Reconstruction of medial meniscus posterior portion deficiency in pigs with an autologous patellar tendon graft: an experimental study.

OBJECTIVE: This study was performed to investigate the effectiveness of two surgical procedures, autologous patellar tendon graft reconstruction and trans-tibial plateau pull-out repair, using a pig model. The primary focus was to assess the repair capability of medial meniscus posterior portion (MMPP) deficiency, the overall structural integrity of the meniscus, and protection of the femoral and tibial cartilage between the two surgical groups. The overall aim was to provide experimental guidelines for clinical research using these findings. METHODS: Twelve pigs were selected to establish a model of injury to the MMPP 10 mm from the insertion point of the tibial plateau. They were randomly divided into three groups of four animals each: reconstruction (autologous tendon graft reconstruction of the MMPP), pull-out repair (suture repair of the MMPP via a trans-tibial plateau bone tunnel), and control (use of a normal medial meniscus as the negative control). The animals were euthanized 12 weeks postoperatively for evaluation of the meniscus, assessment of tendon bone healing, and gross observation of knee joint cartilage. The tibial and femoral cartilage injuries were evaluated using the International Society for Cartilage Repair (ICRS) grade and Mankin score. Histological and immunohistochemical staining was conducted on the meniscus-tendon junction area, primary meniscus, and tendons. The Ishida score was used to evaluate the regenerated meniscus in the reconstruction group. Magnetic resonance imaging (MRI) was used to evaluate meniscal healing. RESULTS: All 12 pigs recovered well after surgery; all incisions healed without infection, and no obvious complications occurred. Gross observation revealed superior results in the reconstruction and pull-out repair groups compared with the control group. In the tibial cartilage, the reconstruction group had ICRS grade I injury whereas the pull-out repair and control groups had ICRS grade II and III injury, respectively. The Mankin score was significantly different between the reconstruction and control groups; histological staining showed that the structure of the regenerated meniscus in the reconstruction group was similar to that of the original meniscus. Immunohistochemical staining showed that the degree of type I and II collagen staining was similar between the regenerated meniscus and the original meniscus in the reconstruction group. The Ishida score was not significantly different between the regenerated meniscus and the normal primary meniscus in the reconstruction group. MRI showed that the MMPP in the reconstruction and pull-out repair groups had fully healed, whereas that in the control group had not healed. CONCLUSION: Autologous patellar tendon graft reconstruction of the MMPP can generate a fibrocartilage-like regenerative meniscus. Both reconstruction and pull-out repair can preserve the structural integrity of the meniscus, promote healing of the MMPP, delay meniscal degeneration, and protect the knee cartilage.

Construction and alidation of a severity prediction model for acute pancreatitis based on CT severity index: A retrospective case-control study.

To construct and internally and externally validate a nomogram model for predicting the severity of acute pancreatitis (AP) based on the CT severity index (CTSI).A retrospective analysis of clinical data from 200 AP patients diagnosed at the Hefei Third Clinical College of Anhui Medical University from June 2019 to June 2022 was conducted. Patients were classified into non-severe acute pancreatitis (NSAP, n = 135) and severe acute pancreatitis (SAP, n = 65) based on final clinical diagnosis. Differences in CTSI, general clinical features, and laboratory indicators between the two groups were compared. The LASSO regression model was used to select variables that might affect the severity of AP, and these variables were analyzed using multivariate logistic regression. A nomogram model was constructed using R software, and its AUC value was calculated. The accuracy and practicality of the model were evaluated using calibration curves, Hosmer-Lemeshow test, and decision curve analysis (DCA), with internal validation performed using the bootstrap method. Finally, 60 AP patients treated in the same hospital from July 2022 to December 2023 were selected for external validation.LASSO regression identified CTSI, BUN, D-D, NLR, and Ascites as five predictive factors. Unconditional binary logistic regression analysis showed that CTSI (OR = 2.141, 95%CI:1.369-3.504), BUN (OR = 1.378, 95%CI:1.026-1.959), NLR (OR = 1.370, 95%CI:1.016-1.906), D-D (OR = 1.500, 95%CI:1.112-2.110), and Ascites (OR = 5.517, 95%CI:1.217-2.993) were independent factors influencing SAP. The established prediction model had a C-index of 0.962, indicating high accuracy. Calibration curves demonstrated good consistency between predicted survival rates and actual survival rates. The C-indexes for internal and external validation were 0.935 and 0.901, respectively, with calibration curves close to the ideal line.The model based on CTSI and clinical indicators can effectively predict the severity of AP, providing a scientific basis for clinical decision-making by physicians.