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Patello-femoral replacement- Smith and Nephew Journey implant

    Overview

    Learn the Patello-femoral replacement: Smith and Nephew Journey implant surgical technique with step by step instructions on OrthOracle. Our e-learning platform contains high resolution images and a certified CME of the Patello-femoral replacement: Smith and Nephew Journey implant surgical procedure.
    The indication for patello-femoral partial knee replacement is isolated arthritis of the patellofemoral joint (PFJ). This is often seen in conjunction with biomechanical abnormalities such as trochlea dysplasia, patella maltracking and patella alta in a relatively young age group, of people in their fifth decade, who require intervention with arthroplasty. An older subset of patients is also recognised less frequently have these associated biomechanics issues with their PFJ arthritis. The degenerative disease in older patients may start in the PFJ, and would eventually progress to a more generalised tricompartmental arthritis should their lifespan allow; until such time they remain suitable candidates for isolated patello-femoral replacement as the risk of progression is low given their age relative to likely life-expectancy .
    The Journey patellofemoral replacement is a sided trochlea on-lay component which is produced in Oxinium to reduce wear and increase wetability. Oxinium is a trade name of a Smith and Nephew product used for joint reconstruction implants; it is oxidised zirconium as the ceramic surface of a transformed alloy through a patented process. This bearing surface is harder, more wettable and lighter than standard metal and has over ten years clinical experience. The use of Oxinium is a unique selling point for this implant with the potential benefits of longevity and better bio-integration on account of its biomechanics properties.
    R.H. Zimlich, M. Levesque, W. Jones, H.D. Schutte, Jr., B.J. Livingston, W. Sauer, M. Spector, and K. Weaver, “In-vitro and in-vivo effect of particulate debris on TKA articulating surfaces”, scientific exhibit SE038, 65th Ann. Mtg. Am. Acad. Orthop. Surg., New Orleans, LA, March 19-23, 1998.
    J. Fisher and D. Dowson, “Tribology of total artificial joints”, Proc. Instn. Mech. Engrs., 205 (H2), 1991, pp. 73-79.
    The Journey Oxinium trochlea is paired with the Genesis II Patella which is produced and distributed in two forms: the three peg onlay and the single peg biconvex inlay design. Whilst both designs have long-term follow-up, my preference is for the inlay biconvex single peg component to allow fine-tuning of the patella (bone and polyethylene) thickness during the preparation steps as described in this technique.
    My reason for using the Journey PFJ is a combination of familiarity with the Genesis II patella (being a Genesis user for total knee replacements) and the theoretical and laboratory suggested benefits of Oxinium to reduce wear and improve wetability.

