What are the risks of ACL surgery?

ACL reconstruction surgery is generally safe. Complications that may arise from surgery or during rehabilitation (rehab) and recovery include:

• Problems related to the surgery itself. These are uncommon but may include: Numbness in the surgical scar area, infection in the surgical incisions damage to structures, nerves or blood vessels around and in the knee, blood clots in the leg and the usual risks of anesthesia.
• Problems with the graft tendon (loosening, stretching, reinjury or scar tissue). The screws that attach the graft to the leg bones may cause problems and require removal.
• Limited range of motion, usually at the extremes. For example, you may not be able to completely straighten or bend your leg as far as the other leg. This is uncommon, and sometimes another surgery or manipulation under anesthesia can help. Rehab usually attempts to restore a range of motion between 0 degrees (straight) and 130 degrees (bent or flexion). You may lack a few degrees at either end of the range of motion after surgery and rehab.
• Grating of the kneecap (crepitus) as it moves against the lower end of the thighbone (femur), which may develop in people who did not have it before surgery. This may be painful and may limit your athletic performance. In rare cases, the kneecap may be fractured while the graft is being taken during surgery or from a fall onto the knee soon after surgery.
• Pain, when kneeling, at the site where the tendon graft was taken from the patellar tendon or at the site on the lower leg bone (tibia) where a hamstring or patellar tendon graft is attached.
• Repeat injury to the graft (just like the original ligament). Repeat surgery is more complicated and less successful than the first surgery.