Pronounced patella baja is leading to pain and decreased motion after implantation of a TKA. Osteotomy of the tibial tubercle is an option, but is limited according to anteriorisation. In true patella baja the patella tendon is shortened. A z-plasty is another option.
Combination of the two options is potentially prone to complications.
Is there any evidence about it?
In revision TKR setting, shifting the femoral component distally (using augments) is one option you must consider., rather than touching extensor mechanism in any way. Most knee revisions would need a constrained implant with augments.
Healing of tissues in revision scenario is a challenge (relatively poor vascularity of all tissues) and compromised extensor mechanism is a potential disaster. So, personally, I would avoid any Z-plasty.
Tibial tubercle osteotomy and advancement may be used if it was essential for cement removal from tibia and can now be shifted proximally as per requirement. Good results have been reported with tibial tubercle advancement as in the article below:
https://online.boneandjoint.org.uk/doi/abs/10.1302/0301-620x.99b7.bjj-2016-1267.r1?journalCode=bjj
Anytime you mess with extensor mechanism, you play with fire.
Tibial tubercle osteotomy is a reasonable option with good technique and soft tissue handling.
I would not consider a Z plasty .
Distalization of the femoral component is another good option.
Treatment would depend on what the true etiology of the issue is.
Article The treatment of acquired patella baja with proximalize the ...
It is a difficult problem and has to be considered and planned prior to the operation.
Described techniques
In Mild patella baja, patella replacement but with a smaller button placed more superiorely and trimming the distal part of the patella bone do reduce impingement on the tibial tray, if necessary.
In Moderate, use augmentation of distal femur and lower tibial cut is considered
In Severe, patellectomy with the use of a posterior stabilising component and/or remove part of the patella bone (about half of patella), is a described procedure.
Tubercle osteotomy can be considered to facilitate the cement removal of the tibial component but has to be placed at the same place, so may not assist with the problem. The technique that personally use is extensive-long medial osteotomy of the tubercle and elevation to the lateral without detaching the lateral soft tissues and periosteum from the osteotomised bone and fix it back with wires through bone holes. In case of complete detachment there is risk of non union and extension lag.
Z-plasty creates extension lag in my hands.
Thank you for the question
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