Fracturas avulsivas tibiales del ligamento cruzado posterior fijadas con tornillos: un estudio clínico y radiológico / Screw fixation of posterior cruciate ligament tibial avulsion fractures: a clinical and radiographic study

OBJETIVO: Realizar la evaluación clínica, imagenológica y funcional de pacientes con fracturas avulsivas tibiales del ligamento cruzado posterior (FTALCPs) fijadas con tornillos canulados con técnica abierta. MÉTODOS: Los pacientes con FTALCP operados entre 2010 y 2017 fueron revisados retrospectivamente. Criterios de inclusión: fracturas agudas, desplazadas, test de cajón posterior grado III, lesiones combinadas de rodilla, seguimiento > 12 meses. Se excluyeron pacientes > 65 años, con FTALCPs bilaterales, lesiones del ligamento cruzado posterior (LCP) intrasustancia, test de cajón posterior grados I-II, fracturas expuestas, lesiones neurovasculares, y seguimientos < 12 meses. Objetivo primario: medir la estabilidad clínica mediante test de cajón posterior y radiografía de estrés arrodillada comparativa. Objetivos secundarios: nvaluar la consolidación en radiografías, complicaciones y funcionalidad con las escalas de Lysholm y Tegner. Resultados Se incluyeron 20 pacientes, con edad media de 41 años (rango: 32 a 61 años). El seguimiento promedio fue de 33,9 meses (rango: 12 a 82 meses). La estabilidad clínica mejoró en 93% (cajón posterior postoperatorio grados 0 y I) de los pacientes. La radiografía de estrés arrodillada mostró una diferencia promedio de 2,6 mm (rango: 0,1 mm a 6,8 mm) de traslación posterior al comparar con el lado sano. Todas las fracturas consolidaron. Siete pacientes presentaron complicaciones. El puntaje promedio de la escala de Lysholm al final del seguimiento fue de 85,17. El promedio preoperatorio del puntaje en la escala de Tegner no varió significativamente en comparación con el postoperatorio. CONCLUSIONES: La fijación de fracturas avulsivas tibiales del LCP con tornillos canulados con técnica abierta es efectiva en restaurar la estabilidad posterior y lograr la consolidación ósea. La funcionalidad clínica a mediano plazo es buena, a pesar del alto número de complicaciones y lesiones concomitantes. NIVEL DE EVIDENCIA: tipo IV.

OBJECTIVE: To report mid-term clinical, radiographic, and functional outcomes following open reduction and fixation of posterior cruciate ligament tibial avulsion fractures (PCLTAFs) with cannulated screws. METHODS: This is a retrospective analysis of patients with PCLTAF operated on from August 2010 to April 2017. Patients with acute fractures, with more than 2 mm of displacement and grade III on the posterior drawer test, combined or not to knee injuries, were included. Patients older than 65 years of age, with bilateral avulsion fractures, intrasubstance posterior cruciate ligament (PCL) lesions, stable grade-I to -II on the posterior drawer test, concomitant neurovascular injuries, mid-substance tears, open fractures, and less than 12 months of follow-up were excluded. Primary outcomes: the clinical stability was assessed using the posterior drawer test and a single comparative knee stress radiograph. Secondary outcomes: radiographic consolidation, complications, Lysholm score, and Tegner activity score. RESULTS: In total, 20 patients with a mean age of 41 years (range: 32 to 61 years) were included. The mean follow-up was of 33.9 months (range: 12 to 82 months). Clinical stability (grade 0 or I on the posterior drawer test) was observed in 93% of the patients. The mean difference in contralateral posterior displacement was of 2.6 mm (range: 0.1 mm to 6.8 mm) on a single comparative knee stress radiograph. All fractures presented radiological consolidation. Seven patients developed complications. The mean Lysholm score at the last follow-up visit was of 85.17. The postoperative Tegner activity scores did no vary significantly compared to the preinjury scores. CONCLUSIONS: Cannulated screw fixation of a displaced PCLTAF through a posterior approach restores clinical and radiographic stability and has excellent union rates. The mid-term functional outcomes are good despite the high rates of combined knee lesions and postoperative complications. LEVEL OF EVIDENCE: IV.