    Indications

    INDICATIONS
    Isolated arthritis of the patellofemoral joint (PFJ). This is often in conjunction with trochlea dysplasia, patella maltracking and patella alta. There is a bi-modal distribution of patient age for PFJ replacement in patellofemoral joint osteoarthritis (PFJOA) . Caution should be exercised with 60-75 year-old patients because their PFJ arthritis may progress into tricompartmental change. Patients in their 50s present early with PFJ arthritis because of a predisposing factors such as trochlear dysplasia or patella alta. In this age group progression of arthritis is unlikely because the predisposing bio-mechanical abnormality is treated with the patella femoral replacement.
    In the elderly population it is acceptable to perform patella femoral replacement for isolated PFJ disease in the absence of a biomechanical abnormality as the chance of progression is relatively low due to likely patient lifetime survival.
    SYMPTOMS & EXAMINATION
    History
    Patients complaining of generalised anterior pain in the knee. This is made worse by periods of inability with the knee flexed such as sitting in a confined space like a cinema seat or aircraft seat or back of a car. activities which load the patellofemoral joint will be more painful with post-activity swelling and stiffness. Classic aggravating activities include stairs (both ascent and descent but often with descent as the most problematic), squatting and kneeling. it is important to ask about personal history of adolescent knee pain including Osgood-Schlatter’s disease patella dislocation or patellofemoral overload often labelled as “Chondromalacia patellae”. In addition a family history should be sought as there are strong familial links to PFJ disease.
    Examination
    The examination should start with an assessment of walking follwed by a Trendelenberg and an attempt at squatting. there is classically an antalgic gate if there is a unilateral disease or a stiff knee gate and bilateral disease. Frequently there is proximal muscle weakness/poor gluteal recruitment Which may be assessed during gate pattern or on a Trendelenberg test. Personally I prefer to perform a Trendelenberg test (in this patient group) asking them to place their hands on the hips over the Iliac crests then standing on one leg at a time, observing pelvic tilt by inequality of hand position; if the abductors are weak in the standing leg then the opposite hand will drop down. During squats testing there is usually audible crepitus and the patient will be unable to proceed due to pain. Frequently patients will lean to their favourite side indicating which joint is most symptomatic.
    Sitting examination is very useful to demonstrate patellofemoral height and tracking. in this position it is also prudent to rotate the hip to exclude any referred pain from the hip joint. The patella often starts laterally In full extension then moves medially as it engages in the trochlea before moving laterally again during deeper flexion. This is a reflection of a number of biomechanical abnormalities which are common in PFJ arthritis. The first of these to detect is patella alta where the patella is proximally positioned relative to the trochlea. Patients often describe this as having ‘knobbly knees’! I look for a positive ‘ski jump’ sign by running my hand distally down the quadriceps muscle and looking for a takeoff jump on the patella. Other techniques described for this include the three finger test for the distance between inferior pole and typical however this is very size dependent both for patient and examiner!
    Supine examination should then be performed to detect effusion, Range of motion, localised areas of tenderness usually in the patellofemoral joint but not in the tibiofemoral joint line and irritability of the PFJ on compression testing – Clarks test. Caution is required here as this is often painful; I would suggest gently positioning the patella into the trochlear groove passively and should this be painful stopping the test at that stage, quadriceps activation only being required if the initial test is negative. A standard knee examination should be completed to exclude intra-articular pathology.
    IMAGING
    Plain x-rays including alignment views particularly looking for excessive valgus, skyline x-rays weight-bearing laterals and Rosenberg views should be performed both to demonstrateThe patellofemoral arthritis with loss of joint space but also to exclude any significant tibiofemoral joint space reduction.
    MRI scan is very useful to demonstrate a well preserved medial and lateral joint as well as the localised PFJ arthritis and the patellofemoral indices. The presence of trochlea dysplasia, patella alta (evidenced by reduced patellotrochlea overlap) and bone loss in a worn dysplastic patella should be recorded. I prefer an MRI in addition to plain radiography.
    ALTERNATIVE OPERATIVE TREATMENT
    Total knee replacement is the standard treatment of end-stage knee arthritis including PFJ arthritis. In the largest RCT comparing PFJ arthroplasty to TKR (Odgard A et al CORR 2018) Isolated patella femoral replacement resulted in better patient reported outcomes and better range of movement than total knee replacement. however the reduced long-term survival rates found in the National Joint Registry must also be remembered and stringent patient selection adhered to.
    In early disease it may be possible to perform tibial tubercle osteotomy to correct biomechanics (distalising and usually medialising) in addition to a subtle anteriorisation, by the direction of the ostoeotomy (posterolateral to anteromedial).
    NON-OPERATIVE MANAGEMENT
    Like all arthroplasty nonoperative treatment must be exhausted before proceeding to replacement. Careful physiotherapy assessment, gait re-education where appropriate and strengthening should be performed. consideration of shock absorbing insoles and walking aids as well as standard analgesic treatments.
    CONTRAINDICATIONS
    General absolute contraindications include active infection and medical comorbidities precluding arthroplasty.
    Specific absolute contraindications include evidence of tibio-femoral arthritis.
    Relative contraindications include patient age (60 to 75) and minor tibiofemoral chondral change or meniscal pathology where there is a risk of disease progression.

