Background Intra-class correlation coefficients (ICCs) provide a statistical means of testing the reliability. However, their interpretation is not well documented in the orthopedic field. The purpose of this study was to investigate the use of ICCs in the orthopedic literature and to demonstrate pitfalls regarding their use. Methods First, orthopedic articles that used ICCs were retrieved from the Pubmed database, and journal demography, ICC models and concurrent statistics used were evaluated. Second, reliability test was performed on three common physical examinations in cerebral palsy, namely, the Thomas test, the Staheli test, and popliteal angle measurement. Thirty patients were assessed by three orthopedic surgeons to explore the statistical methods testing reliability. Third, the factors affecting the ICC values were examined by simulating the data sets based on the physical examination data where the ranges, slopes, and interobserver variability were modified. Results Of the 92 orthopedic articles identified, 58 articles (63%) did not clarify the ICC model used, and only 5 articles (5%) described all models, types, and measures. In reliability testing, although the popliteal angle showed a larger mean absolute difference than the Thomas test and the Staheli test, the ICC of popliteal angle was higher, which was believed to be contrary to the context of measurement. In addition, the ICC values were affected by the model, type, and measures used. In simulated data sets, the ICC showed higher values when the range of data sets were larger, the slopes of the data sets were parallel, and the interobserver variability was smaller. Conclusions Care should be taken when interpreting the absolute ICC values, i.e., a higher ICC does not necessarily mean less variability because the ICC values can also be affected by various factors. The authors recommend that researchers clarify ICC models used and ICC values are interpreted in the context of measurement.

We suggest using hallux valgus angle, intermetatarsal angle, interphalangeal angle, sesamoid rotation angle, and first metatarsal protrusion distance considering their reliability and prediction of the deformity.

PurposeWe aimed to evaluate the nationwide incidence and risk factors for symptomatic deep vein thrombosis (DVT) after major lower limb orthopedic surgeries.Materials and MethodsThe Korean Health Insurance Review and Assessment Service database was used to retrospectively identify International Classification of Disease-10 codes for DVT and operation codes representing hip arthroplasty, knee arthroplasty, and hip fracture surgeries. The age- and gender-adjusted annual incidence of DVT, rates of major lower limb orthopedic surgeries, and the postoperative incidence of DVT according to the surgical procedure were assessed.ResultsThe age- and gender-adjusted annual incidence of DVT was 70.67 per 100000 persons/year. Compared to patients aged <49 years, the relative risk of DVT was five times higher in patients aged 50-69 and 10 times higher in patients aged >70 years (p<0.001). Females showed a greater relative risk for DVT than males (1.08; p<0.001). The incidence of postoperative DVT, according to the type of surgery, was significantly greater for knee replacement arthroplasty than for other forms of surgery (p<0.002). The relative risk of postoperative DVT was higher in females in knee replacement arthroplasty (1.47) and hip fracture surgery (2.25) groups, although relatively lower in those who underwent hip replacement arthroplasty (0.97).ConclusionAmong major lower limb surgeries, advanced age, female gender, and undergoing a knee replacement arthroplasty were found to be risk factors for developing postoperative DVT. These findings further emphasize the need for orthopedic surgeons to consider the development of DVT after surgery in high-risk patients.

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BackgroundThis study was undertaken to investigate the trends of orthopedic publications during the last decade, and to document the country of origin, journal, funding source, and language of contribution using PubMed.MethodsOrthopedic articles published between 2000 and 2009 were retrieved from PubMed using the following search terms: "orthopaedic[Affiliation] AND ("2000/1/1"[PDAT]: "2009/12/31"[PDAT])" and "orthopedic[Affiliation] AND ("2000/1/1"[PDAT]: "2009/12/31"[PDAT])." The articles were downloaded in XML file format, which contained the following information: article title, author names, journal names, publication dates, article types, languages, authors' affiliations and funding sources. These information was extracted, sorted, and rearranged using the database's management software. We investigated the annual number of published orthopedic articles worldwide and the annual rate of increase. Furthermore, the country of publication origin, journal, funding source, and language of contribution were also investigated.ResultsA total of 46,322 orthopedic articles were published and registered in PubMed in the last 10 years. The worldwide number of published orthopedic articles increased from 2,889 in 2000 to 6,909 in 2009, showing an annual increase of 384.6 articles, or an annualized compound rate of 10.2%. The United States ranked highest in the number of published orthopedic articles, followed by Japan, the United Kingdom, Germany, and the Republic of Korea. Among the orthopedic articles published worldwide during the last 10 years, 37.9% pertained studies performed in the United States. Fifty-seven point three percent (57.3%) of articles were published in journals established in the United States. Among the published orthopaedic articles, 4,747 articles (10.2%) disclosed financial support by research funds, of which 4,688 (98.8%) articles utilized research funds from the United States. Most articles were published in English (97.2%, 45,030 articles).ConclusionsThe number of published orthopedic articles has been increasing over the last decade. The number of orthopedic articles, journals publication, and funding sources were dominated by research conducted in the United States, while share and growth of Asian countries including Japan, the Republic of Korea, and China were notable.