Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 15 de 15
Filtrar
1.
BMC Musculoskelet Disord ; 15: 417, 2014 Dec 09.
Artículo en Inglés | MEDLINE | ID: mdl-25488492

RESUMEN

BACKGROUND: Use of a baseplate with a smaller diameter in reverse shoulder arthroplasty is increasing, especially in patients with a small glenoid or glenoid wear. However, the effect of a smaller baseplate on stability of the glenoid component has not been evaluated. Thus, the purpose of this study was to determine whether a smaller baseplate (25 mm) is beneficial to the initial stability of the glenoid component compared to that with a baseplate of a commonly used size (29 mm). METHODS: Micromotion of glenoid components attached to 14 scapulae of fresh-frozen cadavers was measured and compared between 25- and 29-mm baseplates in biomechanical testing. Impingement-free range of motion in abduction, adduction, internal rotation, and external rotation was evaluated by using a simulated computer model constructed based on the same fresh-frozen cadavers used in biomechanical testing. RESULTS: Micromotion at the inferior third of the glenoid-glenosphere interface was higher in the 29-mm baseplate group than in the 25-mm baseplate group during both 0.7- and 1-body weight cyclic loading in biomechanical testing. Adduction deficit was smaller, and total impingement-free range of motion from abduction to adduction and rotation were greater in the 25-mm baseplate group than in the 29-mm baseplate group in the simulated computer model. CONCLUSIONS: Use of a baseplate with a smaller diameter (25 mm) in reverse shoulder arthroplasty is suitable for improving the primary stability of the glenoid component. With a smaller baseplate, impingement-free range of motion is optimized in a smaller glenoid.


Asunto(s)
Artroplastia de Reemplazo/instrumentación , Cavidad Glenoidea/patología , Cavidad Glenoidea/cirugía , Prótesis Articulares , Diseño de Prótesis , Rango del Movimiento Articular/fisiología , Anciano , Femenino , Humanos , Persona de Mediana Edad , Hombro/patología , Hombro/cirugía , Resultado del Tratamiento
2.
ACS Appl Bio Mater ; 7(2): 1146-1157, 2024 02 19.
Artículo en Inglés | MEDLINE | ID: mdl-38282578

RESUMEN

Rotator cuff tears are currently treated with drugs (steroids and nonsteroidal anti-inflammatory drugs) and surgery. However, the damaged rotator cuff requires a considerable amount of time to regenerate, and the regenerated tissue cannot restore the same level of function as that before the damage. Although growth factors can accelerate regeneration, they are difficult to be used alone because of the risk of degradation and the difficulties in ensuring their sustained release. Thus, hydrogels such as gelatin are used, together with growth factors. Gelatin is a biocompatible and biodegradable hydrogel derived from collagen; therefore, it closely resembles the components of native tissues and can retain water and release drugs continuously, while also showing easily tunable mechanical properties by simple modifications. Moreover, gelatin is a natural biopolymer that possesses the ability to form hydrogels of varying compositions, thereby facilitating effective cross-linking. Therefore, gelatin can be considered to be suitable for rotator-to-tendon healing. In this study, we designed photo-cross-linkable gelatin hydrogels to enhance spacing and adhesive effects for rotator cuff repair. We mixed a ruthenium complex (Ru(II)bpy32+) and sodium persulfate into gelatin-based hydrogels and exposed them to blue light to induce gelation. Basic fibroblast growth factor and bone morphogenetic protein-12 were encapsulated in the gelatin hydrogel for localized and sustained release into the wound, thereby enhancing the cell proliferation. The effects of these dual growth factor-loaded hydrogels on cell cytotoxicity and tendon regeneration in rotator cuff tear models were evaluated using mechanical and histological assessments. The findings confirmed that the gelatin hydrogel was biocompatible and that treatment with the dual growth factor-loaded hydrogels in in vivo rotator cuff tear models promoted regeneration and functional restoration in comparison with the findings in the nontreated group. Therefore, growth factor-loaded gelatin-based hydrogels may be suitable for the treatment of rotator cuff tears.


