The patient's patellofemoral joint is underdeveloped, implying that the patient's femoral intercondylar fossa was already abnormal. To what extent, who knows; the damaged posterior tibial plateau means that when reconstituting the posterior cruciate ligament, the femoral stop point on the posterior cruciate ligament of the reshaped femoral intercondylar fossa won't be in a regular position. This factor should be taken into account in the reshaping. Therefore, a very unusual femoral intercondylar fossa needs to be reshaped.
If the previous method is adopted, it would involve mirroring a normal femoral intercondylar fossa from the opposite side for reshaping. The surgery would surely fail, which would lead to the loss of the function of the rebuilt posterior cruciate ligament and instability of the patellofemoral joint.
