Articular cartilage defect repair is a problem that has long plagued clinicians. Although mesenchymal stem cells (MSCs) have the potential to regenerate articular cartilage, they also have many limitations. Recent studies have found that MSC-derived exosomes (MSC-Exos) play an important role in tissue regeneration. The purpose of this study was to verify whether MSC-Exos can enhance the reparative effect of the acellular cartilage extracellular matrix (ACECM) scaffold and to explore the underlying mechanism. The results of in vitro experiments show that human umbilical cord Wharton's jelly MSC-Exos (hWJMSC-Exos) can promote the migration and proliferation of bone marrow-derived MSCs (BMSCs) and the proliferation of chondrocytes. We also found that hWJMSC-Exos can promote the polarization of macrophages toward the M2 phenotype. The results of a rabbit knee osteochondral defect repair model confirmed that hWJMSC-Exos can enhance the effect of the ACECM scaffold and promote osteochondral regeneration. We demonstrated that hWJMSC-Exos can regulate the microenvironment of the articular cavity using a rat knee joint osteochondral defect model. This effect was mainly manifested in promoting the polarization of macrophages toward the M2 phenotype and inhibiting the inflammatory response, which may be a promoting factor for osteochondral regeneration. In addition, microRNA (miRNA) sequencing confirmed that hWJMSC-Exos contain many miRNAs that can promote the regeneration of hyaline cartilage. We further clarified the role of hWJMSC-Exos in osteochondral regeneration through target gene prediction and pathway enrichment analysis. In summary, this study confirms that hWJMSC-Exos can enhance the effect of the ACECM scaffold and promote osteochondral regeneration.

Objective. To compare the effectiveness of arthroscopic partial meniscectomy (APM) and physical therapy (PT) for degenerative meniscus tears. Method. We conducted a literature search through PubMed, Embase, the Cochrane Central Register of Controlled Trials, and ClinicalTrials.gov. Randomized controlled trials in adults with degenerative meniscal tears without symptoms of locking were considered for inclusion. Two researchers independently performed the literature search, assessed the risk of bias, and selected eligible studies. The primary outcome was function at different follow-up time points and the secondary outcome was pain at different follow-up time points. Results. We included 6 randomized controlled trials, with a total of 1006 participants, among which 495 were in the APM group and 511 were in the PT group. We found a small benefit in functional outcomes in the APM group until the 12 months follow-up time point (SMD=0.20; 95%CI=0.0‐0.33; p=0.002; I2=34%), but no significant differences in function between groups at the 24-month follow-up time point (SMD=0.12; 95%CI=−0.04−0.28;p=0.14; I2=28%). There was also small benefit in the APM group until the 12 months follow-up time point for pain (SMD=0.14; 95%CI=0.01−027; p=0.03; I2=36%), but no significant difference in pain between groups at 24 months (SMD=0.11; 95%CI=−0.05−0.28; p=0.18; I2=0%). Conclusion. In the treatment of degenerative meniscus tears, APM yielded better functional and pain outcomes compared with physical therapy in the short term until 12 months, but there were comparable results for pain and functional outcomes between the groups at the 24 months follow-up time point.

The iASSIST navigation system is a handheld accelerometer‐based navigation system that has been applied in clinical practice in recent five years. This meta‐analysis aimed to compare the radiographic and clinical outcomes of iASSIST navigation with conventional surgical techniques for patients undergoing total knee arthroplasty (TKA) and to compare the surgery time between an iASSIST group and a conventional treatment group. This systematic review and meta‐analysis included all comparative prospective and retrospective studies published in Pubmed, Embase, the Cochrane Central Register of Controlled Trials, the Web of Science and the CNKI databases over the past 20 years. Inclusion criteria were studies that compared the iASSIST navigation system with conventional TKA. The primary outcomes were mechanical axis (MA) and outliers, which means postoperative MA varus or valgus of more than 3°. Secondary outcomes were coronal femoral angle (CFA) and coronal tibial angle (CTA). Knee Society Score (KSS) was used to evaluate functional outcome. The Newcastle–Ottawa Scale (NOS) was used to assess the methodological quality of included studies. Eight studies involving 558 knees were included in this meta‐analysis. Of these, 275 patients used the iASSIST navigation system and 283 used conventional surgical techniques. A total of 5 studies were considered high quality and the other 3 were considered to be of moderate quality. The occurrence of malalignment of >3° in the iASSIST group was 13.3%, compared with 29.04% in the conventional group. Postoperative MA of the iASSIST group was significantly better than that of the conventional group (I 2 = 19%, OR = −0.92, 95% CI = −1.09 to −0.75, P < 0.00001). The iASSIST navigation system provided significantly increased accuracy in the coronal femoral angle (I 2 = 79%, OR = −0.88, 95% CI = −1.21 to −0.54, P < 0.00001) and the coronal tibial angle (I 2 = 34%, OR = 0.39, 95% CI = −0.48 to −0.30, P < 0.00001) compared with conventional techniques. However, the duration of surgery using the iASSIST procedure was longer and there was no significant difference in the short‐term KSS in the iASSIST group compared with the conventional group. We found that when pooling the data of included studies, the number of outliers was fewer in the iASSIST group, and compared with conventional TKA techniques, the iASSIST system significantly improved the accuracy of lower limb alignment but the duration of surgery was prolonged in addition to there being no apparent advantage in terms of short‐term functional score.