    Setup

    General anaesthesisa
    Preoperative IV Antiobiotics
    My personal preference is to avoid a tourniquet, but this certainly may be used according to surgeon preference.
    Notice the position of the table within the operating theatre / room to allow all the sets sit with the laminar flow and maintaining the patient’s head, anaesthetist and assistant outside the laminar flow.
    Side support and foot roll at approximately 90 degrees knee flexion, heels over the end of the bed, allowing for standing at the end of the table to assess component rotation.
    Foot pump on the contra-lateral foot.
    Social wash and then 2% chlorhexidine in alcohol preparation and standard draping with an exclusion U-drape, additional large drape around the end of the operating table and then a knee extremity drape. Exclusion draping with Ioban.

    Operation – 1

    Lateral Radiograph of a 51 year old patient with evidence of osteophytes on the patella.

    Preoperative AP radiograph of a 51 year old patient demonstrating well preserved tibia femoral joints.

    Long leg Radiograph shows excellent overall alignment with the weight bearing axis passing through the centre of the knee joint. Note that the medial and lateral tibia-femoral joints are well-preserved.
    Patient selection is key in PFJ replacement and caution should be excercised in significant varus or valgus patients as they are likely to progress on the overloaded tibia-femoral compartment.

    The skyline XR demonstrates lateral facet wear by osteophytes and reduced joint space, but in this case, as sometimes happens, completely underestimates the severity of the OA.
    This is well seen in the MRI below.

    This axial MRI cut through the PFJ shows a dominant lateral facet on both the trochlea and the patella. There is evidence of complete loss of lateral facet chondral surface and underlying bone marrow oedema in the patella lateral facet.
    Thus there is full thickness lateral patellofemoral OA.

    Complete loss of chondral surface in the PFJ in this saggital MRI sequence through the lateral half of the knee. Notice the bone marrow oedema in the lateral trochlea.

    This MRI slice shows a very well preserved medial and lateral tibia-femoral chondral surface, medial and lateral menisci and no underlying bone marrow oedema.

    The set up position is similar to a total knee replacement with a side support and foot roleThe operative table should be placed with the head of the patient on the outline of the laminar flow. This ensures sufficient space within the laminar flow for all the operatives sets.
    Patient warming may be achieved by warmed and a blanket or hot air surrounding blanket, however caution must be observed during application of a forced air warming device to ensure that there is no leak of air over the operative site. Instead the leak of hot air should be from the head end and outside of the laminar flow zone.
    My personal preference is for a foot pump on the contralateral like a pre-wash with chlorhexidine and then 2% alcoholic preparation of chlorhexidine to include the whole lower limb and then draping with U-drape then an exclusion drape.

    The leg is wrapped in a sterile Ioban and the foot roll is set with a knee flexion of approximately 90°.

    Free draping of the limb to allow flexion and extension with a resting position of approximately 90°.

    The skin incision is made with a slightly oblique incisionIt runs proximal medial to distal lateral centred on the medial side of the patella.

    The skin is raised medially to expose the vastus medialis muscle The vastus medialis muscle(1) seen here in the centre of the image.
    Laterally the skin should be raised to expose the patella. It is imperative to maintain full thickness skin flaps to avoid problems with superficial skin necrosis.

    Haemostasis is obtained. There are two very reproducible vessels which require electrocautery during the medial sub-vastus approachThe first of these is in the centre of the vastus medialis seen here held by the forceps and the second is adjacent to the MPFL (medial patellofemoral ligament) which runs on the deep surface of the vastus medialis between the femur and the patella.

    A sub-muscular pocket is developed by blunt the section with the operator’s finger.

    Next the capsulotomy is made in an L-shaped manner for a subvastus approach.To put this in appropriate context the surgeon’s standard approach should be used. In a subvastus approach the distal half of the capsulotomy is identical to a medial parapatellar approach. More proximally the fascia just distal to the Vastus Medialis (VM) should be incised and then the MPFL divided close to its origin. Once this is released the VM will mobilise allowing for subluxation of the patella laterally.