Asunto(s)
Lesiones del Manguito de los Rotadores , Manguito de los Rotadores , Humanos , Manguito de los Rotadores/patología , Manguito de los Rotadores/cirugía , Lesiones del Manguito de los Rotadores/tratamiento farmacológico , Lesiones del Manguito de los Rotadores/patología , Lesiones del Manguito de los Rotadores/cirugía , Hidrogeles/farmacología , Gelatina/farmacología , Preparaciones de Acción Retardada , Tendones , Péptidos y Proteínas de Señalización Intercelular/farmacología
3.
J Clin Med ; 13(10)2024 May 20.
Artículo en Inglés | MEDLINE | ID: mdl-38792546

RESUMEN

Background: Although osteoarthritis (OA) development is epidemiologically multifactorial, a primary underlying mechanism is still under debate. Understanding the pathophysiology of OA remains challenging. Recently, experts have focused on autophagy as a contributor to OA development. Method: To better understand the pathogenesis of OA, we survey the literature on the role of autophagy and the molecular mechanisms of OA development. To identify relevant studies, we used controlled vocabulary and free text keywords to search the MEDLINE, EMBASE, the Cochrane Central Register of Controlled Trials, Web of Science, and SCOPUS database. Thirty-one studies were included for data extraction and systematic review. Among these studies, twenty-five studies investigated the effects of autophagy in aging and OA chondrocytes, six studies examined the effects of autophagy in normal human chondrocytes, and only one study investigated the effects of mechanical stress-induced autophagy on the development of OA in normal chondrocytes. Results: The studies suggest that autophagy activation prevents OA by exerting cell-protective effects in normal human chondrocytes. However, in aging and osteoarthritis (OA) chondrocytes, the role of autophagy is intricate, as certain studies indicate that stimulating autophagy in these cells can have a cytotoxic effect, while others propose that it may have a protective (cytoprotective) effect against damage or degeneration. Conclusions: Mechanical stress-induced autophagy is also thought to be involved in the development of OA, but further research is required to identify the precise mechanism. Thus, autophagy contributions should be interpreted with caution in aging and the types of OA cartilage.

4.
Colloids Surf B Biointerfaces ; 222: 113088, 2023 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-36577342

RESUMEN

Controlled and targeted delivery of growth factors to biological environments is important for tissue regeneration. Polylactic acid (PLA) hydrogel microparticles are attractive carriers for the delivery of therapeutic cargoes based on their superior biocompatibility and biodegradability, uniform encapsulation of cargoes, and non-requirement of organic solvents during particle synthesis. In this study, we newly present controlled growth factor delivery utilizing PLA-based hydrogel microcarriers synthesized via degassed micromolding lithography (DML). Based on the direct gelation procedure from the single-phase aqueous precursor in DML, bovine serum albumin, a model protein of growth factor, and fibroblast growth factor were encapsulated into microparticles with uniform distribution. In addition, by tuning the monomer concentration and adding a hydrolytically stable crosslinker, the release of encapsulated cargoes was efficiently controlled and extended to 2 weeks. Finally, we demonstrated the biological activity of encapsulated FGF-2 in PLA-based microparticles using a fibroblast proliferation assay.


Asunto(s)
Hidrogeles , Poliésteres , Péptidos y Proteínas de Señalización Intercelular , Solventes , Tamaño de la Partícula
5.
J Trauma ; 70(5): E88-92, 2011 May.
Artículo en Inglés | MEDLINE | ID: mdl-21610416

RESUMEN

BACKGROUND: Optimal surgical treatment of unstable distal clavicle fractures is controversial, and various fixation options are available. The objective of this study was to evaluate a new modified tension band fixation technique for unstable distal clavicle fractures. METHODS: Forty-two patients with acute unstable distal clavicle fractures were managed with open reduction and internal fixation using modified tension band fixation. All patients had radiographic and clinical follow-ups at a minimum of 12 months (range, 12-39 months). Bony union and coracoclavicular interval distance were evaluated radiographically. Clinical outcomes were measured with the American Shoulder and Elbow Surgeons Standardized Shoulder Assessment Form. RESULTS: All fractures united solidly within 3 months. All patients had a good functional result, with a mean American Shoulder and Elbow Surgeons Standardized Shoulder Assessment Form score of 92 points and a coracoclavicular interval distance of 8.7 mm (range, 5-14 mm; 1.24 times of normal shoulder) at the final follow-up. CONCLUSION: Surgical treatment for unstable distal clavicle fractures using modified tension band fixation is effective. This technique allows simple, cost-effective, and minimally invasive fixation with universally available implants and good fracture healing.


