The procedures you mentioned can be very effective if done for the right reasons. Patella instability can result from a variety and combination of conditions, so the best surgical method to try really depends on the underlying cause(s) of the instability are.
A medial transfer of the tibial tubercle can help if the instability is due to the tibial tubercle being displaced too far laterally, which is generally indicated if the TT-TG (tibial tubercle to trochlear groove offset) is greater than 20mm. However, instability can also come from the patella sitting too high in the groove (patella alta), a shallow trochlear groove, excessive torsions of the femur and/or tibia, and a slew of other issues that can generally be assess with the proper diagnostic imaging.
The MPFL reconstruction is indicated of course if the medial patellafemoral ligament is torn or stretched out, but whether or not it will stop future dislocations really depends on what else is going on. If the alignment is bad and is not corrected, reconstructing a ligament won't help in the long run as the patella may just dislocate again.
What to expect following the surgery really depends on the doctor's protocol. You could be anything from weight bearing as tolerated with crutches to no weight bearing and immobilized in a brace for up to 6 weeks. It really depends on the doctor and is something you should ask of the doctor. I know for me, the immobilization period and the rehab protocol is something that I used to determine who I wanted to perform the surgery in my signature.
