Total elbow replacement using the Coonrad-Morrey Total Elbow Replacement (Zimmer-Biomet)

Surgery is most easily performed with the patient supported in the lateral position and the arm to be treated supported and free
The arm to be operated upon should be held in a flexed position over a support. Whilst gutter supports are available, I find that these are relatively long for the length of the arm in many rheumatoid patients who come to surgery and so prefer to support the arm across a L-bar.

Surgical props to support the patient and the arm
To maintain the position of the patient, a support at the front and the back of the patient’s pelvis is used; unlike with a hip replacement, it is not essential that the body remains absolutely stationary, merely that it is comfortably supported in a lateral position. I find that a post-type anterior support (A) affords both sensible support of the patient’s front, whilst allowing plenty of room to work in; the elbow will need to be flexed for access at different stages, and so being certain that the elbow will flex without impinging on the patient’s abdomen, or any of the table equipment, is important. The patient’s back can be supported by a padded flat support (B). The L-bar for the arm (C) should be attached to the operating table using a circular clamp (D) so its alignment can be adjusted to be horizontal.

Ensure the metal of the props does not contact the skin of the patientThe post will generally have sufficient padding for the patient but placing a layer of material under the metal elements of the post (A) will minimise the risk of any contact between metal and the patient’s skin, particularly important when treating obese patients.

It is important to ensure that the L-bar (C- lettering of the label as per the overview photo earlier) supporting the arm is horizontal; using a circular clamp (D) helps as this will permit the anaesthetist to keep the head-end of the operating table tilted upwards if it provides better support for the patient whilst allowing you to adjust the clamp to ensure that the bar is horizontal to minimise sliding of the arm during the procedure.

Ensure the dependent arm is appropriately positioned for pressure relief, surgical access and anaesthetic access, before tourniquet applicationThe arm on the dependent side (A) needs to be positioned in a way to minimise pressure upon the arm, allow easy access to the anaesthetist (as this will probably be the site chosen for the intravenous cannula), but also must not get in the way of the surgical positioning.
By taping the forearm to hold it up and across the abdomen, with the hand extending round towards the back, this keeps the arm itself out from under the body, keeps the forearm close to the abdomen and so provides space, and secures the hand without compromising the ability to bring the patient’s shoulders close to the supporting bar, which is important as many patients receiving elbow replacements will have an inflammatory arthropathy and so may well be relatively short in stature if this represents a juvenile idiopathic arthropathy, meaning that the arm will need to be brought across the bar as far as possible to allow optimal surgical access.

With the forearm of the dependent side taped up and across the abdomen in this way, the hand is readily available to the anaesthetist to allow access for monitoring equipment and for access to the intravenous cannula.

During tourniquet application, be careful to maximise the surgeon’s access to the arm
Tourniquet application to control bleeding is important, particularly during cementation of the implant to allow a good bone-cement interface to be achieved; along with most surgeons, in the majority of cases I prefer to perform the procedure under tourniquet control for ease of visualisation and to minimise blood loss, allowing surgery to be undertaken more swiftly. However, particularly as many patients’ arms are relatively short, to ensure that there is sufficient access the tourniquet must be kept as proximal as possible; applying tape to hold the tourniquet high up near the shoulder prior to inflation maximises potential access to the arm.

I start by applying a broad tape to the surface of the tourniquet that will contact the padding around the patient’s upper arm, ensuring that the tape will allow the air inflow (A) to remain superior.

With the tourniquet secured as high as possible on the arm, length of tape is drawn out…

… to then be folded back over the secured tourniquet and onto the skin of the shoulder, so holding the tourniquet as proximal as possible throughout the patient preparation and positioning. (Once the tourniquet is inflated, it will remain in place by itself).

Make sure that the position of the patient will not restrict access to the elbow during the operation
With the arm positioned over the bar, it is best to be certain that sufficient elbow flexion can be achieved for all potential steps in the case, particularly when it comes to exposure for preparation of the ulna and insertion of the components; it is very frustrating to have to use an assistant to “push” the shoulder towards the operating surgeon in order to allow sufficient elbow flexion.
During the procedure, the inflated tourniquet can be used to hold the arm forwards; without this, flexion may be limited by contact between the patient’s hand and the table when the elbow is flexed (A).

With the tourniquet secured proximally, once it is inflated this can be used to “hold” the arm towards the surgical team, so freeing up an assistant; this has the added advantage of creating a slight downward slope to the arm and so allows any bloods that may collect to flow away from the surgical field rather than pooling.

This position will also afford maximal flexion of the elbow.

Once in theatre, skin preparation starts with complete preparation of the hand; the limb should be held by a member of the theatre team with hand and forearm dependent so that excess alcoholic chlorhexidine skin preparation will run off the hand and not up the arm; I prefer to have a dye added to the skin preparation so I can more clearly see that there are no areas that have not been covered by the skin preparation (we add tartrazine to the skin prep, giving the characteristic orange colour seen).

