ACL reconstruction surgery typically takes about two and a half hours from start to finish. That includes anesthesia, the procedure itself, and closing the incision. The actual hands-on surgical work usually falls within a narrower window, but the full time you’ll be in the operating room is roughly in that range. Several factors can push that number up or down, with your choice of graft tissue being the biggest variable.
What Happens During Those Two and a Half Hours
ACL reconstruction is performed arthroscopically, meaning the surgeon works through a few small incisions using a camera and specialized instruments. The damaged ligament is removed, tunnels are drilled into the thighbone and shinbone, and a replacement graft is threaded through and secured in place. The graft serves as scaffolding that your body gradually grows new ligament tissue around over the following months.
Before any of that begins, the anesthesia team needs time to administer either general anesthesia or a regional nerve block (or both). This prep phase, along with positioning your leg and sterilizing the surgical area, accounts for a meaningful chunk of the total operating room time. At the end, closing the incisions and applying dressings adds another several minutes.
How Graft Choice Affects Surgical Time
The single biggest factor influencing how long your surgery takes is where the replacement tissue comes from. There are two broad categories: autograft, which uses tissue harvested from your own body, and allograft, which uses donor tissue from a tissue bank.
When the surgeon uses donor tissue, there’s no harvesting step. The graft arrives pre-prepared and ready to go. That shortcut saves roughly 30 minutes compared to using your own tissue. Research from HealthPartners Institute found that allograft procedures were 27 to 33 minutes faster than any of the three common autograft options: patellar tendon (taken from the front of your knee), hamstring tendon (taken from the back of your thigh), or quadriceps tendon (taken from just above your kneecap).
If your surgeon is using your own tissue, they need to make an additional incision, carefully remove the graft, and prepare it on a back table before the reconstruction can proceed. Each graft type has its own harvesting technique, but the time difference between the three autograft options is minimal. The real time gap is between using your own tissue versus donor tissue.
Other Factors That Add Time
A straightforward, first-time ACL reconstruction on an otherwise healthy knee tends to be the fastest scenario. Several things can extend the procedure:
- Additional injuries: Meniscus tears are common alongside ACL tears. If the surgeon needs to repair or trim a torn meniscus during the same operation, that adds time. A meniscus repair (stitching the tear) takes longer than a partial removal (trimming the damaged portion).
- Cartilage damage: If there’s cartilage wear or loose fragments in the joint, the surgeon may address those while they’re already inside the knee.
- Revision surgery: If you’re having a second ACL reconstruction because a previous graft failed, the procedure is more complex. The surgeon needs to remove old hardware, possibly fill in bone tunnels from the first surgery, and navigate scar tissue. Revision cases can run significantly longer than a first-time reconstruction.
- Multi-ligament injuries: Reconstructing the ACL along with another knee ligament (such as the MCL or PCL) turns a standard procedure into a much longer one.
Time in the Operating Room vs. Total Hospital Time
The two-and-a-half-hour estimate covers what happens in the operating room. Your total time at the surgical center will be considerably longer. Plan for a full-day commitment. You’ll typically arrive one to two hours before your scheduled surgery time for check-in, pre-operative assessment, IV placement, and a conversation with your anesthesiologist.
After surgery, you’ll spend one to two hours in a recovery room as the anesthesia wears off. Nurses will monitor your vital signs, manage your pain, and make sure you can tolerate fluids. A physical therapist may also stop by to fit you with a knee brace and show you how to use crutches safely before you leave. Most ACL reconstructions are outpatient procedures, meaning you go home the same day. From the moment you walk through the door to the moment you’re cleared to leave, expect roughly five to seven hours total.
What Recovery Looks Like Immediately After
You won’t be able to drive yourself home, so arrange a ride in advance. Your knee will be wrapped in a bulky dressing and likely immobilized in a brace. Most people experience significant swelling and moderate pain for the first few days, managed with ice, elevation, and prescribed pain medication. A nerve block given during surgery often keeps the knee numb for 12 to 24 hours, which provides a comfortable window before the sharper post-surgical pain sets in.
Physical therapy typically begins within the first week. Early exercises focus on regaining range of motion and preventing the quadriceps muscle from weakening. Full recovery and return to sports generally takes nine to twelve months, though the timeline varies based on graft type, the extent of additional repairs, and individual healing rates.