Cartilage Loss, Pain and Surgery 1

This week has been a week of dealing with the end stage of incongruence: the loss of the pristine, almost friction free relationship between two opposing hyalinised joint surfaces. The coefficient of friction in a normal joint is so low that the articulation produces almost no extraneous energy; no heat, no noise like Teflon on Teflon. When this surface is absent, we as clinicians can feel this as grinding and crepitation, from the patient's perspective though they experience the pain initially from the contact between two sensitive structures (remember that cartilage is aneural- no nerve endings, like the enamel on your teeth). Ultimately though the body kills the surface by the process of eburnation so that the bone becomes like ebony, polished and dead on the surface. We can see this as sclerosis on radiographs. This strategy does not eliminate pain however it just delays it. The pain these patients experience is that which comes from heating. The heat is derived from friction and this heat can reach (in human hips) temperatures of 45 degrees Celsius. This heat causes bone pain and will “cook” the synovial membrane whose job it is to lubricate the joint. The joint becomes dry and the friction increases. As the friction increases so too does the speed of onset of discomfort.

A femoral head centrally denuded of cartilage.

The effects of friction though can be seen most clearly in the second image above which shows the complete loss of hemisphericity of the femoral head. This patient was felt to be doing fine on constant NSAID administration. Take it away and he was less happy, add Tramadol and he was happier than he was on NSAID alone. No Rehab or medical therapy will take the pain away entirely though and the mechanics of a flat head in a saucer like acetabulum will not be great. So he now has this:

No friction and a ball and socket for the first time for a long while.

This is one of the few procedures where we as surgeons can eliminate entirely the clinical effects of genetic inheritance and phenotypic expression and truly transform the entire life of our patients. No more pain in this hip and a proper and efficient mechanical relationship between femur and pelvis.

Over the weekend I will post another case where the effects of incongruence and subsequent cartilage loss has been replaced by a low friction comfortable articulation.

Snow disrupts plans, but can be fun!

Snow Stops CPD

Just a quick note to let everyone know that our CPD Open Day scheduled for tomorrow 26th January has been postponed due to current weather conditions. Whilst roads may well be passable tomorrow, the main event car park is barely safe from the previous snowfall, with the predicted snow fall for this evening, we felt it safer to cancel tomorrow’s event. Apologies to the delegates. We will reschedule for early February and all delegates booked on this course will be informed of the new date.

The hospital is of course fully manned and working this weekend.

Snow disrupts plans, but can be fun!

Snow disrupts plans, but can be fun!

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Templating Views for THR

This is a quick note on a piece of information that Aldo Vezzoni gave at the THR course in Munich last year. The tendency is to template for stem size and cup size based on a standard, extended hip Ventrodorsal projection as is horn above. The problem with this is that the Kyon cementless THR femoral prosthesis is inserted at an angle that aims to mimic the natural ante version of the hip (20 -25 degrees). This projection will not give a good assessment of the femoral width then in the plane that will be used for implantation.

Standard VD view

In fact when we take our post op views we always do the “yoga” view to assess the penetration of the medial cortex by the stem screws and how closely the stem is apposed to the medial cortex:

This is the best view to use in pre operative assessment of the appropriate stem size also. In countries other than the UK this can be done by manually rotating the femur whilst the radiograph is being taken. In the UK we cannot remain within the radiography room and so we use a combination of sand bags and foam supports to rotate the femur as can be seen below.

This gives us a better projection of the femur and reduces the risk of undersized femoral prostheses.

The standard VD projection indicated that this patient would need a small stem, whilst this projection indicates clearly that a medium stem will easily fit. This will guide the surgical opening and reaming of the femur.

It is also an excellent projection for assessing the cranial and caudal lips of the acetabulum which defines cup size.

 

 

How to find us

OrthoCal is on the App Store!

OrthoCal is on the App the App Store!

In December I had posted that I was in the finishing stages of developing the OrthoCal iPhone App. Yesterday I received the news that Apple have approved the App and today it is available to download from the App Store.

Screen shot from App Store

Screen shot from App Store

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Here are the links:

UK App Store Link

UK App Store Link

US App Store Link

US App Store Link

Months are navigated by swiping forward or back. Dates with events linked are highlighted in the calendar. To find out what the keys to the colour coding is just swipe up to reveal the information screen, this is accessible by pressing the info button on the January screen too. You can find out more or add a personal calendar event to the calendar. The day view can be navigated forward or back again by swiping left or right. Tap on the image at the top of the screen to explore the topic for the month.

