Reason for the chronic recurrent subluxation or luxation:
1) Laxity of Joint capsule 
 condyle will move without Restriction.
2) Shollow | Flat | eroded Articular eminence (Height↓)
Condyle – jump – eminence
3) Trauma to the Joint
Integrity of ligament – ruptured.
Laxity of joint capsule.
Eroded articular eminence.
Trauma to the joint.
All of the above.