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The Painful Knee Replacement TKR for Orthopaedic Exams
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The Painful Knee Replacement TKR for Orthopaedic Exams
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Upload Date:
2024-05-31T00:00:00.0000000
Transcript:
Language: EN.
Segment:0 .
Again, to this Wednesday is teaching. From the far casement to thank you for attending and. I hope the system works well for you, and you can hear us fine. So we tonight, we have time sweet. He is going to talk about painful total knee replacement, which is a topic that could be asked in the forces Viva adult pathology.
Viva! very important. And it's very nice. Concise talk. Juan, I myself will be also supporting him following this session. There will be hot seat sessions also will be extended tonight to hot seat sessions.
I know you guys started expressing interest, so keep that going. So I will. I leave it to time now to get started. Go ahead, Daniel. Can you see the screen now? Yes yes, we can. Go ahead, Yeah.
OK, so today I'm going to talk about painful total knee replacement. It's an important topic. I will not go into all the details, but I just mentioned the important points. I'll give a very brief talk as well about prosthetic joint infections. So the outline of my presentation, I'm going to talk about the cosies, clinical evaluation investigations, and there is a viable scenario.
So it's the key thing about painful total knee replacement. The oil does not see what the mind does not know. So if you don't know the causes, you will not know what you're looking for. So generally, the cause is two big categories extrinsic factors coming from outside the knee and intrinsic factors coming from the knee, extrinsic factors, hip pathology, commonly osteoarthritis.
So you don't want to be doing a total knee replacement with a lovely X-ray and the patient coming back after six months with persistent, painful knee. And then you examine the hip do this X-ray and you can see severe osteoarthritis, which is cause of the pain, or at least partially the cause of the pain. This is very embarrassing. And very frustrating.
Neurological causes, pain effect from the spine like lumbar spine problems or crops, complex regional pain syndrome or vascular causes like vascular communications. Intrinsic factors causes from inside the knee infection is a common problem, I'll talk about this a bit later in details. Aseptic evening wear and ocelots you can see this on radiographs here in this AP radiograph, you can see a way to loosen see on the tibial component if it's any loosening.
This might not be on X-rays and might be obvious on a bone scan, but increased uptake on a bone scan. But remember, bone scan can be hot for up to two years after knee replacement, so it's a good negative decreased joint space, which means wear of the polyethylene, the plastic part in between the two components. So in this x-ray, you can see the table and female components are almost touching each other, which means that the significant wear of the instability, which can be medial lateral due to MQL or LCL deficiency, and to procedure in case of deficient or non-functioning PCL flexion and extension instability.
Muscle alignment, which can be clonal as you can see here in this AP view, dismal alignment of the tibial component and this knee replacement is going into various. This last review is a lateral, another knee replacement, and here you can see the female component is going into flexion. So this line of the posterior female cortex and the positive epicondyle components should be parallel.
And that is sagittal muscle alignment with the rotation, muscle alignment as well, which is the muscle rotation of the femoral or tibial component. And this would be obvious on a CT scan. Other causes of tissue impingement like overhanging tibial component, as you can see in this AP Reddy graph, the tb.e is overhang mediately, which will impinge on the medial structures and cause medial knee pain.
But ulnar claw syndrome, which is common with posterior stabilized knee, as you can see here, this is a cruciate retaining knee and this is a posterior stabilized. This is a camp, this plastic bit and post, and they articulate together in a patella clunk syndrome. What happens is that you have this scarring of the soft tissue just to appear to the patella. And in deep flexion.
This would get caught into the femoral box and cause the patella clunk syndrome, patella impingement and popliteal tendon impingement, which will cause posterolateral knee pain, also fibrosis or stiffness. It's common with infection and the best predictor of range of movement after a knee replacement is the preoperative range of movement extensor mechanism problems like patella multi-tasking underserviced patella oversized patella with joint over stuffing.
