[Impacted acetabular cups]. / Les cotyles impactés.

The failure modes of impacted acetabular cups are: deterioration of the polyethylene insert, disassembly of the modular components, excessive polyethylene wear, severe peri-prosthetic osteolysis. These failures can be explained; solutions are suggested.Primary stability: Screws are pathways for polyethylene debris; impacting elastic cups increases the press-fit effect in order to provide stability without screw fixation.Polyethylene thickness: by increasing polyethylene thickness from a minimum 8 to 10 mm, the risk of insert deterioration is decreased and so too is creep of the core which can induce micromotion between the insert and its metal backing.Liner stability: Tilting of the liner is the most common mecanism of disassembly in two-piece acetabular cups. The solution we suggest is to use a liner with a cylindrical periphery.Polyethylene wear: Excess polyethylene wear in metal backed acetabular cups was reported. Conversly, other authors concluded to no excess wear in impacted cups. This may be due to differences in prosthetic components, as well as patient selection. We noticed no significant wear in our series (0.10 mm per year). Studies are contradictory and it is not obvious that excessive wear in impacted cups has to be feared.Osteointegration is mandatory for obtaining long term stability and is provided by porous coating. The osteoconductive properties of hydroxyapatite have been demonstrated by a large number of studies, including fundamental research, animal experiments and clinical applications. Within a few weeks, hydroxyapatite brings about bonding with the host bone without any intervening fibrous tissue layer. We expect hydroxyapatite-induced osteointegration to prevent particulate migration. Biodegradation of the hydroxyapatite coating occurs after 5 to 10 years. Bone ingrowth later relies on the surface roughness of the substrate.In conclusion, we suggest that the combination of impacted elastic acetabular cups with a thick polyethylene liner and bioactive coating can provide long term durability.

[Variations in bone calcium content according to age and sex in a group of control subjects aged 3 to 18 years (author's transl)]. / La densitométrie osseuse chez l'enfant par absorption d'un faisceau monochromatique (méthode de Norland-Cameron). I. Etude des variations de la charge calcique suivant l'âge et le sexe dans un groupe de sujets témoins de 3 à 18 ans.

More than a thousand bone calcium content measurements were made in a group of children by means of densitometry, using the Norland-Cameron apparatus. The region chosen was that dividing the middle from the lower third of the radius, and the method used ensures that only a very weak dose is delivered to a limited field of the forearm. Errors occur more frequently in children than in adults because of lack of immobility and the large amounts of fatty tissue present. Normal curves were established as a function of age and sex in 405 control children of French nationality. These were similar to those obtained in a group of children from the Cameron but French children appear to have lower mineral levels than American children. This method is reproducible and suitable for surveillance of changes in mineral levels in the same subject.

[Radio-anatomy of uterine malformations]. / Radio-anatomie des malformations utérines

33 cases of uterine anomalies were studied from the external morphological point of views as well as by hysterography. These cases were grouped according to R. Mussel's classification (1964) which is itself the synthesis of radiological and anatomical investigations.

[Double venoma (varicosity) of the neck in an 8 year old child (author's transl)]. / Double veinome du cou chez un enfant de 8 ans

Venous ectasia in the neck, can for esthetic reasons, justify radical surgical treatment. But as it is a benign condition, the decision to operate also depends on the topography of the ectasia. The authors present the case of a double jugular localization, internal and external, explored by the techniques of direct and retrograde phlebography.