Simultaneous medial unicompartmental knee replacement and anterior cruciate ligament reconstruction: a narrative review and technical note.

Background 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.

Oxigenación de músculos respiratorios y locomotores durante el test cardiopulmonar en pacientes con circulación de fontan: serie de casos / Patients with fontan: oxygen consumption in respiratory and Locomotor muscles during excersie testing

Resumen: Antecedentes: Los pacientes con circulación de Fontan (PCF) presentan limitación cardíaca durante el esfuerzo máximo lo que repercute en menor capacidad de ejercicio (VO2-peak). La rehabilitación cardiovascular (RC) revierte este desacondicionamiento, al aumentar el gasto cardíaco y diferencia arteriovenosa de oxígeno, aspectos evaluados con monitorización invasiva y gases exhalados. La valoración no invasiva de la saturación muscular de oxígeno (SmO2) es un método de reciente aplicación para evaluar la limitación muscular al ejercicio. En PCF esta limitación puede atribuirse a la mayor acción de músculos respiratorios (cambios ventilatorios) y/o locomotores (carga periférica). Objetivo: Evaluar el trabajo de músculos respiratorios y locomotores durante el ejercicio físico máximo e incremental mediante los cambios en la SmO2. Métodos: A seis PCF (5 hombres; 13.8±2.9 años; 158±9cm; 49.8±13.3 kg) se les valoró el VO2-peak (23.0±4.5mL·kg-1·min-1) mediante ciclo-ergoespirometría sincrónicamente con SmO2 en músculos respiratorios (SmO2-m.Intercostales) y locomotores (SmO2-m.Vastus-Laterallis) mediante espectroscopía cercana al rango infrarrojo durante el test cardiopulmonar. Resultados: SmO2-m.Intercostales disminuyó desde el 60% del VO2-peak (p<0.05), mientras que SmO2-m.Vastus-Laterallis no cambió. La ventilación pulmonar (VE) aumentó progresivamente, siendo significativo a partir del 60% VO2-peak (p<0.05). La mayor desoxigenación de SmO2-m.Intercostales (∆SmO2) se asoció con los máximos cambios en ventilación pulmonar (∆VE) en ejercicio (rho=0.80; p=0.05). Conclusiones: Durante un protocolo de esfuerzo, los pacientes con circulación de Fontan presentan mayor trabajo muscular respiratorio que locomotor. Los cambios en la ventilación pulmonar se asocian a mayor extracción de oxígeno en la musculatura respiratoria, reforzando la necesidad de incorporar el entrenamiento respiratorio en la rehabilitación cardiovascular.

Abstract: Background: During a maximum incremental exercise patients with Fontan circulation (PFC) show cardiac limitation reducing aerobic exercise capacity (VO2-peak). Cardiovascular rehabilitation (CR) reverses this deconditioning by increasing cardiac output and arteriovenous oxygen difference, aspects that can be evaluated by invasive methods and analyzing the exhaled gases. Non-invasive assessment of muscle oxygen saturation (SmO2) is a novel method for recording local oxygen levels. By this technology, it is possible to evaluate the muscle limitation to exercise. In PFC, that limitation could be attributed to higher contractions of respiratory (ventilatory changes) and/ or locomotor muscles (peripheral load). Objective: To evaluate in PFC the changes at SmO2 of respiratory and locomotor muscles during a maximum and incremental exercise protocol (cardiopulmonary test, VO2-peak). Methods: Six PFC (5 men; 13.8±2.9 years; 158±9 cm; 49.8±13.3 kg) were assessed during the VO2peak test (23.0±4.5mL·kg-1·min-1) by cyclo-ergospirometry synchronously with SmO2 at respiratory (SmO2-m.Intercostales) and locomotor (SmO2-m. Vastus-Laterallis) muscles by Near-Infrared Spectroscopy (NIRS). Results: SmO2-m.Intercostales decreased from 60% of VO2-peak (p<0.05), while SmO2-m.Vastus-Laterallis did not change. Minute ventilation (VE) increased progressively, showing changes to rest at 60% of VO2-peak (p<0.05). The higher deoxygenation of SmO2-m.Intercostales (∆SmO2) correlated to maximum changes of lung ventilation (∆VE) (rho=0.80; p=0.05). Conclusions: During an incremental and maximum exercise protocol, patients with Fontan circulation have more work at respiratory than locomotor muscles. Changes in VE are direct associated with greater extraction of oxygen at respiratory muscles, reinforcing the incorporation of respiratory muscle training in cardiovascular rehabilitation.

