Continuous Vertical Inside-Out Versus Traditional Vertical Inside-Out Meniscal Repair: A Biomechanical Comparison.

Background: Biomechanical assessment of meniscal repairs is essential for evaluating different meniscal suturing methods and techniques. The continuous meniscal suture technique is a newer method of meniscal repair that may have biomechanical differences compared with traditional techniques. Purpose: To evaluate the displacement, stiffness after cyclical loading, and load to failure for a continuous vertical inside-out meniscal suture versus a traditional vertical inside-out meniscal suture in a porcine medial meniscus. Study Design: Controlled laboratory study. Methods: A total of 28 porcine knees were acquired and divided into 2 test groups of 14 medial meniscus each. A 2.0-cm longitudinal red-white zone cut was made in the body of the medial meniscus for each knee. The continuous suture (CS) group received 4 vertical stitches performed with a continuous vertical meniscal suture technique, and the inside-out suture (IO) group received a traditional vertical suture with 4 stitches. Two traction tapes were passed between the sutures and positioned in the biomechanical testing fixture device. Each specimen underwent load-to-failure testing at 5 mm/s, and displacement, system stiffness, and maximum load to failure were compared between the groups. Results: The displacement after the cyclic test was 0.53 ± 0.12 and 0.48 ± 0.07 mm for the CS and IO groups, respectively. There was no significant difference between the groups (P = .2792). The stiffness at the ultimate load testing was 36.3 ± 1.9 and 35.3 ± 2.4 N/mm for groups CS and IO, respectively, with no significant difference between the groups (P = .2557). In the load-to-failure test, the ultimate load was 218.2 ± 63.9 and 238.3 ± 71.3 N in the CS and IO groups, respectively, with no significant group differences (P = .3062). Conclusion: A continuous vertical meniscal suture created a configuration for treating longitudinal meniscal lesions that was beneficial and biomechanically similar to a traditional vertical suture technique. Clinical Relevance: The study findings indicate that use of the continuous vertical inside-out meniscal suture technique is a possible therapeutic option.

Pre-clinical evaluation of fretting-corrosion at stem-head and stem-cement interfaces of hip implants using in vitro and in silico models.

Prior to clinical use, the corrosion resistance of new prosthesis system must be verified. The fretting-corrosion mechanisms of total hip arthroplasty (THA) implants generate metal debris and ions that can increase the incidence of adverse tissue reactions. For cemented stems, there are at least two interfaces that can be damaged by fretting-corrosion: stem-head and stem-cement. This investigation aimed to evaluate, through in vitro and in silico analyses, fretting-corrosion at the stem-head and stem-cement interfaces, to determine which surface is most affected in pre-clinical testing and identify the causes associated with the observed behavior. Unimodular stems and femoral heads of three different groups were evaluated, defined according to the head/stem material as group I (SS/SS), group II (CoCr/SS), and group III (CoCr/CoCr). Seven pairs of stems and heads per group were tested: three pairs were subjected to material characterization, three pairs to in vitro fretting-corrosion testing, and one pair to geometric modeling in the in silico analysis. The absolute area of the stem body degraded was more than three times higher compared with the trunnion, for all groups. These results were corroborated by the in silico analysis results, which revealed that the average micromotion at the stem-cement interface (9.65-15.66 µm) was higher than that at the stem-head interface (0.55-1.08 µm). In conclusion, the degradation of the stem-cement interface is predominant in the pre-clinical set, indicating the need to consider the fretting-corrosion at the stem-cement interface during pre-clinical implant evaluations.

Influence of acupuncture needle physical-chemical properties on needling quality.