    The quadriceps is elevated and patella subluxed.Hohman retractors are inserted under the vastus medalis and the patella subluxed laterally as the knee is flexed.

    The patella and trochlear notch are inspected to identify the extent of arthritic change.The trochlea is exposed allowing the bare bone on the lateral side of the trochlea (1) to be seen. This is the comment pattern of PFJ OA.

    Osteophytes are removed with a combination of Rongeurs and osteotomes.

    Anterior implant alignment is orientated with the anterior femoral cortical guide.The first instrument is the anterior femoral cortical guide which runs up the anterior femur beneath the Rectus Femoris.

    Be careful to look for impingement of the guide rod on the trochlea.This is particularly common in trochlea dysplastic patients who form a large subset of PFJ OA cases.
    In severe trochlea dysplasia the anterior guide wire is artificially elevated risking anteriorisation of the entry hole and subsequent extension or anteriorisation of the trochlea component which is an error in PFJ replacement.

    Preparing for intramedullary alignmentThe next instrument to be applied is often referred to as the ‘L’. In this slide it is being applied to the extramedullary guide wire. The ‘L’ piece offsets a fixed amount from the anterior femur and provides a drill guide for the opening in which to introduce the Intramedullary guide rod. This is a potential source of error due to the differing sizes of patients and the single size of the ‘L’; thus in a large patient the entry hole would be suggested by the jig within the trochlea rather than within the notch of the knee. Similarly there is a risk in trochlea dysplastic patients of falsely anteriorising the extra-medullary femoral guide wire as in the previous slide, which will also then suggest an over interiorised entry hole.

    Preparing for intramedullary rodI have marked the hole determined by the L jig with diathermy (marked ‘1’) but then removed the jig and confirm that this point is sufficiently posterior – ie deep into the trochlea notch.

    Drilling for the femoral Intramedullary rodIf the marked entry hole is too anterior a more posterior entry hole should be selected.
    Here the intramedullary (I/M) canal is being opened by small opening drill on the set. The direction of the drill should be determined by the ‘L’ piece jig in the above slide. In small patients the jig will position the entry hole within the notch and the ‘L’ piece can be left in place.

    Femoral intramedullary rod insertedThe I/M guide rod from the Journey set is introduced and the handle removed.

    Applying the anterior femoral cutting blockThe correct side anterior femoral cutting guide (sided right and left) is then inserted onto the I/M rod through the side slotted couple.

    Operation – 2

    Applying the alignment handle to the anterior femoral cutting blockA quick release handle is inserted into the cutting guide on the anterior aspect.

    Ensure the anterior cutting block is clipped onto the intramedullary rodThe ideal place for the operating surgeon to stand is at the end of the bed facing the knee and jig ‘head on’. This avoids parallax and stops the surgeon twisting their own back!.
    The ‘Cruciform’ alignment device is then inserted through the quick release handle.
    This is an additional reference check for alignment in the coronal and sagittal plane, but this should be achieved by the I/M rod already. The main purpose of this step is to set femoral jig rotation.
    I prefer this method and I align to the transepicondylar axis as in TKR, but remembering to be perpendicular to the tibial shaft.
    There is an extra-medullary tibial clamp which can also be used to set femoral rotation.

    Confirm anterior cutting block rotation and drill in the first pinOnce the surgeon is happy with the position of the jig (particularly rotation in this step) the assistant drills or drill-pins the jig into position being careful not to damage healthy articular surface – there are numerous holes to fit differing patient sizes. Here the most antero-medial hole is being used.

    The anterior femoral cutting block second pin is drilled.The second pin is inserted. There are multiple options, but here one of the central (notch) pin holes is being drill-pinned.

    A stylus used to measure the estimated depth of anterior resection.A bird’s eye view of the anterior femoral cutting block with the stylus inserted(1). I like to position this on the anterolateral cortex of the femur.