Treatment of Meniscal Deficiency with Meniscal Allograft Transplantation and Femoral Osteotomy in a Patient with History of Lateral Discoid Meniscus: 15-Year Follow-up Case Report.

CASE: 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 opening-wedge 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.

Assessment of Cell Viability of Fresh Osteochondral Allografts in N-Acetylcysteine-Enriched Medium.

OBJECTIVE: 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.

Evaluación del trabajo respiratorio mediante oxigenación muscular / Assessment of work of breathing using muscle oxygenation

RESUMEN El aumento del trabajo respiratorio (work of breathing, WOB) es uno de los problemas kinesiológicos frecuentes en el quehacer clínico. Un desafío profesional es contar con valores de variables fisiológicas que permitan objetivar el WOB facilitando así su interpretación entre los diferentes profesionales de la salud. El uso de dispositivos portátiles que registran la longitud de onda cercana al rango infrarrojo (680- 820 nm, Near Infrared Spectroscopy (NIRS)) en músculos superficiales permite obtener valores de hemoglobina total unida a oxígeno (tHb) y oxigenación muscular local (SmO2), variables relacionadas al trabajo muscular pues reportan el flujo sanguíneo en la microcirculación y consumo de oxígeno local, respectivamente. Estos dispositivos situados en musculatura intercostal nos informan el WOB asociado a la respiración. Para evaluar esto, se analizó el comportamiento de tHb y SmO2 en m. intercostal en 20 corredores de maratón durante la valoración de consumo de oxígeno máximo (VO2- max), instancia que implica aumento sostenido e incremental de la ventilación pulmonar (��E), y por tanto de la actividad muscular respiratoria. El aumento de V E en 128,4 L·min-1 ( ��E (máximo-reposo)) implicó una disminución en SmO2- m.intercostal del 34% ( SmO2 (reposo-máximo)), sin cambios en tHb (p=0,805). La tuvo una correlación inversa con SmO2-m.intercostal (rho=-0.565; p=0,001). Se concluye que la valoración de SmO2-m.intercostal es una forma novedosa de objetivar el WOB en sujetos sanos. Conocer la aplicabilidad clínica requiere de otros estudios que evalúen esta herramienta en pacientes con disfunciones cardiorrespiratorias, lo que permitiría incorporar su uso en nuestro desarrollo clínico profesional.

The work of breathing (WOB) increased is a commonkinesiological problems at the clinical practice. A professional challenge is to have values of physiological variables that allows to objective the WOB, thus facilitating its interpretation among different health professionals. The use of portable devices that measure by spectroscopy the near-infrared wavelength (680-820 nm) atsuperficial muscles allows to obtain values of total hemoglobin linked to oxygen (tHb) and local muscle oxygenation (SmO2), variables related to muscle work because give information of the blood flow at the microcirculation and local oxygen consumption, respectively. These devices located at the m.intercostal could give information about the WOB associated to breathing. To evaluate this, the tHb and SmO2 of the m.intercostal in 20 marathon runners were analyzed while they doing the maximum oxygen consumption test (VO2-max), an exercise that increase the pulmonary ventilation and the respiratory muscle activity. The increase of V E (128,4 L·min-1((max-rest)) implied a decrease in SmO2- m.intercostal (34% ( SmO2 (max-rest)), without changes in tHb (p=0.805). The showedan negative correlation to SmO2-m.intercostal (rho= -0.565; p=0.001). It is concluded that the assessment of SmO2-m.intercostal is a novel way to measure the WOB in healthy subjects. Their clinical applicability requires more studies that applied this tool in patients with cardiorespiratory dysfunctions, facilitating their incorporation in the professional clinical practice.

