True rotational variance between femur and tibia 15 degrees to medial border of tibial tuberosity, 30 degrees to medial third of the tibial tuberosity. In both measurements , tibia is externally rotated with respect to the femur.
This is not a complete report. I also have not reviewed the images and this opinion is informational only and may not be totally applicable to your situation. I can provide some thoughts, however. It states the the tibia is externally rotated with respect to the femur. This usually happens when the tibial baseplate is cemented (or screwed) in an
internal rotated position. The ideal placement of the tibial baseplate is for the very front of the baseplate to be inline with the medial 1/3 of the tibial tubercle (that is the reason that they mention that landmark in the report). If the baseplate is placed
internally rotated then when the knee is put back in place to meet with the femoral component, the tibial needs to rotate
externally to align itself with the femur. This will make the entire tibia/ankle/foot rotate
externally.
If the tibia rotates externally, then the patella tendon (attached to the tibial tubercle) will be pulling the patella (knee cap) toward the outside (lateral) part of the knee replacement, rather than in a straight line in the middle of the posthesis. This will created an increased contact force on the outside portion of the knee cap and make the patella more prone to dislocation/pain.
There are several of factors that are important to consider.
1 - If the prosthesis is a rotating platform design then this mismatch will be much less noticeable because the poly can spin (somewhat) to help re-align the leg in a more functional position.
2 - If the knee cap was resurfaced (usually done in the U.S.) then the new patella button may have been medialized, which can reduce the abnormal forces from this mal-alignment from rotation.
3 - If a lateral release was done (cut the tissue on the outside of the knee cap) during surgery, this will also reduce some of the stress on the knee cap from this mal-alignment from rotation.
You can test your tibial rotation by bending the knee 90 degrees and by keeping the ankle and heel directly below the knee (thus keeping the hip in neutral rotation as well). You should not be able to see the ankle or heel because the knee is blocking it from view. Then look straight down to see if the toes are pointed forward. If the tibial is rotated externally then the the toes will point outward. This relationship is dependent on you not having any other lower extremity deformities such as a flat foot, hip arthritis, bunions, etc...
I hope this helps.
Orthodoc