Once the prepared hand has been covered by a stockinette, I hold the hand and ask the theatre team member to use both hands to form a secure “seal” at the junction between the tourniquet (and its padding) and the skin of the arm (A); by working progressively up towards the elbow with the forearm inclined downwards, the sponges used to apply the skin prep will lose some of the preparation “load”, whilst retaining sufficient to then prepare the arm but not to have excess skin preparation that could potentially run under the tourniquet.
There are reports of skin burns arising due to skin preparation soaking underneath a tourniquet. Whilst there are commercially available “dams” that can be applied around the tourniquet, I am concern that these may act as a potential venous constriction band and so when the tourniquet is released towards the end of the procedure, there may be excessive bleeding. By having the assistant provide a secure dam with their gloved hands, I can prepare very close to the tourniquet safe in the knowledge that any excess skin preparation is unlikely to go underneath the tourniquet into the padding wool, and once the arm is fully prepared, I can then hold the forearm horizontal to run around the margin just distal to the tourniquet and its padding wool with minimal risk of contamination underneath the tourniquet into the padding wool.

With the stockinette rolled up the forearm for a short distance, to ensure there is sufficient exposure of the ulna in the hopefully unlikely event that access is required down the forearm, drapes can then be applied to seal off the surgical field. I like to make sure that the surgical side marker is put in a place that allows the team to apply the stockinette up to but leaving exposed some of the marker, whilst being confident that there will be enough exposed forearm in the event of problems during surgery.
The drapes should be applied adherent to the skin as high as possible whilst still excluding the tourniquet from the surgical field. In the event of the arms being very short, I use a sterile tourniquet and infiltrate the proposed line of incision with local anaesthetic mixed with adrenaline so the tourniquet can be applied only intermittently, as and when required.

Having “sealed” the prepared arm with an impervious drape, further layers of drape can be applied; I like to use a “U” draping system for the bottom two layers, sealed off with a straight drape across the top for security. An additional drape with a pouch can be applied if a lot of irrigation will be used in the procedure; this is particularly helpful for revision cases.

Having applied the stockinette to an appropriate level, and the drapes to cover the tourniquet and the patient, the surgical field can be sealed with an incision drape such as Opsite incision drape. I prefer to start by applying the incision drape to the flexed elbow so that whilst the arm is in the position for surgery there will be no creases in the material, and then extend the arm to wrap the incision drape around the arm and forearm, sealing the surgical drapes proximally and the stockinette distally.

The surgical site is now prepared, and you can proceed with planning the surgery itself.

Important palpable landmarks to be marked are the olecranon (both the tip, and its margins- A), the lateral epicondyle (B), the medial epicondyle (particularly if anterior transposition of the nerve is proposed) and the subcutaneous border of the ulna (C).

I then exsanguinate the arm using a combination of elevation and manual compression; you will note that we have changed the outer gloves to a sterile pair for handling the now sterile draped limb. Start by squeezing the hand, then the forearm, and finally the arm (hold and squeeze sequentially in the sequence marked 1-4); if there are insufficient sterile team members to grasp the entire length of the arm, work from distal to proximal to squeeze the venous blood out, relying on pressure from the hands to prevent arterial inflow to the area that has been exsanguinated already.
A sterile Esmarch bandage could be used instead, but I find this a quicker and equally effective method to use, and a step that also makes all members feel engaged in the process!

Avoid the point of the olecranon as wound healing and scar comfort is more reliableI tend to start my skin incision proximally, although there is no reason why one should not start distally and move upwards.
I personally prefer to deviate towards the lateral aspect of the olecranon, although it is equally reasonable to deviate medially. The important step is to ensure that full thickness flaps are raised to maintain flap viability.
As with all operations, the length of the incision is tailored to the size of the patient (longer in obese or muscular individuals) and tends to become shorter as you gain experience (with the option to extend if difficulties or anatomical variations are encountered). As a rule, I start the incision 8-10cm proximal to the tip of the olecranon, and end 5-7cm distal to the tip of the olecranon. I do not hesitate to extend the skin incision if I encounter any problems identifying the ulnar nerve, or with access to the elbow joint during mobilisation or instrumentation.

At the distal end, I run the incision fractionally lateral to the subcutaneous border of the ulna.

Raise full-thickness flapsAs mentioned above, flaps should be raised full thickness. I prefer to start raising the lateral flap to better define the surgical plane, working as far out as the level of the lateral epicondyle.

Find the ulnar nerve on the medial side of the elbowI then work on the medial side, again raising full thickness flaps but looking now for the ulnar nerve; by staying just superficial to the aponeurosis over the flexor carpi ulnaris, working out as far medial as the medial epicondyle (and so the common flexor origin) the path of the nerve will be exposed (U), unless previous ulnar nerve surgery has been performed.

I take care with haemostasis whilst raising flaps as this will save time and reduce bleeding later in the procedure when the tourniquet is released, particularly if for any reason this needs to be undertaken before the implant has been inserted.

