The condition
The ACL is the main ligament in the center of the knee that controls forward and twisting motion. A previous ACL graft can stretch, fail, or re-tear from a new injury or over time, and the knee may give way again. Tunnel position, alignment, or other loose ligaments can contribute.
The surgery
The failed graft is replaced with a new tendon graft through small incisions with a camera; the graft source will be discussed with you. Old hardware may be removed and an outer-knee reinforcement (LET) added. Widened tunnels may need bone grafting first, with the new ACL placed in a second surgery. The final plan is determined during surgery.
Recovery at a glance
- Weight-bearing
- Full weight right away, with crutches until you walk normally; no routine brace (unless an added meniscus repair or other procedure requires one).
- Motion
- Fully straight by 2 weeks and bending to 120° by 6 weeks. Strengthening progresses more slowly than after a first ACL surgery.
- Daily life
- Desk work often within 1–2 weeks. No driving while taking narcotic pain medication.
- Running
- Not before 16 weeks, once strength reaches ~70% of the other leg and swelling has settled.
- Sports
- No sooner than 9 months, after strength and hop testing (typically 9–12 months); a sports brace is recommended the first season.
- If staged
- A bone-graft first stage has a quick recovery like a knee scope, but no running or pivoting until the second surgery (typically 3–6 months later).
A general guide. Your restrictions and timeline may change based on what is found and done at surgery.
Risks & benefits
Benefits: Most patients regain a stable knee, though results are less predictable than after a first ACL surgery. Risks are uncommon and include infection, blood clots, graft stretching or re-tear, the need for a staged (two-step) surgery, injury to nearby structures (such as nerves, blood vessels, or cartilage), stiffness, persistent pain, and the need for further surgery. These will be reviewed with you in detail before surgery.
Patient Surgical Information
Open, save or print. Bring your questions to your pre-op visit.
Before & after every surgery