RESUMEN
As there is evidence that ligamentous laxity is affected by the female hormones, we hypothesized that hormonal changes occurring during pregnancy could have a therapeutic role in preventing the development of a joint contracture. Knee joint contractures were created in pregnant and nonpregnant rats. After 2 wk of immobilization, the degree of contracture was measured with structural properties of the medial collateral and anterior cruciate ligaments and the pubic symphysis. Although not statistically significant, there was a general trend toward reduced contracture in pregnant compared with nonpregnant rats. Cutting the posterior capsule significantly decreased contracture for both the pregnant and nonpregnant groups, confirming the contribution of capsular structures to contracture. Ultimate loads of the medial collateral and anterior cruciate ligaments significantly decreased after immobilization compared with control, but there was no significant effect due to pregnancy. Stiffness and ultimate load of the pubic symphysis were not significantly different between pregnant and nonpregnant groups. The trend toward reduced contracture with pregnancy points toward a possible therapeutic role for female hormones in the prevention of postoperative and/or posttraumatic joint contracture.
Asunto(s)
Contractura/fisiopatología , Inmovilización/efectos adversos , Articulación de la Rodilla/fisiopatología , Preñez/fisiología , Animales , Ligamento Cruzado Anterior/fisiopatología , Fenómenos Biomecánicos , Contractura/etiología , Contractura/prevención & control , Estrógenos/metabolismo , Femenino , Inmovilización/fisiología , Ligamento Colateral Medial de la Rodilla/fisiopatología , Embarazo , Ratas , Ratas Sprague-Dawley , Relaxina/metabolismoRESUMEN
We investigated the effect of vitamin D receptor gene (VDRG) polymorphism on the responsiveness to 1,25(OH)2D3 in human osteoblast-like cells. The cells were obtained from the femoral heads of 18 women with osteoarthritis of the hip. Three different restriction enzymes, BsmI, ApaI, and TaqI, were used to analyse the polymorphism. The genotypes of the 18 patients were bbAaTT (8), bbaaTT (6), BbAaTt (3), and BbAATt (1). Our findings showed that there were no differences according to the VDR genotype, but there was a statistically significant difference in the production of osteocalcin between BbAaTt and bbAaTT, and between BbAaTt and bbaaTT. Northern blot analysis of osteocalcin and VDR mRNA showed no significant differences among the three VDR genotypes. These findings suggest that VDR gene polymorphism affects the individual responsiveness of 1,25(OH)2D3.
Asunto(s)
Alelos , Osteoblastos/metabolismo , Receptores de Calcitriol/genética , Anciano , Artroplastia de Reemplazo de Cadera , División Celular/genética , Femenino , Genotipo , Humanos , Persona de Mediana Edad , Osteoartritis de la Cadera/patología , Osteoartritis de la Cadera/cirugía , Polimorfismo Genético/genética , Esteroide Hidroxilasas/farmacologíaRESUMEN
A free patellar tendon-tibia autograft was performed to reconstruct a tendon insertion to bone of the canine infraspinatus. In this experimental study restoration of mechanical properties at tendon insertion to bone of the patellar tendon-tibia autograft was examined on 0, 42, and 84 postoperative days. Five dogs were used for each time point. Bone union occurred in all grafts by 6 postoperative weeks. The ultimate strength at the tendon insertion to bone recovered from 255.5 N on 0 day to 264.3 N and 439.3 N on 42 and 84 postoperative days, respectively. Stiffness recovered from 141.8 KN/m on 0 day to 201.8 KN/m and 226.3 KN/mN on 42 and 84 postoperative days, respectively. Our results demonstrate that patellar tendon-tibia autograft maintains excellent mechanical properties at tendon insertion to bone in the early healing period. This result suggests that transfer or free graft of tendons with attaching bone plug has a mechanical advantage for reconstruction of the rotator cuff, which may allow the patient to institute early postoperative mobilization.