I find it extremely difficult to adjust the fine wire frame in tibio-calcaneal fusion. Whilst I have gotten lucky quite a few times in the past, recently I failed twice. Dramatically. This kind of event puts me down quite badly and makes me feel rather incompetent but I cannot even imagine how patients feel. On top of the pain and discomfort, they are all faced with prolonged treatment - more time with a ****** cage on their leg.
My strategy so far was to aim and adjust the frame based on X-rays in lateral position and based on clinical examination for the AP correction (translation and valgus). Quite often I see that X-ray of an ankle joint in the AP view is not very clear and inter-/intra-observer variability must be quite significant (never tested it myself but I expect it is). The fact is, I don't know what I am aiming at in relation to an AP ankle X-ray.
I looked at the available options.
Analysing the problem again I realised that my main problem is not being able to see the target. Possible solutions:
It is obviously visible on any X-ray unless covered by the frame, but it needs to be surgically inserted through the sole of the foot creating a scar on the weight bearing area. Not ideal, but in the absence of any better solution I will have to accept it as even worse than a scar on the sole of a foot is another failed tibia-calcaneal fusion.
23 October 2018
Because of the chronic osteomyelitis of the distal tibia and talus, distal tibia and talus were resected. Proximal tibia corticotomy and bone transport using fine wire frame filled the bone defect, but I missed the docking site with the frame. Not good.
In my defence, "dynamisation" period was uneventful and the failure only became obvious after the foot plate was removed.
At this point I looked at other patients where docking site fusion failed after removal of the frame. Surprisingly, they all completed 4 weeks of dynamisation without any problem. My conclusion so far is that whilst dynamisation sounds like a very sensible option, it is very likely not helpful in assessing bony healing. Until we get further evidence we will not use dynamisation as a docking site union confirmation test.
29 October 2018
During the revision surgery 6.5mm cancellous cannulated screw was inserted paying significant attention to where it should be positioned. At this moment I am not aware of the best docking for the tibia - should it dock on calcaneum only or should it dock on calcaneum and navicular.
New foot plate was attached. The docking site was not addressed as per standard procedure.
30 October 2018
09 November 2018
23 November 2018
Further improvement on X-ray and clinically as well.
Clinically alignment of the foot does actually look around 15 deg valgus, a bit of equinuus. I cannot say anything about translation in the AP view.
Mr Matija Krkovic, MD, PhD
I am Consultant Orthopaedic Trauma Surgeon with special interest in Limb reconstructions and bone infections.