Browsing by Author "Espinosa, Maximiliano"
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Item Anterior cruciate ligament regeneration using mesenchymal stem cells and collagen type I scaffold in a rabbit model(Springer, 2014) Figueroa, David; Espinosa, Maximiliano; Calvo, Rafael; Scheu, Maximiliano; Vaisman, Alex; Gallegos, Marcela; Conget, PaulettePurpose: The objective of this study was to determine whether using mesenchymal stem cells (MSC) seeded in a collagen type I scaffold would be sufficient to regenerate the torn anterior cruciate ligament (ACL). Methods: Anterior cruciate ligament transection was performed on both knees in 10 New Zealand rabbits and then repaired with as follows: suture alone (suture-treated group, n = 6), suture associated with collagen type I scaffold (collagen type I scaffold-treated group, n = 8) or suture associated with autologous MSC seeded on collagen type I scaffold (MSC/collagen type I scaffold-treated group, n = 6). At 12-week post-intervention, the animals were killed and the ACLs were characterised macroscopically and histologically. Data of the 3 groups were against normal ACL (normal group, n = 10). Results: Macroscopic observation found that in MSC/collagen type I scaffold group, 33 % of specimens showed a complete ACL regeneration, with a tissue similar to the normal ACL. Regeneration was not observed in the group treated with suture alone or associated with collagen type I scaffold without cells. In the latter, only a reparative attempt at the ends was observed. Histological analysis of the regenerated ACL showed a tissue with organised collagen and peripheric vessels. Conclusions: These results provide evidence that the use of MSC seeded in a collagen type I scaffold in the treatment of ACL injuries is associated with an enhancement of ligament regeneration. This MSC-based technique is a potentially attractive tool for improving the treatment of ACL ruptures.Item Assessment of Cell Viability of Fresh Osteochondral Allografts in N-Acetylcysteine-Enriched Medium(Sage, 2018) Calvo, Rafael; Espinosa, Maximiliano; Figueroa, David; Pozo, Luz María; Conget, PauletteObjective The purpose of this study was to evaluate the effect of N-acetylcysteine (NAC)-enriched storage medium on fresh osteochondral viability at 4°C. Our hypothesis was that the cell viability of chondrocytes obtained from human osteochondral tissue and stored at 4°C significantly improves in the presence of NAC. Design Controlled laboratory study. For this study, 8 samples of femoral condyle osteochondral tissue were obtained from patients undergoing total knee replacement. The samples were stored at either 4°C in phosphate-buffered saline (PBS) or at 3 different concentrations of NAC (NAC 1, 2, and 5 mM). Cell viability was analyzed at time 0 and 4 weeks by flow cytometry. The results of cell viability (median) were analyzed statistically using analysis of variance and Tukey's post hoc test. P values <0.05 were considered statistically significant. Results The viability at time 0 was 95.5% ± 3.7%. At 4 weeks, the cell viability was 56.8% ± 20.1% in the control group (PBS), 83.8% ± 11.9% in the group stored with NAC 1 mM, 73.4% ± 13.6% in the group stored with NAC 2 mM, and 66.4% ± 27.7% in the group stored with NAC 5 mM. A statistically significant difference from the baseline viability (time 0) was observed in the PBS control group ( P = 0.0018) but not in the other groups. A statistically significant difference was observed in the NAC 1 mM group compared with the PBS group ( P = 0.0255). Conclusion The use of NAC at 1 mM concentration improves cell viability after 4 weeks of storage in chondrocytes obtained from human osteochondral tissue.Item Dexamethasone and rosiglitazone are sufficient and necessary for producing functional adipocytes from mesenchymal stem cells(Society for Experimental Biology and Medicine by Sage, 2015) Contador, David; Ezquer, Fernando; Espinosa, Maximiliano; Arango-Rodríguez, Martha; Puebla, Carlos; Sobrevía, Luis; Conget, PauletteThe final product of adipogenesis is a functional adipocyte. This mature cell acquires the necessary machinery for lipid metabolism, loses its proliferation potential, increases its insulin sensitivity, and secretes adipokines. Multipotent mesechymal stromal cells have been recognized as a source of adipocytes