Asunto(s)
Clavícula/lesiones , Fijación Interna de Fracturas/instrumentación , Fracturas Óseas/cirugía , Cinta Quirúrgica , Adolescente , Adulto , Anciano , Hilos Ortopédicos , Clavícula/diagnóstico por imagen , Clavícula/cirugía , Diseño de Equipo , Femenino , Estudios de Seguimiento , Curación de Fractura , Fracturas Óseas/diagnóstico por imagen , Humanos , Masculino , Persona de Mediana Edad , Radiografía , Estudios Retrospectivos , Resistencia a la Tracción , Resultado del Tratamiento , Adulto Joven
6.
J Shoulder Elbow Surg ; 19(4): 617-23, 2010 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-20080051

RESUMEN

BACKGROUND: Rotator cuff tears are common shoulder problems whose propagation is difficult to predict because of the structural and mechanical inhomogeneity of the supraspinatus tendon. We have previously shown that the supraspinatus and infraspinatus tendons interact mechanically when the supraspinatus tendon is intact or exhibits a full-thickness tear, so that an increase in supraspinatus tendon strain is paralleled by an increase in infraspinatus tendon strain. Such interaction is critical and suggests that an increase in infraspinatus tendon strain that accompanies an increase in supraspinatus tendon strain may shield the supraspinatus tendon from further injury, but increase the risk of injury to the infraspinatus tendon. In this study, the mechanical interactions between the supraspinatus and infraspinatus tendons were evaluated for the commonly occurring supraspinatus tendon partial-thickness tears through a range of rotation angles. METHODS: For each joint rotation and supraspinatus tendon tear size evaluated, the supraspinatus tendon was loaded, and images corresponding to 5 N, 30 N, 60 N, and 90 N of supraspinatus tendon load were isolated for the speckle painted supraspinatus and infraspinatus tendons. A region of interest outlining the insertion site was isolated and displacements between the 5 N loaded image and each of the others were measured, from which normalized average principal strains were quantified in both tendons. RESULTS: The observed effect on infraspinatus tendon strain paralleled that observed on strain in the supraspinatus tendon. Introducing a supraspinatus tendon partial-thickness tear and increasing load caused an increase in normalized average maximum and a decrease in normalized average minimum principal strain in the infraspinatus tendon. Increasing rotation angle from internal to external rotation caused a general decrease in normalized average maximum and increase in normalized average minimum principal strain in both tendons. CONCLUSION: The supraspinatus and infraspinatus tendons mechanically interact for the intact and partially torn supraspinatus tendons for neutral and rotated glenohumeral joint.


Asunto(s)
Rango del Movimiento Articular/fisiología , Lesiones del Manguito de los Rotadores , Lesiones del Hombro , Esguinces y Distensiones/fisiopatología , Traumatismos de los Tendones/fisiopatología , Fenómenos Biomecánicos , Humanos , Rotación , Manguito de los Rotadores/fisiopatología , Rotura , Articulación del Hombro/fisiopatología , Índices de Gravedad del Trauma
7.
J Shoulder Elbow Surg ; 18(5): 689-96, 2009.
Artículo en Inglés | MEDLINE | ID: mdl-19278871