Once the medial superficial exposure has been completed, I feel for the path of the ulnar nerve which can reliable be found between the two heads of flexor carpi ulnaris.
I generally prefer to identify the nerve distally and trace its course proximally if there is any doubt or delay in finding the nerve proximal to the elbow. This technique is described in the Orthoracle surgical technique In-situ Depression of the Ulnar Nerve (although clearly the exposure here is substantially more generous! The technique can be viewed here Cubital tunnel decompression: In-situ distal to proximal release of the ulnar nerve ). However, if the nerve becomes apparent proximally during flap elevation, I will usually commence mobilisation of the nerve proximally and trace its course distally, as was the case in this patient.

In the course of mobilising the ulnar nerve place a surgical sling around the nerve (S).I will use this for maintaining gentle tension on the nerve during its dissection and mobilisation, but I do not apply clip to the sling; I would rather have the sling fall on the ground and need to be replaced during the procedure than have a complete loop that is vulnerable to being caught by an assistant or an instrument, and so applying potential inadvertent traction to the nerve.

I make sure that the ulnar nerve has been identified and mobilised throughout its passage into the forearm through the two heads of flexor carpi ulnaris (ulnar- U and humeral- H), so I can be certain to keep it well out of the way during the elbow replacement itself.
I do not routinely transpose the nerve but have a low threshold for doing so, making a decision at the end of the procedure depending on ulnar nerve stability.
As ulnar nerve transposition maybe required, I try to mobilise the nerve with as much perineural fat as is practicable; this will allow me to apply surgical clips (Ligaclips) away from but close to the nerve, and so the clips remain near the nerve; in the event of revision surgery being necessary, a plain film will be able to confirm whether or not the nerve remains securely transposed anteriorly. This often allows the nerve to be safely left undissected once the surgical field has been adequately exposed at the time of any revision procedure that may prove necessary without needing to take the (potentially considerable) time and increased risk of dissecting the nerve out if it remains securely anteriorly transposed and so out of the way.

Expose the elbow joint using a distally-based triceps tongueThe triceps insertion is however over a very broad area, the main tendon to the base of the olecranon process (were it curves round into the forearm) with a wide aponeurotic insertion down the lateral and medially borders of the proximal ulna.
The exposure starts with a full depth incision into the triceps tendon itself proximally (being sure to remain distal to the level were the radial nerve crosses in the spiral groove – in practice this is rarely close to the surgical field in primary cases) skirting towards the lateral side 3-4 cms proximal to the olecranon insertion of the triceps (T). Be sure to keep the tendon tongue attached to the olecranon.
Having passed lateral to the edge of the olecranon, I like to leave a 3-4 mm flap of aponeurosis still attached to the subcutaneous border of the proximal ulnar for secure repair of the triceps mechanism to the ulna at the end of the procedure. I find it easier to do this if I place a finger onto the subcutaneous border of the ulna (F) as this gives me better feedback of the bony anatomy.

Having performed the midline triceps tenotomy extending along the lateral aspect of the ulna, my personal preference is to complete the joint exposure by elevating a distally based tongue to triceps tendon, relatively short when compared to the Campbell technique (long distally-based triceps tongue, commonly used for distal humeral exposure).
This will subsequently allow excellent exposure of the distal humerus and the proximal ulna.
Other techniques have been described. The Mayo approach requires peeling the triceps insertion from the lateral aspect across to the medial side along with periosteum (and potentially small shingles of bone) in order to maintain triceps integrity. I am concerned that the thickness of the periosteum is often surprisingly fragile, particularly in patients with inflammatory arthropathy, and additionally I prefer not to make drill holes in the bone for transosseous repair given the often osteoporotic nature of the proximal ulna in patients with inflammatory arthropathy.
Other techniques describe leaving the triceps mechanism in continuity, although given the coupling mechanism of the Coonrad-Morrey replacement, I find implant insertion and assembly during cementation a lot more reliable with the exposure provided following a triceps turndown.

I like to keep the triceps tongue (T) short and ensure that it remains securely inserted onto the olecranon process. The previous mobilisation of the ulnar nerve gives me confidence when working on the medial side, although as long as one keeps relatively close to the ulna when working into the proximal forearm (again leaving a 3-4 mm aponeurotic tongue for repair on closure), the ulnar nerve (U- held in the sling) is generally well out of the surgical field and so it does not need formal retraction other than to check its position when elevating muscles off the proximal ulna (flexor carpi ulnaris ulnar head). I again like to keep a finger on the subcutaneous ulna (F) for feedback about the bony position whilst dissecting along the medial border of the proximal ulna.

The deep head of triceps (medial head) is muscular a long way down the arm, as far as the elbow. There is no point leaving any muscle fibres attached to the tendon tongue (T), and so having cut through the tendon layer I will then carefully elevate the triceps tongue away from the underlying muscle before completing the exposure, mobilising all muscle fibres with either the lateral or the medial flap.

