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Distal Femur GMRS for Chondrosarcoma

Hi all,

I had a Stryker GMRS inserted in August of 2010 to replace my distal femur, knee and top of tibia. It was my 3rd operation to excise the Stage II Chondrosarcoma in the base of my Femur along with the soft tissue on the outside of my left knee (aswell as resolving a benign tumor on the tip of my tibia).

After a Biopsy and several excision attempts (each taking larger amounts of bone and soft tissue) they decided the last resort prior to ABK amputation was the Distal Femur GMRS and soft tissue removal.

I'm coming up on seven (7) months and although this is a rare form of cancer and surgery I am having significant pain in my patella.

My recovery is moving along, albeit slow, and muscle growth in the Quads, Hamstrings and calves (from Physio) is improving the patella pain is still a significant hinderance despite ongoing management via Endone.

Thus my question(s) if anyone can answer;

1. Why would the Patella remain in a Distal Femur GMRS surgery ?
2. Any suggestions on reducing pain around the Patella (specific muscle groups like the VMO perhaps)?

I was a scratch golfer prior to surgery and have started playing again in a cart but the pain is limiting along with the lack of Quad muscle development.

Appreciate any suggestions or advice from anyone with experience with GMRS. There is not very much information on the internet at all about Post-Op GMRS recovery experiences presumably both due to the rarity of the surgery and the fact its a relatively new option for Bone Cancer around the Knee.
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replied March 5th, 2012
Especially eHealthy

If the patella is not involved in the tumor process, then it is left in place for the proper biomechanics of the quad mechanism.

A patellectomy can be done, but that adversely affects the way the quads work and weakens the quad significantly.

In total knee replacement, the way the patella is managed is very variable. No real consensus has been determined as to the best way to manage the patella.

Some surgeons will leave the native patella in place and let it articulate with the groove in the femoral component. Others will shave off the articular surface and replace it with a button.

However, there is no consistency in terms of pain control after either method. If removal of the articular surface took away the pain, then the button method would always be pain free, but it is not.

So, as to what causes pain around the patella is still not very well understood.

You can treat your problem like patellofemoral syndrome:

- Keeping the quad very strong, especially the VMO with quad sets, straight leg raises, and short arc quad.
- Do not use the knee extension station on the weight machine.
- Avoiding squatting or deep knee bends.
- Avoid sitting with the knee bent for long periods.
- Use of a neoprene sleeve. Some prefer the ones with the cutout for the patella.

Of course, you also need to make sure that the patella is not involved in the tumor process. If the pain has been basically the same since surgery, then it is probably not involved. But, if you have had a recent jump in the amount of pain you have been having, then it should be checked out.

Sorry, you are having problems, but glad that you have been able to keep your leg.

Good luck.
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replied March 5th, 2012
Thanks for the quick responses and apologies for not including that;

1. The Patella contained no signs of cancerous growth
2. No inference was made from the surgeon to any changes in my original patella, it is as it was pre surgery to my knowledge (although i will confirm after my next PETscan)

It is very hard to determine the source of pain after a GMRS as it identifies itself in the majority of cases as referred around the whole site of the knee.

In reference to your treatment points as above;

- I will try and get/keep the Quad strong. It still has a fair way to go but can feel the muscle now.
- I do not use a knee extension station. I use ankle weights totalling 5kg
- Squatting or deep knee bends would be impossible, I would either collapse from pain or the knee would give way.
- I have noticed this, sitting in a cart for 5-10 mins with it bent takes alot longer to get going again than if i sit with it straight (as i do all the time at home)
- I do use a "Futuro" sleeve on my knee when i plan any form of excersion or stress on the area, such as golf or in the garden. This one has the Patella cutout.

Just to be clear on my initial notes. They have removed around 15cm of my Femur, the entire knee (excluding Patella and placed a plate approximately 2cm deep across my shin. The Stryker GMRS has spikes extending approx 12cm down inside the tibia and up into the femur from the point at which they are joined to the bone.
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replied March 7th, 2012
Especially eHealthy

So, basically, your surgeon has elected to leave the native patella alone, and let it articulate with the groove on the femoral component. This is a common method of treating the patella.

The Stryker Global Modular Replacement System is a good one for oncological and complex revision total knee replacements. It offers the surgeon a lot of options.

Again, there is no real consensus as to how the patella should be addressed. No one method has been shown to be greatly better than another.

Many surgeons went with the button method when it was first developed, in hopes of taking care of the patellofemoral pain that many patients had. But, it did not consistently take the pain away and balancing the patellofemoral articulation was more difficult than first thought.

At first, the surgeons put the button in the middle of the patella, thinking that that was the best thing to do (recreate the native patellar articular surface). But, that turned out to be a mistake, causing a lot of problems with patellar tracking. So, the button was medialized, placing it more to the medial side. That made the tracking better, but didn't help the pain much. Go figure.

It sounds like you do have some patellofemoral syndrome going on. One of the hallmark signs of it, is the increased discomfort when sitting with the knee bent for a while. The others include increased pain with going down stairs (up also, but usually not as bad as down) and pain/diffuse swelling around the patella. With no other real explanation for the pain.

Sounds like you are actually progressing well. Rebuilding strength after this extensive of a surgery is difficult. The quads are the main postural muscles of the lower extremity. So, any weakness in the quads is going to really affect one’s gait, balance, and just getting around/standing.

Continue to build your quad strength (stay away from the knee extension station). Doing the straight leg raises and short arc quads (from 0 to about 30 degrees) with the ankle weights is probably the best way (besides walking and golfing).

If the knee sleeve helps, continue to use it. Some patients get relief from the warmth it provides and it does help somewhat with proprioception around the knee.

Try not to sit with your knee bent. Flex and extend it frequently.

Again, it sounds like you are actually doing pretty well after this surgery.

Hope you can get out to the golf course as much as you like. Good luck.
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