The Anterior Cruciate Ligament (ACL) is one of the main stabilizing ligaments inside the knee. It prevents the tibia (shinbone) from sliding out in front of the femur (thighbone) and provides rotational stability during twisting or pivoting movements. An ACL tear is a common sports injury, frequently occurring during basketball, soccer, football, or skiing. It is characterized by sudden knee instability, making it difficult or impossible to return to sports or perform daily activities without the knee “giving out.”
Dr. Francisco Hernandez performs arthroscopic-assisted ACL reconstructions at Hospital Punta Mita, utilizing modern surgical techniques to restore joint stability, mechanical strength, and long-term function.
Classic Symptoms of an ACL Tear (Triage)
If you recently sustained a knee injury, check for these classic signs of an ACL rupture:
- A loud “pop” sound: Hearing or feeling a distinct popping sensation inside the knee at the moment of injury.
- Rapid swelling: Severe joint swelling (hemarthrosis) developing within the first 2 hours due to bleeding from the torn ligament.
- Giving way: A feeling of instability, as if the knee is sliding out of place when attempting to stand or walk.
- Inability to continue playing: Immediate loss of function, making it impossible to run, walk, or put full weight on the leg.
Graft Options for ACL Reconstruction
Because a completely torn ACL cannot heal on its own (due to the lack of blood flow inside the joint fluid), it must be replaced with a tissue graft. The three main options validated by the AAOS are:
1. Hamstring Autograft
- Details: The surgeon harvests the semitendinosus and gracilis tendons from your own leg through a small incision.
- Benefits: Excellent strength, small incisions, and a very low rate of complications at the harvest site.
2. Patellar Tendon Autograft (Bone-Patellar Tendon-Bone or BPTB)
- Details: The surgeon harvests the middle third of your patellar tendon along with small bone plugs from the kneecap and shinbone.
- Benefits: Provides bone-to-bone healing, which is highly secure. This is often the preferred choice for young, high-demand athletes due to its low re-rupture rate.
3. Allograft (Donor Tissue)
- Details: Graft tissue harvested from a certified tissue donor bank.
- Benefits: Eliminates the need to harvest tissue from your own body, resulting in less immediate postoperative pain and a slightly shorter surgery time. It is typically recommended for older patients or revision surgeries.
Weekly Rehabilitation and Fisioterapia Milestones
Recovering from an ACL reconstruction is a structured process that requires patience and dedication to physical therapy to allow the graft to integrate (ligamentization):
Phase 1: Protecting the Graft & Extension (Weeks 1 to 4)
- Goals: Control swelling, restore full passive knee extension (0°), and re-establish quadriceps muscle activation.
- Restrictions: Use a hinged knee brace locked in extension and crutches. Touch-down weight-bearing as tolerated.
Phase 2: Range of Motion & Normal Gait (Weeks 4 to 8)
- Goals: Gradually increase knee flexion to 120°, transition off crutches to achieve a normal walking pattern, and begin light closed-kinetic chain strengthening (mini-squats, leg press).
Phase 3: Strength & Balance (Weeks 8 to 16)
- Goals: Progressive resistance training for quadriceps, hamstrings, and glutes. Focus on single-leg balance (proprioception) and core stability.
Phase 4: Straight-Line Running (Months 4 to 6)
- Goals: Introduce straight-line jogging on flat, soft surfaces under physical therapy supervision. Begin basic coordination and agility drills.
Phase 5: Return to Sports Clearance (Months 8 to 12)
- Goals: Gradual introduction of sport-specific drills, cutting, and contact. Clearance to return to play is granted only after passing a functional battery of tests, verifying a limb-strength symmetry of 90% or more compared to the healthy leg.
Frequently Asked Questions about ACL Reconstruction
What happens if I choose not to have ACL surgery?
If you live a sedentary lifestyle or engage only in low-impact activities (swimming, cycling), you may manage without an ACL. However, if you participate in sports involving cutting, pivoting, or sudden changes of direction, a missing ACL will cause recurrent instability. Each time the knee gives way, it damages the menisci and cartilage, leading to early osteoarthritis.
Can the surgery be performed immediately after the injury?
Generally, no. It is best to wait 2 to 4 weeks after the injury to allow the initial swelling and inflammation to subside and to restore full range of motion. Performing surgery on a stiff, swollen knee significantly increases the risk of artrofibrosis (scar tissue buildup inside the joint that permanently limits mobility).
How long does the new ACL last?
With proper surgical technique, graft placement, and completion of rehabilitation, the reconstructed ACL can last a lifetime. The success rate is between 85% and 92% for restoring stability. However, returning to sports too early (before the graft has fully matured and strength is restored) increases the risk of re-rupture.