Background: Pediatric trigger digit (TD) does not appear at birth but is diagnosed after birth by finding a flexion contracture of the thumb or other fingers. The reported incidence of pediatric TDs varies from 0.5 to 5 cases per 1,000 live births without sex-specific predominance. We performed a nationwide large-scale study to determine the prevalence and incidence of pediatric TDs and analyzed operative treatment for pediatric TDs using the National Health Insurance data of South Korea. Methods: Patients with pediatric TDs, aged 0–10 years between 2011 and 2020, were included in this study. Children born between 2011 and 2015 were set as the reference population and followed up until 2020. We calculated the prevalence and incidence rates of pediatric TDs according to age and sex and analyzed the operation rate, age at surgery, time interval from initial diagnosis to surgery, and follow-up period. Patient selection and treatment were based on International Classification of Diseases, 10th Revision (ICD-10). Results: The prevalence rates of pediatric TDs ranged from 0.063% to 0.084%. Girls had a higher prevalence rate (0.066%–0.094%) than boys (0.060%–0.075%). The total incidence rate was 77.6/100,000 person-years, and the incidence rate was higher in girls (84.8) than in boys (70.7). Among 2,181,814 children born between 2011 and 2015, 12,729 were diagnosed with pediatric TDs, of which 1,128 (8.9%) underwent operative management. The means of age at initial diagnosis, age at surgery, and the time interval between diagnosis and operation were 2.76 ± 1.91 years, 3.79 ± 2.19 years, and 1.15 ± 1.71 years, respectively. Conclusions High prevalence and incidence rates of pediatric TDs were found in 2- to 3-year-old patients. Among pediatric patients, 8.9% underwent operative management that was most frequently conducted between 2 and 3 years of age (within 1 year of initial diagnosis).

Purpose: To compare the short-term clinical and radiologic outcomes of combined posterior cruciate ligament (PCL) and posterolateral complex (PLC) reconstruction to those of isolated PCL reconstruction (PCLR) for patients with posterolateral knee laxity less than grade III. Materials and Methods: We retrospectively reviewed 49 patients (51 knees) who underwent PCLR between January 2008 and December 2015. Patients with a minimum follow-up of 24 months were included and divided into two groups (group A, isolated PCLR; group B, combined PCL and PLC reconstruction). Clinical outcomes were evaluated as the International Knee Documentation Committee (IKDC) subjective, Lysholm, and Tegner activity scale scores. Radiologic outcomes were also assessed using the side-to-side differences in posterior tibial translation via stress radiographs. Results: A total of 30 cases were analyzed. There were no significant differences in the Lysholm and Tegner activity scale scores between the two groups preoperatively and at the final follow-up. However, group B showed a higher IKDC subjective score compared to group A at the final follow-up (group A, 72.8±8.9; group B, 77.7±10.1; p<0.05). Regarding the radiologic outcomes, group B also showed a significantly less side-to-side difference in posterior tibial translation compared to group A at the final follow-up (group A, 4.8±2.3 mm; group B, 3.8±2.1 mm; p<0.05). Conclusion Combined PCL and PLC reconstruction resulted in improved clinical and radiologic outcomes than isolated PCLR in patients who have less than grade III posterolateral laxity of the knee. In cases of PCL rupture with ambiguous PLC injury, combined PCL and PLC reconstruction may help to improve posterior residual laxity of the knee.