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Patello-femoral replacement- Avon implant (Stryker)

    Overview

    Learn the Patello-femoral replacement: Avon implant (Stryker) 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: Avon implant (Stryker) surgical procedure.
    Partial knee replacement is an alternative to total knee arthroplasty when there is a localized pattern of arthritis effecting a single compartment of the knee. There are three well-documented patterns of knee arthritis:
    Medial – this is an anteromedial pattern with a preserved posteromedial ‘shelf’ of medial plateau which maintains the functional length of the Medial Collateral Ligament.
    Lateral – this is more posterocentral in the lateral compartment giving a flexion pain and instability
    Patellofemoral – this is often associated with either patella alta (the patella situated proximal relative to the trochlea) or trochlea dysplasia (where there is an abnormal development of the PFJ with lateral dominance and a shallow or even domed trochlea groove)
    There has been considerable concern over partial knee replacement as the revision rates for these procedures is recorded as being higher than that for total knee arthroplasty on multiple registries. Consequently the longevity of partial knee replacement is lower than total knee arthroplasty in large data-sets. However there are also distinct advantages both to patients and when regarding the broader health care economics of the procedure, as is now evident from the published results of prospective randomized controlled trials of total versus partial (unicompartmental and patellofemoral) knee arthroplasty. The complication rates and mortality rates are certainly lower when comparing the results of partial to total knee arthroplasty.
    The most notable of papers that readers should be familiar with are:
    ” The clinical and cost-effectiveness of total versus partial knee replacement in patients with medial compartment osteoarthritis (TOPKAT): 5-year outcomes of a randomised controlled trial. Beard DJ et al. Published:July 17, 2019 DOI:https://doi.org/10.1016/S0140-6736(19)31281-4
    Patellofemoral Arthroplasty Results in Better Range of Movement and Early Patient-reported Outcomes Than TKA. Odgaard A, Madsen F, Kristensen PW, Kappel A, Fabrin J. Clin Orthop Relat Res. 2018 Jan;476(1):87-100. This paper shows a better functional outcome for PFJ than TKA up to 9 months in may patient reported domains, but by 2 years the only difference is better flexion by 10 degrees in the PFJ group compared to the TKA.
    Adverse outcomes after total and unicompartmental knee replacement in 101,330 matched patients: a study of data from the National Joint Registry for England and Wales. Liddle AD, Judge A, Pandit H, Murray DW. Lancet. 2014 Oct 18;384(9952):1437-45
    45-day mortality after 467,779 knee replacements for osteoarthritis from the National Joint Registry for England and Wales: an observational study. Hunt LP, Ben-Shlomo Y, Clark EM, Dieppe P, Judge A, MacGregor AJ, Tobias JH, Vernon K, Blom AW; National Joint Registry for England and Wales. Lancet. 2014 Oct 18;384(9952):1429-36.
    How long does a knee replacement last? A systematic review and meta-analysis of case series and national registry reports with more than 15 years of follow-up.Evans JT, Walker RW, Evans JP, Blom AW, Sayers A, Whitehouse MR.Lancet. 2019 Feb 16;393(10172):655-663. doi: 10.1016/S0140-6736(18)32531-5. Epub 2019 Feb 14. Erratum in: Lancet. 2019 Feb 20
    The Odgaard paper is the most relevant for this operation technique section, but whilst there are significant benefits for patients with isolated patellofemoral joint OA to undergo patellofemoral arthroplasty it is important to discuss disease progression and possible future revision in order to reach a balanced and mutual decision on which operation is best for each individual patient.
    The Avon patellofemoral joint arthroplasty is a non-sided onlay design which resects the degenerative anterior trochlea and diseased chondral surface of the patella. There is no size constraint to match patella size to trochlea component, in order to achieve correct sizing of each component independently.

    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 inactivity 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 followed by a Trendelenberg test and an attempt at squatting. There is classically an antalgic gate if there is unilateral disease or a stiff knee gait with bilateral disease. Frequently there is proximal muscle weakness/poor gluteal recruitment which may be assessed during gait pattern or on a Trendelenberg test. Personally I prefer to perform a Trendelenberg test (in this patient group) asking the patient 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 take-off 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 on the tibiofemoral joint line) and irritability of the PFJ on compression testing, known as Clarks test. Caution is required here as this is often painful; I would suggest gently positioning the patella into the trochlea 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 assist in detecting associated intra-articular pathology.
    IMAGING
    Plain x-rays including alignment views particularly looking for excessive valgus, skyline x-rays weight-bearing laterals and Rosenberg views( a P-A 45 degree flexion film, to stress the tibiofemoral joints under a simulated load) should be performed both to demonstrate the 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) demonstrated that isolated patellofemoral 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 non-operative 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 (walking poles are often better tolerated than sticks!) 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. When considering PFJ arthroplasty in this age group an MRI is very reassuring if the tibio-femoral joint surfaces are good, with intact menisci.