The joint can now be mobilised to allow dislocationThe proximal element of the olecranon process (O) does not receive any of the triceps tendon insertion (tongue marked T) and can be excised, which helps with dislocation and more importantly with exposure for preparation of the ulna for implantation of the ulnar component.

Releasing the tissues medially and laterally (the capsule and any pannus that may be present, along with any scarring) allows the proximal ulna to be delivered so exposing the joint surfaces (H=humerus; O=olecranon tip). As long as you have mobilised the ulnar nerve and keep checking its position while working on the medial side, and do not go deep into the anterior muscle, the neurovascular structures will be safe.

Excise the tip of the olecranon process to enable preparation of the ulnaOnce sufficient mobilisation has been undertaken, the bony landmarks of the proximal ulna can be better appreciated.
In the picture I am holding the proximal ulna with my index finger within the trochlear notch; the entry point for access to the ulna shaft is surprisingly low within the ulna, and so the olecranon tip excision should be as low as possible without endangering the triceps tendon tongue insertion; this will often involve removing the floor of the trochlear notch.

When cutting the olecranon tip, it is important to be mindful of the rotational orientation of the cut, which can then be used as a reference point when inserting the ulna component.
The ulna component should be inserted perpendicular to the flat surface of the proximal ulna, and so cutting the olecranon tip parallel with the flat surface referencing the rotation of the ulna component much easier later on. The Watson-Cheyne instrument (W) is being held against the subcutaneous border of the ulna to better demonstrate the rotational profile of the ulna.

The saw (S) is held against the proximal ulna as low as the tendon insertion (T) permits, and kept parallel with the flat surface of the proximal ulna whilst cutting the olecranon process tip and the floor of the trochlear notch. Here, the Watson-Cheyne (W) is showing the alignment of the flat surface of the ulna; the saw blade is parallel to the Watson-Cheyne, and passing just deep (posterior) to my finger in the trochlear notch of the ulna (F) to expose the base of the trochlear notch after excision of the olecranon tip.

The excised element can be retained for use as a bone graft if needed later, either under the flange of the humeral component, to fill in a gap between the humeral component and the columns of the distal humerus, or potentially shaped to act as an osseous cement restrictor (although I prefer to use solely cancellous bone for interosseous cement restriction).

To complete exposure of the proximal ulna, the anterior capsule (C) can and should be released from the coronoid process (T); the Coonrad-Morrey implant is a semi-constraint component, and therefore the collaterals can be freely released. The anterior muscle (brachialis) will protect the neurovascular structures (brachial artery, median nerve, radial nerve).

If exposure of the ulna (U) to allow access to the entry point for the ulna component is in anyway difficult, preparation of the distal humerus (H) can be undertaken first.
This however can cause problems with visualisation of the proximal ulna due to bleeding from the prepared humeral bone pooling around the ulna, and so when excellent exposure of the ulna has been afforded as was the case in this patient, I prefer to prepare the ulna first.
The radial head can be excised or retained when using the Coonrad-Morrey implant. I would retain the radial head unless there is significant proximal radio-ulnar joint arthritis, or restricted forearm rotation pre-operatively, as is commonly the case with patients with a systemic inflammatory polyarthropathy.
It is important to emphasise to patients that restriction of forearm rotation may be at least in part due to the distal radioulnar joint.

Start ulnar preparation by defining the entry point to access ulnar intra-medullary canalThe entry point to access the canal of the ulna is surprisingly radial and very low; there is a ridge in the trochlear notch (R) that is often persists despite the arthritis changes (but not always); the Watson-Cheyne instrument (W) is seen pointing to the starting position for the entry point, low down on this ridge.

I start preparation by removing the remaining subchondral bone with a high-speed burr (B), opening over a wide enough area to allow for component and cement insertion; the goal at this stage is to allow access to the canal, so working increasingly posterior into the proximal ulna. If the medullary canal does not become easily apparent, using the Watson-Cheyne to find the direction into the canal bluntly is helpful.

Having accessed the canal, the component rasps can be used to prepare the metaphasis and canal to receive the ulna component.Due to the offset between the entry point and the axis of the canal of the ulna, the ulnar component and instruments are side-specific- i.e., left and right side are different shapes. Be sure to use the correct set for the side you are operating upon!
The rasps are shaped and sized to compact the bone to accommodate the implant and an appropriate cement mantle; the rasp will not remove much bone, so if it is tight, either use a burr or reamer to remove bone to more easily impact the rasp, or stick with the size of implant smaller than the rasp that is not advancing easily.
There is a starter rasp to open up the canal, then work up the sizes (small, regular) until the rasp starts to be held up by the bone. The rasp size is marked on the instruments, as can be seen; the one in the picture is a right-sided regular, the largest available.
The handle of the ulnar rasp (H) can be used to set the rotation of the prepared canal by keeping it perpendicular to the flat surface of the proximal subcutaneous ulna.
The rasps should be seated fully so that the level marked S is flush with the subchondral bone at the entry point.

