Relevance. ACL tears are among the more common serious basketball injuries. A meta-analysis (review of multiple studies) showed that women have a 3:1 increase for ACL tears in basketball but did not show an effective injury prevention strategy. Another study showed, "in girls, the highest ACL injury risks per season were observed in soccer (1.1 percent), basketball (0.9 percent), and lacrosse (0.5 percent). In comparison, the highest risks per season for boys were observed in football (0.8 percent), lacrosse (0.4 percent), and soccer (0.3 percent)."
Stresses on ACL. Injury may be contact or non-contact. If the planted knee is hit from the side (tackling, clipping), the ACL may be overstretched and rupture (break), sometimes with additional injury (meniscus tear, medial collateral ligament) called the "unhappy triad". Rapid directional change can also hyperextend the knee stressing the ACL.
Women have higher ACL injury rates for a variety of reasons, anatomical, hormonal, and physiological (different jumping styles).
Diagnosis. Participants describe acute pain and sometimes describe feeling or even hearing a pop and noticing almost immediate swelling. With a complete tear, internal bleeding occurs, resulting in a joint effusion, which can be aspirated (removed) with hemarthrosis (blood in the joint). The injured player tends to protect the joint with lack of movement and adopt a partially flexed knee posture to reduce pain.
Generally, an MRI confirms the diagnosis.
Options. Surgery isn't necessary for everyone. If a 68 year-old man tears his ACL skiing, he may or may not want to accept the age-related risk and prolonged rehab. Some athletes return to full play without reconstruction (e.g. Buffalo Bill great Thurman Thomas). But many opt for surgery.
The American Academy of Orthopaedic Surgeons (AAOS) cites an 82 to 95 percent success rate for surgery. They discuss reasons for graft failure and surgical complications as well as differing surgical repairs. Some of this will depend on the surgeon's training (which technique learned) and experience. The goal is a stable knee with return to full activities including high intensity sports.
Recovery. AAOS states, "Physical therapy is a crucial part of successful ACL surgery, with exercises beginning immediately after the surgery. Much of the success of ACL reconstructive surgery depends on the patient's dedication to rigorous physical therapy." ACL rehabilitation is lengthy and demanding. Regardless of surgical or non-operative treatment, osteoarthritis is likely over time.
Return to sport. Competitors want the earliest return possible. Physicians want to balance optimal recovery and function with early return. Return too soon risks reinjury. The author writes, "Time questions aside, I don’t allow return to Level I sport (soccer, basketball, football) until there is no pain with activity, no swelling, full range of motion, good stability, strength close to equal to the opposite side." The surgeons in this article discuss their criteria for return and rehabilitation strategies.
Miscellaneous. Recovery is both physical and psychological. Many athletes have a (realistic) fear of reinjury. It took several years for me to resume playing basketball without 'thinking' about possible injury.
As coaches, we need to understand that 'medical clearance' for athletes to return isn't the same as "the athlete is one hundred percent".