    Setup

    The 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 operative sets.
    The set up position is similar to a total knee replacement with a side support and foot roll. 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 leg, a pre-wash of the operative leg with chlorhexidine and no tourniquet. However if a surgeon normally uses a tourniquet then this should be applied and used in their standard manner.
    I then use 2% alcoholic preparation of chlorhexidine to include the whole lower limb and then draping with U-drape then an exclusion drape.

    Operation – 1

    Lateral facet patello-femoral joint arthritis is visible with osteophytes and loss of joint space, but this does not look severe.
    The plain X-ray appearance however can be deceptive as the subsequent MRIs in this pre-operative imaging sequence will demonstrate.

    The lateral radiograph shows loss of joint space in the PFJ and proximal osteophytes.

    The Rosenburg Xray is taken as a P-A 45 degree flexion film, to stress the tibiofemoral joints under a simulated load. It is particularly sensitive to lateral tibiofemoral OA where the wear pattern is usually in mid flexion.
    In this film there is excellent preservation of the tibiofemoral joints under load.

    Good overall alignment with the weight-bearing axis passing through the centre of the knee. One should be aware that severe valgus knees may coexist with with PFJ OA, and this should be looked for.
    Note the Rosenburg X-Ray above which shows excellent preservation of the lateral tibiofemoral joint.

    The axial MRI demonstrates full thickness chondral loss in this case of PFJ osteoarthritis associated with clear trochlea dysplasia.

    The sagittal MRI reveals full thickness PFJ OA but no evidence of patella Alta, as there is good patello-trochlea overlap superiorly.
    The sagittal sequences should also be used to check for the integrity of the medial and lateral tibia-femoral joints as in the next slide on the coronal MRI.

    The coronal MRI showing excellent medial and lateral tibiofemoral joint integrity. Particular attention should be given to:
    Integrity of the menisci – beware any intrameniscal signal change or root damage.
    Chondral surfaces
    Subchondral thickening
    Bone Marrow Oedema.

    The set up position is similar to a total knee replacement with a side support and foot roll.Free limb draping to allow full flexion and extension with a resting position of approximately 90°. Here the exclusion drape used is an Ioban, positioned after marking of the desired incision wound.

    For the skin incision use a slightly oblique incision proximal medial to distal lateral centred on the medial side of the patella.

    The skin is raised medially to expose the vastus medialis muscle, and a sub-muscular pocket is developed by blunt dissection with the operator’s finger underneath the muscle belly.Laterally the skin should be raised to expose the patella. It is imperative to maintain full thickness skin flaps to avoid problems with superficial necrosis

    Haemostasis is secured obtained. There are two very reproducible vessels which require electrocautery during the medial sub-vastus approach; The 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.

    The capsulotomy is made in an L-shaped manner for a subvastus approach, although a surgeon’s standard and alternate approach can be used.
    In a subvastus approach the distal half of the capsulotomy is identical to a medial parapatellar approach up to the insertion of Vastus Medialis (labelled ‘1’). At this point an acute angle should be formed as described in the following steps.

    More proximally the fascia just distal to the Vastus Medialis (VM) should be incised and then the MPFL divided close to its origin.

    Place a Hohmans retractor under the Vastus Medialis, to assist with exposure and patella subluxation.Once the MPFL is released the VM will mobilise allowing the insertion of a Hohman’s retractor and then subluxation of the patella laterally as the knee is flexed to expose the joint as in the next slide.

    An initial step once the knee joint is fully exposed is to remove all the osteophytes to define the normal joint dimensions.The trochlea is exposed allowing the bare bone on its lateral aspect (1) to be seen. This is the common pattern of PFJ OA, lateral facet PFJ OA.
    Osteophytes are removed with a combination of Rongeurs and osteotomes.

    Local anaesthetic infiltration (150ml of 0.1% Bupivacaine with 0.2mg Adrenaline, 30mg Ketorolac and 10mg Morphine) is employed early to reduce bleeding and optimise pain control.
    Three areas should be targeted:
    50 ml in the skin – start of the procedure.
    50 ml periosteal / adductor canal – periosteal injection of the femur shown in this image.
    50 ml popliteal fossa through the notch. (introduced later on in the procedure)

    The first instrument inserted is the anterior femoral cortical guide which is extramedullary and like a finger that sits on the exposed anterior femur.
    Please be careful to look for impingement of the guide 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.

