PROMOTIONAL FEATURE
The seeds for the Atlas cup were first sown in 1985, when a French industrialist set up a small factory under the name of OMCI. And after 30 years, the Atlas cup is still holding …
The Atlas cup was one of OMCI’s first products and the chief engineer started work on the design in 1986. Particular attention was paid to the locking mechanism of the liner with the metal shell, which at the time had been highlighted as a point of failure in a number of contemporary designs.
By 1987, surgeons from three university hospitals – Professors Yves Gerard and Marc Ameil (Reims), Professor Mestdagh of Lille and Professor Fischer of Lyon – had joined forces with OMCI and the cup design was finalised.
Early clinical work in 1988 by Jean Louis Dore, of Tours, discovered that the elastic properties of the cup were responsible for the excellent primary fixation observed, negating the need for screws in most cases.
Pierre Lecestre and Phillippe Poilbout of the SOR group adopted the Atlas cup and were instrumental in the next phase of development with the hydroxyapatite coating, which was added to assist in later bony on-growth.
Fournitures Hospitalieres (later to become FH Orthopedics) acquired OMCI in 1992 on the back of the Atlas cup’s popularity. As a result, the body of French surgeons in the research group GECO adopted the Atlas cup and numbers of implantations increased substantially.
In 1994, the Atlas cup was married with the ESOP stem.
In 1997, the Atlas cup received FDA approval in the USA and in 2003, TGA approval for use in Australia.
In 2000, the cup was introduced into the UK. Prospectively collected data was instigated from the start of implantation in Swansea (and surrounding hospitals) allowing accurate real-time assessment of its survivability in almost 2000 implantations to date.
The Swansea data was used in previously published work by Dambreville [1,2] and Phillipe [3] and submitted to the ODEP for which it was granted one of the first 10A ratings for an uncemented acetabular component in 2013.
Results have also been published on the success of the Atlas IIIP cup from the Swansea group [4].
The Atlas cup remains as popular as ever and more than 125,000 Atlas cups have now been implanted worldwide.
Forming the Atlas cup
The Atlas cup design philosophy was one of a thin walled elastic shell with a thick polyethylene liner. The locking mechanism is unusual as it utilises cold flow of the polyethylene into a rough “back-side” of the cup. This was revolutionary thinking 30 years ago when nearly all other manufacturers were attempting to polish the back-sides of their cups. In the words of Alain Dambreville, “you only need to polish the back-side if you accept movement – we do not”.
In fact, the locking mechanism has been proven to be a strong positive of the Atlas design. The liner expands the flexible shell (see Figure 1 and Figure 2) allowing a complimentary force to the primary fixation.
Figure 1
Figure 2
The pegs of the cup were also found early on to not only give primary stability against rotation failure but, within weeks, were the first area to receive bony on-growth as proved by early histological retrieval.
On this basis, a number of other features have been developed which remain available for surgeon preference:
The Atlas IIIP has holes and spikes.
The ATLAS IVP has no screw holes
The ATLAS MS has