Modelo predictivo de la no unión de tibia / Tibia non union predictive model

OBJETIVOS: Estimar un modelo predictivo para la no-unión en pacientes que presentan fractura de tibia. MATERIALES Y MÉTODOS: Estudio de cohorte retrospectivo, en pacientes con fractura de tibia operadas entre 2012 y 2018, con un mínimo de 12 meses de seguimiento, excluyendo amputaciones traumáticas. Realizamos un modelo de regresión logística con 13 variables descritas en la literatura. Se descartaron las variables estadísticamente no significativas y las que no causaban efecto de confusión. Se evaluó la bondad de ajuste mediante el test de Hosmer-Lemeshow y la discriminación del modelo con la curva ROC. RESULTADOS: Se incluyeron 411 fracturas de tibia, las variables estadísticamente significativas fueron: exposición ósea OR » 2,57(IC:1,15­5,75, p » 0,022), diabetes OR » 3,29 (IC:1,37­7,91, p » 0,008) y uso de tutor externo OR » 1,77(IC:0,81­3,85), el que tuvo efecto de confusión. La bondad de ajuste demostró que los datos se ajustan adecuadamente al modelo (p » 0,35). La curva ROC demuestra un 70,91% de poder discriminatorio. Al evaluar aisladamente las fracturas expuestas, no hubo asociación estadísticamente significativa con ninguna variable. DISCUSIÓN: Al evaluar el modelo, obtuvimos una asociación estadísticamente significativa entre: no unión, exposición ósea, diabetes y uso de tutor externo, información concordante con la literatura. Al estudiar el subgrupo de fracturas expuestas, las demás variables son estadísticamente no significativas. Eso refleja que la exposición ósea es la variable que confiere mayor riesgo. El seguimiento adecuado de esos pacientes es fundamental dado este alto riesgo de evolucionar con no-unión. CONCLUSIÓN: En nuestra serie, la exposición ósea es el factor de riesgo más importante para presentar no unión de tibia.

OBJECTIVES: Estimate a predictive model for non-union in patients presenting with a tibial fracture. MATERIALS AND METHODS: Retrospective cohort study in patients with tibia fractures operated between 2012 and 2018, with a minimum follow-up of 12 months, excluding traumatic amputations. We performed a multivariate logistic regression model with 13 variables described in the literature. The variables that were statistically non-significant and those variables that do not cause confusion, were discarded. Goodness of fit was evaluated using the Hosmer-Lemeshow test and the discrimination of the model with the ROC curve. RESULTS: 411 tibial fractures were included, the statistically significant variables were: bone exposure OR » 2.57(CI:1.15­5.75, p » 0.022), diabetes OR » 3.29(CI:1.37­7.91, p » 0.008) and use of external fixation OR » 1.77(CI:0.81­3.85), being included in the model because of its confounding effect. Goodness of fit demonstrates that the data fit the model adequately(p » 0.35). The ROC curve demonstrates 70.91% discriminatory power. When evaluating the exposed fractures in isolation, there was no statistically significant association with any variable. DISCUSSION: When evaluating the model, we obtained a statistically significant association between non-union, bone exposure, diabetes and use of external fixation, being consistent with the literature. When studying the subset of exposed fractures, the other variables are statistically non-significant. This reflects that bone exposure is the variable that confers the greatest risk. Proper follow-up of these patients is essential given this high risk of evolving with non-union. CONCLUSION: In our series, bone exposure is the most important risk factor for presenting tibial non-union.

