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HOW TO IMPLANT A CORAIL STEM IN 10 POINTS

Jean-Marc SEMAY . ARTRO Group

Good morning everybody. Thank you to be here, so early. I would like to summarize some technical points before the live surgery for an ideal procedure of implantation.

First of all, a message for the beginners with Corail. Don’t worry. CORAIL is a friendly implant, easy to use, with a very short learning curve.

However, several key points must be kept in mind, in order to get constant and reproducible results. We will study shortly 10 key points to be successful in the implantation.

Pre operative planning is the first fundamental step: it allows the surgeon to determine preoperative leg length discrepancy, to assess cup size and position, to determine hip center of rotation, stem size, position and fit of the implant and to assess femoral offset.

High quality radiographs are necessary, using a standardized protocol with known magnification; the different anatomical landmarks : tear drop, obturator foramen, greater and lesser trochanter are used as references.

Using the acetabular template, the new hip center is determined. It is always the first step of the planification. Then, using the different femoral templates, we try to reach this center of rotation and to position the stem all along the femoral axis. Thus, we can determine the kind of implant to use, the level of the neck section and the size of the stem to get an optimum filling.

The CORAIL stem may be implanted using any of the surgical approaches for hip arthroplasty. The geometry of the stem is also adapted to less invasive and tissue preserving surgery.

Nevertheless, the entire acetabular rim and the upper femur as well, must be exposed and the traditional landmarks clearly identified.

On the acetabulum, the labrum, the anterior and posterior walls, the transverse ligament must be perfectly seen.

On the femoral side, The level of the neck osteotomy is determined during templating. By a posterior approach, the reference is usually the lesser trochanter.

By an anterior approach, this landmark is uneasy to appreciate before the neck section. You can make a pre cut and then adjust the resection according to the planification . Using the top of the greater trochanter is also an alternative solution to restore leg length equality.

Proximal cancellous bone compaction and femoral canal preparation are the second major step.

You already know that with Corail we want to preserve as much cancellous bone as possible. A specific impactor and different broaches of increasing size create an adequate cavity in the compacted trabecular bone of the upper femur…You stop broaching as soon as the broach is rotationally and longitudinally stable: the objective is to use the smallest implant possible, which is stable. This rotational stability is a very important key point for an optimal implantation.

On the last broach left in place.

In all the cases, collared or collarless stem,the use of the calcar reamer is necessary to achieve a flat resection of the surface and get a perfect fit.

Trial neck segments and trial modular balls are available to assess joint stability, offset, range of motion and leg length. All these tests are of prior importance, notably when you use ceramic on ceramic couple where the risk of dislocation must be prevented as much as possible.

The CORAIL stem is gently inserted into the femoral canal by 2 fingers. The femoral impactor and a small hammer are used only for the last 1 or 2 cm. Drive the stem until the HA coating is no longer visible or the collar is well sited on the calcar.

This short video shows how to insert the Corail stem by hand or with a specific femoral component holder providing rotational control during implantation. Even with this instrument, don’t use the hammer before the last one or two centimetres.

When the stem is fully sited, the coating must have disappeared within the canal; if there is a gap anteriorly or at the shoulder of the stem, cancellous bone should be packed around the proximal part of the stem.

Ceramic components are carefully inserted. Take care with the acetabular insert : the ceramic inlay must be perfectly engaged within the cone taper of the shell.

The chosen femoral head is placed onto the cone and lightly impacted before the final reduction.

Even rare, some intra operative incidents must be managed carefully. Calcar fissures are mostly anecdotal. Using a Corail with collar prevents the risk of migration, but cerclage and screws are sometimes recommended if the crack extends more distally. The displaced fractures of the greater trochanter, sometimes observed in revisions need usually, internal fixation to restore abductors function and to avoid joint instability.

A question is frequently asked: how to manage a Corail stem stuck before sitting? There are no adverse effects if the stem is stuck 1 to 3 mm before the calcar. If not, the implant must be exchanged to an undersized stem. An alternative solution if you want to insert the planed prosthesis is to increase canal broaching and to ream the diaphyseal cavity. Sometimes, in flutted shaped femurs, it is necessary to ream the canal to get an optimal fit in the metaphyseal area.

The management of the post operative period is very easy: immediate full weight bearing is allowed after surgery. Hospital stay is about 5 to 7 days. 2 crutches are recommended for a couple of weeks. Rehabilitation is mainly dependent on general abilities and, clinical and radiological assessments are imperative at periodic intervals. In conclusion, Corail is an easy-to use stem and forgiving implant. Don’t be anxious. The learning period is very short and a strict observance of these 10 golden rules will assure you to obtain constant and reproducible results.

And now, may be, we can be connected to the Argonay Clinique to look at the live surgery which is planned this morning Thank you.