    The central locking hex head screw is secured once the appropriate height of anterior resection has been set.
    The ideal resection level is flush with the anterior femoral cortex. Some surgeons prefer to introduce some additional flexion here to mimic the anterior femoral bow and to reduce the chance of ‘over-stuffing’ the PFJ by anteriorising or extending the trochlea component .
    This cutting height should be checked with an angel wing before proceeding to the next step.

    The anterior femoral resection is performed.With retractors protecting the laterally subluxed quadriceps, the anterior femoral cut is made.

    The anterior femoral cutting block is removed.The pins are removed and the block removed.

    Initial trial of femoral componentA trial femoral component with built in drill guides is then placed anteriorly to size the cut femoral surface. In this case the most appropriate size is ‘small’ media-laterally, but there is a significant space from the notch to the ‘bottom’ of the implant ie its most posterior point. I have highlighted this with my finger placed at the top of the notch and there is approximately 3mm uncovered remaining trochlea.
    This will be addressed in the next slide by an additional anterior cut to posteriorise and flex the trochlea component. These next steps are only required if there is mismatch of mediolateral and AP dimensions in a particular patient.

    Fine tune the anterior femoral cut freehandThis step is only required if there is a problem of mismatch between mediolateral coverage and and anteroposterior coverage. This occurs in Total Knee Arthroplasty and PFJ arthroplasty in approximately 20% of cases. A freehand anterior cut is started 2mm posterior, but parallel to the existing anterior femoral cut.

    Flexing the anterior femoral cut freehandThe saw is then carefully flexed by approximately 5 degrees to allow a new trajectory in the 2nd and more posterior cut, but without notching the anterior femur more proximally on the cut surface.

    Retrialing the femoral jig/component The small trochlea component/jig is replaced with a quick release handle to ensure the new cut is flush and the component now covers all the trochlear down to the top of the notch.

    Check the femoral component jig position and insert the first pinThe trochlea components jig is then drill-pinned through the ‘target’ holes which have a circular laser mark around them for clarity.

    Check the trochlear component jigs position and rotation before inserting the second pinThe femoral rotation and alignment are checked.

    The second drill pin is inserted to secure the femoral trochlear components jig.

    Once the trochlear jig is in place mark around the trochlea.The quick release handle has been removed just to demonstrate the component/jig in situ, but in normal practice in can be left.

    Leave the femoral trochlear component jig pins in placeAgain here I am using the drill pin holder to highlight the existing pins in the femur. These should be left in situ and the femoral trochlear component jig removed in the next slide.

    Remove the femoral trochlear component jig The quick release handle is replaced here, but remember in normal practice this would not have been removed after the second pin secures the component/jig.
    It is sensible to mark around the trochlea down to the notch with a marker pen or scoring with an osteotome.

    Place the yolk for the trochlea reamer over the existing pins and secure with additional pinsThe femoral yolk is then placed over the existing drill pins in the anterior femur and held down to the notch and the anterior surface of the femur with additional pins.

    Ream for the trochlea component through the femoral yolk, being careful in particular at the outer margins. Trochlea reaming is performed using a yellow sizing stopper. This is the shallowest reamer and is designed to contact the yolk thus limiting the depth of ream. The tip of the reamer is located into the base of the metal jig and the reamer is then turned on and moved medially and laterally. Once sufficient reaming has been performed the yellow plastic will contact the margin of the jig anteriorly
    Green and Blue sleeves are available if required should more reaming be required; green is slightly deeper than yellow and blue is the deepest reaming sleeve.

    Careful attention at the shoulders of the trochlea reaming where the component will eventually sit next to the native cartilage. In order to achieve sufficient depth in the corner regions, one option is to remove the sleeve and deepen under direct vision. Alternatively the green and then blue sleeves could be used.

    “Trial” the mini trochlea component in the bed produced by the reaming.The mini trochlea component checks that sufficient reaming has been performed; whilst maintaining the yolk in situ the mini trochlea is inserted into the reamed area to check that the the component is flush or sunken to the native trochlea. The metal yolk is still in place should any further reaming be required.
    Remember the trochlea component must be flush or recessed to the native cartilage.
    Once the surgeon is satisfied that sufficient bone has been reamed then the yolk is removed.

