PMC:6709048 / 4449-10973 JSONTXT

{"project":"2_test","denotations":[{"id":"31348307-26058747-68500695","span":{"begin":6308,"end":6310},"obj":"26058747"},{"id":"31348307-24276363-68500695","span":{"begin":6308,"end":6310},"obj":"24276363"},{"id":"31348307-23063514-68500695","span":{"begin":6308,"end":6310},"obj":"23063514"},{"id":"31348307-21138790-68500696","span":{"begin":6389,"end":6391},"obj":"21138790"}],"text":"2 Materials and methods\n\n2.1 Data and literature sources\nAlthough the present study involved human participants, ethical approval or informed consent from the participants was not required because all the data were based on previously published studies and analyzed anonymously without any potential harm to the participants.\nMultiple comprehensive databases, including MEDLINE (January 1, 1976 to June 30, 2018), EMBASE (January 1, 1985 to June 30, 2018), and the Cochrane Library (January 1, 1987 to June 30, 2018), were searched for studies that compared pain and function scores, range of motion (ROM), operation time, Insall-Salvati (IS) ratio, complications, and survival rates in patients treated with TKA with previous HTO or primary TKA with short- to midterm (\u003c10 years) or long-term (\u003e10 years) follow-up. There were no restrictions on language. Search terms used in the title, abstract, MeSH, and keywords fields were (‘knee’ [MeSH] OR ‘tibia’ [MeSH] OR ‘osteotomy’ [MeSH]) AND ‘total knee arthroplasty’ [tiab] OR ‘total joint replacement’ [tiab] OR ‘high tibial osteotomy’ [tiab] OR ‘proximal tibial osteotomy’ [tiab] OR ‘opening wedge’ [tiab] OR ‘closing wedge’ [tiab] OR ‘HTO’ [tiab] OR ‘TKA’ [tiab] OR ‘knee’ [tiab]). Following the initial online search, relevant articles and their bibliographies were manually reviewed.\n\n2.2 Study selection\nStudies were included in the meta-analysis if they\n1. assessed human knees that had undergone TKA with and without previous HTO;\n2. had an evidence level of 1 (high quality randomized trial or prospective study) or 2 (lesser quality randomized controlled trial or prospective comparative study) or 3 (case control study or retrospective comparative study);\n3. reported retrospective or prospective comparisons of surgical outcomes between groups with either TKA with previous HTO or primary TKA in studies published after 2000, in order to avoid out-of-date prostheses models;\n4. included basic data on at least one of the following seven parameters: postoperative pain and function scores, ROM, operation time, IS ratio, complications, and survival rates;\n5. reported the number of subjects in each group (TKA with previous HTO and primary TKA) and the means and standard deviations for the seven parameters, and\n6. used adequate statistical methods to compare parameters between groups.\nPostoperative scores on knee outcome scales included the Western Ontario McMaster Universities Arthritis Index (WOMAC), American Knee Society Score (AKSS), Knee Society Score (KSS), Oxford Knee Score (OKS), and Hospital for Special Surgery (HSS). A postoperative complication was defined as an adverse treatment event recorded by the author of the study. Studies were excluded if they\n1. included missing or inadequate outcome data, such as standard deviation or range of values;\n2. included case series, expert opinions, reviews, commentaries, or editorials;\n3. included abstract only;\n4. included animal in vivo and human in vitro.\n\n2.3 Data extraction\nTwo reviewers independently recorded data from each study using a predefined data extraction form and resolved any differences by discussion. Recorded variables included those associated with surgical outcomes such as postoperative pain, functional outcome, ROM, operation time, IS ratio, complications, and survival rates for patients with either TKA with previous HTO or primary TKA. Sample size and the means and standard deviations of surgical outcomes in each group were also recorded. If these variables were not included in the articles, the standardized mean difference was calculated from the P-value and sample size.\n\n2.4 Methodological quality assessment\nTwo reviewers independently assessed the methodological quality of the studies. For the Newcastle-Ottawa Scale, as recommended by the Cochrane Non-Randomized Studies Methods Working Group, we assessed studies based on three criteria—selection of the study groups, comparability of the groups, and ascertainment of either the exposure or the outcome of interest for case-control and cohort studies. Studies of high quality were defined as those with scores higher than 6 points. Two reviewers resolved all differences by discussion, and their decisions were subsequently reviewed by a third investigator.\n\n2.5 Statistical analysis\nThe main outcomes of the meta-analysis were the proportion of cases that developed complications, survival rates, and the weighted mean difference (WMD) in ROM, operation time, and IS ratio. However, standardized mean difference (SMD) was calculated for overall functional outcome and postoperative pain as several different measurement tools, including WOMAC, AKSS, KSS, OKS, and HSS, were used for the same outcome. For all comparisons, odds ratios (ORs) and 95% confidence intervals (CIs) were calculated for binary outcomes, while SMDs or WMDs and 95% CIs were calculated for continuous outcomes depending on the similarity of the used scales. Heterogeneity was determined by estimating the proportion of between-study inconsistencies due to actual differences between studies, rather than differences due to random error or chance. A I2 \u003c 40% indicated that there was no significant heterogeneity, so a fixed effect model was used to calculate the pooled effect size. Otherwise, the random effect model was adopted. I2 statistics with a value of less than 40% represents low heterogeneity and a value of 75% or more indicates high heterogeneity.[14] When statistical heterogeneity was substantial, we conducted meta-regression to identify potential sources of bias such as study type and average length from HTO to TKA. The age and sex of the study subjects were also considered. All statistical analyses were performed with RevMan version 5.3 software and Stata version 14.2. The risks of bias (low, high, or unclear) were independently assessed by two investigators. Publication bias was also assessed using funnel plots. Subgroup analyses based on differences in follow-up period were performed for survival rates to explore a potential source of heterogeneity. As a result, two subgroups were created in each group—short-to midterm (\u003c10 years) and long-term (\u003e10 years) survival rates. Additionally, a sensitivity analysis was performed by excluding one eligible study at a time. Three studies[15–17] with data from a national joint registry were included, and another study[18] with a different surgical technique was included. Pooling of data was feasible for two outcomes of interest—survival rates and ROM."}