CORAIL Primary Cementless
Key Surgical Steps
These key surgical steps are highlights only and may not be used for training purposes. For the detailed procedure, please refer to the CORAIL Portfolio Brochure (9066-35-025) pages 16-20.
The CORAIL Hip System provides pre-operative templates at three different magnifications (100%, 115% and 120%). The templates are placed over the AP and lateral radiographs to help determine the implant size in order to restore the patient’s natural anatomy. When templating ensure that the prosthesis does not make cortical contact. Understand the difference between fit and fill and optimum fit. The surgical objective is a 1–2 mm gap between the cortices and the implant. If in doubt template a size that contacts the cortex and then go down a size.
Templating should be done with a medium neck so that the possibility to change to a short or a long neck still remains in order to adjust leg length. The pre-operative templating will indicate the level of neck resection.
Dorr Type A Femurs
In Dorr Type A (‘champagne flute’) femurs1 proper metaphyseal fit may require a larger size than the femoral canal can accommodate distally.
In these cases consideration should be given to distal reaming to enlarge the canal to accommodate a broach of the appropriate size.
Femoral Neck Resection
The angle of resection should be 45°. The neck resection guide should be used to determine the level of the femoral neck resection in conjunction with pre-operative templating.
Tip: If the resection is too high, it may result in a varus positioned stem
It is important to select a point of entry posterolaterally to the Piriformis Fossa to avoid varus positioning. Use a curette or general instrument to indicate the direction of the canal. Use the bone tamp to compact the cancellous bone proximally. This is an important step as the philosophy of the CORAIL stem is based on bone preservation.
To prevent under-sizing or varus positioning, the greater trochanter may be prepared with an osteotome to allow better insertion of the broaches.
Ensure that broaching is started posterolaterally. The broach should run parallel to the posterior cortex following the natural anatomy of the femur. Begin with the smallest broach attached to the broach handle and increase the size of the broach sequentially until longitudinal and rotational stability is achieved, broaching should then be stopped.
Tip: Careful pre-operative planning is key to help selection of the final broach size.
In Type A Femurs,1 the diaphysis should be reamed prior to broaching to ensure that the CORAIL stem is implanted into compacted cancellous bone in the metaphysis.
If concern around sizing still exists, intraoperative x-rays could be considered, where available.
Leave the last broach in place and use the calcar mill to achieve a flat resection surface. The calcar reaming should allow an optimised fit of the collar on the calcar.
Tip: Caution should be taken during the reaming process. First, use a slow speed to prevent the calcar cracking and any tissue. Speed can then be increased to achieve an even finish.
With the final broach in situ, attach the appropriate trial neck and trial head. Reduce the hip and assess what adjustments, if any, are required to ensure stability through a full range of motion. Remove the trial head, neck trial and final broach. Do not irrigate or dry the femoral canal. This will help to preserve the compacted cancellous bone quality and encourage osteointegration of the stem.
Tip: Impingement of the neck and cup should be checked and rectified if required.
Femoral Component Insertion
Important Note: The protective covers should be left on until the components are ready to be implanted. Before implanting a femoral head, the male taper on the femoral stem should be wiped clean of any blood, bone chips or other foreign materials.
When implanting the definitive stem (that has the same size as the final broach) in the femoral canal, ensure that it is directed in by hand. This will help avoid changing the version as a precautionary measure. You should not have more than a thumb’s breadth between the resection line and the top of the HA coating on the stem. If the stem does not readily go down this far, the surgeon should broach again. If the HA level of the stem sinks below the resection line, the surgeon should consider a larger stem or using a collar. Then lightly tap the stem impactor to fully seat the stem.
Note: The stem is 0.31 mm thicker than the broach to allow the necessary press-fit.
Femoral Head Impaction
A final trial reduction is carried out to confirm joint stability and range of motion.
Important Note: Clean and dry the stem taper carefully to remove any particulate debris.
Place the femoral head onto the taper and lightly tap (especially if a ceramic head is used) it using the head impactor. Ensure bearing surfaces are clean and finally reduce the hip.
Note: A DePuy 12/14 ARTICUL/EZE® head must be used.