Overview
The anterior cruciate ligament runs diagonally inside the knee joint, connecting the femur to the tibia. It is the primary restraint against the tibia sliding forward and against rotational pivoting — exactly the forces generated during cutting and landing in sport. A torn ACL leaves the knee unstable for pivoting activity and often accompanies meniscal and cartilage injuries that compound over time.
How the Procedure Works
The first decision is what tissue to use as the new ligament — the graft. Three good options: a strip from the patellar tendon below the kneecap (which heals fastest because it carries bone on both ends), tendons from the hamstrings (a reliable alternative when we want to spare the front of the knee), or a strip from the quadriceps tendon above the kneecap (which gives us a thicker graft with modest impact at the donor site). Your surgeon picks the graft based on your sport, your anatomy, and your priorities. Once the torn ACL is cleared out arthroscopically, the new graft is fed through tunnels drilled in the thigh bone and shin bone, placed at the exact spots where the original ligament used to attach. Tunnel position is the single most technique-sensitive step in the operation — even a few millimeters off-center increases the chance of rotational instability and a re-tear. The graft is tensioned, locked at both ends, and stress-tested through the full arc of knee motion before closing. One thing to know: the graft isn't a working ligament on day one. It remodels into one over months of progressive loading — which is why how you pace rehab matters as much as how the surgery went.
When to Consider ACL Reconstruction
ACL reconstruction is generally offered when your symptoms, imaging, and your goals together point to surgery as the next step. The typical patient profile:
Active Patients Wishing to Return to Sport
Athletes who want to return to pivoting or cutting sports — soccer, basketball, skiing, football — where a stable ACL is non-negotiable.
Young Patients with a Long Active Life Ahead
Reconstruction protects the meniscus and cartilage from the repeated giving-way episodes an ACL-deficient knee produces.
Associated Injuries That Need Addressing
Meniscal tears, cartilage damage, or multi-ligament injury that should be surgically managed at the same sitting.
Conditions This Treats
Physicians Who Perform ACL Reconstruction
Providers Who Surgically Assist with ACL Reconstruction
Risks & Why We Still Recommend It
Every operation carries risk. The reason we offer this procedure is that the alternative — leaving an unstable knee unchanged — has its own real costs: repeated giving-way episodes that damage the meniscus and cartilage a little more each time, and a permanent end to pivoting sports. We aren't eliminating risk; we're choosing the smaller of two unfavorable paths.
The risks we discuss with you before ACL reconstruction include:
- bleeding and infection
- anesthesia risk
- graft-site pain (patellar or hamstring) that usually settles
- stiffness or loss of terminal extension
- graft re-tear, especially with early return to cutting sport
- blood clot (DVT/PE)
- rarely, injury to nearby nerves or vessels
The indication to proceed is a functionally unstable knee in a patient who wants to return to pivoting activity, confirmed on exam and MRI. Patients who don't need this operation don't get it.
Further Reading
External patient-education references and related OSI pages for additional background: