Background: Our study aimed to evaluate the clinical and radiologic results of all-arthroscopic treatment of terrible triad injuries followed-up for a minimum of 5 years and investigate how arthroscopic partial excision for radial head fractures affects the results at the final follow-up. Methods: We retrospectively reviewed consecutive patients with terrible triad injuries who underwent all-arthroscopic treatment between January 2011 and June 2018. In group I, we performed conservative or arthroscopic fixation of stable radial head fractures, while in group II, arthroscopic partial excision of unstable radial head fractures involving <30%–50% of the articular surface area was performed. Clinical outcomes were measured by visual analog scale score and assessment of instability, range of motion (ROM), and Mayo Elbow Performance Score. Radiological outcomes were evaluated using x-rays, and the integrity of the repaired lateral collateral ligament complex was confirmed through magnetic resonance imaging. Results: Thirty-two patients with an average age of 49.5±16.2 years met the inclusion criteria and were followed-up for a mean of 82.7±22.2 months. Twenty patients were assigned to group I and 12 patients to group II. Clinical outcomes showed no significant differences between the two groups at the final follow-up (P>0.05). On radiological evaluation, more heterotopic ossifications were found in the radial head excision group (group II, 66.7% vs. group I, 35%; P=0.02); however, there was no significant difference in ROM between the two groups (P>0.05). Conclusions In all-arthroscopic treatment of terrible triad injuries, arthroscopic partial excision of the radial head did not seem to have a significant impact on elbow joint stability.Level of evidence: III.

In recent years, treatment using implants has become common. Since 2016, dental implants have been insured as part of strengthening health insurance coverage. Consequently, the demand for implants is increasing. Accordingly, the importance of implant maintenance has been emphasized. Of which, implant retrievability is an important factor in implant success. Although the screw-retained type is an advantageous easy-to-retrieve prosthesis, an occlusal point cannot make it to the central axis of the implant. Thus, we aimed to introduce an implant setting method (screw hole indexing) that enables the maintenance of the proper occlusal point and enables retrievability by marking the screw holes of the implant.

Background: Our study aimed to evaluate the clinical and radiologic results of all-arthroscopic treatment of terrible triad injuries followed-up for a minimum of 5 years and investigate how arthroscopic partial excision for radial head fractures affects the results at the final follow-up. Methods: We retrospectively reviewed consecutive patients with terrible triad injuries who underwent all-arthroscopic treatment between January 2011 and June 2018. In group I, we performed conservative or arthroscopic fixation of stable radial head fractures, while in group II, arthroscopic partial excision of unstable radial head fractures involving <30%–50% of the articular surface area was performed. Clinical outcomes were measured by visual analog scale score and assessment of instability, range of motion (ROM), and Mayo Elbow Performance Score. Radiological outcomes were evaluated using x-rays, and the integrity of the repaired lateral collateral ligament complex was confirmed through magnetic resonance imaging. Results: Thirty-two patients with an average age of 49.5±16.2 years met the inclusion criteria and were followed-up for a mean of 82.7±22.2 months. Twenty patients were assigned to group I and 12 patients to group II. Clinical outcomes showed no significant differences between the two groups at the final follow-up (P>0.05). On radiological evaluation, more heterotopic ossifications were found in the radial head excision group (group II, 66.7% vs. group I, 35%; P=0.02); however, there was no significant difference in ROM between the two groups (P>0.05). Conclusions In all-arthroscopic treatment of terrible triad injuries, arthroscopic partial excision of the radial head did not seem to have a significant impact on elbow joint stability.Level of evidence: III.

Background: Our study aimed to evaluate the clinical and radiologic results of all-arthroscopic treatment of terrible triad injuries followed-up for a minimum of 5 years and investigate how arthroscopic partial excision for radial head fractures affects the results at the final follow-up. Methods: We retrospectively reviewed consecutive patients with terrible triad injuries who underwent all-arthroscopic treatment between January 2011 and June 2018. In group I, we performed conservative or arthroscopic fixation of stable radial head fractures, while in group II, arthroscopic partial excision of unstable radial head fractures involving <30%–50% of the articular surface area was performed. Clinical outcomes were measured by visual analog scale score and assessment of instability, range of motion (ROM), and Mayo Elbow Performance Score. Radiological outcomes were evaluated using x-rays, and the integrity of the repaired lateral collateral ligament complex was confirmed through magnetic resonance imaging. Results: Thirty-two patients with an average age of 49.5±16.2 years met the inclusion criteria and were followed-up for a mean of 82.7±22.2 months. Twenty patients were assigned to group I and 12 patients to group II. Clinical outcomes showed no significant differences between the two groups at the final follow-up (P>0.05). On radiological evaluation, more heterotopic ossifications were found in the radial head excision group (group II, 66.7% vs. group I, 35%; P=0.02); however, there was no significant difference in ROM between the two groups (P>0.05). Conclusions In all-arthroscopic treatment of terrible triad injuries, arthroscopic partial excision of the radial head did not seem to have a significant impact on elbow joint stability.Level of evidence: III.