So when you're faced with this situation, how can you evaluate. So if the causes, you know what you'll be looking for in history, clinical examination and investigation. So as any medical problems, your diagnosis or your management includes the history, examination, investigation, and if the causes, you will know what you're looking for. So for history, you need to go back to the pre-op history.
So what was the indication of the total knee replacement? Was it rheumatoid arthritis or was it disease? Because this can be the cause of painful knee replacement, the underlying cause? How bad is the pain before the operation, after the operation? Patient expectations sometimes patients have a knee replacement because they can't kneel while praying or doing the job, and they would be very frustrated if they don't know that most patients, after a knee replacement, would not be able to meet patients who have depression or anxiety are less likely to be satisfied after a knee replacement.
You need to inquire about wound problems your post-op. Was there any leaking wound? Was the patient put on antibiotics by the gp, which all indicates infection in terms of symptoms they might present with pain, swelling, stiffness or instability? Pain is the most common symptom, and you need to inquire more about the pain. So what is this pain?
Since day one, as they say, it never felt right, which might indicate an extensive cause or an infection from day one is the sharp catching pain because of impingement. Is it painful to touch when you touch the skin due to some sort up pain, which is which gets better common with loosening and pain with stairs or getting up from a chair with a patellofemoral problems and flexion instability effusion and light pain are common with infection and inquire about associated neurology, pins and needles any weakness in the leg, which might be due to lower spine problem clinical examination.
Again, you keep it simple. Examination is look, feel and move, so you start with the gait. If there is a thrust, this might indicate a significant instability. Hip examination is very important. Whenever I examine any, I always screen the hip first. So with the hip inflection to internal and external rotation, this is not after a total knee replacement.
Even before putting a patient on the list, you always have to examine the hip skin. There might be erythema warmth, painful to touch or atrophic changes with Erps or vascular problem. Need to see if there is any effusion localized tenderness on the patella from the joint or patella femur irritability medial tenderness due to overhanging tibia or persons runs bas status, possibly lateral tenderness or clicking with polytheists impingement cutaneous neuroma.
This would be superficial and they will have positive and sign can give local anesthetic to a nerve block and would be diagnostic. Again, the range of movement you need to examine the pathological tracking patella long and to complete your examination, you need to do a spinal hip, foot examination. So in terms of investigations, first of all, you need to get plain radiographs and the plain radiographs.
AP lateral and skylon skyline view is a part of any X-ray. OK, and in a situation where you have a painful knee replacement, you need to have a long leg alignment view as well. So what will we be looking for in the X ray? You'll be able to see the alignment if there is any loosening of celoxis polyethylene wherewith where there will be decreased joint space overhanging, you need to check the joint line is the patella bar the patella?
Is there any stress fracture potential to sorry? In the CT scan, you'll see a mild rotation of the female component of the Civil component here in this city. The yellow line is the epicondyle axis and the blue line is the axis of the female component. And this should be part of all three degrees. External and internal rotation of the female component or tibial component goes knee pain.
Also, bone scan for bone scan is a triple phase technician bone scan. If if this increased uptake in all three phases, that might indicate indicate infection. But again, remember, the bone scan is normally hot 1 to two years after a knee replacement. It's highly sensitive but not specific, so it's a good negative. So if the bone scan is cold or there is no increased uptake, you can say with confidence that there is no dosing or infection.
Indian bone scan, which is Indian labeled leukocytes. It's more specific for infection, but rarely used in reality. Not investigation, full account, what's the White cell count? Yes, or above 30. And you need to know that Yes or is normally indicated for up to three months after the operation, CRP go goes down to normal level three weeks post-op, and it's significant if it's higher than 10 interleukin six, which is if higher than 10 picograms per milliliter.
But again, in reality, we don't ask for this investigation. Synovial fluid aspiration. So for any painful need before considering a revision, you need to Ferre Disney. And when you do an aspiration, you need to send it for a gram stain. You need to send it for a differential blood count. Check the White cell count in the synovial fluid. So if it's higher than 3000, that's significant in case of acute infection, or it's in case of chronic infection and 10,000 in cases of acute infection.