Seudoartrosis atrófica: Efecto de la aplicación de ondas de choque extracorpóreas en un modelo experimental en tibia de conejos / Atrophic pseudoartrosis. Effect of extracorporeal shock waves application in an experimental model in tibia of rabbits

Introducción: Los efectos de las ondas de choque extracorpóreas se han investigado en osteoblastos humanos, focos fracturarios, seudoartrosis y células periósticas. Los mejores resultados del tratamiento de la seudoartrosis con ondas de choque extracorpóreas se han documentado para seudoartrosis hipertróficas. El objetivo de este estudio fue investigar el efecto de la terapia con ondas de choque extracorpóreas sobre un foco de seudoartrosis "atrófica" generado en tibia de conejo. Métodos: Se establecieron tres grupos: A, fracturados sometidos a ondas de choque extracorpóreas; B ("control"), fracturados no sometidos a ondas de choque y C, no fracturados (pierna derecha). Se trataron 37 conejos (cuniculus NV) blancos y esqueléticamente maduros de Nueva Zelanda. Se practicó la cauterización del periostio con electrobisturí bipolar en una extensión de 20 mm, en ambos muñones óseos (proximal y distal). Luego se aplicaron ondas de choque extracorpóreas en una sola sesión. Se realizaron tinciones con hematoxilina-eosina. Se efectuó el análisis biomecánico con un método de carga a "3 puntos". Se estudiaron la carga máxima aplicada y el módulo de elasticidad para cada grupo. Resultados: El estudio histológico permitió registrar signos de consolidación -callo fracturario perióstico y endostal- considerablemente mayores en las tibias de los animales del grupo A (tratado con ondas de choque extracorpóreas) que en las del grupo B "control". Conclusión: En un modelo experimental original de seudoartrosis atrófica generada por electrocauterización en tibia de conejos, se registraron cambios significativos radiográficos e histológicos luego de la intervención del foco mediante ondas de choque extracorpóreas. Nivel de Evidencia: II

Introduction: The effects of extracorporeal shock wave therapy (ESWT) have been investigated in human osteoblasts, fracture foci, nonunion and periosteum cells. The best results of nonunion treatment with ESWT have been documented for hypertrophic type. The objective of this study was to investigate the effects of ESWT in an atrophic nonunion focus generated in a rabbit tibia model. Methods: Three groups were included: A, fractures receiving ESWT; B ("control"), fractures not receiving ESWT, and C, no fractures (right leg). A total of 37 New Zealand white and skeletally mature rabbits (cuniculus NV) were treated. Periosteum was cauterized using bipolar electrocautery at 20 mm in both bone stumps (proximal and distal). Then ESWT was applied in one session. Staining with hematoxylin-eosin was used. A biomechanical analysis with a 3-point loading system was performed. Maximum load and elastic modulus were evaluated in each group. Results: Histological study evidenced signs of union (periosteal and endosteal fracture callus) which were considerably larger in tibias of Group A (treated with ESWT) as compared to the control group (Group B). Conclusion: In an experimental model of atrophic pseudarthrosis caused by electrocautery in tibias of rabbits, significant radiographic and histological changes were observed after focus intervention with the application of ESWT. Level of Evidence: II

Analysis of fracture healing in osteopenic bone caused by disuse: experimental study

Osteoporosis has become a serious global public health issue. Hence, osteoporotic fracture healing has been investigated in several previous studies because there is still controversy over the effect osteoporosis has on the healing process. The current study aimed to analyze two different periods of bone healing in normal and osteopenic rats. Sixty, 7-week-old female Wistar rats were randomly divided into four groups: unrestricted and immobilized for 2 weeks after osteotomy (OU2), suspended and immobilized for 2 weeks after osteotomy (OS2), unrestricted and immobilized for 6 weeks after osteotomy (OU6), and suspended and immobilized for 6 weeks after osteotomy (OS6). Osteotomy was performed in the middle third of the right tibia 21 days after tail suspension, when the osteopenic condition was already set. The fractured limb was then immobilized by orthosis. Tibias were collected 2 and 6 weeks after osteotomy, and were analyzed by bone densitometry, mechanical testing, and histomorphometry. Bone mineral density values from bony calluses were significantly lower in the 2-week post-osteotomy groups compared with the 6-week post-osteotomy groups (multivariate general linear model analysis, P<0.000). Similarly, the mechanical properties showed that animals had stronger bones 6 weeks after osteotomy compared with 2 weeks after osteotomy (multivariate general linear model analysis, P<0.000). Histomorphometry indicated gradual bone healing. Results showed that osteopenia did not influence the bone healing process, and that time was an independent determinant factor regardless of whether the fracture was osteopenic. This suggests that the body is able to compensate for the negative effects of suspension.