I hope you find the App useful. I will be updating content and function throughout the year.

 

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Happy New Year

The January Screen

I'd like to take this opportunity to wish you all a healthy and prosperous 2013. There are 3500 users of the iPhone App using the app to access the information on this site. That is a phenomenal increase, so thank you for downloading the App. Android still seems a bit more difficult than I had imagined but perhaps this will change in 2013.

I am just finishing another iPhone App which is in the form of a functional calendar that has an orthopaedic topic per month accessed by tapping the image at the top of the month view as you can see from the image above, January's topic is Elbow Dysplasia.

Tapping the 26 button reveals the following screen:

 

From there you can explore the subject for the day in a flip book format with info about the content, speakers and so forth. You can even book places on the course from there.

To help you find your way to the course, there is a location aware map to plan your journey:

 

 

You can also use the application as your own Calendar for 2013 and by tomorrow I will have added the ability to maintain your own CPD Record which is always useful at the end of the year to show that you have been engaged in training courses and so forth.

The key for events is accessed from the info screen:

 

It also functions as an event/appointment calendar for your personal use:

 

So if you are a Vet or Vet Nurse interested in keeping up to date with what is going on at Torrington Orthopaedics and having a topic per month way of exploring new ideas in Veterinary Small Animal Orthopaedics this is the App for you. If you are a referring Vet then you can even use the App to refer a patient to us using the following screen. It couldn't be easier!

 

If you are a provider of CPD, then maybe this approach will work for you, people engage more thoroughly with Native Applications on their mobile devices than they do with desktop or Web Apps. If you are interested in having a similar App or to have your CPD events included in our calendar, e mail me at andy@torvet.co.uk and I can discuss your needs with you.

I will let you know when you can download the Free App very shortly.

I also pledge that 2013 will be a year with much more content, so make sure you have added the App to your Notification centre on your phone or visit the site more regularly if you are using the desktop version.

Again Happy New Year!

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News

First, apologies for the long interval between posts! I have been working furiously on finishing my application for TTA planning and a few other projects and lecture commitments. I will definitely aim to have more regular posts from now on.

I am currently in Munich for the fourth (I think) PAUL course tomorrow (Elbow Dysplasia) and a THR two day course beginning on Saturday. Both courses are full to capacity so if you see these courses coming up in future (check the Kyon web site) I would recommend you book quickly! If I get a chance I will try to blog from the courses but I can't promise anything as these courses are pretty full on.

If you are interested in learning TTA you have the opportunity of having comprehensive training at our practice next Saturday. There are still a couple of places left. Instructors include Slobodan Tepic, Daniel Koch, Turlough O'Neill and myself (Andy Torrington). The date is 8th December so you had better get your skates on if you want to attend and I assure you it is worth it. It is the only official Kyon training course in the UK. You can book from the Kyon website.

Coming soon…screenshots of the new TTA planner. This will allow digital templating even if you don't have digital radiography and will be available at a fraction of the costs of standard planning systems. It has been designed, coded and used by me and makes the whole process easy and accurate. This is the benefit of having a system devised by a surgeon who performs the procedure! Stay tuned for further info and release date.

 

 

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New Page Added- Elbow Dysplasia

This post is to let you know that I have added a new page under the Joint Disease section on Elbow Dysplasia and the rationale behind the PAUL (Proximal Aligning Ulnar Osteotomy) technique devised by Ingo Pfeil. We were part of the clinical trial phase for this technique and as a result of the positive outcomes experienced here and at other participating centres it is now part of the Kyon Training Program. If you are a vet and are interested in learning more about this technique and using it for your Elbow Dysplasia patients, keep an eye on the Kyon website for upcoming training courses. The next scheduled training course is in Las Vegas (October 2012) after which there is a course planned for early December 2012 in Munich. Learn more by clicking the image below to visit the page on Elbow Dysplasia on this site:

Kyon TTA

Calling All Users in Southern Hemisphere!

Do you live in the Southern Hemisphere?

Are you performing TTA surgery for Cranial Cruciate Deficiency?