OBJECTIVES: This study analyzed the physical-chemical properties of three different brands of acupuncture needle, classified by acupuncturists as high (A), medium (B) and low (C) quality. METHODS: Experienced acupuncturists, rated, in terms of perceived needling quality, three acupuncture needle brands as high (A), medium (B) and low (C) quality. Next, scanning electron microscopy (SEM) images of the tip and surface finish of the needles of each brand were analyzed. A mechanical test was developed and performed to evaluate the compressive force required to insert the needles through a smooth surface (silicon). In addition, X-ray fluorescence spectroscopy (XRF) and dispersive energy spectroscopy (DES) were conducted to analyze the material composition of the needles and presence of oxidation. RESULTS: SEM images revealed that needle brands A and B presented a sharper tip and a more regular surface finish in comparison to brand C. In the insertion test, needle brands A and B had similar performance characteristics, with A requiring less force to penetrate the silicon device when compared to B, while C failed to penetrate the silicon and complete the test. The XRF analysis did not reveal any differences in material composition between the three brands. However, brand C exhibited particles embedded on the needle surface and DES confirmed oxidation. CONCLUSION: This study demonstrates that perceived needling quality by acupuncturists can be correlated with physical-chemical properties of the needles, especially those related to finishing quality of the tip and the surface of the needles.

Tendon grafts with preserved muscle demonstrate similar biomechanical properties to tendon grafts stripped of muscular attachments: a biomechanical evaluation in a porcine model.

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.

Biomechanical performance of Bio Cross-Pin and EndoButton for ACL reconstruction at femoral side: a porcine model

Abstract 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.

Graft tendon slippage with metallic and bioabsorbable interference screws under cyclic load: a biomechanical study in a porcine model

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 single-cycle 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.

Simulação numérica tridimensional da mecânica do joelho humano / Three-dimensional numerical simulation of human knee joint mechanics

OBJETIVO: Por ser a articulação mecanicamente mais solicitada de nossa estrutura e pelo grande número de lesões associadas, motivaram a construção de um modelo tridimensional da articulação do joelho humano para simular a cinemática da articulação e obter as solicitações mecânicas nos principais ligamentos durante o movimento de flexão do joelho. Essas informações podem futuramente ser empregada como ferramenta de apoio à decisão médica em ortopedia, fornecendo subsídios na escolha do procedimento cirúrgico. MÉTODOS: Método dos Elementos Finitos foi utilizado para construir um modelo biomecânico, tridimensional, da articulação do joelho. Nesse modelo com seis graus de liberdade é aplicado movimento de flexão/extensão sendo os demais cinco graus de liberdade governados pelas interações entre os componentes da articulares. RESULTADOS: Foram obtidas informações dos movimentos, das rotações interna/externa e adução/abdução, das translações anterior/posterior, lateral/medial e superior/inferior e dos esforços nos quatro principais ligamentos articulares, no decorrer de um amplo movimento de flexão/extensão. Estes valores foram comparados, de forma qualitativa, com valores equivalentes obtidos na literatura. CONCLUSÃO: A análise de resultados permitiu observar que vários aspectos cinemáticos são satisfatoriamente reproduzidos. A pré-carga inicial dos ligamentos e o posicionamento das inserções ligamentares no modelo mostraram-se variáveis relevantes nos resultados.

OBJECTIVE: The knee joint is the part of our structure upon which most mechanical demands are placed and a large number of lesions are associated to it. These factors motivated the construction of a three-dimensional model of the human knee joint in order to simulate joint kinematics and obtain the mechanical demands on the main ligaments during knee flexion movements. METHODS: The finite elements method was used to build a three-dimensional, biomechanical model of the knee joint. In this model with six degrees of freedom, the flexion/extension movement is applied, while the other five degrees of freedom are governed by the interactions between joint components. RESULTS: Data was collected on the movements, on the internal/external and adduction/ abduction rotations, on the anterior/posterior, lateral/medial and upper/lower translations, and on the forces acting upon the four main joint ligaments, during a wide flexion/extension movement. These values were qualitatively compared with comparable values available in the literature. CONCLUSIONS: It was observed through an analysis of the results that several kinematic aspects are satisfactorily reproduced. The initial pre-load of the ligaments and the positioning of the ligament insertions in the model were shown to be relevant variables in the results.