Diabetes mellitus affects the biomechanical function of the callus and the expression of TGF-beta1 and BMP2 in an early stage of fracture healing

Transforming growth factor beta 1 (TGF-β1) and bone morphogenetic protein-2 (BMP-2) are important regulators of bone repair and regeneration. In this study, we examined whether TGF-β1 and BMP-2 expressions were delayed during bone healing in type 1 diabetes mellitus. Tibial fractures were created in 95 diabetic and 95 control adult male Wistar rats of 10 weeks of age. At 1, 2, 3, 4, and 5 weeks after fracture induction, five rats were sacrificed from each group. The expressions of TGF-β1 and BMP2 in the fractured tibias were measured by immunohistochemistry and quantitative reverse-transcription polymerase chain reaction, weekly for the first 5 weeks post-fracture. Mechanical parameters (bending rigidity, torsional rigidity, destruction torque) of the healing bones were also assessed at 3, 4, and 5 weeks post-fracture, after the rats were sacrificed. The bending rigidity, torsional rigidity and destruction torque of the two groups increased continuously during the healing process. The diabetes group had lower mean values for bending rigidity, torsional rigidity and destruction torque compared with the control group (P<0.05). TGF-β1 and BMP-2 expression were significantly lower (P<0.05) in the control group than in the diabetes group at postoperative weeks 1, 2, and 3. Peak levels of TGF-β1 and BMP-2 expression were delayed by 1 week in the diabetes group compared with the control group. Our results demonstrate that there was a delayed recovery in the biomechanical function of the fractured bones in diabetic rats. This delay may be associated with a delayed expression of the growth factors TGF-β1 and BMP-2.

A comparative in vivo ultrasonometric evaluation of normal and delayed fracture healing in sheep tibiae

OBJECTIVE: To compare normal and delayed bone healing by measuring ultrasound conduction velocity across the bone callus. METHODS: A model of transverse linear and 5 mm resection osteotomies of sheep tibiae was used. Fourteen sheep were operated on and were divided into two groups of seven according to osteotomy type. The procedure was performed on the right tibiae and the intact left tibiae were used as controls. The transverse and axial ultrasound velocities were measured at 30-day intervals for 90 days, after which the animals were killed and both the right and left tibiae were resected for in vitro biomechanical analysis. RESULTS: Both the transverse and axial ultrasound velocities progressively increased, but the increase was smaller for the delayed union that resulted from the resection osteotomy. The mechanical resistance was higher for the normally healed tibiae that resulted from a linear osteotomy; this result closely correlated with the ultrasound velocity results. Significant differences were found for the comparisons between the intact and operated tibiae in both groups and between the groups for both the transverse and axial ultrasound velocities, but the differences were greater for the latter. CONCLUSION: We conclude that in vivo transverse and axial ultrasound velocities provide highly precise information about the healing state of both linear and resection diaphyseal osteotomies, but the axial ultrasound velocity most likely has greater discriminatory power. This method has the potential for clinical application in humans. .