both in vivo and in vitro. The in vitro adipogenic differentiation of human MSC (hMSC) has been induced up to now by using a complex stimulus which includes dexamethasone, 3-isobutyl-1-methylxanthine, indomethacin, and insulin (a classical cocktail) and evaluated according to morphological changes. The present work was aimed at demonstrating that the simultaneous activation of dexamethasone's canonical signaling pathways, through the glucocorticoid receptor and CCAAT-enhancer-binding proteins (C/EBPs) and rosiglitazone through peroxisome proliferator-activated receptor gamma (PPAR-gamma) is sufficient yet necessary for inducing hMSC adipogenic differentiation. It was also ascertained that hMSC exposed just to dexamethasone and rosiglitazone (D&R) differentiated into cells which accumulated neutral lipid droplets, expressed C/EBP-alpha, PPAR-gamma, aP2, lipoprotein lipase, acyl-CoA synthetase, phosphoenolpyruvate carboxykinase, adiponectin, and leptin genes but did not proliferate. Glucose uptake was dose dependent on insulin stimulus and high levels of adipokines were secreted (i.e. displaying not only the morphology but also expressing mature adipocytes' specific genes and functional characteristics). This work has demonstrated that (i) the activating C/EBPs and PPAR-gamma signaling pathways were sufficient to induce adipogenic differentiation from hMSC, (ii) D&R producing functional adipocytes from hMSC, (iii) D&R induce adipogenic differentiation from mammalian MSC (including those which are refractory to classical adipogenic differentiation stimuli). D&R would thus seem to be a useful tool for MSC characterization, studying adipogenesis pathways and producing functional adipocytes.Item Intraarticular administration of dexamethasone after mesenchymal stem cells implantation does not improve significantly the treatment of preestablished full-thickness chondral defect in a rabbit model(Sage Publications, 2013) Espinosa, Maximiliano; Vaisman, Alex; Nazal, Nicolas; Figueroa, David; Gallegos, Marcela; Conget, PauletteObjective: The aim of this study was to evaluate the contribution to hyaline cartilage regeneration of dexamethasone intraarticular administration after autologous mesenchymal stem cells (MSCs) implantation into a preestablished knee full-thickness chondral defect. Design: Full-thickness chondral defects of 4.5 × 4.5 mm2 were surgically made in both medial femoral condyles of adult male New Zealand rabbits. Two weeks later, autologous ex vivo expanded bone marrow–derived MSCs were embedded in hyaluronic acid and implanted into the chondral defects. Immediately and every week after the intervention, dexamethasone 0.25 mg/kg was intraarticularly administered (MSC/dexa-treated group). Six weeks after MSC transplantation, the animals were euthanized and condyles were characterized molecularly according to aggrecan, collagen type II, and collagen type I gene expression (quantitative reverse transcriptase-polymerase chain reaction) and histologically (hematoxylin–eosin staining). Data of MSC/dexa-treated condyles were compared with untreated, dexa-treated, MSCtreated, or normal unlesioned condyles. Results: The ratio between collagen type II expression versus collagen type I expression in MSC/dexa-treated condyles was higher than one, even though the group mean value was not statistically different from that of untreated defects. Histological changes were observed between MSC/dexa-treated and untreated defects mainly in surface regularity and in hyaline matrix abundance. However, International Cartilage Repair Society score analysis did not support robust differences between those groups. Conclusion: Intraarticular administration of dexamethasone after autologous MSC implantation into a preestablished full-thickness chondral defect does not contribute significantly to the regeneration of a tissue with molecular and histological characteristics identical to hyaline cartilage.Item Prediction of semitendinosus-gracilis graft diameter in children and adolescents using anthropometric measures.