RESUMEN

HYPOTHESIS: The purpose of this study was to develop and validate a disease-specific appraisal method for patients with rotator cuff disorders. The Korean Shoulder Scoring System (KSS) includes 5 domains totalling 100 points: function, 30 points; pain, 20; satisfaction, 10; range of motion, 20; and muscle power, consisting of strength, 10; and endurance, 10. METHOD: The KSS was used to evaluate clinical outcomes of 430 patients with rotator cuff disorder for a period of 6 months postoperatively. RESULT: The KSS had an acceptable level of internal consistency (alpha = 0.840). The KSS scores also correlated strongly with the Constant scores (r = 0.802), but less so with the American Shoulder and Elbow Surgeons scores (r = 0.602) and the University of California Los Angeles shoulder scores (r = 0.573). A large effect size (r = 1.234) and a standardized response mean (r = 1.317) for KSS were evident at 6 months postoperatively. CONCLUSION: The KSS is a useful measurement tool that combines subjective and objective evaluations for shoulder function related to rotator cuff disorders.


Asunto(s)
Inestabilidad de la Articulación/diagnóstico , Rango del Movimiento Articular/fisiología , Manguito de los Rotadores/fisiopatología , Índice de Severidad de la Enfermedad , Dolor de Hombro/diagnóstico , Actividades Cotidianas , Adulto , Artroscopía/métodos , Femenino , Humanos , Corea (Geográfico) , Masculino , Persona de Mediana Edad , Fuerza Muscular/fisiología , Dimensión del Dolor , Examen Físico/métodos , Calidad de Vida , Reproducibilidad de los Resultados , Articulación del Hombro/fisiopatología , Dolor de Hombro/terapia , Sociedades Médicas
8.
Orthopedics ; 31(1): 74, 2008 01.
Artículo en Inglés | MEDLINE | ID: mdl-19292164

RESUMEN

This study examined the technique and outcome of arthroscopically assisted mini-deltopectoral rotator cuff repair. The mini-deltopectoral approach enables the repair of large or massive rotator cuff tears while preventing injury to the deltoid muscle and axillary nerve often caused by splitting and excessive traction during conventional mini-open repair. This technique also is useful in the repair of subscapularis tears and thus could extend the indications for mini-open repair.


Asunto(s)
Artroscopía/métodos , Músculos Pectorales/cirugía , Procedimientos de Cirugía Plástica/métodos , Lesiones del Manguito de los Rotadores , Manguito de los Rotadores/cirugía , Adulto , Anciano , Femenino , Humanos , Masculino , Persona de Mediana Edad , Resultado del Tratamiento
9.
J Orthop Res ; 36(12): 3318-3327, 2018 12.
Artículo en Inglés | MEDLINE | ID: mdl-30175855

RESUMEN

Various types of suture anchor designs are currently available for rotator cuff repair. The purpose of our study was to investigate the pullout strength of such anchors based on their structural design and the predominant geometric design factors affecting the pullout strength using finite element analysis. Finite element models were constructed using five cadaveric humeri and ten suture anchors with different designs. The pullout strength and distribution of bone stress around the anchor at three different directions of the applied force (0°, 45°, and 75°) were analyzed. The following geometric factors of suture anchor design were computed and their correlations with pullout strength assessed: Overall length, minor, and major diameters; number of threads; height of thread; distance between threads; helix angle; contact surface area between the anchor threads and surrounding bone; contact surface area between the cylindrical portion of the anchor; and surrounding bone and total contact surface area between the anchor and surrounding bone. The pullout strength and distribution of bone stress around the anchor varied according to the suture anchor designs and the direction of the applied force, respectively. The pullout strength had a strong positive correlation with the contact surface area between the anchor threads and surrounding bone, overall length, and the number and height of threads. This study demonstrated that suture anchor designs with increased contact surface area between the anchor threads and surrounding bone, overall length, and the number and height of threads can enhance the pullout strength during rotator cuff repair. © 2018 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:3318-3327, 2018.


