1975 : creation of the Association for the Research in TRaumatology and Orthopaedics

From 1975 to 1978

Seven young orthopaedic surgeons settle in the Lyon region.

When they end their assistantships in university hospitals, they decide to carry on their collegial
practice of their specialty by founding a working group called “Artro Group” (Association for the Research in TRaumatology and Orthopaedics).

In addition to their bibliographic work, their common file reviews and their study tours to meet foreign colleagues, they share their major interest for total hip arthroplasty which is booming. Trained to the use of Charnley’s and Mackee’s prosthesis, they follow the evolution of Maurice Muller’s selflocking prosthesis by attending courses in Switzerland.

Thus, they turn to Judet’s, then Lord’s cementless stems.

Being unsatisfied, they compile the specifications of an ideal stem “that would combine new advantages : forged titanium, ceramic replacement heads, but above all a specific shape to achieve 3D stability”, improving the self-locking prosthesis by an antero-posterior enlargement of the femoral stem in the metaphyseal region, thus defining the concept of stereo-stability that characterises the TITAN prosthesis, which, in addition, has an efficient ancillary instrumentation with a trial prosthesis
and colour marks (1982).

This cemented stem with its specific socketing, its anodising process and its polished surface, proved very effective as shown by its dissemination through Europe and its survival rate curve in the Norwegian Register. Above all, its excellent primary stability before cementing naturally led us to a cementless option when, in 1984, we discover with Osborn the bioactive feature of some ceramics and more particularly the osteo-integration capacities of Calcium Hydroxy-Apatite.

Therefore, a decisive biological input supplemented the purely mechanical conceptions of hip arthroplasty.

For Artro, the next step was the animal testing, with the implantation of blocks of blasted titanium in dogs bones, with two faces, with or without Hydroxy-Apatite, which brought the histological confirmation that no fibrous membrane formed in contact with bioactive ceramic.



Artro performs close to one hundred implantations of titan-patite prostheses, which are titan stems blasted with corundum and coated with HA by plasma spraying (total coating of the stem, with a layer of 150 microns) and the early clinical and radiological results are very encouraging.

Therefore, Artro could develop the cementless femoral implant from the titan stem, making it longer and thinner distally and above all with original macrostructures in the form of horizontal grooves in the metaphyseal area and vertical grooves in the diaphyseal area.

The Corail was born, called bio-dynamic prosthesis to underline the interaction between the bone and the bioactive ceramic coating (very close to the structure of sea coral, which explains its name) since its conception.

The intra-medullary characteristics of the Corail never changed: neither the characteristics of the HA coating (purity, crystallinity, thickness) nor the technique of preserving entirely the cancellous bone.

The surgeons of the Artro group, in their daily practice, quickly realised that other implants were necessary for revisions, dysplasia, etc.

The initial Corail was the first in the “Corail system”, which is a big prosthetic family.



Long revision Corail called Kar.

Reconstruction Corail with distal locking called Reef.

The acetabulum with HA coated cups was developed either in the Tropic screwed cup concept (1987), then Spirofit (20..), or in the press-fit concept, Lagoon cup (1997) with its option of PE or ceramic insert.

For major loosening, a module of acetabular reconstruction was designed combined with bone compaction: octopus (199.)

The Artro group, beside its conception activity, was very involved in comparing ideas and results during scientific congresses.

Fostered by tours abroad and publications, the sharing of experience could also be achieved in the French and foreign “Corail clubs” as well as in the “Learning Centres” in Annecy and Lyon.

As the “Corail system” spread around the world, it was necessary for the Artro group to expand and to strengthen by co-opting new members, passionate experts in hip arthroplasty, until reaching the current number of 14.

An Institute was created by the group to boost the communications, the exchanges and the education activities.

“Artro Institute” more particularly makes it possible financially to host young surgeons from any country who wish to improve their skills in hip arthroplasty in general and with the Corail system in particular, through direct contact with Artro group members.

The Artro group develops its own surgical techniques, its own patents, but remains in close relationship with its industrial partner (Landanger Cie 1988-1997, then Depuy Cie 1997-2012) which manufactures and sells the Corail.

With more than 30 years of existence, the Artro group has shown exceptional longevity that should continue, if it keeps its on-going renewal, its inventiveness with careful thinking, its openness to “exchanges with a priority to the transfer to younger generations”, because the Artro group is first and foremost a group of operating surgeons !


prothese Reef


28-29 June. 2018

learning Centre

60 participating surgeons. The Corail PINNACLE learningCentre is designed for experienced THA surgerons ... Learn more