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.
 

For articular cartilage lesions, they can be treated arthroscopically either by debridement, repair e.g. Microfracture or drilling of small holes in the defect and let new cartilage grows or Restorative, e.g transplanting of cartilage from a healthy part of your knee. 
 

For the meniscus : The damage will be repaired if repairable.  Only those that cannot be repaired or does not need to be repaired  will be removed.  The key of repair is to restore its smooth surface and to keep the meniscus in a functional position to preserve the mechanic of the knee as much as possible.  Certain specific character of the meniscus injury is its scanty blood supply and its varied architecture of the tear which must be aware of.  Each repair technique must keep the tear firmly together while minimally disturb its blood supply.  This is one of the most challenging issue of knee arthroscopy. Your doctor will discuss with you further based on the type of tear.