(Springer International Publishing AG, 2016) Calvo R., Rafael; Espinosa, Maximiliano; Figueroa, David; Calvo M., RafaelPURPOSE: The aim of this study was to evaluate whether the anthropometric and demographic measures of patients under 18 years can be used to predict the diameter of STG autograft in ACL reconstruction surgery. METHODS: Retrospective series of 169 patients under 18 years (112 men, 57 women, average age 15.8 years) underwent ACL reconstruction surgery with STG autograft. We recorded anthropometric measures (weight, height and BMI), demographics (age and gender) and autograft diameter used. Correlation coefficients, linear regression and unpaired t test were used to determine the relationship between anthropometric/demographic variables and the diameter of the graft. p values <0.05 were considered statistically significant. RESULTS: Correlation analysis showed a significant positive relation between height and graft diameter (r = 0.483, p < 0.0001) as well as between weight and graft diameter (r = 0.248, p = 0.001). However, age and BMI did not correlate with graft thickness (r = 0.098 and p = 0.203, r = 0.009 and p = 0.905, respectively). The mean graft diameter in men was 8.2 (range 6-10) and 7.5 in women (range 6-9), a difference that was statistically significant (p < 0.001). CONCLUSIONS: Prediction of the STG graft diameter according to the height of the patient is an easy and reliable method in children and adolescents. These data may provide relevant preoperative information about the need of an alternative graft source and can be useful when counselling patients.Item Proximal oblique sliding closing wedge osteotomy for hallux valgus(Sage Publications, 2013) Wagner, Emilio; Ortiz, Cristián; Gould, John; Naranje, Sameer; Wagner, Pablo; Mococain, Mococain; Keller, Andrés; Valderrama, Juan; Espinosa, MaximilianoBACKGROUND: The proximal oblique sliding closing wedge osteotomy (POSCOW) technique was developed to address moderate to severe hallux valgus deformity. We present a retrospective multicenter study to analyze the midterm radiological and clinical outcomes of patients treated with this type of proximal osteotomy fixed with plates. MATERIALS AND METHODS: One hundred and forty-four patients (187 feet) were operated on between May 2005 and June 2010 in 2 separate centers. Inclusion criteria were symptomatic moderate to severe incongruent hallux valgus deformity, no significant restriction in the first metatarsophalangeal joint movement, none to minimal degenerative changes in the first metatarsophalangeal or the tarsometatarsal joints, and no hypermobility. The median age was 60 years. The preoperative hallux valgus angle (HV) was 35.6 degrees, intermetatarsal angle (IM) was 15.3 degrees, AOFAS score was 53 points. The median follow-up was 35 months (range, 12-73). A POSCOW osteotomy was performed in all patients and fixed with plates. We recorded the satisfaction rate, postoperative clinical and radiological results, and complications. RESULTS: The patient satisfaction rate was 87%. The mean postoperative HV angle was 12.3 degrees, IM angle 4.8 degrees, AOFAS score 89 points. The mean decrease in the first metatarsal length was 2.2 mm (range, 0-8). Twelve feet (6.4%) with recurrence of the deformity required revision surgeries. Removal of complete or partial hardware was needed in 23 feet (12.3%) for symptomatic hardware. Five feet (2.6%) developed hallux varus but only 2 required surgery. Transfer metatarsalgia was noted in 9 feet (4.8%). CONCLUSIONS: The POSCOW osteotomy was an effective and reliable method for relieving pain and improving function. A learning curve was present, as most of the complications happened in the initial cases. To our knowledge, this is the largest reported series of proximal closing wedge osteotomy for hallux valgus deformities. LEVEL OF EVIDENCE: Level IV, case series.Publication Simultaneous medial unicompartmental knee replacement and anterior cruciate ligament reconstruction: a narrative review and technical note(2023) Macchiarola, Luca; Espinosa, Maximiliano; Pirone, Massimo; Lucidi, Gian Andrea; Cucurnia, Ilaria; Grassi, Alberto; Marín Fermín, Theodorakys; Zaffagnini, StefanoBackground and Objective: Reconstruction of the anterior cruciate ligament (ACL) simultaneously with medial unicompartmental knee arthroplasty (UKA) has been suggested as an alternative treatment in patients with ACL deficiency and localized osteoarthritis (OA) in young patients. The objectives of this review were to report the current concepts on the topic and describe an original surgical technique of simultaneous