Care needs to be taken to respect the rotational profile of the rasp in order to ensure that the ulna is prepared in the correct rotation to receive the component; the handle of the rasp (R) should be perpendicular to the flat surface of the subcutaneous ulna (marked by the Watson-Cheyne- W). If there is any concern about the diameter of the canal, a flexible cannulated intramedullary reamer can be used to expand the medullary canal over a guide wire (although this was not necessary for this patient).

Sequentially larger and larger rasps are inserted, being sure to seat them fully.

The rasp can be advanced by hitting gently with a small to medium sized hammer; do not be temped to use a very heavy hammer given the bone is potentially weakened by the underlying inflammatory arthropathy in many patients receiving an elbow replacement.
The rasps are seated fully sequentially until a snug fit is achieved; don’t be concerned to try to fully insert a larger rasp if it is difficult to advance, but stop when it starts to become tight.
The component is cemented and so slightly increasing the mantle size by incomplete rasping for a larger implant than the one ultimately used will not matter if undertaken only proximally.

A low threshold should be had for further expanding the canal with a burr or reamer if significant resistance is met with the rasps.

Insert trial component to ensure it seats and the rotation is appropriate

If there is any difficulty inserting the trial, the burr should be used to expand the proximal metaphasis (the entry point in the original joint), looking to see and so address the most likely position where the component is being held up.

The prosthesis trial should be inserted to the level where the ring is centred within the anticipated profile of the old trochlear notch (between the coronoid and the olecranon process).

Preparation of the humeral metaphysis can be undertaken using the system jigs, but is easier performed “freehand”?Instruments and jigs are available for humeral preparation, but an alternative that allows quicker preparation involves using a trial component reversed to provide an outline for the metaphyseal preparation.
The humeral trials and components are symmetrical (and so not sided). The picture shows the profile of the trial component of the left (T) and the jig on the right (J); they have been positioned with the metaphyseal parts at the same level. You can see that the profile of the metaphyseal element of the two is essentially identical.

The metaphyseal element of the humeral trial and jig is essentially identical, as confirmed by the two overlapping; I have positioned the jig over the metaphyseal part of the trial component in this picture. This means that the trial component can be used to template the bone of the distal humerus for excision to prepare the humeral metaphysis for the humeral implant.

By placing a trial of the appropriate sized component back-to-front on the posterior surface of the humerus(H), with the stem of the trial component centred over the shaft of the humerus (you can feel this with your finger, as per the picture). The tip of the stem will be distal to the level where the radial nerve crosses in the spiral groove. Be careful to keep the stem on the surface of the bone nonetheless.
The articulation (the holes in the trial component) should be at the level of the axis of joint rotation, which lies along a line between the antero-inferior aspect of the medial epicondyle and the centre of the arc of the capitellum.
In practice, capitellar bone loss makes the medial epicondyle a more reliable reference, relying on the stem of the trial lying centrally over shaft of the humerus to set the level appropriately. Once the height has been checked, the trial metaphysis will outlie the area of metaphyseal bone that needs to be resected.

Once you are happy with the component position (the height, and alignment), mark the outline of the trial on the posterior surface of the humerus with monopolar diathermy. Mark around the outline of the metaphysis, joining up the two sides at the base of the trial stem.
The medial and lateral columns (the supracondylar bone columns medially and laterally) should be kept as thick as possible, but the bony resection has to accommodate the trial and so as long as the joint line has been appropriately referenced and the stem was accurately centred on the humeral shaft, the marked resection is what is needed.

Use an oscillating saw to remove the templated metaphyseal bone. Try not to overlap the corners where the vertical limb of the cut (from the joint surface proximally) meets the oblique shoulder cut at the proximal end of the resection.
This would cause a potential stress riser, and predispose to fracturing of the condyle. While condyle fracture has been found not to compromise function, the fracturing event is painful and alarming to the patient if it happens during the recovery period (and to the surgeon if it occurs intra-operatively!).
Take care to protect the ulnar nerve while using power tools on the medial column; the nerve (N) is protected by the right-angle retractor, but can be retracted using the sling if necessary. The olecranon with the attached triceps turn-down (O) and the distal humerus (H) have been marked.

Having completed the bony cuts (which may need some patience, especially at the anterior cortex) the block of metaphyseal bone (M) can be mobilised and removed. I prefer to use a saw, as it is easier to control, and to work anterior-to-posterior, move the saw, and repeat the anterior-to-posterior cut at different points, rather than “sliding” the moving saw up and down the bone surface. The anterior part of the distal cut can be completed by cutting from the elbow joint line longitudinally into the humerus (i.e., cut up from the bottom).
This bone should be retained as it is a useful source of potential bone graft, particularly the cancellous element which can be shaped to fashion osseous medullary canal plugs to use as cement restrictors.
A thin sheet of bone from the excised humeral metaphysis can also be used between the anterior flange of the humeral component and the anterior humeral cortex; this, once it has incorporated, will help to give rotational stability to the component.

