Introduction: The method of graft fixation is critical in anterior cruciate ligament (ACL) reconstruction surgery. Success of surgery is totally dependent on the ability of the implant to secure the graft inside the bone tunnel until complete graft integration. The principle of EndoButton is based on the cortical suspension of the graft. The Cross-Pin is based on graft expansion. The aim of this study was to evaluate the biomechanical performance of EndoButton and Bio Cross-Pin to fix the hamstring graft at femoral side of porcine knee joints and evaluate whether they are able to support of loading applied on graft during immediate post-operative tasks. Methods: Fourteen ACL reconstructions were carried out in porcine femurs fixing superficial flexor tendons with Titanium EndoButton (n = 7) and with 6 × 50 mm HA/PLLA Bio Cross-Pin (n = 7). A cyclic loading test was applied with 50-250 N of tensile force at 1 Hz for 1000 cycles. The displacement was measured at 20, 100, 500 and 1000 load cycles to quantify the slippage of the graft during the test. Single-cycle load-to-failure test was performed at 50 N/mm to measure fixation strength. Results: The laxity during cyclic loading and the displacement to failure during single-cycle test were lower for the Bio Cross-Pin fixation (8.21 ± 1.72 mm) than the EndoButton (11.20 ± 2.00 mm). The Bio Cross-Pin (112.22 ± 21.20 N.mm -1 ) was significantly stiffer than the EndoButton fixation (60.50 ±10.38 N.mm -1 ). There was no significant difference between Bio Cross-Pin (failure loading: 758. 29 ± 188.05 N; yield loading: 713.67 ± 192.56 N) and EndoButton strength (failure loading: 672.52 ± 66.56 N; yield loading: 599.91 ± 59.64 N). Both are able to support the immediate post-operative loading applied (445 N). Conclusion: The results obtained in this experiment indicate that the Bio Cross-Pin technique promote stiffer fixation during cyclic loading as compared with EndoButton. Both techniques are able to support the immediate post-operative loading applied.
A recent change in the ISO 7206-2, Implants for Surgery – Partial and Total Hip Joint Prostheses – Part 2: Articulating Surfaces Made of Metallic, Ceramic and Plastics Materials, with regard to hip joint prostheses, altered the recommended cutoff for measuring the roughness of the articulating surfaces of the femoral head and acetabular cup but did not encompass two key sites: the bore head and the trunnion. The aim of this study was to evaluate whether the standardized parameters and sites established in ISO 7206-2 are appropriate for evaluating the quality of the surface finish of total hip arthroplasty implants. Three kits containing the polymeric acetabular components, metallic heads, and stems from 5 manufacturers were used for testing. Contact profilometry was performed on the internal acetabular cup, external head, head bore, and trunnion surfaces. Additionally, the external head surface was evaluated with an interferometer to increase the accuracy. The evaluation of the external surface of the femoral head with a profilometer seems to be inadequate, because of a limitation of the contact method associated with highly polished surfaces. The average roughness (Ra) values obtained with an interferometer were lower than those measured with the profilometer and revealed significant differences between the manufacturers. The use of an 0.80-mm cutoff is more appropriate for the Ra range normally found for acetabular cups, enhancing the power to detect acetabular cups with inadequate roughness. The absence of a standard for the surface finish of the stem-head interface generates heterogeneity between manufacturers and between samples produced by a single manufacturer, revealing a lack of quality control.
BACKGROUND: Glucosamine hydrochloride (GlcNÁHCl) has been shown to inhibit cell growth and matrix synthesis, but not with N-acetyl-glucosamine (GlcNAc) supplementation. This effect might be related to an inhibition of critical growth factors (GF), or to a different metabolization of the two glucosamine derivatives. The aim of the present study was to evaluate the synergy between GlcNÁHCl, GlcNAc, and GF on proliferation and cartilage matrix synthesis. METHOD: Bovine chondrocytes were cultivated in monolayers for 48 h and in three-dimensional (3D) chitosan scaffolds for 30 days in perfusion bioreactors. Serum-free (SF) medium was supplemented with either growth factors (GF) TGF-b (5 ng mL -1 ) and IGF-I (10 ng mL -1 ), GlcNÁHCl or GlcNAc at 1mM each or both. Six groups were compared according to medium supplementation: (a) SF control; (b) SF ? GlcNÁHCl; (c) SF ? GlcNAc; (d) SF ? GF; (e) SF ? GF ? GlcNÁHCl; and (f) SF ? GF ? GlcNAc. Cell proliferation, proteoglycan, collagen I (COL1), and collagen II (COL2) synthesis were evaluated. RESULTS:The two glucosamines showed opposite effects in monolayer culture: GlcNÁHCl significantly reduced proliferation and GlcNAc significantly augmented cellular metabolism. In the 30 days 3D culture, the GlcNÁHCl added to GF stimulated cell proliferation more than when compared to GF only, but the proteoglycan synthesis was smaller than GF. However, GlcNAc added to GF improved the cell proliferation and proteoglycan synthesis more than when compared to GF and GF/GlcNÁHCl. The synthesis of COL1 and COL2 was observed in all groups containing GF. CONCLUSION: GlcNÁHCl and GlcNAc increased cell growth and stimulated COL2 synthesis in long-time 3D culture. However, only GlcNAc added to GF improved proteoglycan synthesis.
