Key Surgical Steps
The key surgical steps above are highlights only and may not be used for training purposes. For the detailed procedure, please refer to the CORAIL Revision® Surgical Technique (DSEM/JRC/0117/0762) pages 5-13.
Pre-operative planning is essential for precise reconstruction of the hip joint. The CORAIL Revision Stem prosthesis comes with a comprehensive set of X-ray templates which include a clear indication of the scale used and both standard and high offsets for all sizes of the range.
Femoral Canal Preparation - Distal Reaming
Once the failed implant has been retrieved, the femur is cleared of any remaining cement or debris, if present. Rigid reamers are available in a range of sizes that should be used sequentially to prepare the distal femoral canal.
Reaming should begin in a central position in alignment with the intramedullary canal. A 10 mm reamer can be used as a starter to allow the easy introduction of the 11 mm reamer. It may be necessary to increase the size of the reamer to a 12 mm or 13 mm to allow free passage of the trial stem to the desired depth. In all cases, trialling should be performed to evaluate stem seating and stability.
Each rigid reamer has mechanical engravings showing the desirable depth of reaming, corresponding to each stem length (lengthened by 10 mm to take into account the tapered shape) as referenced from the tip of the stem to the shoulder of the stem.
Note: The use of a transfemoral approach can be used during the implantation of a CORAIL Revision Stem. Generally, the femoral tube is closed by cerclage wiring to reconstruct the femoral shaft, and then the femoral preparation is carried out as it would be for a closed femur procedure. The primary stability of the stem inside the host bone is the limiting factor. In the case of a highly enlarged metaphysis, the gap should not be filled by bone graft but a tightening femoroplasty performed around the CORAIL Revision Stem (using cerclage wiring).
Access to the femoral canal should be enlarged laterally into the greater trochanter, using a box chisel, to ensure that the broaches do not enter the femur in varus. The first broach, with a size adapted to the defect, is attached to the broach handle and the proximal femur is prepared by progressively increasing broach sizes.
It is essential that the final broach is completely rotationally and axially stable in the femur in order to ensure stem stability in the metaphysis.
Important note: The Revision broaches are intended for preparation of CORAIL Revision stems only.
Caution: The CORAIL Revision Stem Broach should not be used to perform a trial reduction of the hip. This is to ensure that the integrity of the prepared femoral envelope is maintained. In this instance, the trial stem should be used.
Trial Stem Introduction
The final broach is extracted and the trial stem of the same size is attached to the broach handle. The trial stem is lightly inserted into the femoral canal using a hammer. It should be stable at the level defined during pre-operative planning relative to the greater and lesser trochanter.
Note: The trial stem should seat at the same height as the broach. if it seats higher it may then be necessary to use the 13 mm reamer to open the canal distally.
If the trial stem is not stable, a trial stem one size larger can be tried in order to obtain stability at the correct level. In case visual access is available, it can be useful to check that the ‘minimal embedding level’ is reached using the dedicated witness groove on the trial stem.
Neck and Head Trialling
The corresponding type of trial neck is then attached into the trial stem. Two options are available, standard (STD) and high offset (KHO).
A trial head is placed on the neck of the trial stem, and the hip is reduced and assessed for stability, through a full range of motion.
Note: When using the CORAIL Revision Stem upgrade set, care should be taken not to use the coxa-vara trial neck (KLA) which is available as part of the CORAIL primary instrument set.
Definitive Stem Introduction
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.
The definitive implant of same size as the trial stem and same offset as the trial neck is inserted into the femoral canal. The introduction is managed using the stem impactor while ensuring the correct restored anteversion is applied.
The stem is cautiously impacted using a hammer while avoiding any impact on the neck.
Tip: Where a horseshoe-shaped structural allograft is used, this should be placed to fill the defect before final impaction. The graft will be stabilised by the collar after final impaction. The goal of this calcar graft is to ensure the right level of implantation and minimise the potential for subsidence.
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 it (especially if a ceramic head is used) using the head impactor. Ensure bearing surfaces are clean and finally reduce the hip.
Note: A DePuy Synthes 12/14 ARTICUL/EZE™ Head must be used.