Asunto(s)
Manguito de los Rotadores/cirugía , Anclas para Sutura , Fenómenos Biomecánicos , Femenino , Análisis de Elementos Finitos , Humanos , Persona de Mediana Edad , Estrés Mecánico
10.
J Orthop Res ; 34(6): 1061-8, 2016 06.
Artículo en Inglés | MEDLINE | ID: mdl-26621211

RESUMEN

Glenoid component fixation with inferior tilt has been suggested as one of the surgical methods to decrease scapular notching and improve stability, but its clinically beneficial effect remains a concern. We evaluated the influence of inferior tilt fixation of the glenoid component on primary stability in reverse total shoulder arthroplasty by finite element analysis. Finite element models were constructed from cadaveric scapulae of females over the age of 60 years and glenoid components from reverse total shoulder arthroplasty. The relative micromotion at the bone-glenoid component interface, distribution of bone stress under the glenoid component and around the screws, contact area between the bone and screws, and cut surface area of the cancellous bone exposed after glenoid reaming were analyzed and compared between a neutral and 10° inferior tilt fixation of the glenoid component. The 10° inferior tilt fixation demonstrated greater relative micromotion and higher bone stress than the neutral tilt fixation. Eccentric reaming, which is done to produce the inferior tilt fixation of the glenoid component, increased glenoid cancellous bone exposure and decreased bone-screws contact area. Inferior tilt fixation of the glenoid component may adversely affect primary stability and longevity after reverse total shoulder arthroplasty. © 2015 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 34:1061-1068, 2016.


Asunto(s)
Artroplastía de Reemplazo de Hombro/métodos , Anciano , Artroplastía de Reemplazo de Hombro/instrumentación , Tornillos Óseos , Análisis de Elementos Finitos , Humanos , Estrés Mecánico
11.
J Orthop Surg Res ; 9(1): 12, 2014 Mar 01.
Artículo en Inglés | MEDLINE | ID: mdl-24580752

RESUMEN

BACKGROUND: In vivo studies showing the effects of biologic healing-promoting factors on tendon-to-bone healing after rotator cuff repair have focused only on biologic healing-promoting factors and have not taken into consideration the effect of the carrier vehicle. Moreover, most studies have evaluated the healing process using different carrier vehicles, each of which may have specific effects on tendon healing. This may explain the large variability seen in outcomes in research studies. In this study, we investigated the effects of Poloxamer 407 as a carrier vehicle on rotator cuff healing at the repair site and compared it with those of a collagen sponge, which is a commonly used carrier vehicle. METHODS: Fifty-seven adult male Sprague-Dawley rats underwent detachment and immediate repair of the bilateral supraspinatus tendons. Rats were randomly assigned to three groups: repair only, repair with collagen sponge, and repair with Poloxamer 407. The repairs were evaluated at 1, 2, 4, and 8 weeks after surgery with histological analysis and biomechanical testing. RESULTS: At 4 weeks, more cellular organization, a greater number of collagen fibers, and increased maturity of collagen fibers were observed in the repair with Poloxamer 407 group than in the other groups. The repair with collagen sponge group had delayed development and collagen fiber maturation. Significant differences in the biomechanical properties were found between groups at 4 weeks. Stiffness in the case of the repair with Poloxamer 407 group was significantly higher than that in the repair with collagen sponge group. The modulus was significantly lower in the repair with collagen sponge group than in the repair only group. However, the use of Poloxamer 407 versus the collagen sponge did not significantly affect the biomechanical properties of the repaired tendons at 8 weeks. CONCLUSIONS: Carrier vehicles may have differing effects at the early stages of rotator cuff healing. The use of Poloxamer 407 as a carrier vehicle may be useful for promoting the early stages of healing and for maintaining the initial biomechanical properties of the repaired rotator cuff tendon.


Asunto(s)
Excipientes/farmacología , Poloxámero/farmacología , Manguito de los Rotadores/efectos de los fármacos , Traumatismos de los Tendones/tratamiento farmacológico , Cicatrización de Heridas/efectos de los fármacos , Animales , Colágeno/farmacología , Modelos Animales de Enfermedad , Masculino , Ratas , Ratas Sprague-Dawley , Lesiones del Manguito de los Rotadores
13.
J Biomech ; 43(4): 778-82, 2010 Mar 03.
Artículo en Inglés | MEDLINE | ID: mdl-19931082