Resumo Objetivo O objetivo deste estudo foi avaliar a associação da anteversão femoral e da força dos músculos do quadril em indivíduos com síndrome do impacto femoroacetabular. Método Os ângulos de versão femoral descritos nas imagens de ressonância magnética articular e os testes isocinéticos foram avaliados retrospectivamente entre julho de 2016 e dezembro de 2017. Os critérios de inclusão foram: a) versão femoral avaliada pelo mesmo radiologista; b) ângulo α ≥ 55°; e c) ausência de dor limitante durante o teste isocinético. Os picos de torque em flexão/extensão, abdução/adução e rotação interna/externa foram avaliados a 30°/s em 5 repetições. A correlação entre a versão femoral e a força muscular foi avaliada por meio de regressão linear simples, com nível de significância estatística de 5%. Resultados Um total de 37 mulheres atenderam aos critérios de inclusão. Foram avaliados 51 quadris sintomáticos. Não houve correlação da anteversão femoral nos picos de torque em flexão, extensão, abdução, adução, rotação externa e rotação interna. Conclusão A anteversão femoral não foi correlacionada à força dos músculos do quadril em mulheres com impacto femoroacetabular sintomático.
Introduction: The rupture of the anterior cruciate ligament (ACL) is the most common type of knee injury.Reconstructive surgery is the 'gold standard' treatment. During the immediate post-operative period, the fixation of the graft is entirely dependent on the ability of the grafted implant to be secured inside the bone tunnel under the cyclical loads associated with daily tasks. Poor fixation can lead to graft slippage, thus impairing the healing and integration of the graft. The aim of this study was to evaluate the biomechanical performance of tendon graft fixation devices with metallic and bioabsorbable interference screws. Methods: Twenty ACL reconstructions were carried out in porcine tibias using deep flexor tendons to fix 9 × 20 mm metallic (n=10) and PLLA 70/30 bioabsorbable screws (n=10). To verify the ability of a construct to resist immediate postoperative (PO) rehabilitation protocols for immediate load bearing, a cyclic loading test was applied with 50-250 N of tensile force at 1 Hz for 1000 cycles, and the displacement was measured at 10, 50, 100, 500 and 1000 load cycles to quantify the slippage of the graft during the test. After the cyclic loading test, a singlecycle load-to-failure test was applied. Results: The slippage of the graft using metallic screws did not differ (P = 0.616) from that observed when using bioabsorbable screws. Conclusion: The results obtained in this experiment indicate that metallic screws may promote a similar amount of graft slippage during low cyclic loading as bioabsorbable screws. Additionally, there was no difference in the biomechanical performance of these two types of screws during high failure loads.
Objective:To describe the MR arthrographic findings in subjects with suspected acetabular labral tears of the hip. Method: 108 hip MRa results were analyzed in [2007][2008]. Two radiologists independently interpreted the images, and the consensual answers between them were considered for analysis. Based on their opinions, information was obtained on the location, staging of the chondral and labral lesions, anatomic alterations, and the presence of trochanteric bursitis and tendonitis. Results: 1st degree labral lesions occurred in 41% of cases, 2nd degree in 31%, and 3rd degree in 29%. The cam type FAI was common in 36% of cases, pincer FAI in 11%, and mixed cam-pincer FAI in 13%; in these cases 57% had grade III labral lesions. 1st degree chondral lesions were observed in 51% of acetabulum, 2nd degree in 13%, and 3rd degree in 18%. Conclusion: The morphologic alterations that cause cam type FAI were the most common. With respect to the degree of labral and chondral lesions, 1st degree lesions were the most common, irrespective of the presence or type of FAI, except in mixed cam-pincer FAIs, in which 3rd degree lesions were predominant. No relationship was observed between the degree of labral and chondral lesion.
Purpose (1) To evaluate the biomechanical properties of a porcine flexor digitorum superficialis tendon graft with preserved muscle fibers and (2) to compare these results with the biomechanical properties of a porcine tendon graft after removal of associated muscle. Methods Eighty-two porcine forelegs were dissected and the flexor digitorum superficialis muscle tendons were harvested. The study comprised of two groups: Group 1 (G1), harvested tendon with preserved muscle tissue; and Group 2 (G2), harvested contralateral tendon with removal of all muscle tissue. Tests in both groups were conducted using an electro-mechanical material testing machine (Instron, model 23-5S, Instron Corp., Canton, MA, USA) with a 500 N force transducer. Yield load, stiffness, and maximum load were evaluated and compared between groups. Results The behavior of the autografts during the tests followed the same stretching, deformation, and failure patterns as those observed in human autografts subjected to axial strain. There were no significant differences in the comparison between groups for ultimate load to failure (p = 0.105), stiffness (p = 0.097), and energy (p = 0.761). Conclusion In this porcine model biomechanical study, using autograft tendon with preserved muscle showed no statistically significant differences for yield load, stiffness, or maximum load compared to autograft tendon without preserved muscle. The preservation of muscle on the autograft tendon did not compromise the mechanical properties of the autograft. Level of evidence Level III Controlled laboratory study
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