    Reapply the femoral trochlea component jig again after reaming of the trochlea surface. The same femoral component/jig is reapplied into the reamed trochlea.
    If there is concern over any proud bone centrally then a rasp is provided to smooth this down.

    Femoral component position is rechecked with the reapplied femoral trochlea component jig.The surgeon holds this position whilst the assistant pins through the non-laser lined holes. Thus these are different pin holes to those drilled earlier in the procedure.
    Remember the holes drilled initially are through the laser-lined holes.

    The reapplied femoral trochlear component jig is pinned into place again.First pin to secure the femoral trochlea component jig in situ.

    Operation – 3

    Securing the trial trochlea component/jig.Second pin to secure the femoral component jig in situ.

    Final position check of the trochlea.The position of the trochlea component should be checked again at this stage before the lug-holes are drilled.
    Remember:
    Alignment – cruciform pointing to the ASIS
    Rotation – handle of the cruciform jig slightly externally rotated to the trance-epicondylar axis.
    The trochlea component must be flush of slightly sunken relative to the native trochlea.

    The first femoral lug-hole is drilled There are four lug-hole drills. Here the most proximal hole is being drilled. Once drilled the holes can be plugged with custom-made pegs on the Journey set.
    I always use the first one and sometimes a second depending on bone quality, but rarely require the 3rd or 4th.

    The femoral lug-hole has been plugged.Here there is a peg in the first lug drill hole at the most proximal hole of the component jig.

    Three more lug-holes are then drilledThere is the option to plug all four; I always use one and sometimes two in soft bone.

    Femoral Component trial with lugs inserted and impactedThe small left femoral (lugged) trial is then inserted and impacted.

    Once the femoral component trial in position trial the prosthetic trochlea agains the native patella to ensure there is no jumpingThe femoral component is in position.
    At this stage I like to trial the prosthetic trochlea agains the native (still arthritic) patella to ensure there is no jumping. If there is any jumping at this stage then there is a problem with the trochlea. If this step is missed out and only trialled later it is not known whether the problem is in the trochlea or the patella.

    Attention is then turned to the patella. In this slide the patella is exposed by a Lane’s tissue clamp on the quadriceps and a Hohman’s retractor lifting the vastus medialis away.

    Osteophyte removal from the patellaThe peri-patella osteophytes are then removed. I prefer to use the saw, but bone nibblers would also work.

    Patella Biconvex Inset Jig positioned and clampedWith a Hohman under the lateral edge of the patella lifting it into view and the knee in extension, a clear view of the patella is obtained. The most appropriate sized patella tower is then chosen. It is important that there is some surrounding patella bone to provide a shoulder which will support the inset patella.
    If a resurfacing technique is preferred for the patella, this is also available with this design. This uses a flat patella cut and a three-pegged onlay patella.


    The patella is measured with callipers both mediolaterally for width and antero-posteriorlyThe patella is measured with callipers both mediolaterally for width and antero-posteriorly through the jig which has a hole cut out to allow measurement; this gives the native patella thickness.
    I try to reconstruct as close as possible to the natural ratio observed in the native knee as published by Sullivan et al and described as BIPWiT (Bristol Index of Patella Width to Thickness. (Knee. 2014 Dec;21(6):1058-62)
    The real benefit of this tower and reaming system is that the thickness of the final construct can be fine-tuned.

    The patella is then reamed through the jig.The minimum ream is to create an inset patella so that there is a shoulder of bone around the patella insert. Once this has been achieved the depth stop can be set and the overall construct thickness re-measured.
    Thus the minimum reaming depth will produce a good shoulder around the polyethylene button.
    There is a 9mm resection guide which removes the same amount of bone as the patella replacement, but this does not allow any fine-tuning of the patella thickness.

    Trial patella button inserted down the jigThe 23mm inset patella is positioned into the tower.

