Chronic postsurgical pain (CPSP) is a common complication after thoracic surgery and associated with long-term adverse outcomes. This study aims to develop two prediction models for CPSP after video-assisted thoracic surgery (VATS). Methods and Analysis: This single-center prospective cohort study will include a total of 500 adult patients undergoing VATS lung resection (n = 350 for development and n = 150 for external validation). Patients will be enrolled continuously at The First Affiliated Hospital of Soochow University in Suzhou, China. The cohort for external validation will be recruited in another time period. The outcome is CPSP, which is defined as pain with the numerical rating scale score of 1 or higher 3 months after VATS. Univariate and multivariable logistic regression analyses will be performed to develop two CPSP prediction models based on patients' data of postoperative day 1 and day 14, respectively. For internal validation, we will use the bootstrapping validation technique. For external validation, the discrimination capability of the models will be assessed using the area under the receiver operating characteristic curve, and the calibration will be evaluated using the calibration curve and Hosmer-Lemeshow goodness-of-fit statistic. The results will be presented in model formulas and nomograms. Conclusion: Based on the development and validation of the prediction models, our results contribute to early prediction and treatment of CPSP after VATS. Trial Registration: Chinese Clinical Trial Register (ChiCTR2200066122).

Background Posterior tibial slope (PTS) increases after medial open-wedge high tibial osteotomy (OWHTO) is challenging for patients. This study aims to determine whether use of a suspended and straightened knee joint position during the fixing of steel plates can prevent an increase in the PTS after OWHTO. Methods This study retrospectively analyzed 112 subjects (122 knees) [34 males, 78 females; mean age 59.1 ± 6.6 (range 48–76) years; mean body mass index 28.06 ± 3.61 kg/m2] who underwent OWHTO. A total of 78 knees that were suspended and extended by placing a sterile cloth ball under the ipsilateral ankle during the fixing of steel plates comprised the suspended and straightened knee joint position (SSP) group, and 44 knees that were kept naturally straightened without placing a sterile cloth ball under the ipsilateral ankle during the fixing of steel plates comprised the naturally straightened knee joint position (NSP) group. Patients were clinically assessed according to the visual analog pain scale (VAS), the Western Ontario and McMaster Universities (WOMAC) osteoarthritis index, the Knee Society Scores (KSS) knee and function scores, the Hospital for Special Surgery (HSS) knee scores and the Lysholm knee scores. Radiological assessment was performed according to the changes in the PTS between preoperation, 1-day postoperation, and the final follow-up periods. Ultimately, the difference in postoperative PTS changes between the two groups was statistically analyzed. The median follow-up period was 2.2 years (range 1.6–3.7 years). Results In the final follow-up period, significant improvements were observed in the clinical VAS scores, WOMAC scores, KSS knee and function scores, HSS scores and the Lysholm knee scores in both groups (P < 0.001), and no difference was found between the two groups. Radiological assessment showed that there was no statistical difference in the preoperative PTS between the two groups. The 1-day postoperative PTS and the most recent follow-up PTS were significantly greater than the preoperative PTS in the NSP group (t = − 3.213, − 6.406, all P < 0.001), but no significant increase was seen in the SSP group (P > 0.05). The increase in PTS in the NSP group was significantly greater than that in the SSP group at the 1-day postoperative (t = 2.243, P = 0.030) and final follow-up periods (t = 6.501, P < 0.001). Conclusions For OWHTO, the use of a suspended and straightened knee joint position rather than a naturally straightened knee joint position during the fixing of steel plates could effectively prevent the increase in postoperative PTS. Level of Evidence: Retrospective Study Level III.

Background: Posterior tibial slope (PTS) increases after medial open-wedge high tibial osteotomy (OWHTO) is challenging for patients. This study aims to determine whether use of a suspended and straightened knee joint position during the fixing of steel plates can prevent an increase in the posterior tibial slope after OWHTO.Methods: This study retrospectively analyzed 112 subjects (122 knees) [34 males, 78 females; mean age 59.1±6.6 (range 48–76) years; mean body mass index (BMI) 28.06±3.61 kg/m²] who underwent OWHTO. A total of 78 knees that were suspended and extended by placing a sterile cloth ball under the ipsilateral ankle during the fixing of steel plates comprised the suspended and straightened knee joint position (SSP) group, and 44 knees that were kept naturally straightened without placing a sterile cloth ball under the ipsilateral ankle during the fixing of steel plates comprised the naturally straightened knee joint position (NSP) group. Patients were clinically assessed according to the visual analog pain scale (VAS) and the Western Ontario and McMaster Universities (WOMAC) osteoarthritis index. Radiological assessment was performed according to the changes in the posterior tibial slope between preoperation, 1-day postoperation, and the final follow-up periods. Ultimately, the difference in postoperative PTS changes between the two groups was statistically analyzed. The median follow-up period was 2.2 years (range 1.6–3.7 years).Results: In the final follow-up period, significant improvements were observed in the clinical VAS and WOMAC scores in both groups (P < 0.001), and no difference was found between the two groups. Radiological assessment showed that there was no statistical difference in the preoperative PTS between the two groups. The 1-day post-operative PTS and the most recent follow-up PTS were significantly greater than the preoperative PTS in the NSP group (t=-3.213, -6.406, all P < 0.001), but no significant increase was seen in the SSP group (P >0.05). The increase in PTS in the NSP group was significantly greater than that in the SSP group at the 1-day postoperative (t=2.243, P=0.030) and final follow-up periods (t=6.501, P<0.001).Conclusion: For OWHTO, the use of a suspended and straightened knee joint position rather than a naturally straightened knee joint position during the fixing of steel plates could effectively prevent the increase in postoperative PTS.Level of Evidence: Retrospective Study Level III