    The “anterior finger” is then attached to the femoral jig for sagittal alignment and the rotational alignment is then determined using the surgeon’s favoured method, for example the trans-epicondylar axis.
    Other options in determining rotation are :
    Perpendicular to the tibia
    The anterior femur
    Whiteside’s line, the sulcus of the trochlea to the top of the notch. Beware in PFJ arthritis cases because, as in trochlea dysplasia, there will be lateral dominance and thus Whiteside’s line will be relatively internally rotated.

    Secure the femoral guide in place with pins.Once the surgeon is happy with the rotation of this jig, it is drill-pinned in position.

    The final jig position, now pinned in place.

    The “anterior finger” is removed to allow for attachment of the anterior femoral cutting guide.

    The anterior femoral cutting guide is positioned at the appropriate depth of cut, which is flush with the anterior femoral cortex.Remove all the native trochlea, and “dial in” some external rotation to help with patella tracking.

    The anterior femoral cutting guide is locked in place with the screw-driver, at the desired cut height.

    If there is any movement of the jig and cutting guide then additional pins should be used.

    Perform the anterior femoral resectionWith soft tissue protection by Hohman retractors (always a blunt Hohman medially) the arthritic and dysplastic trochlea of the anterior femur is then removed by oscillating saw.

    Operation – 2

    The resected specimen of the trochlea. Note the lateral eburnated bone highlighted by the angel wing in the image. Also notice how the resected specimen is longer on the lateral side (1) than the medial side (2) which confirms the desired external rotation of the cutting guide and resultant anterior femoral cut. This will help with patella tracking.

    The anterior femoral cut surface is sized.

    A trial femoral component, with built in drill guides, is placed anteriorly to size the cut femoral surface.
    In this case the most appropriate size is ‘small’ media-laterally and there is a good coverage deep down into the trochlea reaching the femoral notch.
    If the implant does not reach the notch then the component should be upsized or further anterior femoral resection (without notching!). A practical tip to avoid notching in these case sis to increase the flexion of the anterior femoral cut – this applies to TKA and PFJA.
    The trial femoral component is marked in situ by the diathermy.

    Trial femur removed to expose the diathermy marked trochlea component outline, and then incised with an osteotome.

    The diathermy mark is then incised by an osteotome.

    Deepen the trochlea groove to accept the trial Avon component.By using the saw perpendicular to the trochlea, the sclerotic pathological bone of the PFJ OA can be recessed to accept the trochlea component. Alternatively a burr can be used for this step if the surgeon is not confident with this ‘fettling’method.

    A hand rasp is provided on the set to complete this excavation of the trochlea to fit the trochlea implant.

    Notice that the trial implant sits perfectly flush to the native chondral surface.

    The trochlea trial/guide is then drill-pinned into position and the lug holes drilled.

    The Avon trochlea trial is inserted and impactedThe lugged trochlea trial component is introduced onto the femur in a flexed position and then extended.

    The trial component is gently hit home (extending the component), from the flexed position so that the lugs engage and the trial is flush to the anterior femoral cortex.

    Assessment of tracking with the trochlea component trial and native patella.The knee is then cycled with the femoral trial in position, but still with the native patella. There should be no jumping as the patella moves from trochlea trial to the native condyles.
    Attention is then turned to the patella and the lateral facet osteophyte is identified.


    A lateral facetectomy of the patella is performedThis lateral facet osteophyte is then excised by oscillating saw. Notice the sharp Hohman lifting up the lateral patella (1).

    The bony excision fragment (1) of the lateral facet osteophyte is then removed.

    The widest part of the patella medio-laterally is measured by calliper, followed by its thickness.

    The patella thickness is 14-18mm depending on where the reading is taken due to the dysplasia and wear pattern.
    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.
    Knee. 2014 Dec;21(6):1058-62. doi: 10.1016/j.knee.2014.07.007.
    Bristol index of patellar width to thickness (BIPWiT): a reproducible measure of patellar thickness from adult MRI.
    Sullivan NP, Robinson PW, Ansari A, Hassaballa M, Robinson JR, Porteous AJ, Eldridge JD, Murray JR.