Background: Our study aimed to evaluate the clinical and radiologic results of all-arthroscopic treatment of terrible triad injuries followed-up for a minimum of 5 years and investigate how arthroscopic partial excision for radial head fractures affects the results at the final follow-up. Methods: We retrospectively reviewed consecutive patients with terrible triad injuries who underwent all-arthroscopic treatment between January 2011 and June 2018. In group I, we performed conservative or arthroscopic fixation of stable radial head fractures, while in group II, arthroscopic partial excision of unstable radial head fractures involving <30%–50% of the articular surface area was performed. Clinical outcomes were measured by visual analog scale score and assessment of instability, range of motion (ROM), and Mayo Elbow Performance Score. Radiological outcomes were evaluated using x-rays, and the integrity of the repaired lateral collateral ligament complex was confirmed through magnetic resonance imaging. Results: Thirty-two patients with an average age of 49.5±16.2 years met the inclusion criteria and were followed-up for a mean of 82.7±22.2 months. Twenty patients were assigned to group I and 12 patients to group II. Clinical outcomes showed no significant differences between the two groups at the final follow-up (P>0.05). On radiological evaluation, more heterotopic ossifications were found in the radial head excision group (group II, 66.7% vs. group I, 35%; P=0.02); however, there was no significant difference in ROM between the two groups (P>0.05). Conclusions In all-arthroscopic treatment of terrible triad injuries, arthroscopic partial excision of the radial head did not seem to have a significant impact on elbow joint stability.Level of evidence: III.

Purpose: This subgroup analysis of the Korean subset of patients in the phase 3 LASER301 trial evaluated the efficacy and safety of lazertinib versus gefitinib as first-line therapy for epidermal growth factor receptor mutated (EGFRm) non–small cell lung cancer (NSCLC). Materials and Methods: Patients with locally advanced or metastatic EGFRm NSCLC were randomized 1:1 to lazertinib (240 mg/day) or gefitinib (250 mg/day). The primary endpoint was investigator-assessed progression-free survival (PFS). Results: In total, 172 Korean patients were enrolled (lazertinib, n=87; gefitinib, n=85). Baseline characteristics were balanced between the treatment groups. One-third of patients had brain metastases (BM) at baseline. Median PFS was 20.8 months (95% confidence interval [CI], 16.7 to 26.1) for lazertinib and 9.6 months (95% CI, 8.2 to 12.3) for gefitinib (hazard ratio [HR], 0.41; 95% CI, 0.28 to 0.60). This was supported by PFS analysis based on blinded independent central review. Significant PFS benefit with lazertinib was consistently observed across predefined subgroups, including patients with BM (HR, 0.28; 95% CI, 0.15 to 0.53) and those with L858R mutations (HR, 0.36; 95% CI, 0.20 to 0.63). Lazertinib safety data were consistent with its previously reported safety profile. Common adverse events (AEs) in both groups included rash, pruritus, and diarrhoea. Numerically fewer severe AEs and severe treatment–related AEs occurred with lazertinib than gefitinib. Conclusion Consistent with results for the overall LASER301 population, this analysis showed significant PFS benefit with lazertinib versus gefitinib with comparable safety in Korean patients with untreated EGFRm NSCLC, supporting lazertinib as a new potential treatment option for this patient population.

Purpose: Diffuse large B-cell lymphoma (DLBCL) is the most common hematologic malignancy worldwide. Although substantial improvement has been achieved by the frontline rituximab-based chemoimmunotherapy, up to 40%-50% of patients will eventually have relapsed or refractory disease, whose prognosis is extremely dismal. Materials and Methods: We have carried out two prospective cohort studies that include over 1,500 DLBCL patients treated with rituximab plus CHOP (#NCT01202448 and #NCT02474550). In the current report, we describe the outcomes of refractory DLBCL patients. Patients were defined to have refractory DLBCL if they met one of the followings, not achieving at least partial response after 4 or more cycles of R-CHOP; not achieving at least partial response after 2 or more cycles of salvage therapy; progressive disease within 12 months after autologous stem cell transplantation. Results: Among 1,581 patients, a total of 260 patients met the criteria for the refractory disease after a median time to progression of 9.1 months. The objective response rate of salvage treatment was 26.4%, and the complete response rate was 9.6%. The median overall survival (OS) was 7.5 months (95% confidence interval, 6.4 to 8.6), and the 2-year survival rate was 22.1%±2.8%. The median OS for each refractory category was not significantly different (p=0.529). Conclusion In line with the previous studies, the outcomes of refractory DLBCL patients were extremely poor, which necessitates novel approaches for this population.

