RESUMEN
The purpose of this study was to determine whether the mechanical properties of the rat anterior cruciate ligament (ACL) vary when tested in vitro at different stages of the estrous cycle. Sixty female rats were allocated to four groups according to their stage of the estrous cycle: diestrus (n=16), proestrus (n=17), estrus (n=13) and metestrus (n=14). Right hindlimbs were harvested for mechanical testing and left hindlimbs were harvested for immunohistochemical staining to confirm the presence of the estrogen receptor. Results from the first relaxation test showed a significant difference between the estrus and proestrus stage, which was not observed in a second subsequent relaxation test. Likewise, no significant differences were found when comparing failure load and stiffness between the different stages of the estrous cycle. These results suggest that normal physiological fluctuations in estrogen during the estrous cycle did not alter the failure properties of the rat ACL.
Asunto(s)
Ligamento Cruzado Anterior/fisiopatología , Ciclo Estral/fisiología , Animales , Ligamento Cruzado Anterior/metabolismo , Receptor alfa de Estrógeno/metabolismo , Femenino , Miembro Posterior/fisiología , Inmunohistoquímica , Técnicas In Vitro , Ratas , Ratas Sprague-Dawley , Estrés Mecánico , Soporte de Peso/fisiologíaRESUMEN
In ACL reconstruction, stiffness and strength of a tendon graft complex are important features for knee stability and rehabilitation. The fixation between tendon and bone is known to be one of the weakest components of the graft complex. We examined the tensile load-displacement characteristics of looped semitendinosus tendons in a porcine femoral tunnel. Two groups of six cadaveric semitendinosus tendons and porcine femurs were tested, secured with either an aperture or non-aperture fixation method. Constructs were tested at 1 mm/s until failure in a materials testing machine, which allowed force and displacement data to be recorded. The non-aperture fixation group was significantly less stiff for the first 4 mm of displacement and had significantly higher ultimate failure loads. Provided that adequate ultimate strength can be achieved, stiffness properties of a tendon graft will be improved by using aperture fixation in femoral-site ACL reconstruction.
Asunto(s)
Ligamento Cruzado Anterior/cirugía , Fémur/cirugía , Traumatismos de la Rodilla/cirugía , Procedimientos de Cirugía Plástica/métodos , Tendones/trasplante , Animales , Fenómenos Biomecánicos , Técnicas In Vitro , Porcinos , Resistencia a la TracciónRESUMEN
Deficiency of the anterior cruciate ligament (ACL) is a common disorder which can lead to changes in lifestyle. We followed 59 patients who had had arthroscopic reconstruction of the ACL using a central-third patellar-tendon autograft for seven years to assess the long-term effectiveness of recent advances in reconstruction of the ACL. The standard criteria for evaluation of the International Knee Documentation Committee, the Lysholm knee score and measurements using the KT 1000 arthrometer all showed satisfactory results. Deterioration in the clinical performance after seven years was associated with osteoarthritic changes and correlated with chronic ligament injuries and meniscectomy. There were three traumatic and three spontaneous ruptures. We believe that the procedure can be successful, but remain concerned about failure of the graft and osteoarthritis. The results raise questions about the best time to operate and suggest that early surgery may reduce the risk of osteoarthritis.
Asunto(s)
Lesiones del Ligamento Cruzado Anterior , Ligamento Cruzado Anterior/trasplante , Artroscopía/métodos , Fijación Interna de Fracturas/métodos , Inestabilidad de la Articulación/complicaciones , Traumatismos de la Rodilla/terapia , Rótula/cirugía , Adolescente , Adulto , Ligamento Cruzado Anterior/fisiopatología , Tornillos Óseos , Tirantes , Femenino , Estudios de Seguimiento , Fijación Interna de Fracturas/instrumentación , Humanos , Inestabilidad de la Articulación/terapia , Articulación de la Rodilla/diagnóstico por imagen , Articulación de la Rodilla/fisiopatología , Masculino , Meniscos Tibiales/diagnóstico por imagen , Persona de Mediana Edad , Radiografía , Rango del Movimiento Articular , Recurrencia , Reoperación , Rotura/terapia , Rotura Espontánea/etiología , Rotura Espontánea/terapia , Tendones/trasplante , Lesiones de Menisco Tibial , Trasplante Autólogo , Resultado del TratamientoRESUMEN
Anterior cruciate ligament (ACL) reconstruction using four-strand hamstring graft with round-headed, cannulated, interference (RCI) screw fixation requires osteointegration of the tendon graft. This report describes the histology at the bone-tendon junction of two specimens retrieved from patients undergoing revision surgery after traumatic mid-substance ACL graft rupture at 6 and 10 weeks after initial reconstruction. Revision was performed at 12 and 15 weeks. Integration of the graft was evident by observation of collagen fiber continuity between bone and tendon. This histology plus the low incidence of early graft failure suggest that free tendon autograft attached to bone by RCI screw allows adequate osteointegration between 6 and 15 weeks after surgery.
Asunto(s)
Ligamento Cruzado Anterior/cirugía , Oseointegración/fisiología , Tendones/trasplante , Ligamento Cruzado Anterior/fisiología , Lesiones del Ligamento Cruzado Anterior , Tornillos Óseos , Humanos , Reoperación , Tendones/fisiología , Trasplante AutólogoRESUMEN
Three children with hydatid disease of the central nervous system (CNS) were seen. In two patients the lateral ventricles were involved, whilst one case involved the cerebellar hemisphere. In addition, one child presented with a deposit in the maxillary antrum, and deposits were also found in the liver. Operative removal of the deposits was performed, followed by post-operative treatment with praziquantel and albendazole. Investigation of other sites outside the CNS was undertaken for occult lesions. All hydatid cysts were clearly demonstrated on CT, but two cases posed the pre-operative problem of differential diagnosis from arachnoid cysts.