She has history of acute onset of pain 3 months ago, with progressive valgus deformity of the knee.
The primary surgery was done 14 years ago. ORIF for periprosthetic # was done 3 months post op. Was doing well until recently
Dear Raju
This is very interesting. I haven't seen this before.
Do you think that the fibular fracture could be present as hailine fracture at the original x-rays following the injury resulting the periprosthetic fracture 3 months ago?
I am mentioning this as the fibula is healed with good callus.
Also, the valgus position, is it possible to be the result of soft tissue imbalance as result of either collapse of the fracture during the healing process or due to that position the fracture was fixed?
I am saying this because she has, in my eyes, patella baja. On top of this the distal femur is placed in some extension so there is the possibility of some comminution due to the patient's osteoporosis.
X-rays of the fracture before surgery may help.
This is very interesting problem and I can see the solution with a potential revision of all metalwork with a hinged prosthesis if necessary. All depends on patient's clinical condition.
I do not think the fibula fracture is the problem in this case. I believe the valgus position is the problem, and one can imagine it is caused by prosthesis instability (medial soft-tissue instability or loosening with subsidence of tibial implant for osteoporosis ). Obviously revison is needed. You should be prepared for exchange of the prosthesis with reconstruction (augmentation) of the tibial plateau and a higher inlay size or even hinge prosthesis as ultima ratio.
Thank you, George and Panayot for your ever so positive involvement. in discussions. In my Arthroplasty career of 29 years, I have never encountered a stress # around an implanted TKA. I am attaching 3 months old X-rays, which clearly show no visible fracture of the fibula. I feel that this stress # had occurred due to slowly progressive valgus deformity due to time bound failure of this joint, due to stress concentration in the fibula. I agree with your treatment advise, about total revision of this TKA, after all implants removal, using a more constrained implant with longer stems.
Dear Raju
You maybe right. Fractures around the fibula are not seen in the new Xrays.
I am not sure if there is an element of rotation or even lack of full extension on the films. The knee is in more valgus than someone could expect and possibly this is one of the reasons the medial tissues gave. From the AP view seems that the fibula could be a weight bearing bone as the tibial tray is overhanging on the head and as the soft tissues gave way the load is going through the fibula more and forced the fracture.Do you think that this may be the reason? It is very interesting.
I feel that progressively developing valgus due to wear had caused this stress #. Once the fibular restraint gave way, the valgus deformity suddenly increased.
Interesting case. The fibular fracture is - on my opinion - the consequence and probably not the triggering factor which is certainly the VALGUS.
Looks like that the tibia plateau doesn't fit perfectly the bony structures with postero-lateral sliding of the spacer. The severe local osteoporosis probably didn't help as well.
So revision with constraint implants is probably the best answer, if possible...
I did the revision of this knee. The medial collateral ligament was very lax and attenuated. The femoral condyles were damaged and the distal femur looked like typical "ice cream cone". I used a hinged prosthesis of Stryker here.
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