Types of ACL injuries include grades I, II and III sprains in addition to ACL avulsions, states WebMD. Grade I sprains feature a minimal amount of swelling, tenderness and a stretching of the ligament's fibers. No tear is present, and the knee retains its stability. A grade II sprain includes partial tearing, moderate swelling and some stability of the knee joint. A grade III sprain comprises a complete tear or rupture, tenderness, little-to-no swelling and pronounced instability of the knee.
ACL avulsions are comparatively rare in adults and most often occur in children, according to WebMD. An ACL avulsion occurs when the ACL tears away from the leg bone along with a piece of bone. This can occur in either the upper leg or the lower leg.
Treatment options for those who suffer ACL injuries depend on both the injury itself and the lifestyle of the patient, says the American Academy of Orthopedic Surgeons. Nonsurgical procedures can be effective for adults who do not play sports that require agility, while athletes usually opt for surgery in serious ACL injury cases. Nonsurgical treatment includes bracing and physical therapy, and surgical treatment relies on reconstruction of the ACL with a tissue graft. Common graft sources include hamstring tendons and patellar tendons.