Alloclassic® Variall™ Cup
Product Information
Uncemented screw cups are a reliable solution for many different indications if stable anchorage is achieved through the design, the thread construction and the material used. The Variall screw cup with self-tapping thread meets these three requirements ideally.
Its design is based on the proven designs with a 15° cone, but it differs from other types of screw cup in two important respects :
- The floor of the cup is spherical and therefore has no sharp edges. This flattening prevents perforation of the inner cortex of the acetabulum and loss of bone substance.
- The new Variall screw cup has a cylindrical thread that penetrates into the bone stepwise and makes it easier to screw in.
The uncemented Variall acetabular cup system offers a high degree of flexibility and is also interesting from the economic point of view. It requires few components, so that all types of bearing materials can be used. Thanks to the modular design of the system, it is possible to select the ideal bearing materials for practically every indication. The Variall cup is characterised by its reliability, its versatility and a simple surgical technique. This system therefore sets a new standard for uncemented screw cups.
Indications
With the uncemented Variall screw cup, the proven one shape, combined with the spherical floor of the cup, not only ensures good tilt stability but also increases the reliability of the anchorage. Thanks to the gently rounded shape, the risk of penetration of the cup into the small pelvis is kept to the minimum. The excellent stability of the anchorage is thus combined with a very high degree of reliability of the implantation. An important criterion for the indication of the Variall screw cup is the condition of the bone. The quality of the bone of the acetabulum must be sufficiently good so that after it is screwed in the cup sits firmly. The Variall cup is successful only if perfect primary stability is present from the outset.
Primary And Revision Operations
The uncemented Variall screw cup is indicated for both primary implantations and revision operations. The most important indications for a primary operation are practically all cases of coxarthrosis, for example idiopathic coxarthrosis, dysplastic coxarthrosis, post-traumatic coxarthrosis, protrusion coxarthrosis or coxarthrosis following pelvic osteotomy. The Variall screw cup can, however, also be used in other cases, such as in idiopathic necrosis of the femoral head or revision of a Girdlestone resection.
The Condition Of The Bone As The Decisive Criterion For The Indication
If the Variall screw cup cannot be anchored with primary stability, implantation should not be carried out. Inadequate bone quality, which represents a contraindication, is to be found in osteoporosis, rheumatoid arthritis, status following coxitis, rapidly destructive arthrosis with disintegration of the core of the acetabulum, radionecrosis, secondary malignant destruction of the acetabulum or in arthrodesis of the hip joint. For revision operations the same basic conditions must exist as for first implantations, for the use of a Variall screw cup to be considered. The bone quality is decisive for the indication or the contraindication. For example there must be no cavitary or segmental bone defects.