[Analysis of restraint of the femur head. Experimental study of allograft of cold bone and autoclaved bone to kill the HIV virus]. / Analyse des contraintes de l'extrémité supérieure du fémur. Etude expérimentale allogreffes os congelés - os autoclaves en vue de la destruction du virus H.I.V.

The retrovirus S.I.A.D. grown in marrow bone and iatrogenic infections may be possible after bone graft in following total hip arthroplasties. Previous investigators proposed several methods to kill the virus, but without bacteriological safety. They found 20 to 55% of loss on mechanical properties. The present study reports the response of autoclaved femoral heads compression testing on material machine Model 1026 Instron. The stress response of marrow bone to stains showed a classic peak and with linear regression study we saw a relationship between autoclaved bone and cold bone. The cortical bone resists to strains highly 12% of load.

Biomechanics of the hip: forces exerted during walking.

Since the work of Pauwels, the forces exerted on the coxofemoral joint during walking have been studied either in different spatial planes (frontal, sagittal and horizontal) or by three-dimensional spatial analysis. Starting from the findings of our own studies, our aim was to compare the two methods of analysis (two-dimensional and three-dimensional) in order to provide a better understanding of the benefits and limitations of each method. In pursuit of this aim, we studied the pressure forces exerted on the coxofemoral joint, using a geometric plane technique following a method similar to that of Pauwels [20], and with a three-dimensional modelling technique using the finite element method. The material, taken from the published literature, was the same in both our studies. The results are expressed in terms of the size and orientation of the pressure force exerted on the coxofemoral joint during the monopodal weightbearing phase of walking. A comparison of these two methods of analysis clearly demonstrates the simplicity of two-dimensional analysis (which must incorporate as a minimum the frontal plane and the sagittal plane) and the richness of the three-dimensional analysis. The latter method, by appropriate manipulation of the information obtained, provides a starting point for computer simulations performed with the aim of testing a biomechanical or therapeutic hypothesis.

[Comparative mechanic resistance of frozen and irradiated spongy bone]. / Résistance mécanique comparative de l'os spongieux congelé et irradié.

The mechanical properties of 20 frozen (-30 degrees C) femoral heads are determined. 10 were treated by gamma radiations. It is noted that the rate of weakness of cancellous bone is 20%.

[Stress and quantification of pressures borne by the hip in unilateral support in the sagittal plane. I]. / Etude des sollicitations et quantification des pressions subies par la hanche en appui monopodal dans le plan sagittal.

Thanks to the works of Pauwels, the pressures sustained by the hip during unilateral weightbearing in the frontal plane are now well known and have given rise to a number of surgical applications. Considered as negligible by Pauwels, the sagittal plane has been little studied; in fact, with Pauwels' methodology, but taking into account the muscular moments, it appears that the forces exerted in the sagittal plane are far from being negligible and vary, according to the phase of weightbearing, from once the weight of the body (weightbearing on the sole) to two and a half times the weight of the body (weightbearing on the heel).

[Changes in the pressure borne by the hip during the phase of unilateral support in locomotion. II]. / Variation des pressions subies par la hanche durant la phase d'appui monopodal de la marche.

Adopting the methodology that we have just described, our study completes that of Pauwels in that we take into consideration the pressures sustained by the hip not only in the frontal plane but also in the horizontal and sagittal planes during the phase of unilateral weightbearing when walking. Thanks to the work of Braune and Fischer (1) the forces exerted on the hip are now well known and are represented by the weight of the body, the muscular forces and the dynamic forces generated by walking. From these data, we have been able to quantify the pressures sustained by the hip in each plane during the different phases of unilateral weightbearing when walking (weightbearing on heel, sole and toes).

Anatomical and functional study on the musculus semimembranosus.

The dissection of 18 knees taken from fresh cadavers has led to a detailed description of the semimembranosus muscle (musculus semimembranosus). It is exclusively tibial with its three tendons rendering the muscle functional, whatever the position of the knee may be. There are other attachments, sometimes described are merely expansions extending to the menisco-tibial and menisco-femoral formations, from which this distal termination must be distinguished. Electromyography performed on 17 specimens confirms that this muscle serves more as a brake on outer rotation than an inner rotator muscle, especially when the hip is flexed and the knee stretched.