Once the metaphyseal block of bone has been removed, the canal is preparedThe apex of the prepared metaphysis will end at the level of the sheet of cortical bone where the olecranon and coronoid fossae meet.
The remaining bone at the superior aspect of the fossa will need to be removed to provide access to the humeral medullary canal. This may require use of a high-speed burr if the bone is hard, but often a pair of bone nibblers can be used instead if the bone is porotic, as was the case for this patient.

Having penetrated the bony ridge, a burr is usually the quickest and easiest method of expanding the opening to the medullary canal to allow broaches to be passed to prepare the humerus for the stem of the component.

Preparation of the humeral medullary canal for the component stemBefore passing broaches up the humeral canal, I like to reassure myself of the alignment of the canal and that I have safely accessed the canal as the bone can be surprisingly soft and so vulnerable to inadvertent penetration.
I feel for the medial and lateral sides of the humerus and pass an instrument up through the prepared hole (E) retrograde into the canal, passing it in a line that passes directly between my fingers.
I like to use the curved, flattened end of a Watson-Cheyne (W) as I can then rotate the instrument to all four sides, drawing it in and out to reassure myself that there is bon of all sides. I will sometimes repeat this step having completed the preparation of the medullary canal, again to reassure myself that I have not penetrated the humerus during the preparation.
In the event of penetration (which is more common in the ulna than the humerus- I have not personally penetrated the humerus in a primary procedure), I would assess the size of the hole, consider bone grafting if the defect is large, and ensure that the component stem will pass well beyond the site of the penetration to minimise the potential for the hole acting as a stress riser for a periprosthetic fracture- stem tip at least 2 cortical diameters beyond the defect, if possible.

The canal is provisionally opened using the pointed hand drill from the Coonrad-Morrey instruments.

The drill is passed in to an appropriate depth, far enough to clear any bone for passage of the broach for the planned humeral stem, but not too far, to minimise the potential for a long column of cement passing up the humeral canal.
Again, I place a finger on the centre of the back of the humerus (F) to ensure I am aiming the hand drill in the correct direction.

If the hand drill does not pass easily, a the alignment guide for the humeral cutting jig (seen here) can be used to open the medullary canal by hand, potentially with a cannulated reamer thereafter; I have not found it necessary to ream the humerus as the canal is usually relatively capacious.

Next, use the humeral rasps to prepare the canal; the humeral component is not side-specific, so only one set of rasps is available. The posterior side of the rasp is marked on the instruments, to avoid confusion; in the picture, the posterior surface is at the bottom of the picture. Note that the handle is larger than that of the ulnar rasp, which should prevent confusion when rasps are passed, over and above the very different shapes!
The rasp should be seated fully into the humerus (to the level marked S posteriorly, which is better seen in the exposed field).

The canal can then be prepared by sequential broaching with the appropriate length rasps (usually 4-inch for a primary) up to the desired width.
The broach can be passed by hand, being careful to maintain appropriate rotation- the handle should be perpendicular to the axis of rotation- to the point where resistance is felt…

The broach is fully seated (to fully bury the rasp to the end of the flare, as outlined 2 slides earlier) using controlled blows from a moderate weight mallet.

Once the broach size feels secure, a trial component of the size of the final broach is inserted. Be sure that the humeral component flange will easily pass in front of the anterior humeral cortex.

If the metaphyseal element does not pass easily, more bone can be removed from any point of impingement until the trial fits in easily, but ideally still snugly.
If there is a wide gap having inserted the definitive component, any residual bone from the metaphyseal resection can be sliced to provide bone graft to fill in the gap, which should afford additional rotational stability to the humeral component.

Confirm motion range with trial componentsOnce the trial humeral component can be reproducibly inserted, the ulnar trial component can be re-inserted.

I like to do this by passing the ulnar component through the yoke of the humeral trial, as this will rehearse the steps for insertion of the definitive components when cementing, so you and any assistants know what will be required.

The trial components can be coupled with a trial bearing (pin).

The trial components can be coupled with a trial bushing pin (P), which will allow you to check the available range of motion and for potential bony impingement.
The humeral component needs to be backed out of the humerus to expose the holes in the metaphyseal part of the component to allow the bushing to be passed across through the aligned holes of the humeral and ulnar components, before seating the components fully. Ensure the flange of the humeral component is passing anterior to the anterior cortex of the humerus, particularly if any resistance is encountered.

Check the range of motion and implant stabilityWith the trial components in place and coupled, confirm that an adequate range of extension can be achieved.
If there is significant residual fixed flexion, confirm that there is no residual anterior capsular tightness or posterior impingement (and address these issues if present); the humeral component can be recessed further to improve extension range if needed (which will require re-cutting and re-broaching of the distal humerus).
The picture shows the extension range achieved- if the fixed flexion is too great (which will depend upon the patient- I will accept 20-30 degrees of residual fixed flexion as long as the anterior soft tissues have been adequately released), then humeral preparation will need to be repeated, potentially re-cutting the bone to allow the humeral component to sit more proximally; this is more common in post-traumatic cases in my experience.