Biomechanical Analysis of Operative Methods in the Treatment of Extra-Articular Fracture of the Proximal Tibia

BACKGROUND: To determine relative fixation strengths of a single lateral locking plate, a double construct of a locking plate, and a tibial nail used in treatment of proximal tibial extra-articular fractures. METHODS: Three groups of composite tibial synthetic bones consisting of 5 specimens per group were included: lateral plating (LP) using a locking compression plate-proximal lateral tibia (LCP-PLT), double plating (DP) using a LCP-PLT and a locking compression plate-medial proximal tibia, and intramedullary nailing (IN) using an expert tibial nail. To simulate a comminuted fracture model, a gap osteotomy measuring 1 cm was created 8 cm below the knee joint. For each tibia, a minimal preload of 100 N was applied before loading to failure. A vertical load was applied at 25 mm/min until tibial failure. RESULTS: Under axial loading, fixation strength of DP (14,387.3 N; standard deviation [SD], 1,852.1) was 17.5% greater than that of LP (12,249.3 N; SD, 1,371.6), and 60% less than that of IN (22,879.6 N; SD, 1,578.8; p < 0.001, Kruskal-Wallis test). For ultimate displacement under axial loading, similar results were observed for LP (5.74 mm; SD, 1.01) and DP (4.45 mm; SD, 0.96), with a larger displacement for IN (5.84 mm; SD, 0.99). The median stiffness values were 2,308.7 N/mm (range, 2,147.5 to 2,521.4 N/mm; SD, 165.42) for the LP group, 4,128.2 N/mm (range, 3,028.1 to 4,831.0 N/mm; SD, 832.88) for the DP group, and 5,517.5 N/mm (range, 3,933.1 to 7,078.2 N/mm; SD, 1,296.19) for the IN group. CONCLUSIONS: During biomechanical testing of a simulated comminuted proximal tibial fracture model, the DP proved to be stronger than the LP in terms of ultimate strength. IN proved to be the strongest; however, for minimally invasive osteosynthesis, which may be technically difficult to perform using a nail, the performance of the DP construct may lend credence to the additional use of a medial locking plate.

Alloxan-induced diabetes delays repair in a rat model of closed tibial fracture

A closed fracture was performed on the left tibia of 3-month-old Wistar rats weighing 250 to 350 g that were either healthy (N = 24) or made diabetic with alloxan (N = 24) to investigate the effect of alloxan-induced diabetes on the course of bone fracture healing. Histomorphometric analysis of the fracture site was performed at 7, 14, 25, and 35 days. After 7 days, diabetic rats had significantly less cartilage (P = 0.045) and greater fibrous connective (P = 0.006) tissue formation at the fracture site compared to controls. In contrast, marked callus formation was seen in diabetic rats with significant osteogenesis (P = 0.011, P = 0.010, P = 0.010, respectively, for 14, 25, and 35 days) and chondrogenesis (P = 0.028, P = 0.033, P = 0.019) compared to controls. Radiographic analysis revealed a displaced fracture with poor bone fragment alignment and delayed consolidation at these times in the diabetic group. The levels of alkaline phosphatase were significantly higher in diabetic rats at 25 days (P = 0.009). These results suggest that the initial excessive formation of fibrous connective tissue associated with delay in chondrogenesis and osteogenesis may not provide suitable stability of the fractured site, contributing to the inappropriate alignment of fragments and an increase in the volume of callus in later stages of repair. The resulting displaced fracture in diabetic rats requires long periods for remodeling and complete bone consolidation.

Estudo do desvio rotacional da tíbia / Study of the tibial rotational deviation

OBJETIVO: avaliar o desvio rotacional pós-operatório das fraturas diafisárias da tíbia de pacientes tratadas com haste intramedular bloqueada não-fresada e placa em ponte, utilizando a tomografia computadorizada. MÉTODOS: foram tratados 113 pacientes com fraturas diafisárias da tíbia, sendo que em 42 fraturas os autores utilizaram haste intramedular bloqueada e em 71 foram utilizadas placa em ponte. O método tomográfico utilizado ara se obter as medidas da rotação tibial. Foi empregada a classificação AO das fraturas; à exposição: fechadas e expostas e a percentagem de desvios em rotação interna e externa. RESULTADOS: foi demonstrado não haver diferença significativa de rotação tibial nos seguintes parâmetros analisados: localização, rotação interna ou externa e nos tipos A e B da classificação AO. Porém, nas fraturas do tipo C e nas fraturas expostas, a haste intramedular bloqueada apresentou diferença rotacional significativamente menor (p = 0,028) e (p = 0,05), quando comparada à placa em ponte. CONCLUSÃO: independente da localização das fraturas diafisárias da tíbia, os desvios rotacionais estão relacionados à energia do trauma, apresentando uma maior dificuldade de controle com a técnica placa em ponte.

OBJECTIVE: to evaluate the postoperative rotational deviation of diaphyseal tibial fractures in patients treated with non-reamed, interlocking intramedullary nailing and bridge plate, using computerized tomography for measurement. METHOD: one hundred and thirteen patients with diaphyseal tibial fractures were treated; 42 fractures were treated with non-reamed, interlocking intramedullary nailing, and 71 fractures were treated with bridge plate. Tibial rotation measurements were obtained by using the CT scan. All of the fractures were classified by the AO scale, by their presentation (closed and open) and the percentage of deviation on internal and external rotation. RESULTS: no significant difference in tibial rotation was found as a function of fracture location, internal or external rotation, and types A or B of fractures. However, in the case of type C fractures and open fractures, the treatment with non-reamed, interlocking intramedullary nailing resulted in a much smaller rotation in comparison to the treatment with bridge plate (p = 0.028 and p = 0.05, respectively). CONCLUSIONS: rotational deviations, regardless of the location of the diaphyseal tibial fractures, are associated to the trauma energy, thus presenting a greater challenge to control it by using the bridge plate.

Pulsed electromagnetic fields for the treatment of bone fractures.

The effectiveness of electrical stimulation and Pulsed Electro Magnetic Field (PEMF) stimulation for enhancement of bone healing has been reported by many workers. The mechanism of osteogenesis is not clear, therefore, studies look for empirical evidence. The present study involved a clinical trial using low amplitude PEMF on 19 patients with non-union or delayed union of the long bones. The pulse system used was similar in shape to Bassett's single pulse system where the electric voltage pulse was 0.3 mSec wide repeating every 12 mSec making a frequency of about 80 Hz. The peak magnetic fields were of the order of 0.01 to 0.1 m Tesla, hundred to thousand times smaller than that of Bassett. Among the 13 who completed this treatment schedule the history of non-union was an average of 41.3 weeks. Within an average treatment period of 14 weeks, 11 of the 13 patients had successful bone healing. The two unsuccessful cases had bone gaps greater than 1 cm following removal of dead bone after infection. However, use of such a low field negates Bassett's claim for a narrow window for shape and amplitude of wave form, and justifies further experimental study and an attempt to understand the underlying mechanism.

Fijadores externos tubulares en las fracturas expuestas de la tibia / Tubular external fixators for treatment of open tibial fractures

Se presentan los casos de 82 pacientes con fractura expuesta de la tibia que ingresaron al Servicio de Fracturas Expuestas del Hospital de Traumatología ®Magdalena de las Salinas¼ de enero a diciembre de 1993, y que fueron tratados con fijadores externos tubulares. La región anatómica mayormente afectada fue la diafisaria con 48 casos, la configuración del fijador más utilizada fue la uniplanar no transfictiva en 50 tibias, el tipo de exposición que se encontró con mayor frecuencia fue el III A 2 con 42 casos, se aplicó injerto óseo en 68 tibias, el tiempo promedio de dinamización del fijador fue a las 13 semanas, con un índice de infección de 6.9 por ciento; concluyendo que los fijadores externos deben ser utilizados en la estabilidad primaria de las fracturas expuestas graves y cuando por el tipo de fractura éste así lo requiera

Evaluación del tratamiento de las fracturas diafisarias de tibia con enclavado endomedular fresado y encerrojado a cielo cerrado con clavos / Evaluation of the processing of the diafisarias fractures of tibia with eclavado to endomedular milling and blocked to sky closed with nails

