The anterior cruciate ligament (ACL) plays a key part in knee stability and is often affected by injuries, particularly in sports and activities involving sudden movements. A torn ACL can lead to instability, discomfort, and limitations in daily activities or physical pursuits. In many cases, surgery is considered to improve knee function and support a return to an active lifestyle.
This guide provides a thorough overview of ACL surgery, covering when it may be considered, the different surgical techniques available, the preparation process, and the recovery journey.
The ACL and Its Function
The ACL is one of four primary ligaments in the knee joint, connecting the femur (thigh bone) to the tibia (shin bone). It provides stability by controlling excessive forward movement of the tibia and supporting rotational movements. The ligament is particularly engaged during activities involving sudden stops, directional changes, and jumping.
When the ACL is torn, knee stability may be affected, resulting in difficulties with movement and an increased risk of further knee damage. Depending on the severity of the injury and lifestyle demands, ACL surgery may be an option to restore knee function.
When Might ACL Surgery Be Considered?
Surgical reconstruction of the ACL is typically recommended when non-surgical approaches do not provide sufficient stability. Some common scenarios where surgery may be advised include:
Knee instability in daily movements
If the knee frequently gives way during routine activities, ACL surgery may be considered to improve stability. Persistent instability may also contribute to additional knee injuries, such as damage to the meniscus or cartilage.
Return to sports or active pursuits
Individuals participating in activities requiring sudden turns, jumps, or rapid changes in movement may require surgical reconstruction to improve knee function and reduce the risk of further injury.
Recurrent or complex ACL injuries
Repeated ACL tears or injuries affecting other knee structures may be managed more effectively with surgery compared to non-surgical treatment options.
In general, there are 2 main reasons for considering ACL surgery:
- In the short term, it provides for a stable knee to return to an active lifestyle.
- In the long term, it provides for a stable knee which reduces the risk of a rapid degeneration of the knee over time.
ACL Surgery Techniques
ACL surgery involves different approaches and graft options, with the choice depending on the severity of the injury and patient-specific factors.
ACL Reconstruction vs ACL Repair
ACL Reconstruction
This approach replaces the damaged ligament with a graft and is the most widely performed procedure. It is typically recommended for complete or longstanding ACL tears, as it provides a reliable outcome for restoring knee function.
ACL Repair
In some cases, the torn ligament can be reattached rather than replaced. This technique is generally considered for recent, partial tears where the remaining ligament tissue is in good condition. However, it is not suitable for all injuries.
Graft Options for ACL Surgery
Autografts (patient’s own tissue)
A graft may be taken from the patellar tendon, hamstring tendon, or quadriceps tendon. These grafts provide strong tissue for reconstruction, though recovery may take longer due to healing at the donor site.
Allografts (donor tissue)
Sourced from a donor, allografts eliminate the need for a second surgical site. They may be a suitable option for some individuals, though integration into the knee can take longer.
Preparing for ACL Surgery
Proper preparation before ACL surgery can help optimise the recovery process. Key steps include:
Medical Examination and Assessment
A physical examination is performed to assess knee stability, range of motion, and any swelling or tenderness. Tests such as the Lachman test or pivot shift test help determine the extent of ligament damage and any associated knee conditions.
Imaging (MRI and X-ray)
MRI scans provide detailed images of the ACL and surrounding structures, allowing the surgeon to plan the procedure effectively. X-rays may also be used to assess any involvement of bone structures.
Pre-Operative Requirements
Blood tests and other screenings may be conducted to assess overall health before surgery. Medications that affect blood clotting may need to be reviewed, with temporary adjustments made as required. Strengthening exercises may also be recommended before surgery to support recovery.
What Happens During ACL Surgery?
The surgical procedure follows a structured sequence of steps to ensure the graft is correctly positioned and secured.
Cleaning and Preparing the Joint
The damaged ligament remnants and any loose cartilage or debris are removed to create a clear surgical field. This step helps ensure there are no obstructions to graft placement.
Arthroscopic Assessment
A small camera (arthroscope) is inserted into the knee joint through a keyhole incision, providing a detailed view of the affected structures. This allows the surgeon to assess the extent of the injury and address any additional damage, such as meniscus or cartilage injuries.
Graft Preparation and Placement
The selected graft is prepared and shaped to match the knee’s dimensions. Small tunnels are created in the femur and tibia, allowing the graft to be positioned in line with the original ACL.
Securing the Graft
The graft is fixed in place using screws or other fixation devices to provide stability. The surgeon then tests the graft’s position and tension to ensure it allows for both movement and support.
Final Inspection and Closure
After confirming that the graft is secure, the surgeon inspects the joint before closing the incisions with sutures. A bandage is applied to minimise swelling and protect the knee during the initial healing phase.
Recovering After ACL Surgery
Recovery from ACL surgery requires a structured rehabilitation programme. Physiotherapy plays a key part in regaining knee function, improving mobility, and reducing the likelihood of complications.
Early Post-Operative Care
Crutches and a knee brace are typically used to limit movement and protect the graft during the early healing phase. Pain management may involve prescribed medication and cold therapy to help control discomfort and swelling. Elevating the leg can assist in reducing swelling and preventing stiffness. Follow-up appointments allow the surgeon to monitor progress and adjust care as required.
Recovery Timeline
Recovery progresses in phases, with each stage focusing on specific goals. During the first six weeks, the priority is reducing swelling, protecting the graft, and restoring basic movement through gentle exercises. From six to twelve weeks, muscle strengthening exercises are introduced, and weight-bearing increases gradually. By three to six months, advanced physiotherapy, including sports-specific exercises, may be introduced to support a return to full activity. Safe return to full activities, including contact sports, will typically be close to a year post-surgery.
Potential Risks and Considerations
ACL surgery is generally well tolerated, but as with any procedure, there are some associated risks. These include infection, bleeding, nerve injury and reactions to anaesthesia, which are managed with appropriate care. In some cases, the graft may not fully integrate, requiring further treatment. Knee stiffness can develop if rehabilitation is inadequate, but this can often be improved through physiotherapy.
Reducing the Risk of Future ACL Injuries
Strengthening the muscles around the knee, particularly the quadriceps and hamstrings, can help support the joint. Physiotherapy or structured exercise programmes focusing on strength, flexibility, and movement techniques may reduce the risk of re-injury. Wearing appropriate footwear and avoiding sudden, high-risk movements can also contribute to knee stability.
Conclusion
ACL surgery is a recognised method for improving knee stability following ligament injuries. With appropriate preparation, a structured rehabilitation plan, and commitment to recovery, many individuals regain mobility and return to their desired activities.
If you are considering ACL surgery, schedule a consultation to discuss your treatment options and learn more about the procedure and recovery process.
