromosome and the autosomes display substantially different defects in pairing and recombination when SC structure is disrupted, suggesting that the X chromosome is potentially regulated differently from the autosomes.

22In Drosophila, meiotic recombination is initiated by the formation of programmed DNA double-23 strand breaks (DSBs), which occur within the context of the synaptonemal complex (SC). To 24 better understand the role of the SC in mediating recombination we created an in-frame deletion suggesting that discontinuity in the euchromatic SC-rather than failed pairing-might cause the 39 altered crossover distribution. These phenotypes reveal that different chromatin states or 40 regions have differing requirements to maintain both the SC and homologous pairing. 41

Objectives: Lateral ankle ligament stabilization may be performed with concomitant arthroscopy. Arthroscopy has been shown to aid in the diagnosis of intra-articular defects that often accompany lateral ankle ligament injuries. This study compares the differences in cost, complications, newly diagnosed intra-articular defects, and reoperations among patients with ankle sprain/chronic instability who underwent lateral ankle ligament repair/reconstruction with or without concomitant arthroscopic procedures. Methods: Data was collected from the PearlDiver Technologies Humana dataset using CPT and ICD9/10 codes. Patients included in this study (n=2,188) had records of ankle sprain or ankle instability prior to or on the same day as one of two procedures: lateral ankle ligament repair (n=1,141) or lateral ankle ligament reconstruction (n=1,063). This population was subdivided by whether patients had records of arthroscopic procedure(s) on the same day as the ligament surgery. This yielded four groups: repair with arthroscopy (n=219), repair without arthroscopy (n=922), reconstruction with arthroscopy (n=325), reconstruction without arthroscopy (n=738). Cost, complications, newly diagnosed intra-articular defects, and reoperations were assessed. Results: Average cost per patient was higher for both arthroscopy groups: repair with arthroscopy ($6,207.78) versus repair without arthroscopy ($3,677.11; p < 0.0001); reconstruction with arthroscopy ($5,758.21) versus reconstruction without arthroscopy ($4,601.13; p = 0.0039). There was a significantly higher proportion of patients with complications in the reconstruction without arthroscopy group than in the reconstruction with arthroscopy group (7.59%, 4.31%; p = 0.0431), but the difference between repair groups was insignificant (p = 0.0626). The proportion of patients with newly diagnosed intra-articular defects was significantly higher in both arthroscopy groups: repair with arthroscopy (53.0%) versus repair without arthroscopy (35.6%; p < 0.0001); reconstruction with arthroscopy (56.0%) versus reconstruction without arthroscopy (39.8%; p < 0.0001). There was a significantly higher proportion of patients who underwent reoperation for intra-articular defects in the combined (repair plus reconstruction) arthroscopy group (7.18%) than in the combined non-arthroscopy groups (4.91%; p = 0.049). Most importantly, the average time until reoperation for intra-articular defects was significantly shorter in the combined arthroscopy group (271.923 days) than in the combined non-arthroscopy group (411.473 days; p = 0.024). Conclusion: Concomitant arthroscopy with lateral ankle ligament surgery is more expensive but does not appear to increase the overall complication rate and may allow surgeons to diagnose and treat more intra-articular pathology. Among patients requiring reoperation for intra-articular defects, the average time to reoperation was nearly 5 months shorter for patients receiving arthroscopy than for patients who did not receive arthroscopy.

Category: Ankle, Arthroscopy Introduction/Purpose: Lateral ankle ligament stabilization may be performed with concomitant arthroscopy. Arthroscopy has been shown to aid in the diagnosis of intra-articular defects that often accompany lateral ankle ligament injuries. This study compares the differences in cost, complications, newly diagnosed intra-articular defects, and reoperations among patients with ankle sprain/chronic instability who underwent lateral ankle ligament repair/reconstruction with or without concomitant arthroscopic procedures. Methods: Data was collected from the PearlDiver Technologies Humana dataset using CPT and ICD9/10 codes. Patients included in this study (n=2,428) had records of ankle sprain or ankle instability prior to or on the same day as one of two procedures: lateral ankle ligament repair (n=1,236) or lateral ankle ligament reconstruction (n=1,211). This population was subdivided by whether patients had records of arthroscopic procedure(s) on the same day as the ligament surgery. This yielded four groups: repair with arthroscopy (n=314), repair without arthroscopy (n=922), reconstruction with arthroscopy (n=473), reconstruction without arthroscopy (n=738). Cost, complications, newly diagnosed intra-articular defects, and reoperations were assessed. Results: Cost was higher for arthroscopy groups: repair with arthroscopy ($5,991.32) versus repair without arthroscopy ($3,677.11; p<0.001); reconstruction with arthroscopy ($5,744.83) versus reconstruction without arthroscopy ($4,601.13; p=0.001). Proportionately more patients had complications in the repair without arthroscopy group than in the repair with arthroscopy group (9.87%, 5.41%; p=0.013). Proportionately more patients had newly-diagnosed intra-articular defects in arthroscopy groups: repair with arthroscopy (57.0%) versus repair without arthroscopy (35.6%; p<0.001); reconstruction with arthroscopy (63.0%) versus reconstruction without arthroscopy (39.8%; p<0.001). Proportionately more patients underwent reoperation for intra-articular defects in the combined arthroscopy group (6.89%) than in the combined non-arthroscopy group (4.18%; p=0.006). The average time until reoperation for intra-articular defects was shorter in the combined arthroscopy group (302.536 days) than in the combined non-arthroscopy group (473.886 days; p=0.045). Conclusion: Concomitant arthroscopy with lateral ankle ligament surgery is more expensive but does not appear to increase the overall complication rate and may allow surgeons to diagnose and treat more intra-articular pathology. Among patients requiring reoperation for intra-articular defects, the average time to reoperation was over 5 months shorter for patients receiving arthroscopy than for patients who did not receive arthroscopy.