Whether an ACL injury can heal on its own is based on the extent of the injury. Slight injuries can generally heal on their own, while severe ligament injuries generally require treatment to heal.
Slight ACL injuries, i.e. partial tear of the ligament with the main body intact, can basically heal on their own through proper rest and rehabilitation training under the guidance of a medical professional.
For serious ACL injuries, i.e., complete ligament tears, surgery is needed if the ligament cannot heal on its own. By repairing and reconstructing the cruciate ligament to restore its functional integrity, complete recovery can be achieved through professional rehabilitation training after the operation, which will not affect the life and work in the future.
If you have the above symptoms, you should go to the hospital in time, complete the examination, and give targeted treatment or therapy after clarifying the cause of the disease.