Press Play to see a video of Hindlimb anatomy relating to Patellofemoral Joint function and Structure. I am testing whether I can use this method to embed multimedia in the iPhone App. If it doesn’t work for you please let me know. If it does, let me know that too! So far it doesn’t work in the App but you can press the view Video button below to see the video.
Okay I think I have it now:
This is an apologetic post for the lack of new content this week. I have been preparing for tomorrow’s CPD on Elbow Dysplasia. I have a tendency to get carried away with 3D modelling for these things and have taken it a stage further with pretty complex animated models showing the pathogenesis of Elbow Dysplasia and the rationale behind the newer “geometry modifying” procedures for this debilitating disease. An example of the new approach to Elbow Dysplasia is the Stepped Ulnar Osteotomy using a modified Kyon Alps Plate to shift the ulna and offload the medial compartment of the elbow.
The concept behind this procedure is not easy to understand and so I have used a 3D model animated to show how the intra operative change translates to reduced medial compartment load in the Dysplastic Elbow.
If you can’t make the seminar, I will I am sure upload some of the content as we move forward.
In other news, for all of you iPhone App users, there is an update on the way with better iOS4 compatibility like background activity and a pull to refresh function that was sadly absent in the first version. I think you will like the changes. If you don’t have the App yet, why not follow the link in the previous post or simply search for Torrington Orthopaedics in the App store.
This may seem like a strange question, surely TTA is Tibial Tuberosity Advancement. I suppose we need to ask how we know when anything is anything. We could argue that we know for example that a table is a table because it looks like a table. If we follow this argument then appearance to the senses is the defining characteristic of the object.
Function is also used to define an object. From a functional perspective, a table is an object that functions to hold objects in a stable position above the level of the ground. The inclusion of function with regards to correctly identifying an object is generally more powerful than observing its appearance. A garden trampoline looks like a table, but it certainly wouldn’t function as one. This would be an example of understanding that one object is not another despite sharing similar appearances as a result of lacking the characteristics that permit it to function as the true object.
In reality an object is a table when it functions as a table. Anything else is not a table. Function is derived from the various parts of the object acting to perform a specific action or behave in a specific way and therefore many things that function in a similar way will have similar parts arranged in a similar way. It is this last fact that often leads to the classification of objects by appearance and this often leads to reaching the wrong conclusion regarding the identification of an object.
How can we apply this to the question in the title: “When is a TTA not a TTA?”. Well I suppose if we go back to our analogy we would argue that it is when it looks like a TTA and functions like a TTA. On that basis, it is not a TTA if it simply looks like one!
My Definition of TTA: The definition of a TTA is an opening osteotomy of the tibia in the craniocaudal plane such that the tibial tuberosity comes to occupy a position cranial to the proximal tibia resulting in an angle between the Straight Patellar Tendon and the Tibial Plateau of 90 degrees. The advanced tibial tuberosity is held in this position by a plate anchored to the tibial tuberosity and the tibial diaphysis and a cage of variable size. The osteosynthesis should be of sufficient strength to withstand the distractive pull of the Quadriceps mechanism to permit the osteotomy gap to fill with bone.
A TTA...or is it?
So that is all about appearance then, there is a gap, there is a plate, there are screws and there is a cage. The key part of that (overly long) sentence above though is “resulting in an angle between the Straight Patellar Tendon and the Tibial Plateau of 90 degrees”. That sentence is key because it is that aspect of the appearance that gives TTA its function. If we have a set of post op radiographs following TTA and that element is missing then:
That is not a TTA
No combination of plate, screw, fork, cage is a TTA unless it stabilises the cruciate deficient stifle. The goal of TTA; neutralisation of the cranial displacement of the tibia in a Cruciate Deficient stifle has been shown to be achievable by Kim and Pozzi. Their work is “Proof of Concept”. The goal is however only achieved when the angle of the common tangent of the femorotibial joint is perpendicular to the Straight Patellar Tendon. Surely if this is the goal, and we do not achieve it; we have failed.
Question: How many surgeons measure the relationship between the Common Tangent and the Straight Patellar Tendon Post Operatively? Be honest now. Instead, the tendency is to focus on the implant position, the osteotomy and so forth. This is the same as someone selling a Trampoline as a table! Failure to understand how something actually functions leads to the production of things that look similar but do not possess the appropriate mechanical characteristics.
Call to Arms: If you are a TTA surgeon, measure how close to the goal you got.
Did we even get close to the target? Did we hit the Bull’s eye? If you don’t check the target after you shoot, you won’t know! If you don’t check your post op radiographs for proximity to the goal, you won’t know either.
So if we write in our clinical notes: Performed TTA, but don’t follow that statement with ” and achieved a post op angle of 90 degrees” then the first statement was wrong.
This is the first in a series of articles on TTA. If you are the kind of reader that likes a conclusion, then here it is:
If you get an alert, Push Notifications are now working if you signed up for them on the App. If you have any problems with this, get in touch.
One of our patients returned for Radiographs at 12 weeks post Total Hip Replacement. This is our standard protocol in patients with the Kyon Cementless THR, in order that we can assess bony ingrowth (cup) and ongrowth (stem). We can clearly see in the image below bony ingrowth into the fenestrated portion of the cup with no evidence of lucency.
Close Up of Operated side
Notice the absence of lucency behind the cup, the thickening of the medial (inner) cortex of the femur and the triangle of endosteal new bone below the base of the stem.
In addition, we can see from the following images of thigh circumference that there is a markedly better muscle mass on the operated side already.
(Unoperated: 37 Cm thigh circumference)
Surgical at 12 weeks: 45 cm Thigh Circumference
The difference is clear and is a good indication of the improved limb use that follows successful Total Hip Replacement. Remember that this is only 12 weeks post surgery. During this period, activity is limited but the difference is that the operated limb is loaded at all times once the pain and mechanical deficiencies associated with Hip Dysplasia have been resolved.
This is a presentation I gave on decision making in pelvic fractures. In future I intend to voice over these but for now, this is just the slides.
Often decision making is guided by the non-orthopaedic consequences of trauma and this slideshow discusses these.
Pelvic Fractures Keynote YouTube
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I have just uploaded a new form, using Gravity Forms for vets to use for clinical referrals. You can upload images and history using this form. It is easy to use and in my humble opinion looks very nice.
I think in 2011, this is the way to go, we are all used to filling in online forms. I will soon be encouraging practices to join the site and by logging in, enable pre filling of the practice data.
Let me know if you have any problems.
You can see it here…
If you are reading this in the App, then you know this already. If you are using the WebApp version or the Desktop version, you may be interested to know that the Apple App Store approved our App. Now you can view and interact with this site using the native iPhone App. Search for it in the App Store using “Torrington Orthopaedics” as your search term or follow this link:
Use the form below to become a registered user. This will allow you to post comments and questions. Over time it will also allow you to have your own info on the site whenever you visit. This will be particularly useful to iPhone App users.
Friday September 23, 2011 – Friday September 23, 2011
Torrington Orthopaedics
Description:
Use this form to request an Imaging Appointment at Torrington Orthopaedics for CT. Excellent for bony definition and very useful for evaluation of pathology of the bullae for example in patients with suspected middle ear pathology.