    The patella clamp / cutting guide is positioned and the patella resection is performed.Notice how this has been applied perpendicular in this image whereas in the next slide it has been rotated slightly, either proximally or distally, as the fit is often better and thus less likely to slip during resection.

    Notice how this has been applied perpendicular in this image whereas in the next slide it has been rotated slightly, either proximally or distally, as the fit is often better and thus less likely to slip during resection.
    With Hohman retraction and the cutting guide/clamp in position the patella cut is made, resecting the minimum bone possible from the worn lateral side.

    The remaining patella bones’ thickness is measured.Repeat measuring step with the callipers for a patella remnant thickness (13mm). Once added to the patella button thickness of 9mm will reach a construct of 22mm later.

    Size the patella component with an appropriate sized patella guide.A size small patella guide is chosen as the most appropriate size based on the objective that there should be good coverage but no overhang.

    Three patella lug holes are drilled.

    Total construct thickness of the reconstructed patella is measured with the trial patella in situ.The trial patella component inserted but not ‘clamped down’. The callipers measure a width of 22mm

    The knee is then cycled with the trial components in place into both extension and flexion There should be good tracking and no jumping.

    There should be good tracking and no jumping.

    The knee is in deep flexion with the trials in position. Notice that the Vastus Medialis is completely covering the implant. A generous 140 degrees of flexion is achieved with calf to thigh.

    Operation – 3

    Local Infiltration Anaesthesia using a long needle; a grey (16G) venflon needle with both screw cap and adaptor removed is ideal for this purpose.
    I use a cocktail of 150ml of 0.1% Marcaine with 0.6mg Adrenaline, 30mg Ketorolac and 10mg Morphine. As always the volume used needs to be calculated on a per weight basis.
    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.
    The last 50ml of LIA is being infiltrated posteriorly in this slide.
    Always both aspirate and warn the anaesthetist before infiltrating.

    The trial implants are removed and the cut bone surfaces lavaged with pulsatile Normal Saline.During total knee arthroplasty I routinely use chlorhexidine lavage, but not with partial knee replacement where there is retained chondral surface.

    Bone cement – I use regular viscosity Palacos with Gentamicin from Heraeus.

    The bone cement is gunned into the clean and prepared femoral surface.

    Mantle of bone cement on the femoral surface before insertion of the trochlea component.

    Apply bone cement to the Avon trochlea component and implant it, engaging the most distal lug-hole close to the femoral notch.Please ensure the pegs are visible to aid implantation into the femoral lug-holes.

    The Avon trochlea component is introduced in an extended position, engaging the most distal lug-hole close to the femoral notch. Notice the gap (1) proximally which will be closed in the next slide.

    The Avon trochlea component is impacted.The femoral impactor is applied at approximately 45 degrees to the axis of the femur and then lifted perpendicular to the anterior surface. When this is impacted gently with a mallet, the trochlea component is reduced home into the prepared femoral surface to ensure the component is not proud to the native joint surfaces, nor overstuffing the patellofemoral joint by being flush to the anterior femoral cortex.

    Excess bone cement is removed.

    The patella is then exposed using a Hohman retractor under its lateral margin. Notice the blood-covered surface which now needs to be lavaged and dried.
    For surgeons who use a tourniquet this will be less obvious, but still it is important to ensure that no debris has blocked the patella drill holes during trochlea preparation and implantation, before the patella surface is cemented.

    The patella surface is pulse-lavaged and the patella lug-holes are dried. The patella surface is pulse-lavaged with Normal Saline.

    The patella lug-holes are dried with a fresh swab.

    Bone cement is gunned into the patella prepared surface.

    Bone cement is applied to the Avon patella componentSimilar to the trochlea component, ensure that the pegs are visible to aid location of the pegs into the lug-holes during implantation.

    The patella clamp is applied once the patella implant has been inserted.Ensure this is the correct way round with soft surface to the implant and metal ‘teeth’ to the anterior native patella bone.

    Excess patella bone cement is removed.

    The cemented patella is reduced onto the trochlea and the tracking re-tested.Once the bone cement has cured the patella is reduced onto the trochlea, the knee cycled through flexion and extension and patella tracking observed.

    Perform a final check (and then lavage) of the Avon trochlea component : double check for loose cement or bone fragments and remove them.

    A final check of the components is made and the joint lavaged.Finally check (and then lavage) the Avon patella component : again double check for loose cement or bone fragments.

    The capsule is closed.When using the medial subvastus approach the apex of the capsule should be closed first. I use a number 2 barbed monofilament suture.

