ACL reconstruction surgery typically takes one to two hours from the first incision to the last stitch. The total time you spend at the surgical facility, though, is significantly longer once you factor in pre-operative preparation and post-surgery recovery. Most patients should plan on being at the hospital or surgery center for roughly four to six hours overall.
What Happens During the One to Two Hours
ACL reconstruction is performed arthroscopically, meaning the surgeon works through a few small incisions using a tiny camera and specialized instruments. The damaged ligament is removed and replaced with a graft, a piece of tendon that serves as scaffolding for a new ligament to grow. The surgeon drills small tunnels into the thighbone and shinbone, threads the graft through, and secures it in place with screws or other fixation devices.
The procedure lands closer to one hour when the ACL is the only structure being addressed. It stretches toward two hours (or occasionally beyond) when the surgeon also needs to repair a torn meniscus, fix cartilage damage, or reconstruct another ligament. These combined procedures are common because ACL tears frequently happen alongside other knee injuries.
Graft Choice Affects Operating Time
One of the biggest variables in how long you’re on the table is where the replacement graft comes from. There are two main options: an autograft, which uses tendon tissue harvested from your own body, and an allograft, which uses donor tissue from a tissue bank.
Autografts require an extra surgical step. The surgeon has to harvest the tendon, usually from your patellar tendon (below the kneecap) or hamstring tendons (back of the thigh), and then prepare it before implanting it. This adds time to the procedure. Allografts skip that step entirely because the tissue arrives pre-prepared, which shortens the overall operation. Your surgeon will recommend one over the other based on your age, activity level, and the specific demands of your sport or lifestyle, not just speed.
Time Before and After the Procedure
The surgical clock doesn’t capture the full picture of your day. You’ll typically arrive one to two hours before the scheduled surgery time. During this window, nursing staff starts an IV line, the anesthesiologist reviews your plan, and the surgical team marks the correct knee and runs through safety checks. You may receive a nerve block to manage pain after surgery, which takes additional time to administer and verify.
After surgery, you’ll spend time in a recovery area while the anesthesia wears off. How long this takes depends partly on the type of anesthesia used. General anesthesia (where you’re fully asleep) tends to allow a somewhat faster discharge from the recovery unit compared to certain types of spinal anesthesia, though spinal anesthesia often results in less nausea and pain in the hours immediately after surgery. Either way, expect to spend roughly one and a half to three hours in recovery before the team clears you to go home.
ACL reconstruction is almost always an outpatient procedure, meaning you go home the same day. You will need someone to drive you.
Factors That Can Extend Surgery
Several things can push the procedure past the typical one-to-two-hour window:
- Additional injuries: A torn meniscus repair or cartilage restoration procedure performed at the same time is the most common reason surgery runs longer.
- Revision surgery: If a previous ACL graft has failed and you’re having a second reconstruction, the surgeon may need to remove old hardware and deal with scar tissue, adding complexity and time.
- Complex anatomy or multi-ligament injuries: Patients who have damaged more than one ligament require a more involved reconstruction.
Your surgeon can usually give you a personalized time estimate based on your MRI findings and surgical plan. If they anticipate additional repairs, they’ll let you know beforehand so you can plan accordingly.
What the Recovery Timeline Looks Like
While the surgery itself is relatively quick, the recovery is not. Most people use crutches for two to six weeks and wear a brace during the early phase. Physical therapy starts within days of surgery, initially focusing on reducing swelling and restoring range of motion. Strengthening exercises ramp up over the following months.
Return to desk work is realistic within one to two weeks for many people. Jobs that require physical labor typically need six to twelve weeks. Full return to cutting and pivoting sports, like soccer, basketball, or skiing, generally takes nine to twelve months. The graft needs time to mature and integrate with your bone before it can handle high-stress movements, and rushing this timeline increases the risk of re-tearing.