The anterior cruciate ligament (ACL) is one of four major ligaments in the knee, connecting the thigh bone (femur) to the shin bone (tibia). This strong fibrous tissue provides approximately 85% of the restraining force against the tibia sliding forward relative to the femur (anterior tibial translation). The ACL also maintains rotational stability, especially during activities involving pivoting or sudden stops. When the ligament is torn, the resulting instability often requires surgical reconstruction to restore function and prevent further joint damage.
Many people search for “laparoscopic” ACL surgery, but the correct medical term for this minimally invasive joint procedure is arthroscopy. Arthroscopy is the standard method for reconstructing the torn ligament, allowing surgeons to operate inside the joint without large incisions. This technique reduces trauma to surrounding tissues, leading to less post-operative pain and a quicker initial recovery compared to traditional open surgery.
Clarifying the Surgical Technique: Arthroscopy vs. Laparoscopy
The distinction between arthroscopy and laparoscopy lies in the area of the body being treated. Arthroscopy is a specialized technique used exclusively for operations within a joint, such as the knee, shoulder, or ankle. The term derives from the Greek words for “joint” (arthron) and “to look” (skopein).
A surgeon performs an arthroscopy by making two or three small incisions, often called portals, around the knee. Through one portal, a narrow tube containing a light and a miniature camera (an arthroscope) is inserted. This instrument transmits real-time, magnified images of the joint’s interior structures to a video monitor.
The remaining small incisions are used to pass specialized surgical instruments into the joint space to perform the repair. This allows the surgeon to work on the damaged ACL, menisci, and cartilage without exposing the entire joint capsule. In contrast, laparoscopy is a similar minimally invasive technique reserved for procedures within the abdominal and pelvic cavities, such as gallbladder removal or hernia repair.
The Steps of Minimally Invasive ACL Reconstruction
Once the arthroscope is in place and the joint is visualized, the surgeon first removes the remnants of the torn ACL using specialized instruments. This clears the anatomical space where the replacement ligament will reside.
The next phase involves the precise creation of bone tunnels in the femur and the tibia to anchor the new ligament. Using a guide wire and a drill, tunnels are created in both the tibia and the femur. These tunnels must be accurately placed to mimic the attachment points of the original ACL, ensuring the new ligament provides correct function and rotational stability.
The new graft material is then threaded through the tibial tunnel and pulled into the femoral tunnel. The graft is secured at both ends using various fixation devices, which may include bioabsorbable interference screws, metal buttons, or continuous-loop suspensory devices. Final tensioning of the graft is performed to ensure the correct tightness and stability before the incisions are closed.
Choosing the Graft Material
The choice of tissue used to replace the torn ACL is a significant consideration, affecting both the surgical technique and the recovery process. Graft material is categorized into two main groups: autograft and allograft. Autograft uses the patient’s own tissue, which eliminates the risk of disease transmission and has a lower failure rate, especially in younger, active patients.
The most common autograft options are the bone-patellar tendon-bone (BPTB) graft, hamstring tendons (semitendinosus and gracilis), and the quadriceps tendon. The BPTB graft, taken from the middle third of the patellar tendon, is considered a standard due to its reliable bone-to-bone healing. Hamstring autografts involve a smaller incision and are associated with less anterior knee pain.
Allografts use tissue sourced from a deceased donor, often utilizing tendons such as the patellar, quadriceps, or Achilles. A major advantage of allograft is the elimination of donor site morbidity, meaning there is no pain or weakness from harvesting the patient’s own tissue. However, the tissue processing required for sterilization can compromise the graft’s integrity, and allografts have been linked to a higher risk of re-rupture in individuals under the age of 25.
Rehabilitation and Recovery Milestones
Following ACL reconstruction, dedicated physical therapy is necessary for a successful outcome, with the entire recovery process spanning nine to twelve months. The immediate post-operative phase, lasting the first one to two weeks, focuses on controlling pain and swelling through elevation, icing, and gentle range-of-motion exercises. Patients begin working on regaining full knee extension immediately, as achieving complete straightening of the leg is a primary goal in this early phase.
The subsequent phase, from weeks three to six, emphasizes regaining full range of motion and initiating gentle strengthening exercises. Patients work to achieve full flexion and begin low-level closed kinetic chain exercises, such as mini-squats, to build stability around the joint. Around two to four months after surgery, the focus shifts to advanced strengthening, including leg presses and balancing drills, to improve neuromuscular control.
More advanced functional training, like straight-line running, may begin around four to six months, provided the patient meets specific strength and stability criteria. The final stage involves sport-specific training and agility drills, which occurs between six and nine months post-operation. Return to full, unrestricted sporting activity is only permitted after functional testing confirms the reconstructed leg has reached at least 85-90% strength compared to the uninjured leg. This milestone occurs between nine and twelve months to minimize the risk of re-injury.