Before having or doing an aspiration, the patient needs to be off antibiotics for at least two weeks. You can find a stress test. That's the urine dipstick test, a very simple and cheap test and detects what cells in the synovial fluid. So a new version, which is relatively new. And this detects the alpha defense and it's very accurate test as they claim.
So I'm going to touch very briefly on the prosthetic joint infections, because when you're faced with a painful total knee replacement again, the discussion will go towards revision principles or revision knee replacement or peripatetic infection. So the approach you would like to say, you will discuss with your local bone infection unit and NDT approach orthopedic surgeons, microbiology and physiotherapy.
The rates of prosthetic joint infections are 1% to 2% definition for a peripatetic joint infection. This was in the international consensus meeting 2015, and we have two major criteria and 5 minor criteria. So you need at least to have one major criteria or three out of five minor criteria. So the major criteria are two positive cultures with the same organism and/or a sinus tract communicating with the one.
So if you have any one of those, that's by definition, is an infection. The minor criteria are elevated CRP and ESR. That's one criterion. Elevated synovial fluid white cell count or positive leukocyte stress test, elevated synovial neutrophils, positive histology from prostatic tissue or a single positive culture. So if you have three out of five minor criteria, that's infection.
These numbers, if you want to remember anything, the synovial white cell count that is more than 10,000 in acute infections and 3,000 in chronic infections in different studies, you will have different numbers if you want to remember any numbers. These are easy ones to remember. Classifications, early infections, less than three to four weeks or late infection less than three to four weeks after the operation or from start of symptoms in case of hematologist infection for management team need to know the concept of a biofilm, which is a polysaccharide filled forms on the implant.
Shortly after the infection and what happens after having a biofilm? It reduces the access of antibiotics to bacteria and enhances bacterial nutrition as well. So once the biofilm is formed, the implant needs to come out in terms of management. The options are their procedure, the air, which is deployment, antibiotics and implant retention. And this is actually an option on the early infection less than 3 or four weeks.
So what happens with this procedure is you do a very, very good deployment and change the modular components. So for a knee replacement. You change the public and then keep the implant. Give antibiotics, according to the cultures. In case of established infection more than three or four weeks, you'll have to do a revision and this will be either two stage or single stage.
Two stage revision is the gold standard, and the first stage would be a thorough department. Put immense space with antibiotics, give IV antibiotics for six weeks, and then you do the second stage later, at least after six weeks. When you have your inflammatory markers down and you do a culture which comes back as negative, and again, if you're doing a culture before the second stage, you need to have the patient two weeks of antibiotics.
A single stage vision that's not the standard, and you do this in case of low virulence organism with a known sensitivity. The advantage of a single stage of vision is lower cost early mobility to the patient, and it's only done in certain centers and has got variable results. But for the sake of the exam, I would say a two stage revision. Long term antibiotic suppression, this is for patients who are frail, frail, not fit for surgery, and they need to have, well, fixed implants and sensitive to some oral antibiotics.
So you can send them home. Also, this is very rarely done now, and this is an option for young active patients who have got a problem with the extensor mechanism or poor bone stock or multiple resistant organisms. And remember, if all the options fails, amputation is an option, especially if there is a current septicemia and hospital admissions and infections out of control.
So to summarize again, the key thing about painful and replacement know the causes and then it would be very easy can go through the history examination investigations because what you're looking for. I think hard work beats talent, so don't let anyone tell you can't do this, you're not ready, work hard and you go through this. My last advice?
You can survive a practice. You can do a video recording. This is really, really helpful. You can see yourself. How do you talk in a voiceover situation? Practice as much as you can and don't try to challenge or teach the example, please. Thank you. That's great, thank you very much, Tanya.
It was excellent, the presentation, I like how you presented the stepwise approach to the candidates, and I think it's very important. Start simple history examination, move on swiftly to the core of the topic and also what you mentioned the intrinsic and extrinsic factors. Once you start talking about these buzzwords, the examiner, you will embrace them.