Dexamethasone and rosiglitazone are sufficient and necessary for producing functional adipocytes from mesenchymal stem cells.

The 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.

Transphyseal anterior cruciate ligament reconstruction in patients with open physes: 10-year follow-up study.

BACKGROUND: The treatment of anterior cruciate ligament (ACL) injuries in skeletally immature patients is controversial. Current evidence supports the view that surgical techniques restore knee stability and prevent progressive articular damage. However, most of the studies on this topic are small case series or they have short- or medium-term follow-up times. PURPOSE: To determine the long-term functional outcomes and secondary complications of transphyseal intra-articular ACL reconstruction with hamstring graft in skeletally immature patients. STUDY DESIGN: Case series; Level of evidence, 4. METHODS: Transphyseal ACL reconstruction with autograft hamstrings was performed in 27 skeletally immature patients. The average age at surgery was 13 years (range, 12-16 years), and the average follow-up time was 10.6 years (range, 10-13 years). Clinical outcomes were assessed with preoperative and final follow-up Tegner, International Knee Documentation Committee (IKDC) subjective, and Lysholm scores. Surgery details, return to sports, and ACL reconstruction failures were collected. The anteroposterior knee laxity was assessed by arthrometry, and the presence of deformities and lower limb length discrepancies were evaluated by radiographs. The presence of degenerative signs on anteroposterior and lateral knee radiographs at final follow-up was also evaluated. RESULTS: Transphyseal ACL reconstruction was performed with vertically oriented tunnels, 7 to 10 mm in diameter, using semitendinosus-gracilis autograft. The average preoperative Tegner, IKDC, and Lysholm scores were 7, 55, and 40, respectively. Significant differences in these scores were observed at the time of the final assessment (Tegner, 6 [P = .026]; IKDC, 94 [P < .001]; Lysholm, 92 [P < .001]). Two patients reported instability during sports activity. Three patients had a rupture of the ACL graft. No leg length discrepancy, axis malalignment, or degenerative changes were observed. CONCLUSION: The transphyseal ACL reconstruction in skeletally immature patients is a safe option, with high functional and satisfaction results, without significant growth plate damage in this series of patients.

Anterior cruciate ligament regeneration using mesenchymal stem cells and collagen type I scaffold in a rabbit model.

PURPOSE: 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.

Proximal oblique sliding closing wedge osteotomy for hallux valgus.

BACKGROUND: 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.

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.

OBJECTIVE: 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 mm(2) 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, MSC-treated, 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.

A new elevating metatarsal osteotomy: geometrical design and applications.

For metatarsalgia and lesser toe deformities, a commonly performed procedure is the Weil osteotomy, which inevitably depresses the metatarsal head, changing the intrinsic muscle axis and generating phalanx extension. The objective of this study is to present a new metatarsal osteotomy that shortens or lengthens and elevates the metatarsal head, the elevating metatarsal osteotomy (EMO), with its geometrical analysis and possible applications. A geometrical model was designed, planning an oblique subcapital osteotomy with slice resection and distal displacement. A trigonometric analysis was done to calculate how to shorten, elevate, or lengthen the metatarsal head. The EMO elevates the head in one-third of the width of the resected slice. Distal and dorsal displacement of the metatarsal head results in an elevation and lengthening of the metatarsal bone (60% elevation and 65% lengthening). Performing an elevating metatarsal osteotomy will lengthen and elevate the metatarsal head, which sometimes is necessary when treating toe deformities and instability.

Steroids and Platelet-Rich Plasma as Coadjuvants to Microfracture for the Treatment of Chondral Lesions in an Animal Model: Can the Healing Be Enhanced?

OBJECTIVE: 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 mm(2) 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.