ANTERIOR CRUCIATE LIGAMENT (ACL) RECONSTRUCTION

Restoring knee stability after anterior cruciate ligament (ACL) injury

ACL RECONSTRUCTION

The anterior cruciate ligament (ACL) is one of the key stabilising ligaments in your knee. It connects the femur (thighbone) to the tibia (shinbone) and helps control forward movement and rotation of the knee joint. ACL injuries often occur during sports that involve sudden stops, pivots, or changes in direction, but can also result from awkward landings or traumatic knee twists.

A torn ACL does not usually heal on its own. If left untreated, it can lead to ongoing instability, reduced knee function, and increased risk of damage to other structures in the knee, including the meniscus and articular cartilage.

Symptoms of an ACL injury

Early Indicators of Anterior Cruciate Ligament Damage

Symptoms include:

A sudden ‘pop’ sound or sensation at the time of injury

Rapid swelling within the first few hours.

A feeling of instability or the knee giving way during activity

Difficulty pivoting or changing direction

Pain when walking or bearing weight, especially on uneven ground

How ACL injuries are diagnosed

Dr Paterson will perform a thorough clinical assessment, beginning with a discussion about how your injury occurred and the symptoms you’re experiencing. Key steps include:

1. Physical Examination

The doctor checks for knee swelling, range of motion, and overall joint stability. This helps identify signs of ligament injury early on.

2. Lachman’s and Pivot Shift Tests

These manual tests assess how stable the knee is. Abnormal movement suggests a torn or weakened ACL.

3. MRI Scan

An MRI provides detailed images to confirm an ACL tear. It also checks for damage to the meniscus or cartilage.

4. X-Rays

X-rays help rule out bone fractures or bruising. They’re used to check for other injuries that may accompany an ACL tear.

This information helps guide whether surgical reconstruction is the right option for you and which approach may be most suitable.

When is ACL reconstruction recommended?

ACL reconstruction may be recommended if:

  • You’re experiencing instability during daily activities or sport
  • You want to return to sports that involve pivoting, cutting, or jumping
  • You have other associated knee injuries, such as a meniscal tear
  • Non-operative treatment has not restored your confidence or knee function

What is ACL reconstruction surgery?

ACL reconstruction is a surgical procedure where the torn ligament is replaced with a graft—tissue taken from another part of your body. This graft acts as a scaffold that eventually integrates and functions like a new ligament. The procedure is usually done arthroscopically using small incisions and specialised instruments.

Dr Paterson performs two commonly used ACL reconstruction techniques: patellar tendon graft and hamstring tendon graft. The most appropriate option will be determined based on your individual anatomy, activity goals, and lifestyle.

The Patellar tendon graft (bone–patellar tendon–bone) ACL Reconstruction

This method uses the middle third of the patellar tendon, along with small pieces of bone from the kneecap and shinbone. These bone plugs are securely placed into tunnels drilled into the femur and tibia.

  • Strong initial fixation using bone-to-bone healing
  • Long track record in high-level athletes
  • May offer slightly quicker graft integration in some individuals
  • May cause kneeling discomfort or anterior knee pain
  • Rare risk of patellar fracture or tendon irritation
  • Slightly larger incision than the hamstring method
Dr Scanning Thigh

The Hamstring tendon graft ACL Reconstruction

This technique uses one or two tendons from the hamstring muscles, typically the semitendinosus (and sometimes gracilis), which are folded to create a strong graft. The graft is secured in bone tunnels using fixation devices.

  • Less anterior knee pain and easier kneeling in recovery
  • Smaller incision at the front of the knee
  • Suitable for many active individuals and athletes
  • Slight risk of hamstring weakness during early rehab
  • May take a little longer to fully incorporate into the bone
  • Not always ideal in patients with small or weak hamstring tendons
Dr Scanning Thigh

What happens during ACL reconstruction Surgical Procedure?

ACL reconstruction is usually performed under general anaesthetic, either as day surgery or with an overnight stay.

The steps typically include:

Arthroscopic inspection

Arthroscopic inspection of the joint to confirm the ACL tear and check for other damage

Harvesting the graft

Harvesting the graft (patellar or hamstring tendon)

Creating bone

Creating bone tunnels in the femur and tibia

Placing the graft

Placing and securing the graft using screws or fixation devices

Repairing other structures

Repairing other structures, such as meniscus tears, if needed

Closing the incisions

Closing the incisions and applying a sterile dressing

Recovery and rehabilitation following ACL reconstructioN

Rehabilitation is a key part of a successful ACL reconstruction. Your recovery will be closely guided by Dr Paterson and your physiotherapist. While each plan is individualised, general milestones include:

  • 0–2 weeks: Rest, ice, pain management, and early movement exercises
  • 2–6 weeks: Gradual return to walking without crutches, regain full range of motion
  • 6–12 weeks: Progressive strengthening and proprioception work
  • 3–6 months: Functional and sport-specific training begins
  • 6–12 months: Gradual return to high-level sport, once cleared by your care team
Full recovery timelines vary depending on the type of graft used, your sport, and your commitment to rehabilitation.

ACL Reconstruction Risks and potential complications

ACL reconstruction is a commonly performed and generally safe procedure. However, all surgery carries some risk. Potential complications may include:

  • Infection or bleeding
  • Blood clots (deep vein thrombosis)
  • Graft failure or re-tear
  • Knee stiffness or reduced range of motion
  • Nerve irritation or numbness
  • Ongoing pain or instability (rare)
Dr Paterson will discuss these risks with you as part of the informed consent process.

Will ACL reconstruction surgery restore my knee to normal?

While ACL reconstruction can restore stability and improve function, it may not make the knee exactly as it was before injury. Ongoing strengthening and conditioning are important for long-term joint health. Many people return to their pre-injury level of sport, although this depends on many factors including graft type, rehabilitation, and other associated injuries.

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