Background: The Omicron variant has become the most prevalent SARS-CoV-2 variant. Omicron is known to induce milder lesions compared to the original Wuhan strain. Fatal infection of the Wuhan strain into the brain has been well documented in COVID-19 mouse models and human COVID-19 cases, but apparent infections into the brain by Omicron have not been reported in human adult cases or animal models. In this study, we investigated whether Omicron could spread to the brain using K18-hACE2 mice susceptible to SARS-CoV-2 infection. Results: K18-hACE2 mice were intranasally infected with 1 × 105 PFU of the original Wuhan strain and the Omicron variant of SARS-CoV-2. A follow-up was conducted 7 days post infection. All Wuhan-infected mice showed > 20% body weight loss, defined as the lethal condition, whereas two out of five Omicron-infected mice (40%) lost > 20% body weight. Histopathological analysis based on H&E staining revealed inflammatory responses in the brains of these two Omicron-infected mice. Immunostaining analysis of viral nucleocapsid protein revealed severe infection of neuron cells in the brains of these two Omicron-infected mice. Lymphoid depletion and apoptosis were observed in the spleen of Omicron-infected mice with brain infection. Conclusion Lethal conditions, such as severe body weight loss and encephalopathy, can occur in Omicron-infected K18-hACE2 mice. Our study reports, for the first time, that Omicron can induce brain infection with lymphoid depletion in the mouse COVID-19 model.

Background/Aims: Little attention is paid to chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL) in Korea due to the rarity of the disease. With its rising incidence, we aimed to evaluate recent changes in treatment patterns and survival outcomes of patients with CLL/SLL. Methods: A total of 141 patients diagnosed with CLL/SLL between January 2010 and March 2020 who received systemic therapy were analyzed in this multicenter retrospective study. Results: The median patient age was 66 years at diagnosis, and 68.1% were male. The median interval from diagnosis to initial treatment was 0.9 months (range: 0–77.6 months), and the most common treatment indication was progressive marrow failure (50.4%). Regarding first-line therapy, 46.8% received fludarabine, cyclophosphamide, plus rituximab (FCR), followed by chlorambucil (19.9%), and obinutuzumab plus chlorambucil (GC) (12.1%). The median progression-free survival (PFS) was 49.3 months (95% confidence interval [CI], 32.7–61.4), and median overall survival was not reached (95% CI, 98.4 mo– not reached). Multivariable analysis revealed younger age (≤ 65 yr) (hazard ratio [HR], 0.46; p < 0.001) and first-line therapy with FCR (HR, 0.64; p = 0.019) were independently associated with improved PFS. TP53 aberrations were observed in 7.0% (4/57) of evaluable patients. Following reimbursement, GC became the most common therapy among patients over 65 years and second in the overall population after 2017. Conclusions Age and reimbursement mainly influenced treatment strategies. Greater effort to apply risk stratifications into practice and clinical trials for novel agents could help improve treatment outcomes in Korean patients.

Purpose: Circulating tumor DNA (ctDNA) is emerging as a valuable non-invasive tool to identify tumor heterogeneity and tumor burden. This study investigated ctDNA dynamics in metastatic colorectal cancer patients treated with regorafenib. Materials and Methods: In this prospective biomarker study, plasma cell-free DNA (cfDNA) samples obtained at baseline, at the first response evaluation after 2 cycles of treatment, and at the time of progressive disease were sequenced using a targeted next-generation sequencing platform which included 106 genes. Results: A total of 285 blood samples from 110 patients were analyzed. Higher baseline cfDNA concentration was associated with worse progression-free survival (PFS) and overall survival (OS). After 2 cycles of treatment, variant allele frequency (VAF) in the majority of ctDNA mutations decreased with a mean relative change of –31.6%. Decreases in the VAF of TP53, APC, TCF7L2, and ROS1 after 2 cycles of regorafenib were associated with longer PFS. We used the sum of VAF at each time point as a surrogate for the overall ctDNA burden. A reduction in sum (VAF) of ≥ 50% after 2 cycles was associated with longer PFS (6.1 vs. 2.7 months, p=0.002), OS (11.3 vs. 5.9 months, p=0.001), and higher disease control rate (86.3% vs. 51.1%, p < 0.001). VAF of the majority of the ctDNA mutations increased at the time of disease progression, and VAF of BRAF increased markedly. Conclusion Reduction in ctDNA burden as estimated by sum (VAF) could be used to predict treatment outcome of regorafenib.