Knee cap (patella) dislocation.

In 2002 April , my left knee cap hit against the corner of a Cot and was dislocated. During that time, my leg was plastered for 6 weeks and after that physiotherapy was done. Then it reoccur 3 more times... In 2006 December , 2010 March and 2015 June. ..Now I used to wear a knee cap... It should be tight... Otherwise subluxation occurs... Is there any permanent solution for this? I have heard about corrective surgery for ligament damage... Both positive and negative comments...... Some said it will not be a success.... Some said after surgery you will be having pain in knee throughout your life ...Is it effective? Please help me... Always I have the worry that whether my patella dislocate and fell down... Please help me.