Background: Osteochondral lesions of the talus (OLTs) with large subchondral cysts are challenging to treat. Purpose: To determine the safety and efficacy of autologous chondral grafting and malleolus osteotomy for treating OLTs associated with large subchondral cysts. Study Design: Case series; Level of evidence, 4. Methods: A total of 19 patients underwent autologous chondral grafting and malleolus osteotomy. We obtained the visual analog scale (VAS), American Orthopaedic Foot and Ankle Society (AOFAS) ankle-hindfoot, and magnetic resonance observation of cartilage repair tissue (MOCART) scores at 1 and 2 years postoperatively. The International Cartilage Repair Society (ICRS) score was collected 2 years postoperatively during second-look arthroscopic surgery. Results: In all patients, the osteotomy site healed without nonunion or malunion. Only 1 patient developed joint space narrowing. No donor site complications occurred. The mean AOFAS score significantly improved at 1 year (from 72.8 ± 4.8 preoperatively to 93.7 ± 4.6; t = –13.708; P < .0001). The 1- and 2-year AOFAS scores were similar ( t = –0.755; P = .455), indicating stable improvement. The mean VAS score significantly decreased at 1 year (from 4.68 ± 0.67 preoperatively to 0.47 ± 0.69; t = 18.974; P < .0001). The 1- and 2-year VAS scores were similar ( t = –0.705; P = .455), as were the 1- and 2-year MOCART scores (64.2 ± 7.5 vs 67.4 ± 7.3, respectively; t = –1.312; P = .198). The ICRS scores were as follows: 7 points (abnormal) in 1 (5.2%) patient, 8 to 11 points (nearly normal) in 9 (47.4%) patients, and 12 points (normal) in 9 (47.4%) patients. Conclusion: Osteotomy combined with autologous osteochondral transplantation provided good functional outcomes in patients with OLTs and large subchondral cysts. Second-look arthroscopic surgery showed healthy cartilage healing.

The healing of tendon–bone in the rotator cuff is featured by the formation of the scar tissues in the interface after repair. This study aimed to determine if the 3D-printed poly lactic-co-glycolic acid (PLGA) scaffolds loaded with bone marrow-derived mesenchymal stem cells (BMSCs) could augment the rotator cuff repair in the rabbits. PLGA scaffolds were generated by the 3D-printed technology; Cell Counting Kit-8 assay evaluated the proliferation of BMSCs; the mRNA and protein expression levels were assessed by quantitative real-time polymerase chain reaction and western blot, respectively; immunohistology evaluated the rotator cuff repair; biomechanical characteristics of the repaired tissues were also assessed. 3D-printed PLGA scaffolds showed good biocompatibility without affecting the proliferative ability of BMSCs. BMSCs–PLGA scaffolds implantation enhanced the cell infiltration into the tendon-bone injunction at 4 weeks after implantation and improved the histology score in the tendon tissues after implantation. The mRNA expression levels of collagen I, III, tenascin, and biglycan were significantly higher in the scaffolds + BMSCs group at 4 weeks post-implantation than that in the scaffolds group. At 8 and 12 weeks after implantation, the biglycan mRNA expression level in the BMSCs–PLGA scaffolds group was significantly lower than that in the scaffolds group. BMSCs–PLGA scaffolds implantation enhanced collagen formation and increased collagen dimeter in the tendon–bone interface. The biomechanical analysis showed that BMSCs–PLGA scaffolds implantation improved the biomechanical properties of the regenerated tendon. The combination of 3D-printed PLGA scaffolds with BMSCs can augment the tendon–bone healing in the rabbit rotator cuff repair model.

The aim of this study was to explore the biological effects of the amount of chemical extraction treatments performed on an allogeneic tendon through histomorphology, biological mechanics testing, and an immunogenicity assay. Sixteen New Zealand rabbits (body weight 2.5-3.0 kg) were randomly divided into four groups: group A (chemical extraction once), group B (chemical extraction twice), group C (chemical extraction three times), and group D (blank control group), with four rabbits in each group. The Achilles tendons of each rabbit were separated and subjected to a chemical extraction process with Triton X-100 and sodium deoxycholate, followed by hematoxylin and eosin staining, electron microscopy observation, biomechanical testing, and mixed lymphocyte culture. There were no significant differences in the surface color and fiber bundles between groups A and B and the blank control group, whereas group C showed clear differences from the blank control group with a rough surface, loose fibers, and poor tension. There were no significant differences in the biomechanics among the four groups. The four groups showed significant differences in the lymphocyte conversion ratio, with reduced rates of lymphocyte conversion along with increasing treatment numbers. Two chemical extractions of the tendon allowed for retaining most of the integrity of the original tendon fiber while removing immunogenicity with good biological properties. These findings lay a foundation for application of this method to human tendons so as to provide a good tissue source for tendon transplantation.