    Button in place The patella trial is sitting in situ within the tower on the clamp.

    Check patella measurements with the trial implant temporarily in-situ.Repeat measuring with callipers to check overall construct thickness. The ideal construct thickness may be calculated using the ratio of patella width to thickness. In order to match the native patella the width/thickness = 1.8. This can therefore applied to the reconstruction of worn patellae when the width is known, an estimation of the ideal construct thickness may be calculated by dividing the width by 1.8.
    Thus if a patella is 45mm wide then the ideal construct thickness should be 45/1.8 = 25mm
    The jig is then removed.

    The patella button in situ. Notice the surrounding osteophytes.

    Further chamfering of the native patella margins once the trial is in situ.Excision of patella osteophytes. I prefer the saw but this can be achieved by other means for example bone nibblers.

    Patella trial in positionBiconvex patella button sitting appropriately inset into the patella with the surrounding bone trimmed.

    Local anaesthetic Infiltration, pulsed lavage and dry.Local Infiltration anaesthesia using a long needle; a grey (16G) venflon needle with both screw cap and adaptor removed makes a good, cheap and long needle for this purpose.
    REMEMBER TO ASPIRATE AND TELL THE ANAESTHETIST BEFORE INFILTRATING.
    We use a cocktail (known locally as ‘Murray Mix’) of 150ml of 0.1% Marcain with 0.6mg Adrenaline, 30mg Ketorolac and 10mg Morphine.
    The Ketorolac and Morphine are placed in one of the three 50ml syringes.
    Syringe 1. Skin – infiltrated at the start of the procedure.
    Syringe 2. Periosteal and capsule – instilled after preparation
    Syringe 3 (Morphine and Ketorolac) – instilled deep into the posterior capsule – it is vital to aspirate and I suggest moving the needle 4 times to guard against intravascular infiltration.
    Pulsed lavage with Normal Saline (as opposed to my usual chlorhexidine for total knee arthroplasty) in view of partial joint replacement and concern over the remaining cartilage with chlorhexidine.

    The components are checked (small left Journey trochlea and 23 mm biconvex Genesis II patella) and then opened.

    The femoral trochlea is lavaged, dried and the femoral component implanted.I use Palacos Regular cement with Gentamicin (Heraeus)


    Cement on both bone and implant surfaces prior to femoral (trochlea) component implantation.

    The trochlea component is inserted by hand.

    Impaction of trochlea componentThe trochlea component is impacted into place.

    Clear the excess cement from the trochlea componentExcess cement is removed by a MacDonald retractor.

    Operation – 4

    The Oxinium Journey trochlea component in situ.

    Remove the patella trial button and lavage the prepared patella bed.The patella trial is then removed. I like to keep this in situ in the lateral gutter during the trochlea cementation to protect the shoulder of bone on the patella.

    Notice how the patella bed is blood stained.

    Pulsed lavage with normal Saline (as opposed to my usual chlorhexidine for total knee arthroplasty) in view of partial joint replacement and concern over the remaining cartilage with chlorhexidine.
    The patella bed is now clean, dry and ready for cement.

    Cement and clamp the patellaPalacos regular cement with Gentamicin (Heraeus) is gunned into the prepared patella bed.

    The patella button is introduced by hand to engage the peg of the button and then.

    The patella clamp is positioned and tightened.

    Removal of excess patella cementThe excess cement is removed by MacDonald retractor.

    Final view of the patella button in situ before reduction.

    Reduction of the subluxed patella once the patella cement has set.The extensor mechanism has now been reduced over the trochlea. Notice how the vastus medalis covers the whole arthroplasty with this medial subvastus approach.

    Final check of range and trackingA final check of range of movement and patella tracking is performed.

    Capsular closureClosure in layers:
    Capsule – I use a barbed number 1 monofilament absorbable suture.


    Deep dermal closureDeep dermis is closed with interrupted then continuous 2-0 absorbable sutures.

    Skin closureSkin – subcuticular absorbable barbed 2-0 monofilament is my personal preference

    Skin glue – application of this with the skin wet makes the glue cure much quicker.