With the trial components still in place and coupled, confirm that an adequate range of flexion can be achieved; in the picture, I have externally rotated the shoulder to allow me to fully flex the elbow as flexion to 135 degrees was possible in this case (hand to shoulder).
If there is a significant block, which often is manifest as the humeral component pistoning out of the bone, confirm that the coronoid tip is not impinging in the coronoid fossa. Consider removing the tip of the coronoid process if this is the case, assuming the ulnar component is adequately seated.
If the ulnar component is proud, the coronoid tip will potentially impinge on the superior wall of the coronoid fossa, due to the increased distance between the axis of rotation and the tip of the coronoid process.

Prepare and insert osseous cement restrictorsI prefer to use cancellous bone to block the canals of the bones and so limit cement propagation along the canals and allow for pressurisation to improve integration.
The bone will compress into and fill the canal, and can be broached through in revision surgery, unlike commercially-available restrictors. In primary cases, the excised humeral metaphyseal bone is a good source of bone, as is the radial head (if resected). Try not to include any of the sclerotic cortical bone as this removes the advantage of more easily working through the bone in future operations. For this reason, the olecranon tip is a less attractive choice.
In the picture, I am undertaking the second cut for the humeral restrictor (1st cut marked 1)

Cut the cancellous bone down by and to a size and shape that is similar to, but just bigger than the tip of the broach used to prepare the ulna and humeral canals respectively

The cancellous bone can be inserted into the canal and impacted into place using the broach of the appropriate size for the implant to be used; in this picture, the rasp still has just over 1cm to go until it is seated. By using only cancellous bone, the bone plug can easily be advanced to the appropriate level by the rasp.
This will make space for an appropriate cement mantle beyond the implant tip.

Confirm that the trial component can still be easily seated having impacted the bony cement restrictor into place.Confirm that the trial component can still be easily seated having impacted the bony cement restrictor into place.
If the trial does not seat to the original level (axis of rotation of the humerus to the level of the anterio-inferior medial epicondyle; ulnar ring to the centre of the old trochlear notch), re-broach the canal. The same steps are taken to insert and confirm appropriate positioning of the restrictor in the ulna, using the relevant broach and a narrower bony restrictor.

Clean and dry the canalsI then irrigate the canals with saline from a bladder syringe, then pack the canals with ribbon gauze to dry the bone tunnels and ensure haemostasis before changing my top gloves and preparing the components

Prepare bone graft for the humeral flangeI use a trimmed slice of cancellous bone (G) to sit behind the flange of the humeral component (F).
I try to select a wedge-shaped slice and put the wider end distally; the cancellous bone should compress to prevent the humerus being held proud, so be sure to remove any cortical or sclerotic elements. Press the positioned graft onto the textured surface on the deep surface of the flange to hold the graft in place better.
The anterior surface of the humerus should be roughened with a periosteal elevator, both to free the soft tissues to allow easy passage of the flange, and to encourage bone integration of the graft behind the flange to ensure a good press-fit in the long term, and so rotational stability for the component. By staying on the bone, there is no danger to the neurovascular structures anteriorly.

Prepare the definitive implants for insertionThe Coonrad-Morrey is coupled by an axle sleeve (1) and retaining split pin assembly mechanism (2). The split pin is behind the humeral component, with the plate and proximal part of the pin seen.
The tip of the pin flares out, and the pin is split longitudinally into quadrants so that the four elements of the pin can squeeze together when the pin is inserted into the end of the axle sleeve; the four elements will than spring back apart when the expanded tip has passed out of the plate end of the axle sleeve, and so hold the assembly mechanism securely together.
Having lined up the holes in the polyethylene in the humeral (3) and ulnar (4) components, the axle sleeve of the assembly mechanism is passed through the holes, with the split pin than passed through the centre of the axle sleeve to couple the components together. To do this, the holes in the humeral component will need to be clearly accessible away from the humeral bone, either by assembling the components before fully seating the humeral component (as is usually dome), or by resecting the tips of the medial and lateral epicondyles to expose the holes having fully seated the component, once the cement has cured. This is outlined in greater detail in the next slides.

Cement into the ulna first, followed by humerus, and pressurise.I use antibiotic-impregnated cement and a revision nozzle on the gun, as it is narrower.
While using a double-mix seems un-necessary, the process of inserting cement into both bones, both of the components, assembling the coupling and seating the components is enough to worry about. I think it is better to have too much rather than too little cement available!
I usually insert cement into the ulna first, as then the canal is filled by cement. Any blood that may come down from the humerus will not be able to pool in the ulna.
I tend to start to insert the ulnar cement with the cement still relatively soft, as the canal is tight. The canal has the ribbon gauze removed by an assistant usually between 2 mins 15 secs and 2 mins 30 secs on the cement clock (depending upon the theatre temperature- ask how quickly cement has been curing in other theatres in the same suite if possible).
Having injected the cement retrograde, an assistant can pressurise the cement with a clean glove, and remove any obvious excess cement.