RESUMEN

Due to inadequate healing, surgical repairs of torn rotator cuff tendons often fail, limiting the recovery of upper extremity function. The rat is frequently used to study rotator cuff healing; however, there are few systems capable of quantifying forelimb function necessary to interpret the clinical significance of tissue level healing. We constructed a device to capture images, ground reaction forces and torques, as animals ambulated in a confined walkway, and used it to evaluate forelimb function in uninjured control and surgically injured/repaired animals. Ambulatory data were recorded before (D-1), and 3, 7, 14, 28 and 56 days after surgery. Speed as well as step width and length were determined by analyzing ventral images, and ground reaction forces were normalized to body weight. Speed averaged 22+/-6 cm/s and was not affected by repair or time. Step width and length of uninjured animals compared well to values measured with our previous system. Forelimbs were used primarily for braking (-1.6+/-1.5% vs +2.5+/-0.6%), bore less weight than hind limbs (49+/-5% vs 58+/-4%), and showed no differences between sides (49+/-5% vs 46+/-5%) for uninjured control animals. Step length and ground reaction forces of the repaired animals were significantly less than control initially (days 3, 7 and 14 post-surgery), but not by day 28. Our new device provided uninjured ambulatory data consistent with our previous system and available literature, and measured reductions in forelimb function consistent with the deficit expected by our surgical model.


Asunto(s)
Modelos Animales de Enfermedad , Miembro Anterior/fisiopatología , Marcha , Lesiones del Manguito de los Rotadores , Manguito de los Rotadores/fisiopatología , Traumatismos de los Tendones/fisiopatología , Traumatismos de los Tendones/cirugía , Animales , Pie/fisiopatología , Humanos , Masculino , Ratas , Ratas Sprague-Dawley , Manguito de los Rotadores/cirugía , Estrés Mecánico , Resultado del Tratamiento
14.
J Bone Joint Surg Am ; 91(10): 2421-9, 2009 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-19797578

RESUMEN

BACKGROUND: Surgical repairs of torn rotator cuff tendons frequently fail. Immobilization has been shown to improve tissue mechanical properties in an animal model of rotator cuff repair, and passive motion has been shown to improve joint mechanics in animal models of flexor tendon repair. Our objective was to determine if daily passive motion would improve joint mechanics in comparison with continuous immobilization in a rat rotator cuff repair model. We hypothesized that daily passive motion would result in improved passive shoulder joint mechanics in comparison with continuous immobilization initially and that there would be no differences in passive joint mechanics or insertion site mechanical properties after four weeks of remobilization. METHODS: A supraspinatus injury was created and was surgically repaired in sixty-five Sprague-Dawley rats. Rats were separated into three postoperative groups (continuous immobilization, passive motion protocol 1, and passive motion protocol 2) for two weeks before all underwent a remobilization protocol for four weeks. Serial measurements of passive shoulder mechanics (internal and external range of motion and joint stiffness) were made before surgery and at two and six weeks after surgery. After the animals were killed, collagen organization and mechanical properties of the tendon-to-bone insertion site were determined. RESULTS: Total range of motion for both passive motion groups (49% and 45% of the pre-injury values) was less than that for the continuous immobilization group (59% of the pre-injury value) at two weeks and remained significantly less following four weeks of remobilization exercise. Joint stiffness at two weeks was increased for both passive motion groups in comparison with the continuous immobilization group. At both two and six weeks after repair, internal range of motion was significantly decreased whereas external range of motion was not. There were no differences between the groups in terms of collagen organization or mechanical properties. CONCLUSIONS: In this model, immediate postoperative passive motion was found to be detrimental to passive shoulder mechanics. We speculate that passive motion results in increased scar formation in the subacromial space, thereby resulting in decreased range of motion and increased joint stiffness. Passive motion had no effect on collagen organization or tendon mechanical properties measured six weeks after surgery.


Asunto(s)
Lesiones del Manguito de los Rotadores , Manguito de los Rotadores/cirugía , Traumatismos de los Tendones/rehabilitación , Traumatismos de los Tendones/cirugía , Animales , Modelos Animales de Enfermedad , Periodo Posoperatorio , Rango del Movimiento Articular , Ratas , Ratas Sprague-Dawley , Cicatrización de Heridas
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA