Wicking in a powder.

We investigate the wicking in granular media by considering layers of grains at the surface of a liquid and discuss the critical contact angle below which spontaneous impregnation takes place. This angle is found to be on the order of 55° for monodisperse layers, significantly smaller than 90°, the threshold value for penetrating assemblies of tubes. Owing to geometry, impregnating grains is more demanding than impregnating tubes. We also consider the additional effects of polydispersity and pressure on this wetting transition and discuss the corresponding shift observed for the critical contact angle.

Rolling ribbons.

We present the results of a combined experimental and theoretical investigation of rolling elastic ribbons. Particular attention is given to characterizing the steady shapes that arise in static and dynamic rolling configurations. In both cases, above a critical value of the forcing (either gravitational or centrifugal), the ribbon assumes a two-lobed, peanut shape similar to that assumed by rolling droplets. Our theoretical model allows us to rationalize the observed shapes through consideration of the ribbon's bending and stretching in response to the applied forcing.

[Value of puncture-arthrography in the diagnosis of infection of total hip arthroplasty]. / Intérêt de la ponction-arthrographie de hanche dans le diagnostic d'infection sur prothèse totale.

Arthrography with hip aspiration was performed in 143 patients with hip arthroplasties to determine its effectiveness as a technique for diagnosing infection. Thirty-three cases of infection were found. On 26 occasions the germ responsible was isolated in the joint fluid. In six other cases infection was revealed from cytologic or arthrographic findings, or from both. Only once was a diagnosis of infection not arrived at. In this series of patients, except in cases of evolutive inflammatory rheumatism, cytologic examination of the joint fluid was a discriminative factor in diagnosis. Hip aspiration arthrography had a sensitivity of 79 per cent for the diagnosis of infection in arthroplasty with isolation of the germ and a specificity of 100 per cent. The sensitivity of the diagnosis rose to 91% when any one of the following features was observed: leucocytosis of the joint fluid higher than 10,000 elements/mm3; presence of a fistula or of fistulization on arthrography; isolation of the germ in the joint fluid or the rinsing liquid.

[False images of foreign bodies of plant matter in the limbs of children. Apropos of 3 case reports]. / Masque trompeur des corps étrangers végétaux des membres chez l'enfant. A propos de trois observations.

Vegetal foreign bodies in the limbs cannot be demonstrated by X-ray examination and may lead to erroneous diagnosis. The answer should be given by surgical exploration, however, and this is particularly true for mobile foreign bodies in the joint, a high degree of suspicion is necessary at surgery. Three observations are presented in this paper which emphasize practical recommendations to perform without delay the simple efficient surgical procedure consisting in removal of the foreign body.

[Progressive tibial lengthening in children (author's transl)]. / L'allongement progressif du tibia chez l'enfant. A propos de 48 cas.

The authors have studied 38 "simple" tibial lengthenings and 10 "iterative" tibial lengthenings in children, with the use of an external rigid distractor. Four out of five of these lengthenings have been performed in cases of constitutional shortness. The authors got an average lengthening of 4,2 cm (that is 17,5 p. 100) for first procedure and 5,5 cm (16,5 p 100) for iterative ones. Consolidation has been obtained after about 3 months and free walking was authorized after 6 months for simple lenghtenings. These delays are longer (5 months and 6 and a half months) for iterative lengthenings. The bone and articular complications observed are closely linked to the technic used. The authors recommended the use of an external distractor of Wagner type, an oblique osteotomy with ample oblique section and extensive tenotomies and aponevrotomies. Out of the author's own experience, the most frequent complications were: delay in consolidations, especially in acquired shortness, and foot complications, especially frequent on those patients with previous alterations at that level. Progressive tibial lengthenings must be, of course, part of a complete program of length equalization of the inferior limbs and must however be preceded by the necessary surgery to obtain rightness and stabilisation of the knee, leg, ankle and foot before starting the required lengthening.

[Radiological appearances of osteochondritis of the hip in children]. / Aspects radiologiques de l'ostéochondrite de hanche chez l'enfant.

Radiological examinations are of primary importance in the diagnosis of osteochondritis of the hip in the children, and enable appropriate therapy to be selected. The classification described by Catterall is preferred to that of Taillard, which describes the classical stages of the disease, as it has prognostic value when frontal and profile hip x-rays are taken.

[Progressive femoral lengthening in children. Apropos of 36 cases]. / L'allongement progressif du fémur chez l'enfant. A propos de 36 cas.

The authors have analysed the result of femoral lengthening in 36 cases, 24 of them congenital. The technique, which is fully described, was that of progressive lengthening using external distraction either by the Judet or Wagner method. The average lengthening obtained was 18,3 p. 100 of the initial length of the femur--that is 5.2 centimetres on average. The bony and articular complications are described. The authors believe that, thanks to modifications of their technique, one femur should normally be able to be lengthened by 20 to 25 p. 100 in 30 days and should be solid in six months.

[Traumatic separation of the epiphysis of the lower end of the femur]. / Décollements épiphysaires traumatiques de l'extrémité inférieure du fémur

The authors have treated 28 cases of traumatic separation of epiphysis of the lower end of the femur. They have noted the particular severity of the initial trauma. The results were less satisfactory when the child was younger and when the plate was crashed. However, 4 cases of fractures in breech delivery had rather good results. The authors think that a good reduction is essential, either close reduction fixed by Kirchner's wires or open reduction when the former is impossible.

[Treatment of post-traumatic cubitus varus in children. A propos of 32 cases]. / Traitement du cubitus varus post-traumatique de l'enfant. A propos de 32 cas

The authors have reviewed 32 cases of severe varus deformity following supra-condylar fractures in childhood. The sequellae were mainly cosmetic, the function being preserved. All cases were treated by supra-condylar osteotomy fixed by screwing. The technique is described. The results were satisfactory in 20 cases.