    Steristrips crossed so that they sit within the non-adherent part of the occlusive dressing

    Clear occlusive, showerproof dressing.

    Compression bandage is appliedWool and Crepe for 24 hours, which is then reduced and a tubigrip applied

    Post-operative AP Radiograph showing a well-centred trochlea component with the patella button co-linear with the proximal part of the trochlea component.

    Post-operative lateral radiograph showing the trochlea component flush with the anterior cortex of the femur and the distal most extent of the trochlea component deep in the femoral notch at Blumensaat’s line. As in the AP above the patella I sitting overlying the trochlea component and the overall construct thickness of the patella looks appropriate.

    Post Operative

    Over the last year we have changed PFJ arthroplasty into a day case or overnight stay procedure depending on the time of operating. Case performed in the morning or early afternoon tend to be day-case, whereas later afternoon and evening session cases stay in our Medirooms overnight – the equivalent of a day-case facility – and the are discharged first thing the following morning, allowing the mede-rooms to be available for the next-day’s patients.
    Standard care postoperatively
    Antibiotics: 24 hours prophylaxis – we use Flucloxacillin 1000mg x 3 postoperatively, in addition to the induction Flucloxacillin and Gentamycin on induction. The remaining doses (of the 24 hour schedule) on patient discharge are given orally as take-away medication.
    Overnight stay or day case surgery.
    Weight Bearing: full weight bear as soon as possible.
    Bloods: Haemocue in revovery.
    Radiograph: Anteroposterior and lateral XR
    Dressing: Bulky wool compression bandage reduced at 12 hours and replaced with a single tubigrip.
    Dressing: occlusive dressing left in situ for 2 weeks, ideally undisturbed from theatre, but changed on the rare occasions that the wound leaks.
    Venous thromboembolism prophylaxis: Aspirin 150mg for 6 weeks orally for standard risk. Patients with previous VTE receive 10 days of low molecular weight heparin (LMWH) in addition to their Aspirin. Patients on prophylactic long term anticoagulants including NOACs should simply return to their normal medication on day 2, using LMWH at prophylactic dose on day 1.
    Follow-up – depending on the patient’s functional ability we usually ask them to remove their own dressing at 2 weeks, but where this is impractical we review in our outpatient department at 2 weeks. Subsequent review is scheduled as: 6-8 weeks, 12 months, 2 years, 7, 10,13 years continuing every 3 years as per UK National Guidance
    Variance – Any concerns with the wound should trigger a review by the treating surgical team and must not be managed in the community.

    Recommended Reading

    There are limited results for any patellofemoral replacement system.
    At a mean of seven years we found an 88% survival of implants and good patient satisfaction.
    Knee. 2016 Oct;23(5):900-4. doi: 10.1016/j.knee.2016.03.004 .The Journey patellofemoral joint arthroplasty: A minimum 5year follow-up study.
    Ahearn N, Metcalfe AJ, Hassaballa MA, Porteous AJ, Robinson JR, Murray JR, Newman JH.
    Knee. 2016 Oct;23(5):900-4. doi: 10.1016/j.knee.2016.03.004 .The Journey patellofemoral joint arthroplasty: A minimum 5year follow-up study.
    Ahearn N, Metcalfe AJ, Hassaballa MA, Porteous AJ, Robinson JR, Murray JR, Newman JH.

    As a comparison using the Avon PFJ replacement the implant survival was 77% at 10 years and 67% at 15 years.
    Bone Joint J. 2018 Sep;100-B(9):1162-1167. doi: 10.1302/0301-620X.100B9.BJJ-2018-0174.R1. The Avon patellofemoral joint arthroplasty: two- to 18-year results of a large single-centre cohort.
    Metcalfe AJ, Ahearn N, Hassaballa MA, Parsons N, Ackroyd CE, Murray JR, Robinson JR, Eldridge JD, Porteous AJ.

    Reference

    • orthoracle.com

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