Management of Femoral defects

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:

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

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

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 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:

1. ATLS protocol and resuscitation/stabilisation of the patient in A&E
2. Adequate imaging
3. Theatre as per BOA/BAPRAS guidelines
4. Soft tissue debridement/management
5. Bone debridement/management
6. Dead space management with antibiotic carrier only (no cement spacers or cement beads)
7. Temporary stabilisation with spanning external fixator
8. Standard or negative pressure wound dressing if the wound can not be closed
9. 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.
10. 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).
11. 8 days after the distraction starts using external magnets, rate 0.25mm, 4 times per day until the whole defect is filled
12. If the defect is longer than 5-8cm, intermittent unlocking of the nail, expanding and relocating of the nail is required.
13. There is no docking procedure required as standard.

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

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

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 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:

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

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 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:

1. Physio
2. Bone transport
3. Remain non weight bearing

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 29 June 2018 
As planned. 

Plan:

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

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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:

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

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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:

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

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

Plan:

1. Bone transport
2. Physio
3. Non weight bearing

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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:

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

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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:

1. Hip and knee physio
2. Standard bone transport regime
3. Non weight bearing

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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:

1. Maintain the transport speed
2. Non weight bearing
3. Physio for hip and knee

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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:

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

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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.

Plan:

1. Continue with transport
2. Physio for knee and hip
3. FU on Tuesday coming to confirm everything is working

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13 November 2018 
Moving. Causing some pain in the hip area. Will slow down back to 1mm/day as for the last week we were doing 1.6mm per day.

Plan:

1. 1mm/day in 4 increments
2. Followup in 2 weeks.

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27 November 2018 
Moving 1mm/day. Not sure if the plate is more bent or not. So far no major pain or discomfort.

Plan:

1. Bone transport
2. Booked in 3 weeks to reposition the nail

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17 December 2018 
Fragment locked to the plate, although the locking screw did not lock completely. Decided not to drill another hole as there were already too many in the fragment. Unfortunately it did not work as expected. Nail unlocked.

On lengthening the nail there was initially not response as I marked the magnet position to proximally. On corrected position the nail moved but moved the fragment as well .

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20 December 2018 
Nail expanded to around 4 cm and but we were not able to move the fragment at all. Not even with femoral distractor. Decided to lock the nail back and re-lengthen it back to the position where we were on Monday, 17 December 2018.

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Plan:

1. Restart bone transport until the nail reaches the final position.
2. Remove the nail, ream the canal, expand the nail with fast distractor and reinsert the nail for final compression.

Not ideal, but if this will be our main complication, it will be great.

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04 January 2019 
It looks that the fragment has "sprung" back due to the nail malfunction. Not sure. But the plate is certainly straighter suggesting less tension.

Plan:

1. Exchange the nail

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14 January 2019 
As expected the nail was faulty. It looks that 8.5mm nail is strong enough for pushing but not for pulling. Certainly when the nail removed, the telescoping part was mobile.
The fragment itself was not mobile anymore. Axial and rotational stable. New corticotomy was required to mobilise the fragment.

New tibial nail 10.7X155mm Precice nail was inserted.

Plan:

1. Restart bone transport today 1mm/day
2. Remain non weight bearing
3. Follow up in 2 weeks

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29 January 2019 
Back on track. Sincerely hope so.

Plan:

1. 1mm/day in 4 steps
2. Walking with crutches non weight bearing
3. FU in 2 weeks

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12 February 2019 
The nail is working again. Plat bending but we closed another 14 mm since the last time.

Plan:

1. 1mm/day
2. Repositioning of the nail on 25 February

25 February 2019 
Repositioning of the nail done. Unfortunately had to do it in two sessions as the fast distractor does not come close enough to re-expand the nail.

Plan:

1. Continue with 1mm per day in 4 steps
2. Physio
3. Non weight bearing

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15 March 2019 
Back on track. No major pain.Pate is bending again. Fingers crossed.

Plan:

1. ​As before.

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05 April 2019 
No problems but no movement of the fragment either. Not clear what is the problem. Nail or external magnet?

I think that we can safely dismiss the explanation that new bone formation in the docking site is preventing the docking. In my opinion the nail is far too strong not to crush the new bone in the docking site.

Plan:

1. Change the external magnet and compress the lengthen the nail for 5mm.

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12 April 2019 
Nail has re-expanded as expected. Either the external unit is a problem (I sincerely hope so), or...

Another problem just became obvious. Proximal locking screws in the plate became "unlocked". Don't know how is this even possible.
​

Plan:

1. Compress the nail
2. Observe

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26 April 2019 
Nail has moved but not as much as expected - a bit more than 1cm. Still acceptable. We are not sure we know/understand what the problem is. The nail should be able to cope with the load.

Plan:

1. Continue with bone transport
2. As you can see on the X-rays there is still around 2 cm gap.

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10 May 2019 
It is not moving.

Plan:

1. Revision on Monday - remove everything and replace it with a retrograde femoral nail and monorail external fixator (example)

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13 May 2019 
We had to go back to "old days". Not the happiest feeling. Hopefully will be able to finish it with and external fixator.

Plan:

1. Complete the bone transport
2. Lengthen the femur (We were not able to radiologically confirm the middle two pins are in the fragment, due to the monorail shadow. Clinically it certainly felt like it and the fragment moved when tested. But ...). When all done then
3. Lock the nail proximally
4. Lock the docking site with a small fragment plate
5. Remove the Orthofix monorail external fixator

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31 May 2019 
The construct did not work as expected. No transport. It looks that I did not put the transporting pins in the fragment. Very disappointed. Cannot image what the patient is going through. Will have to reposition the two pins on coming Monday.

Plan:

1. Redo.

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