Estudo comparativo macroscópio e histológico da origem labial do tendão da cabeça longa do bíceps braquial / Histological and macroscopic comparative study of labral origin from long head biceps brachii tendon

A região superior do lábio da glenóide pode apresentar lesões labiais e tendinosas do bíceps braquial, sendo o conhecimento das variações anatômicas de grande importância para a realização de procedimentos artroscópicos. O objetivo do trabalho é determinar a origem labial do tendão da cabeça longa do bíceps braquial, comparando a visão macroscópica com a avaliação histológica. Foram realizadas dissecções de 36 ombros de 18 cadáveres conservados em formaldeído, no Laboratório de Ciências Morfológicas da Universidade Federal de Santa Catarina (LCM-UFSC). Foram avaliadas a estrutura macroscópica e a histológica da região do lábio superior, incluindo o local de origem labial do tendão da cabeça longa do bíceps braquial (CLB). A classificação anatômica utilizada foi a de Vangsness, que considera quatro tipos de origem labial da CLB. Foram feitos cortes histológicos seriados da região superior do lábio, com o objetivo de estudar a origem do tendão. Macroscopicamente, a principal origem labial da CLB foi na porção póstero-superior. A histologia mostrou que na maioria dos casos havia origem associada na porção ântero-superior. A avaliação macroscópica não é, portanto, confiável para determinar a origem labial do tendão da cabeça longa do bíceps braquial

Resultado funcional da artroplastia total do joelho: análise de 27 pacientes / Functional result of kneeÆs total arthroplasty: analysis of 27 patients

Vinte e quatro pacientes com diagnóstico de artrose tricompartimental e três com artrite reumatóide, foram submetidos à artroplastia total unilateral do joelho, utilizando prótese condilar total, com estabilizador posterior (Sistema Insall-Burstein), no Hospital Governador Celso Ramos, Aorianópolis, entre setembro de 1991 e setembro de 1997. Este estudo avaliou o resultado funcional de pacientes submetidos à artroplastia total do joelho. O tempo de seguimento pós-operatório foi de 14,9 meses, em média. Todos os pacientes referiram alívio do quadro doloroso; 78% foram capazes de caminhar .por 20 minutos ou mais no pós-operatório; 100% deles conseguiram caminhar mais de 300 metros e 81 % tiveram melhora da mobilidade articular. Com a colocação da prótese, as atitudes viciosas de flexão foram corrigidas em 87% dos casos e os pacientes tiveram menor dificuldade para subir escadas. Houve 2 casos de soltura asséptica dos componentes. Não houve nenhum caso de instabilidade articular no pós-operatório. Nos pacientes submetidos à artroplastia total do joelho houve diminuição da dor, aumento da distância e do tempo de caminhada, aumento da mobilidade articular e as complicações foram, na maioria das vezes, de pequena gravidade...

Estudo crítico dos anéis do aparelho de Ilizarov / Critical approach of Ilizarov apparatus rings

Foi analisado o comportamento dos anéis do aparelho Ilizarov com 130, 160 e 200mm de diâmetro sob carga de compressäo, montado com fios de Kirschner de 1,5mm, com e sem tensäo, dobrados ou näo, e sobre três ou quatro apoios. Observou-se perda da estabilidade em anéis de maior diâmetro e em anéis sobre três apoios. O dobramento da extremidade dos fios näo melhorou a fixaçäo, mas permitiu identificar o início do escorregamento. Observou-se também comportamento diferente da fixaçäo dos fios nos parafusos com orifício central e fenda lateral

Ligamento cruzado anterior e tendäo patelar: estudo mecânico e correlaçöes clínicas / Anterior cruciate ligament and patellar tendon: mechanical study and clinical correlations

Pelo estudo de 20 joelhos de cadáveres frescos determinou-se näo haver proporcionalidade entre as características mecânicas do ligamento cruzado anterior e do terço central do tendäo patelar. A resistência do ligamento cruzado anterior é proporcional ao tamanho do joelho e o mesmo näo acontece com a porçäo central do tendäo patelar. A resistência das estruturas estudadas näo se altera com a idade. Outros parâmetros foram estuddos e inter-relacionados