Are you interested in learning about the PAUL (Proximal Abducting Ulnar Osteotomy) for helping those tricky Elbow Dysplasia Patients?


If you answer yes to two out of three of the above questions then you will be interested in the following:

TTA Masterclass in Carrara, Australia Monday June 25th

This is a full day of lectures on the Tibial Tuberosity Advancement technique for those who are currently performing the technique and for those interested in finding out more about TTA. The technique devised by Slobodan Tepic and Pierre Montavon has been used by us at Torrington Orthopaedics in over 900 patients and worldwide by thousands of surgeons. In my view TTA is unsurpassed in terms of ease of use, low complication rate and restoration of Stifle Mechanics post surgery. Slobodan Tepic will be attending and running the Masterclass, a unique opportunity to learn from the originator of the technique. I (Andy Torrington) will also be there, discussing some of the refinements in technique and planning derived from my clinical experience. If you can make this I would definitely recommend registering using the link above or clicking here: Register

ALPS & PAUL Course in Carrara, Australia Tuesday June 26th

ALPS (Advanced Locking Plate System) has significant advantages in terms of biology and biomechanics when it comes to fracture management. The key principles and hands on experience will be part of this day course. The other subject for this day class is the PAUL (Proximal Abducting Ulnar Osteotomy) which is  a new method to use for our patients with Elbow Dysplasia, either in the early phase of the disease or to ameliorate the chronic consequences of the disease. This is accomplished by modifying the load profile across the elbow, reducing the medial compartment pressures that are now known to be a significant cause of pathology and pain. The technique devised by Ingo Pfeil (Germany) has been used by over 30 surgeons worldwide (myself included). This is your chance to understand the rationale behind the technique and become familiar with the application of the technique in your patients.

Short Radius Syndrome

Don’t miss this opportunity. So far this course has been given in Europe and the USA only. This opens up the opportunity to use this technique to Orthopaedics Surgeons from the Southern Hemisphere without the “Long-Haul”.

Find out more by clicking here

If you have any queries of course you are welcome to post them here, but why not have a look on the Kyon website first as this will most likely answer your queries.

I know there are a good number of iPhone App users in the Southern Hemisphere in general and in Australia in particular. It would be great to meet you on one or both of these courses.

Kyon TTA

Tibial Tuberosity Advancement Planning Part 1: Radiographic Considerations

First let me apologise for the lack of posts recently…things have been a bit hectic in the past couple of months. We now have over 1200 users accessing the site via the iPhone App which is fantastic. The key with these things though is user interaction, so if you have any comments or queries regarding this or other posts, don’t hesitate to feedback.


Introduction

This series is drawn from a presentation I prepared and presented at last weekend’s TTA training course at Zurich Vet School and at the Kyon Symposium 2012 again in Zurich. The point of this series is to explore the variables regarding post operative TTA radiographs and using our planning to control these, thereby getting a more consistent piece of surgery with more consistent outcome for our patients and clients. TTA (when performed with Kyon implants) is a procedure which forgives the surgeon for a reasonable amount of deviation from the ideal post operative appearance in most cases. It is for precisely this reason that we as surgeons need to be more diligent in terms of our planning. This sounds like a contradiction but if we consider that the ideal outcome will be derived from the ideal modification of the geometry of the tibia, when we miss the mark, we may not give our patients all of the potential benefits that have been shown to be associated with Tibial Tuberosity Advancement (TTA) such as normalisation of intra articular pressure profile and therefore the long term benefits that may be associated with this unique attribute (progression of DJD, Incidence of Late Meniscal Injury etc). So the surgeon “gets away with it” but our patients may not!

