Viability of Collagen Matrix Grafts Associated with Nanohydroxyapatite and Elastin in Bone Repair in the Experimental Condition of Ovariectomy.

Bone lesions have the capacity for regeneration under normal conditions of the bone metabolism process. However, due to the increasing incidence of major traumas and diseases that cause bone-mineral deficiency, such as osteoporosis, scaffolds are needed that can assist in the bone regeneration process. Currently, natural polymeric scaffolds and bioactive nanoparticles stand out. Therefore, the objective of the study was to evaluate the osteoregenerative potential in tibiae of healthy and ovariectomized rats using mineralized collagen and nanohydroxyapatite (nHA) scaffolds associated with elastin. The in-vivo experimental study was performed with 60 20-week-old Wistar rats, distributed into non-ovariectomized (NO) and ovariectomized (O) groups, as follows: Controls (G1-NO-C and G4-O-C); Collagen with nHA scaffold (G2-NO-MSH and G5-O-MSH); and Collagen with nHA and elastin scaffold (G3-NO-MSHC and G6-O-MSHC). The animals were euthanized 6 weeks after surgery and the samples were analyzed by macroscopy, radiology, and histomorphometry. ANOVA and Tukey tests were performed with a 95% CI and a significance index of p < 0.05. In the histological analyses, it was possible to observe new bone formed with an organized and compact morphology that was rich in osteocytes and with maturity characteristics. This is compatible with osteoconductivity in both matrices (MSH and MSHC) in rats with normal conditions of bone metabolism and with gonadal deficiency. Furthermore, they demonstrated superior osteogenic potential when compared to control groups. There was no significant difference in the rate of new bone formation between the scaffolds. Ovariectomy did not exacerbate the immune response but negatively influenced the bone-defect repair process.

In Vivo Biological Behavior of Polymer Scaffolds of Natural Origin in the Bone Repair Process.

Autologous bone grafts, used mainly in extensive bone loss, are considered the gold standard treatment in regenerative medicine, but still have limitations mainly in relation to the amount of bone available, donor area, morbidity and creation of additional surgical area. This fact encourages tissue engineering in relation to the need to develop new biomaterials, from sources other than the individual himself. Therefore, the present study aimed to investigate the effects of an elastin and collagen matrix on the bone repair process in critical size defects in rat calvaria. The animals (Wistar rats, n = 30) were submitted to a surgical procedure to create the bone defect and were divided into three groups: Control Group (CG, n = 10), defects filled with blood clot; E24/37 Group (E24/37, n = 10), defects filled with bovine elastin matrix hydrolyzed for 24 h at 37 °C and C24/25 Group (C24/25, n = 10), defects filled with porcine collagen matrix hydrolyzed for 24 h at 25 °C. Macroscopic and radiographic analyses demonstrated the absence of inflammatory signs and infection. Microtomographical 2D and 3D images showed centripetal bone growth and restricted margins of the bone defect. Histologically, the images confirmed the pattern of bone deposition at the margins of the remaining bone and without complete closure by bone tissue. In the morphometric analysis, the groups E24/37 and C24/25 (13.68 ± 1.44; 53.20 ± 4.47, respectively) showed statistically significant differences in relation to the CG (5.86 ± 2.87). It was concluded that the matrices used as scaffolds are biocompatible and increase the formation of new bone in a critical size defect, with greater formation in the polymer derived from the intestinal serous layer of porcine origin (C24/25).

A simple method to minimize vascular lesion of the popliteal artery by guidewire during transtibial posterior cruciate ligament reconstruction: a cadaveric study.

PURPOSE: To compare the outside-in transtibial lateral and medial approaches for posterior cruciate ligament (PCL) reconstruction regarding the guidewires and popliteal artery integrity. METHODS: Twenty-two human cadaveric knees were used. A PCL tibial aimer was arthroscopically placed within the PCL footprint through the anteromedial portal for the medial approach and through the anterolateral portal for the lateral approach. For the medial approach, the drill guide was introduced through the anteromedial tibial cortex and the guidewire was advanced with the reamer beyond the posterior tibial cortex. For the lateral approach, the drill guide was introduced through the anterolateral tibial cortex and the guidewire was advanced with the reamer beyond the posterior tibial cortex. After this, the knee was dissected. The depth distance (DD) was defined as the distance between the popliteal artery and the tibial posterior cortex projected at the tibial level at which the guidewire intersected or passed by the artery. The guidewire travel distance was calculated as the distance the guidewire had to advance beyond the tibial cortex to intersect the popliteal artery or pass by it. RESULTS: With the medial approach, the popliteal artery was intersected in all knees with a mean DD of 12.20 mm and a mean guidewire travel distance of 15.90 mm. With the lateral approach, the popliteal artery was not intersected in any knee; its mean medial distance from the artery was 4.8 mm at a DD of 10.05 mm. There was a significant difference in the popliteal artery intersection incidence and DD between both groups (P < .0001 and P = .0003, respectively). CONCLUSIONS: The transtibial lateral approach for PCL reconstruction was a safer method than the medial approach regarding popliteal artery injury by a guidewire. CLINICAL RELEVANCE: This study presents a slight modification of the most frequently used PCL reconstruction technique, intending to minimize guidewire injury to the popliteal artery.

Tratamento da lesäo aguda do ligamento cruzado anterior / Treatment of the acute lesion of the anterior cruciate ligament

Os autores estudaram a evoluçäo de 73 pacientes com lesäo do ligamento cruzado anterior submetidos a reconstruçäo por duas técnicas distintas. Quarenta e seis foram operados pela técnica que utiliza o terço médio do tendäo patelar como enxerto e 27 pela técnica que utiliza o tendäo do músculo semitendíneo triplo. Os resultados quanto ao retorno Ós atividades que antecederam o trauma foram bons na maioria dos casos, independente da técnica empregada. A análise do período de reabilitaçäo demonstrou que os pacientes operados pela técnica que utiliza o terço médio do tendäo patelar apresentaram maior número de problemas.