Purpose: Developmental dysplasia of the hip (DDH) can increase the pressure between the joints, which causes secondary hip osteoarthritis. The aim of the present study was to fabricate poly(D, L-lactic acid)-poly(ethylene glycol)-poly(D, L-lactic acid) (PELA) electrospun fibrous scaffolds, immobilized with bone morphogenetic protein-2 (BMP-2), to repair the acetabulum defects. Methods: The characteristics of PELA electrospun were analyzed using scanning electron microscopy, the release kinetics of BMP-2 in vitro were analyzed using enzyme-linked immunosorbent assays. Human mesenchymal stem cells (hMSCs) were used for in vitro experiments, the biocompatibility of the electrospinning materials was investigated using a cell counting kit-8 (CCK-8) kit, and osteogenic differentiation was tested via alkaline phosphatase (ALP) activity and relative gene expression. Eighteen miniature pig animal models were used in the in vivo experiment. The pigs were sacrificed at 24 weeks after surgery, and the reconstructed acetabulum was evaluated using histological sections. Results: Structural analysis revealed that the diameter of the PELA electrospun fiber was 0.8195 ± 0.16 μm. The PELA electrospun fiber materials showed good hydrophilicity and biocompatibility and could continuously release BMP-2 within 27 days: 16.07 ± 0.11 ng of BMP-2 was released from the scaffold. A total of sixteen implants fully filled the defects, and hematoxylin and eosin staining and Goldner’s trichrome staining showed that the simple tendon group (T group) was mostly fibrous tissues, lots of fibroblasts and small amounts of chondrocytes were observed in the polydopamine-coated electrospun fiber group (DP group). The DP plus BMP-2 (DPB) group showed a large number of chondrocytes and partial new bone tissues. Conclusion: PELA electrospun fibrous scaffolds are good sustained-release carriers, which can not only induce implant differentiation into cartilage and bone but also are completely degraded without toxicity. Therefore, the material can be used for bone and cartilage regeneration.

Background: The purpose of this study was to retrospectively analyze the clinical outcomes of patients with recurrent patellar dislocation who underwent arthroscopic medial patellofemoral ligament (MPFL) reconstruction using gracilis tendon autograft and a modified double-patellar tunnel method. We hypothesized that our modified method would provide good clinical outcomes. Methods: Patients who underwent arthroscopic MPFL reconstruction with autograft gracilis tendon and modified double-patellar tunnels technique for recurrent patellar dislocation and were followed up for a minimum of 5 years were identified, and the clinical and follow-up data were retrospectively analyzed. Preoperatively, joint hypermobility was assessed with the Beighton score. The Insall–Salvati ratio, TT–TG distance, and Q angle were measured on radiographic images. Patient-reported outcomes including the Kujala, Lysholm, and Tegner scores were collected preoperatively and postoperatively. Patient satisfaction was assessed at the end of 5 years. Complications and recurrent dislocation occurring after surgery were recorded. Results: A total of 79 patients (94 knees) were enrolled; of these, 13 (16.5%) were lost to follow-up. The data of 66 patients (80 knees) were available for final analysis. Mean age at surgery was 21.3 ± 7.8 years. Mean follow-up time was 66.1 ± 5.5 months (range, 60–78 months). Postoperative patient-reported outcome was not associated with Beighton score, Insall–Salvati ratio, or TT–TG distance. Q angle was negatively correlated to Kujala scores and Lysholm scores. Severity of trochlear dysplasia was not associated with postoperative patient-reported outcome. The mean Kujala score increased from 69.4 ± 7.9 to 96.1 ± 1.9, the mean Tegner score increased from 3.1 ± 1.3 to 5.9 ± 1.3, and the mean Lysholm score increased from 73.5 ± 14.6 to 95.3 ± 3.4. Two patients experienced recurrent patellar dislocation during follow-up. Conclusions: MPFL reconstruction using autologous gracilis tendon under arthroscopy appears to be a reliable and safe method for treating recurrent patellar dislocation. Level of evidence: Level IV.