Management of Femoral defects

2/6/2018

femoral defect, bone defect, bone transport, precise nail, bone lengthening, bone transport, corticotomy, limb alignment, AxSOS plate

Femoral defect are fortunately quite rare. Still we will see them often after high energy trauma, osteomyelitis or tumours. Until recently we managed them using one of the techniques:

Bone graft (Autografts (iliac crest, RIA,...) or allografts)
Weber's method using cable and fine wire frame for bone transport along the nail
Bone transport using monorail external fixator
Bone transport using cable and pulleys

Just recently we started using PRECICE nails, which are telescopic nails controlled by external magnets.

09 April 2018
As you can see on the images below, the injury was pretty significant, high energy trauma with an open distal femoral fracture (Gustilo-Andresen 3B).

We can argue what is the best way of treating/managing injuries like this one. For us is as follows:

ATLS protocol and resuscitation/stabilisation of the patient in A&E
Adequate imaging
Theatre as per BOA/BAPRAS guidelines
Soft tissue debridement/management
Bone debridement/management
Dead space management with antibiotic carrier only (no cement spacers or cement beads)
Temporary stabilisation with spanning external fixator
Standard or negative pressure wound dressing if the wound can not be closed
Definitve fixation when patient stable (using a nail or AxSOS3 plate). At this time will correct the rotation and the leg length (our aim is to keep the injured leg 1-2cm shorter comparing to the uninjured leg). At the same time microbiology samples are taken.
After 6-8 weeks microbiology samples again, insertion of a PRECICE nail (retrograde if possible), low energy corticotomy and compression of the corticotomy using the nail at the same sitting (takes around 18min to compress for 2.5mm).
8 days after the distraction starts using external magnets, rate 0.25mm, 4 times per day until the whole defect is filled
If the defect is longer than 5-8cm, intermittent unlocking of the nail, expanding and relocating of the nail is required.
There is no docking procedure required as standard.

11 April 2018
Definitive fixation was done as per our protocol above.

11 May 2018
Post operative X-rays are self explanatory.

31 May 2018
We will wait for 6 weeks before we do anything with the bone defect. One of the reasons is infection and the second one is spontaneous bony activity in the defect which is not as rare as someone would expect.

Plan:

Physio
Chase microbiology results
Start bone transport 8 days after the procedure
Follow up in two weeks to monitor the progress

15 June 2018
Apart from pain in the thigh at the time of distraction everything else is going well. Clinically no sign of infection.

If you compare the plate shape prior the transport and now you will see a significant bent suggesting a significant force on the plate. Exactly what we usually see.

Plan:

Physio
Bone transport
Remain non weight bearing

29 June 2018
As planned.

Plan:

Continue with bone transport
Follow up in 2 weeks
Booked for surgery to reposition of the nail in 18 days

14 July 2018
Good progress but there is a significant strain on the plate visible on the X-ray. I can only suspect that the force required for callus distraction can vary from patient to patient. I can see in the other patients that those plates are not loaded so much. We will probably have to consider augmentation of the plate.
For now I cannot see any sign of failure of the construct, eminent or waiting to happen, apart from the bend in the plate.

Plan:

Repositon of the nail in 10 days as there is still a lot of "nail" left
Maybe we should consider "speeding up" the transport as the regenerate looks very strong.

26 July 2018
Precice nail reached its final position in compression. To continue with the bone transport we have to:

lock the fragment to prevent proximal migration due to the regenerate elasticity,
unlock the nail,
re-expand the nail,
lock the nail,
unlock the fragment and
continue with bone transport.

The main problem is(was) how to re-expand the nail in the same day as it takes around 6 hours to expand it with standard magnet and probably only 30 min with the fast distractor. With standard magnet we need to have two anaesthetics when with fast distractor we need significant wound to access the nail but one anaesthetic only.

Because we know that higher the number of procedures (opening of the skin), higher the chance of deep infection, we decided to proceed with percutaneous locking-unlocking and two anaesthetic sessions. First one first thing in the morning and second late in the afternoon leaving enough time to expand the nail using standard magnet.

First procedure

Second procedure

Everything went extremely well. Exactly as planned. It did take some preparation to coordinate theatre time, distraction on the ward and reprogramming the magnet every 2.5mm due to the software limitations, but it was well worth it. Only three small wounds in combined length less than 2 cm.
Plan:

Continue with bone transport 1mm/day as of today
Non weight bearing
Passive and active physio to minimise the knee flexion contracture
Repeting of the same procedure in approx. 45 days

07 August 2018
So far everything well. Flexion contracture is gradually improving.

Plan:

Bone transport
Physio
Non weight bearing

28 August 2018
No major problems, but as you can see, the plate is more and more bent. Will need to augment it, just don't know exactly how. Various options in consideration.

PLan:

Remain non weight bearing
Continue with bone transport
Regular physio
For repositioning of the nail on 10/09/2018

10 September 2018
We have reached the end of the nail compression. Repositioning of the Precise nail was required.
Whilst the AxSos plate is still bent, it didn't look more bent than before, hence we decided not to augment it with another plate.
It looks that 6 hours of expanding the nail on the ward with standard magnet is a good alternative to relatively large approach and use of fast distractor whilst in theatre.

Unexpectedly the right hip is very stiff. Must admit I wasn't expecting that and haven't seen it before.

Plan:

Hip and knee physio
Standard bone transport regime
Non weight bearing

02 October 2018
It looks that the plate is bending. Not completely sure that there is massive difference since the last X-ray but the plate is definitively bend.
In my opinion if we slow the transport will very likely create even more strain on the plate causing more bent comparing to proceed with the same speed and not let the regenerate mature prematurely. It is certainly a difficult call.

Plan:

Maintain the transport speed
Non weight bearing
Physio for hip and knee

19 October 2018
Unfortunately the magnet stopped working. How and why we don't know yet. As you can see on the images below there is no improvement since the previous X-rays. Apart from stronger regenerate.

Plan:

To restart the movement of the magnets otherwise will exchange the nail (which will need to do anyway)

01 November 2018
Not working nail exchanged for a shorter one. When existing nail removed and tested it worked. Not clear why it did not work whilst in.
Fragment was still not fixed so very unlikely premature consolidation was the reason. My though is that we put nail through many full cycles and this is very likely something the nail is not designed for. Something to bear in mind.