La cantidad de variantes en el tratamiento de fracturas de la diáfisis tibial a pesar de los adelantos en a asistencia operatoria y no operatoria indican que no se ha llegado a un consenso que nos refiera el tratamiento ideal, creemos que su tratamiento demanda diferentes maneras de encarar el mismo problema conforme a las distintas circunstancias. El presente es un estudio descriptivo con observación indirecta de fuente documental aplicando técnicas extensivas, realizado en 70 pacientes, entre Enero de 1992 y Diciembre de 1993 que ingresaron al servicio de Ortopedia y Traumatología del Hospital Carlos Andrade Marín con diagnóstico de fractura diafisaria de tibia, los mismos que fueron tratados con enclavado endomedular fresado y encerrojado a cielo cerrado con clavos AO y Grosse-Kempf observándose una consolidación temprana (84,8 20,1 días), sin importar el tipo de fractura, la edad o el sexo del paciente, aunque este se prolonga en presencia de infección. Se encontró un bajo índice de complicaciones tanto intra como postoperatorias, independientemente del tipo de fractura tratada, además de un tiempo de incapacidad laboral corto (63,5 17,2 días) independientemente de la edad, sexo o tipo de fractura (p 0,05). En base a los resultados obtenidos en los pacientes objeto de este trabajo, el empleo de esta técnica en los mismos, aseguró un tiempo de consolidación corto, un bajo índice de complicaciones intra y postoperatorias así como una integración temprana a las actividades laborales, resultados que concuerdan con los obtenidos por Koval KJ. et al en 1991 y Kempf y col. quien revisó 397 fracturas tratadas con clavo Grosse-Kempf en Francia...

Avaliaçäo da resistência óssea com e sem a administraçäo prévia de calcitonina de salmäo em ratos com desnutriçäo protéica / Evaluation of osseous resistance with and without previous adminsitration of salmon calcitonin in rats with proteic malnutrition

Foi realizado trabalho experimental com ratos da raça Wistar para avaliar a influência da calcitonina de salmao e da desnutriçao protéica, isoladas e associadas, na resistência mecânica e na rigidez do tecido ósseo. Os ratos foram divididos em quatro grupos: dieta normal, dieta normal mais calcitonina, desnutridos, desnutridos mais calcitonina. Após duas semanas, foram submetidos a fratura manual da tíbia direita e, ao término de seis semanas, sacrificados. Foram avaliados os parâmetros mecânicos de resistência e rigidez óssea das tíbias fraturadas e nao fraturadas (controle) dos quatro grupos. Concluiu-se que: a administraçao de calcitonina reduziu a resistência máxima das tíbias-controle do grupo com dieta normal; a resistência e rigidez das tíbias fraturadas (processo de consolidaçao) e controle (processo de remodelaçao) foram prejudicadas pela desnutriçao protéica; no grupo desnutrido, a administraçao de calcitonina nao compensou a diminuiçao da resistência e da regidez das tíbias, mas reduziu a ocorrência de pseudartrose.

Effect of pulsed electromagnetic field on healing of experimental nonunion in rat tibiae.

To see the effect of Pulsed Electromagnetic Field (PEMF) on nonunited fracture healing, nonunion was induced in rat tibiae and PEMF was applied on it. Out of five different techniques utilised for inducing nonunion soft tissue interposition was found to be the most suitable and effective method of experimental induction of nonunion. Twenty eight experimental and 15 control rats were finally evaluated for the effect of PEMF applied for up to 8 weeks. After sacrifice of 8 experimental and 4 controls, 6 experimental and 3 controls, again 6 experimental and 3 controls and finally 8 experimental and 5 controls at 2, 4, 6 and 8 weeks respectively of PEMF application no significant difference as to the quality of healing was observed between the experimental and control animals. It was thus concluded that PEMF appeared to have no beneficial effect on the healing of nonunited fractures in experimental set-up.