medial UKA and ACL reconstruction. Methods: A literature search was performed on PubMed, including articles written in English until June 2021. The articles regarding ACL reconstruction and UKA were reviewed using the narrative approach. Inclusion criteria: (I) original articles about ACL reconstruction and unicompartmental knee replacement; (II) written in English; (III) involving three or more cases. Two non-blinded authors reviewed the titles and abstracts of each article identified in the literature search. Key Content and Findings: The articles regarding ACL reconstruction and UKA were reviewed using the narrative approach. Conclusions: There is controversial evidence about performing the UKA simultaneously with an ACL reconstruction. Biomechanical and clinical studies show that the benefits of restoring good joint stability outweigh the possible risks associated with performing both surgeries at the same time. With this strategy, it is possible to obtain good clinical results with a high survival rate of the implant and patient satisfaction.Item Steroids and Platelet-Rich Plasma as Coadjuvants to Microfracture for the Treatment of Chondral Lesions in an Animal Model: Can the Healing Be Enhanced?(Sage Publications, 2012) Vaisman, Alex; Figueroa, David; Calvo, Rafael; Espinosa, Maximiliano; Melean, Patricio; Gallegos, Marcela; Conget, PauletteObjective: The aim of this study was to evaluate the contribution to hyaline cartilage regeneration of the microfracture (MFx) technique plus intraarticular betamethasone (BMS) or platelet-rich plasma (PRP). Design: Full-thickness chondral defects of 3 × 6 mm2 were surgically performed in both femoral condyles of each knee in 13 New Zealand rabbits and then treated with MFx associated with intraarticular BMS or PRP. At 12 weeks postimplantation, the animals were killed and the condyles were characterized macroscopically, molecularly according to collagen type II and I gene expression (quantitative reverse transcriptase–polymerase chain reaction), and histologically (hematoxylin–eosin staining). For the latter, samples were scored using the International Cartilage Repair Society visual histological scale. Data of MFx/BMS-treated and MFx/PRP-treated condyles were compared against untreated, MFx-treated, or normal condyles without lesions. Results: Our macroscopic findings showed that in MFx/BMS-treated and MFx/PRP-treated groups, the defects were filled with an irregular, partially rough tissue similar to the MFx-treated group. No differences in the ratio between collagen type II versus collagen type I expression were observed among groups. Histological changes were observed between MFx/BMS-treated and MFx/PRP-treated groups versus untreated defects mainly in surface regularity and cell distribution. However, International Cartilage Repair Society score analysis did not support statistical differences between MFx/BMS-treated and MFx/PRP-treated groups versus MFx-treated group. Conclusions: These results provide evidence that the use of intraarticular BMS or PRP as coadjuvants to the microfracture technique in the treatment of acute chondral lesions is not associated with a significant improvement of hyaline cartilage regeneration.Item Treatment of Meniscal Deficiency with Meniscal Allograft Transplantation and Femoral Osteotomy in a Patient with History of Lateral Discoid Meniscus(2020) Zaffagnini, Stefano; Espinosa, Maximiliano; Marcacci, Maurilio; Neri, Maria Pia; Grassi, AlbertoCase: A 15-year-old woman with multiple arthroscopic procedures for left lateral discoid meniscus since the age of 9 presented with pain, swelling, and mechanical symptoms. A meniscal allograft transplantation (MAT) and lateral openingwedge femoral osteotomy was performed. At the 6-year follow-up, the patient presented a visual analog scale (VAS) score of 0, subjective International Knee Documentation Committee (IKDC) of 88, and Lysholm of 95. At 15-year follow-up, the VAS score was 0, subjective IKDC 85.1, and Lysholm 86. Conclusions: MAT associated with femoral osteotomy was an effective procedure in this patient with pain and functional limitation after total meniscectomy in the setting of discoid meniscus and valgus malalignment. Good clinical and magnetic resonance imaging-related outcomes were achieved at the intermediate and long-term follow-up.