The treatment to preserve both types of cartilages one  need to address 2 factors

1 Pressure.: This can be done by adjustment of  activity, avoid strong impact, weight reduction; avoid deep flexion position which caused high pressure in the knee joint.  Abnormal position of the knee can also lead to high pressure spot that can lead to early cartilage damage.  Minor abnormal knee position can be corrected with specific stretching.  Major abnormal position may need corrective surgery, if it seem to correlate with the cartilage damage. 

2. Stability : ligament injury of the knee will cause abnormal movement leading to cartilage damage.  Minor change in this stability can be addressed with activity modification or specific muscle exercise.  However, if there is significant change in the stability one may need surgery to reduce this instability. 
For injury to both types of these cartilages, Only after these 2 factors were addressed and the damage progressed despite all full conservative measures, arthroscopic (Key hole) surgery will be considered.