The cement is injected retrograde into the humerus using a similar sequence of steps; I use my digits to restrict cement extrusion at the mouth of the humerus when the gun is nearly out to allow for some pressurisation.
Depending on the cement viscosity (which varies from mix to mix, particularly in warmer theatres), I aim to have the cement in place and be inserting the components within 3 mins-3 mins 30 secs after starting to mix; err on the side of caution by inserting the components relatively early as you don’t want to be up against time when assembling and seating the components.

Humeral component sub-total insertion is performed first, after the cement has been pressurisedI insert the humeral component first, taking care to get the rotational alignment correct, and that the flange and graft engage the anterior cortex, ideally without any interposed cement.

At this stage, stop inserting the humeral component just short of the ultimate seated position.
This allows the component to be marginally backed-out to couple the split pin mechanism at a later stage while still allowing seating of the component into a good cement mantle when finally seating the assembled component.
Clear any obvious excess cement quickly at this stage before getting on with inserting the ulnar component (your assistant can usefully help with this; don’t delay getting the implants in and assembled as the cement can be cleared later.)

The ulnar stem is introduced between the slightly prominent medial and lateral limbs of the humeral yoke (Y).Be careful to insert the ulnar component perpendicular to the flat surface of the subcutaneous proximal ulna, as was the case during preparation; my right thumb (T) is on the flat portion of the subcutaneous ulna.
Note that the holes in the humeral component for the coupling mechanism are still proud of the bone of the humeral metaphysis (Y).

Insert the ulnar component fully, and remove excess cement promptly.
At this stage you will need to make a judgement call as to whether or not you think you will be able to complete coupling of the components and drive them home to their fully-seated positions before the cement cures (in which case, continue as below- this is almost invariably the case) or not (in which case you are better off seating the components fully now, holding them in place until the cement cures, and only then assembling the coupling mechanism, which will require you to remove the bottom of the medial and lateral condyles of the humerus to expose the humeral component holes).

The holes in the polyethylene of the ulnar component should be placed centrally between the holes in the two humeral polyethylene bearings.This provide a single tunnel through which the axle sleeve of the pin assembly is passed; this holds the two components together, and is made secure by passing the split pin through the axle sleeve.
Be sure to remove any cement from the mechanism while aligning the polyethylene as this is your last opportunity to clear cement from the polyethylene (and so prevent third body wear) without having to remove the tips of the condyles and dis-assemble the components after the cement has cured.
The tip of the shaft of the axle sleeve can be seen in the centre of the humeral polyethylene in the picture.

To secure the split pin assembly, the split pin needs to be fully inserted down the central hole in the axle sleeve.The plates at the ends of both the axle sleeve and the split pin will then sit securely in the recessed rims of the humeral component holes.
The plate of the axle sleeve should be held firmly inside the recessed rim of the hole of the humeral component to stop it being pushed out while the split pin is passed along the central hole in the axle sleeve; it does not really matter which side the axle sleeve is inserted from, but I find it easier to pass the axle sleeve from medial to lateral. In the picture, I am holding the axle sleeve into the humeral component medially (M) and pushing the split pin home from the lateral side with my right hand (L).
To be sure that the split pin has fully seated and engaged, I find it helpful to ask everyone to be quiet in the theatre so that the click of the split pin quadrants springing back open can be heard.

Full seating of the splint pin assembly mechanism can be confirmed by inspecting the tip of the split pin and ensuring that the pin can rotate independently; this can be demonstrated by putting the tip of a McDonald’s dissector (M) or a scalpel blade into the gaps between the quadrants of the split pin and rotating it.

The components are now fully seated by extending the elbow fully, which pushes the humeral component home.
If for any reason the humeral component does not insert easily, there is a pushing instrument on the set to allow you to tap the component home.
In this event, confirm that the flange has not become perched on the anterior cortex at the mouth of the humeral canal, which could be an explanation for the component remaining proud.

When confirming the humeral component has fully seated, take the opportunity to clear any residual extruded cement from the articulation while it is still soft enough to wipe it away; be careful not to pull cement out from the canals while doing this!

Once the cement has cured, confirm the range of motion…

… and that there is no cement to cause polyethylene wear, or impingement between the arm and forearm and so restrict flexion.
Confirm also that the ulnar nerve is stable and is not impinging upon the articulation, transposing the nerve if there are any concerns.

After copious irrigation, and haemostasis having released the tourniquet, the extensor mechanism is closed.
I prefer multiple interrupted figure-of-8 sutures using #2 Vicryl on a stubby needle, burying the knots deeply.
I pick up the tip of the triceps flap with a horizontal pass through the tip, like with a skin corner stitch.

I prefer to close the skin with a 2-layer technique, using a continuous intra-dermal stitch supported by steristrips for the superficial layer.
Unless the patient has a bleeding diathesis (such as haemophilia), I would not routinely use a suction drain

Having applied a waterproof adhesive dressing, I apply a bulky wool’n’crepe dressing; I do not routinely immobilise the elbow.