Goals of Planning

There are four main goals in our TTA planning:

  • Determining Optimal Plate Size.
  • Determining Optimal Plate Position.
  • Determining Osteotomy Position and Orientation.
  • Determining the required amount of advancement to give a 90 degree relationship between the Straight Patellar Tendon and the Tibial Tuberosity.
This post will deal with the key to establishing these measurements/assessments which is optimal positioning for radiography.
Basis for Precise Planning
It is not possible to achieve optimal planning from suboptimal radiographs. The key variables are:
  1. Stifle Angle.
  2. Rotation (Femur and/or Tibia).
  3. The presence of femorotibial subluxation.
These must be controlled prior to engaging in planning for TTA.
1. Stifle Angle
There has been a bit of confusion here. The key is to remember that TTA is designed to provide femorotibial stability in stance phase. For this reason, all of the templating should be performed with the stifle in the normal standing angle on the mediolateral projection. This will vary from breed to breed and patient to patient. Previously people suggested that the stifle should be at 135 degrees extension, this should not be used for the reasons just stated. It can be difficult to assess the normal standing angle in cruciate deficient patients as, if the condition is unilateral, the contra lateral limb is likely being held in slight hyperextension to offload the affected limb, if it is bilateral, the patient’s pathological standing angle will be altered too. For this reason we should not simply rely on the person positioning the patient but go to the patient and palpate the Straight Patellar Tendon (SPT), if this feels to have low tone, then we are in an overextended position for that patient if it is very taut then we are likely in hyper flexion, we should use our experience in this assessment. If we see the following appearance on the radiograph then we are definitely hyper extended:

Note the wavy appearance of the Straight Patellar Tendon indicating Hyper Extension.

This abnormality is easily identifiable and the stifle should be re positioned to eliminate this appearance. Measuring advancement from hyper extended radiographs will underestimate the required amount of advancement and therefore influence post operative stability and all that may result from this.

2. Rotation.

Measuring from radiographs with rotated femur and/or tibia will seriously affect our measurement in terms of plate, advancement required and osteotomy position and orientation. We should reposition the patient until we have the ideal. Whilst there are adjustments we can make in our templating in radiographs with a rotated femur, it will always be more precise if our templating is from perfect mediolateral projection with femoral condyles superimposed. We will return to the issue of femoral rotation when we look at assessment of advancement. For now we will focus on Tibial rotation.

Given that the Cranial Cruciate Ligament (CCL) limits internal tibial rotation, pathology of the CCL will result in increased internal tibial rotation and therefore this is the most common problem encountered. We first need to be able to recognise when this has happened, and this is not as easy as determining femoral rotation. The key areas to look at are:

  • The caudal cortices of the Tibia.
  • The relationship between the Tibia and the Fibula.
  • The definition of the distal aspect of the Tibial Crest.

The images below show Perfect unrotated, internally rotated and external rotated isolated tibias:

The Tibia is perfectly positioned. The asymmetry of the caudal tibial cortices is minimal.

The Tibia is externally rotated and the medial cortex of the tibia is in a cranial position.

 

The Tibia has been internally rotated and the lateral cortex is now positioned cranially.

The degree of rotation above is not exaggerated beyond that which we may commonly encounter in our radiography pre surgery. The following image shows the change in relationship between the Tibia and Fibula associated with rotation of the tibia.

Left: Normal, Middle Internal Tibial Rotation, Right External Tibial Rotation

The Image below shows the impact on the definition of the Tibial Crest of the same types of rotation (this can also be seen above). The effect of this will vary between patients but in general if it is difficult to identify the distal aspect of the crest on the radiograph, go to the patient and palpate this area. If you can feel it distinctly in the patient, you should be able to see it on the radiograph!

3. Femorotibial Subluxation

If the tibia is cranially displaced (due to CCL pathology) on our planning radiograph, this will have a variable impact on our estimation of required advancement as the Tibial Tuberosity is already advanced. We need to identify landmarks that may indicate that this is present. These are:

  1. The relationship between the Tibial Eminence and the intercondylar region of the femur.
  2. The relationship between the caudal aspect of the tibial condyles and the femoral condyles.
  3. The relationship between the Origin of the Long Digital Extensor Tendon and the Sulcus for this tendon on the tibia.

The image below shows these points. If we identify subluxation, we need to correct it before proceeding to templating otherwise we will undersize the cage and fail to achieve sufficient advancement. Note also that the tibia and femur are rotated on the radiograph below as identified by a lack of superimposition of the femoral condyles, indistinct fibula, indistinct distal aspect of the crest and increased distance between the tibial cortices.

If we avoid these three potential pitfalls, we will be more likely to achieve reliable measurements in our planning that will guide our surgical execution and determine our surgical outcome. We need to make precise measurements from well positioned radiographs in order to deliver the perfect opportunity for perfect outcome.

Next… Plate Size and Position.