    Capsular closure is continued running medially to the MPFL where the capsule runs out (1) as further proximally there is only muscle. At this point I return the suture, heading back to the patella and then distally in a running mattress.

    The capsule is fully closed and ‘watertight’ without excess tension. I prefer the running mattress with a barbed suture for this reason as each ‘bite’ of suture works as an individual point of fixation as I work from the starting point at the apex (1) to the most medial portion of capsule close to the MPFL (2) and then returning back via the apex (1) and down to the most distal extent of the arthrotomy (3).

    Skin closureI then close the skin in my standard manner with 4-5 interrupted size ‘0’ sutures to the deep dermis, then a continuous 2-0 to the deep dermis and then 2-0 barbed monofilament subcuticular. When the occlusive drape is removed, additional aqueous chlorhexidine is used to wash the wound and exposed skin.

    Please ensure the knee is flexed – depending on the glue, it is advisable for the skin to be wet for most skin glues.

    Steri-strips are applied obliquely to fit inside the padded non-stick island of the clear occlusive dressing.

    Operation – 4

    A padded non-stick island clear occlusive dressing is applied with the knee in flexion.

    Ankle to thigh wool and crepe are applied – I like to apply the crepe in a herring-bone pattern to reduce slippage of the bandage during early mobilisation. This is exchanged for a tubigrip prior to discharge – either later the same day or the following morning depending on the timing of surgery. This allows the patient to remove the tubigrip easily to shower (the dressing is shower proof) and then reapply to reduce swelling.

    AP Postoperative XR

    Lateral Postoperative XR

    Skyline Postoperative XR

    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 Medi-rooms overnight – the equivalent of a day-case facility – and the are discharged first thing the following morning, allowing the medi-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, however there have been interesting recent trials published reporting benefits of partial rather than total knee replacement, despite the known higher revision rates of partial knee replacement from well publicised from registries.
    In relation to the PFJ, Anders Odgaard conducted a randomised controlled trial of patellofemoral versus total knee replacement for the treatment of isolated PFJ OA.
    The Mark Coventry Award: Patellofemoral Arthroplasty Results in Better Range of Movement and Early Patient-reported Outcomes Than TKA.Odgaard A, Madsen F, Kristensen PW, Kappel A, Fabrin J. Clin Orthop Relat Res. 2018 Jan;476(1):87-100.
    We have published our Avon results from Bristol since the development of this implant. The Avon PFJ replacement the implant survival was 77% at 10 years and 67% at 15 years.
    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. Bone Joint J. 2018 Sep;100-B(9):1162-1167. doi: 10.1302/0301-620X.100B9.BJJ-2018-0174.R1.
    As a comparison using the Journey system, we found at a mean of seven years we found an 88% survival of implants and good patient satisfaction.
    The Journey patellofemoral joint arthroplasty: A minimum 5year follow-up study. Ahearn N, Metcalfe AJ, Hassaballa MA, Porteous AJ, Robinson JR2 Murray JR, Newman JH. Knee. 2016 Oct;23(5):900-4. doi: 10.1016/j.knee.2016.03.004
    Other papers referenced in this technique:
    Bristol index of patellar width to thickness (BIPWiT): a reproducible measure of patellar thickness from adult MRI. Sullivan NP, Robinson PW, Ansari A, Hassaballa M, Robinson JR, Porteous AJ, Eldridge JD, Murray JR. Knee.2014 Dec;21(6):1058-62. doi: 10.1016/j.knee.2014.07.007.
    Adverse outcomes after total and unicompartmental knee replacement in 101,330 matched patients: a study of data from the National Joint Registry for England and Wales. Liddle AD, Judge A, Pandit H, Murray DW. Lancet. 2014 Oct 18;384(9952):1437-45.
    45-day mortality after 467,779 knee replacements for osteoarthritis from the National Joint Registry for England and Wales: an observational study. Hunt LP, Ben-Shlomo Y, Clark EM, Dieppe P, Judge A, MacGregor AJ, Tobias JH, Vernon K, Blom AW; National Joint Registry for England and Wales. Lancet. 2014 Oct 18;384(9952):1429-36.
    How long does a knee replacement last? A systematic review and meta-analysis of case series and national registry reports with more than 15 years of follow-up.Evans JT, Walker RW, Evans JP, Blom AW, Sayers A, Whitehouse MR. Lancet. 2019 Feb 16;393(10172):655-663. doi: 10.1016/S0140-6736(18)32531-5. Epub 2019 Feb 14. Erratum in: Lancet. 2019 Feb 20

    Reference

    • orthoracle.com

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