This year, the ANA.NOVA cup looks back on 20 years of clinical use. Dr Harald Kuhn, Cloppenburg, has been an ANA.NOVA user since day one. We take a look back with him at the beginnings and examine the design and the range of indications.

ARTIQO: What must a good cup system have?

Dr Kuhn: It should enable high primary and secondary stability, be easy and user-friendly to use and have a clear and ergonomically favourable set of instruments. It should provide a good and reliable feeling of stability during impaction and visually support correct placement.

ARTIQO: What convictions led to the development of the ANA.NOVA cup 20 years ago?

Dr Kuhn: It was based on the belief in the cementless implantation technique. The users of screw cups relied on high tilt stability and pull-out resistance. Many press-fit cups required meticulous preparation or additional stabilisation with fixation screws. It was time to optimise this situation with the help of new implant designs. In retrospect, it is fascinating that engineers and physicians alike pursued ideas for the technical improvement of existing systems. Such things are much easier to realise in constructive cooperation.

ARTIQO: You have known the ANA.NOVA since its beginnings. What design elements characterise this cup?

Dr Kuhn: Anyone who wants to perform bone-saving and minimally invasive surgery will benefit from this design: although it is milled spherically, the ANA.NOVA cup is flattened at the pole and clamps at its equator without touching down. It also leaves room for fresh bone integration at the base of the cup, which in turn is promoted by the BONIT® coating. The discreetly slanted wings, which do not extend into the cup equator, leave the acetabular rim untouched on the one hand, and on the other hand they are very effective against tilting and rotational forces. From 2006 onwards, we have increasingly chosen 36 ceramic bearing couples, which is already possible from a cup diameter of 50. Patients and the good reputation of the prosthetics benefit from the greater safety against luxation and the significantly greater range of movement. The fine BONIT® surface coating confirmed the positive observations we had previously made elsewhere with regard to osteointegration and secondary stability.

What do you particularly like about the ANA.NOVA cup?

The simplicity.

ARTIQO: You have extensive experience with the ANA.NOVA cup. Which patients can be treated with it?

Dr Kuhn: I don’t see any restrictions for standard implantations. The positive experiences with the ANA.NOVA cup, which were already scientifically substantiated with the HI screw cup under Prof Küster, have also been continued with the ANA.NOVA cup for dysplasia treatment with cup notch or cup base plasty.

ARTIQO: The cup is not only suitable for primary treatment, but also – without additional screw fixation – for revision cases. What is your experience of revisions with the ANA.NOVA?

Dr Kuhn: I am a fan of impaction graft reconstruction and prefer anatomical reconstruction even for larger and oval cavities if the cup base is stable. Following good planning, the position and the centre of rotation can be restored very well. This is often done in the size of the primary cup, i.e. with minimal implantation of foreign metal material. I mix the grafts with resorbable bone substitute containing antibiotics for infection treatment. The minimally invasive implanted short stem prosthesis has been found to have a significantly lower infection rate in the arthroplasty register. The significantly lower traumatisation of the tissue and the low-abrasion modern bearing couples are expected to reduce the revision rate.

ARTIQO: What results do you see with the ANA.NOVA cup in your patients?

Dr Kuhn: The good osteointegration allows me to look back on the last 20 years with satisfaction. On this point, I would say that we have backed the right horse. The good range of motion also ensures a high level of patient satisfaction. In combination with a short stem, the 36 glide pairings are extremely secure against luxation.

ARTIQO: Screw cups seem to be gradually disappearing from the market. What would you recommend to screw cup enthusiasts with regard to the ANA.NOVA hybrid cup?

Dr Kuhn: I recommend enthusiasts to follow their love. In most cases, however, we’re talking more about the way things have been learnt by former bosses or habits. So if you want to explore your own abilities, I recommend that you simply give it a try. This will quickly reveal the stable primary strength. Only in sizes over 60 mm in diameter do the screw cups become flatter and possibly more bone-saving in comparison to the ANA.NOVA cup, as the cup is not as strong as the ANA.NOVA cup.