Reciprocal angulation of vertebral bodies in a sagittal plane: approach to references for the evaluation of kyphosis and lordosis.

In order to establish a sagittal plane curve reference table for standing subjects examined laterally, we determined an easily reproducible standard posture. A sample of 100 healthy subjects from 20 to 29 years of age, was chosen (43 women, 57 men). The reciprocal angulations of each vertebral body in relation to the others were fed into a digitalizer and studied by computer. The study particularly concerns maximum kyphosis, maximum lordosis, sacral base slopes, and the tilt of intermediate vertebral bodies. The dispersion of the results is remarkably wide and, within the extreme values, the distribution is irregular. Individual correlations of these values are often dispersed, but spinal morphotypology. For considerable lengths, average values cannot be used as norms, given the wide span of values. Only the extreme limits are useful for the appreciation of curves as excessive, insufficient, or inverted.

[Resistance to traction of the periarticular ligaments and tendons of the knee]. / De la résistance à la traction des ligaments et tendons péri-articulaires du genou.

The authors present a methodical study concerning traction strength of the ligaments and the periarticular tendons of the knee. The straining potential and the mechanical strength of these elements are made clear. This study permits applications in chronic laxities of the knee by giving the mechanical value of the different kinds of tendon reconstruction.

[Anterior strut grafting in kyphosis and kyphoscoliosis (author's transl)]. / Greffes antérieures en étai dans le traitement des cyphoses et cyphoscolioses.

The authors have reviewed 58 cases submitted to strut grafting in the concavity of the curve. There were 44 kyphoscolioses and 12 kyphoses. The average follow-up was more than two years and the average pre-operative deformity was 127 degrees. The average improvement was 38 degrees and the secondary loss was only 3 degrees. The results are analysed with regard to the surgical technique used. In some cases, posterior fixation was added and the graft was either from the tibia, the fibula or a rib. In 16 cases a secondary fracture of the graft was found. It appeared between the fourth and tenth post-operative months. During this period, reduction of the graft was seen. The graft was found to thicken later at about the eighteenth post-operative month. It is concluded that the technique is worthwhile provided it is associated with posterior internal fixation, and that an external brace is worn for at least eighteen months after operation.

[Fracture of the odontoid process (author's transl)]. / Fractures de l'apophyse odontoïde (dens) de l'axis. 102 cas dont 73 fractures récentes.

102 cases of fractures of the odontoid process have been seen by the author - 73 recent cases and 29 old ones. It was important to distinguish basal fractures (29 cases), which all united after conservative treatment by reduction and skull traction for six weeks followed by a plaster cast for six to eight weeks, and fractures of the body (44 cases). 41 body fractures were treated conservatively, of which 6 died and only 20 united. The authors consider that treatment by skull traction must always be tried. An eventual indication for surgery can be made at about the 20th day if displacement is found to be present in spite of treatment. Fusion in these cases must be limited to C1-C2. It is best obtained by a combination of wiring and grafting.

[Lumbar venography in the diagnosis of disc herniation (author's transl)]. / Apport de la phlébographie lombaire dans le diagnostic des hernies discales.

The authors have performed lumbar venography on 120 occasions in patients with low back pain. In 58 patients in whom the herniated disc was confirmed, the result of venography was positive and the localisation was precise in 67 cases. It is concluded that the method is safe, reliable and allows precision in diagnosis to allow better selection for surgical treatment. The examination is particularly useful in recurrent sciatica, fractures of the lumbar spine, recent or old, and in spinal stenosis. It may be associated with discography when the result is not clear cut.

[Arterial vascularization of the os coxae]. / Vascularisation artérielle de l'os coxal.

Study of the arterial vascularization of the coxal bone by microangiographic methods. Nutritive and periosteal blood-vessels come from Iliaca interna and Iliaca externa arteries. The ilium is vascularized by the Ilio-lumbalis artery which is a nutritive blood vessel. A eriosteal vascularization also exists. Ischium and pubis have a periosteal vascularization. Blood vessels are oriented toward the sus-acetabulum area where many anastomoses exist.