The anterior cruciate ligament (ACL) is one of the most important structures in the knee. It helps keep the joint stable during movement, especially when running, pivoting, or changing direction. When the ACL tears, it can severely limit mobility, cause instability, and increase the risk of further injuries.
For many patients, the most effective treatment is ACL reconstruction surgery. This guide provides clear, detailed, and easy-to-understand information about ACL reconstruction, recovery, risks, and what to expect before and after surgery.
Understanding the ACL
The ACL is one of four key ligaments in the knee. It connects the thighbone (femur) to the shinbone (tibia) and keeps the knee stable.
When the ACL is injured, stability is lost. Patients often describe their knee as “giving way,” especially when turning or twisting. This instability makes sports and even daily activities more difficult.
How Common Are ACL Injuries?
ACL injuries are very common worldwide.
- In Australia, more than 15,000 ACL reconstructions are performed every year.
- Globally, about 200,000 ACL reconstructions are done annually.
- Women are 2–8 times more likely than men to tear their ACL.
- Around 70% of ACL injuries occur without direct contact, often during sudden stops, pivots, or awkward landings.
These numbers highlight the importance of treatment options for patients dealing with ACL injuries.
Causes of ACL Tears
ACL injuries often occur during high-intensity activities but can also happen during everyday tasks.
Common Causes
- Sudden changes in direction
- Stopping too quickly while running
- Jumping and landing awkwardly
- Direct contact or collision during sports
- Slipping on uneven ground
These movements place stress on the ligament, causing it to stretch or tear.
Symptoms of an ACL Tear
The signs of an ACL tear are usually immediate and noticeable.
- A loud “pop” sound at the time of injury
- Rapid swelling within hours
- Severe pain and difficulty walking
- Knee instability or “buckling”
- Limited range of motion
Patients often seek medical help quickly after experiencing these symptoms.
Diagnosing an ACL Injury
A doctor or orthopaedic specialist will perform physical tests, such as the Lachman test or pivot-shift test, to check for instability. Imaging scans may also be recommended:
- MRI scans help confirm the diagnosis and detect other injuries, such as meniscus tears.
- X-rays rule out bone fractures that may occur alongside ligament injuries.
Do All ACL Tears Require Surgery?
Not every patient with an ACL tear needs surgery. Treatment depends on factors such as age, activity level, and lifestyle.
Non-Surgical Management
- Rest, ice, compression, and elevation (RICE)
- Physiotherapy to strengthen the surrounding muscles
- Knee braces to improve stability
- Lifestyle modifications to avoid high-impact activities
This approach may work well for older or less active patients.
Surgical Management
Surgery is usually recommended if:
- The patient wants to return to sports or physical work.
- The knee frequently gives way during daily activities.
- There are additional injuries, like meniscus or cartilage damage.
What Is ACL Reconstruction Surgery?
ACL reconstruction surgery involves replacing the torn ligament with a graft. This is not a repair but a reconstruction.
Types of Grafts
- Hamstring tendon graft – commonly used, reliable, and less painful at the donor site.
- Patellar tendon graft – strong and often used in athletes, but may cause more post-surgery pain.
- Quadriceps tendon graft – an alternative for patients with specific needs.
- Allograft (donor tissue) – useful in revision surgeries or for patients who prefer not to use their own tendon.
The Procedure Step by Step
- The patient is given general anaesthesia.
- Small incisions are made around the knee.
- An arthroscope (tiny camera) is used to view the joint.
- The torn ligament is removed.
- Tunnels are drilled into the femur and tibia.
- The graft is inserted and secured with screws or buttons.
- The incisions are closed, and the patient is moved to recovery.
The surgery usually takes 60–90 minutes.
Recovery Timeline After ACL Reconstruction
Recovery is a gradual process that requires patience and commitment.
Weeks 1–2
- Focus on reducing swelling and pain.
- Use of crutches for walking support.
- Gentle mobility exercises begin.
Weeks 3–6
- Physiotherapy becomes more intensive.
- Exercises strengthen muscles around the knee.
- Patients start walking more confidently.
Months 3–4
- Light jogging and controlled exercises begin.
- Balance and stability training progress.
Months 6–9
- Sport-specific drills introduced.
- Confidence in knee stability improves.
Months 9–12
- Most patients return to sports and high-impact activities.
A study published in the British Journal of Sports Medicine found that 82% of athletes return to sports after ACL reconstruction, but only 65% reach their previous performance level.
Risks and Complications
ACL reconstruction is safe, but as with any surgery, risks exist.
- Infection (less than 1%)
- Graft failure or re-tear (5–10%)
- Knee stiffness or loss of motion
- Blood clots (rare)
- Pain at the graft site
Following medical advice reduces the risk of complications significantly.
Long-Term Outcomes of ACL Surgery
Most patients regain stability and function after ACL reconstruction.
- 90% of patients report improved knee stability.
- Surgery reduces the risk of further meniscus tears.
- Early surgery leads to better long-term outcomes.
However, studies show that up to 50% of patients may develop arthritis in the knee within 15–20 years after surgery. This highlights the need for continued care.
Rehabilitation: The Key to Success
Rehabilitation is as important as the surgery itself. Physiotherapy focuses on:
- Restoring range of motion
- Building muscle strength
- Improving balance and coordination
- Preparing the knee for daily activities and sports
Patients who commit to physiotherapy usually recover faster and achieve better long-term results.
Returning to Sports After ACL Surgery
Returning to sports requires clearance from a surgeon and physiotherapist. Key indicators include:
- Full range of motion restored
- No pain or swelling
- Strong quadriceps and hamstring muscles
- Ability to perform sport-specific movements safely
Patience is vital; returning too soon increases the risk of re-injury.
Life After ACL Reconstruction
Life after surgery often improves significantly. Patients report being able to walk, run, and play sports without worrying about their knee giving way.
However, it’s important to maintain a healthy lifestyle. Strength training, flexibility exercises, and avoiding unnecessary strain on the knee are all important in protecting the joint.
Choosing the Right Surgeon
The success of ACL reconstruction depends heavily on the surgeon’s experience. For patients in Western Australia, consulting an experienced orthopaedic surgeon Perth ensures expert care and personalised treatment.
Frequently Asked Questions
Is ACL reconstruction painful?
Some pain and discomfort are expected, but medication helps manage them. Most patients walk with crutches within a week.
Can an ACL tear heal naturally?
A complete ACL tear cannot heal on its own because ligaments have a poor blood supply.
How long will it be before I can drive again?
Most patients can drive within 4–6 weeks, depending on the progress of their recovery and which leg was operated on.
How successful is ACL reconstruction?
Studies show success rates of around 85–95%, with most patients regaining stability and function.
What happens if I don’t get surgery?
Without surgery, the knee may remain unstable, increasing the risk of cartilage damage and arthritis.
