About to have 2nd torn meniscus surgery... Is a repair or removal better and why does this keep happening. Only 24 and never had accident or injury?

Repair if possible. Only certain types of tears (peripheral around the rim) are repairable. Results are somewhat age dependent younger better than older people have better results. Partial meniscectomy still has a chance of increased arthritis in the long run. Joe dimaggio ripped his meniscus standing up on a bus so there doesn't have to be result of an accident.