You show them, you know, your systemic, you know what to look for and always, you know, complex issues like this painful. Take or NDT approach to this anything complex always throw this word MDT approach. And also, if you add to that, those criteria that are mentioned in his presentation for diagnosis of infection, these criteria would be considered as literature quoting literature, and therefore you'll be scoring the top marks for this.
We have had one question time here. We've been asked, you know, is there any evidence behind the time period when it's acute infection, when you could do their treatment or is that not? There's no consensus in this. I think it's a bit variable, but from the American academy, it says three weeks. But in practice, you can stretch it a little bit special issue again.
And right. What they're looking at is higher order thinking, why you're thinking about what you're thinking, what is your approach? Is it a Black and white approach. Or is it a sensible kind of stepwise approach to the problem? There's another question. We'll arthroscopic wash out worse as it has three graphs.
I can't just see the chart thing. How can I see this the bottom of the screen? Click on a chart next to screen share. it could be on the top on your screen. That's OK, we are telling. There is no see it now. Yeah, Yeah. We'll have to wash up work or it has to be open, wash out.
I think there is no space for arthroscopic to wash out. You have to have proper deployment and change the line. There's nothing so medical procedure, what does there mean to pry, mint and implant replacement so loose and replace Frydman antibiotic implant retention? Oh, I apologize. I don't know what was I thinking. You're right. So it merely means washing out the knee basically a proper wash out of the knee replacement.
So, yeah, but not arthroscopic, I would never say, Oh yeah, no, no. Exactly remember, guys, this is about the exam. So we. We just stay safe for the sake of the exam. OK, final question is essential while doing the right mint or off of antibiotics for two weeks and culture will be enough. I don't get the question.
So I think the question is asking, do you need tissue culture when you're doing your development? Of course, Yeah. Whenever you're doing the brain for infection, you take five samples for cultures. And if it's an acute infection or if the patient was off antibiotic, that's fine. If the patient was unwell or systemically unwell and you can't, you have to start antibiotics, that's fine.
But if not, no sample, no antibiotics before taking samples. And again, the same question. Do you have to change the liner in there? Yes it makes sense, isn't it, so if it makes sense it in the exam? That's good. Just the thing. Any any joint replacement that you're going to sample for infection or even implant any implant metal, anything like that, even from a trauma case, you you talk about the Oxford trace sampling system, which is 5 separate lives, five separate forceps, which are each one used to take one sample from a different part of the wound, as opposed to all at the same depth and all at the same area.
OK that's great, thank you. I think, guys, my advice. You know, look at this topic and presentation as sort of building framework to you of how you approach any complex postoperative complication or unsatisfactory outcome from an operation in the exam. This could be applied to any field operation, any infected hip or and so you build up this system of how systematically approach this MDT.
Looking for all the factors showing the examiner you really systemic, safe, you looking for everything? All right, and no one would expect you to, even as a consultant to out infected you by yourself, especially when you're starting. So they expect you to involve senior colleagues involved. And revision specialists about. The slide for the causes again.
So there is this review article. It's mandala, it's all from bone and joint. I think it was 2008 and has got this table. It will be the video. Anything else, guys? Anyone wants any further questions or any comments from the mentors. No so thank you.
I think we will if there are no we have also Ramesh here, I don't know if you want to add anything, Ramesh. No, no, no, no, that's fine. Good, thank you. That's OK. Um, so we will end this session now. I will post invite again on.
On the telegram group and also send it to you via Zoom. We just not sure which one works better, the next session will be the hot seat session. Few people have expressed interest. So far, and please let me know as soon as possible. If you want to take part. Others can take part or just watch and learn. And obviously, you take the best learning is by taking part, but you don't have to take part.
You could just sit and watch. OK, guys, I'll end this meeting now, and I will send an invite straightaway to join the session. OK, thank you. Thank you, Chris. Thank you. Talking thanks, Juan.