ACL Reconstruction

ACL Reconstruction

What is the aim of this surgery? 

In simple terms the aim is to stabilise your knee after ACL rupture. This is important as studies have shown us that continuing with an unstable knee (one that gives way or feels wobbly) leads to further damage to the protective cartilage layers of the knee joint leading to the early onset of arthritis. It is therefore important that you don’t just put up with knee instability.

Who might benefit from this procedure?

Anyone with symptomatic instability (a wobbly or unstable knee) diagnosed with an ACL tear.

Will I need to stay in hospital overnight?

No – this is commonly a day case procedure. The surgery is typically performed under general anaesthetic. A supplementary nerve block (see other information regarding what to expect before surgery) may be used in more complex cases.

What does the procedure involve? The graft of choice will first be “harvested”. I almost always use your own Hamstring or Quadriceps tendon for this – an incision of approximately 5cm being made over the front of the knee. This “autograft” is then fashioned in to your new cruciate (ACL) ligament. A tourniquet will be inflated to improve visualisation. Two small (1cm) incisions will then be made on either side of the kneecap, one for the camera and one for the other surgical instruments. Two smaller incisions are needed above the kneecap. A full keyhole (arthroscopic) assessment of your knee joint will then be carried out to confirm the damage and evaluate the knee fully. Pictures of the knee are taken – we can go through these at the follow-up clinic appointment. Bone tunnels are then drilled through both the thigh bone (femur) and the shin bone (tibia) under direct vision and in the correct anatomical location for the ACL. The graft is then pulled through these tunnels using passing sutures and held in position with two screws. The graft is tested for stability. Any meniscus or cartilage repair surgery will be performed at the same time as the ACL reconstruction. The knee wounds are then closed with absorbable sutures under the skin and steristrips.


ACL rupture in a young athlete. A probe is used to evaluate the internal knee structures (here seen stressing a very lax remnant of the ACL.

Carefully placed bone tunnels under direct vision ensure an anatomical reconstruction. Passing sutures (blue cables) are then used to pull the new ligament through these tunnels.

The new ACL (pink) sitting in its normal anatomical position.

What are the chances of an improvement in my symptoms: 

ACL reconstruction has very good outcomes and restores near normal knee function in more than 90% of patients. Recovery is, however, long. This is due to the fact that the “new ACL” is actually just a scaffold that the body has to grow new blood vessels in to and lay down a new ligament – this process takes months. A huge amount of scientific work has focused on the return to sport.

Returning to Dynamic Sport guidelines:-

Sport-Specific Training Match Ready Return to Pre-Injury Level
Elite athletes 6 months 7-9 months 83%
Non-elite athletes 9 months 9-12 months 66%
Young athletes <16 12 months 18 months

These statistics are interesting. There is a significant psychological role with knee ligament injury and returning to sports after reconstruction. Our sports psychologists are available to all of our patients – please enquire for details or follow this link.

What can I expect after surgery? –

Once the local anaesthetic has worn off you will need tablet painkillers for a period of time.

Post-operative Pain Control Measures:-

  1. Take regular Paracetamol and an anti-inflammatory (Naproxen or Ibuprofen) regularly for 2 weeks after surgery*
  2. Elevate your leg whenever resting – this means the knee higher than your pelvis and allows the swelling to leave your leg which relieves pressure pain.
  3. Regularly ice you knee for the first 5 days – up to 10 minutes in every hour – the brace can be undone to facilitate this.
  4. If still in pain despite these measures then take a stronger Opioid painkiller (Zomorph or Oxycontin)

*Do not take anti-inflammatory medication if you have any contra-indications, a history of gastritis or gastric ulcer disease, asthma or allergy to this medication.

You will be encouraged to mobilise early with our specialist physiotherapy team and typically discharged home on the day of surgery. For more complex cases, such as ligament reconstructions or meniscal repair, you will need to take blood thinning tablets (Aspirin commonly) or a daily injection for up to 6 weeks after surgery whilst less mobile and on crutches. Ongoing physiotherapy after surgery is essential to restore a good range of motion and ultimately to help you build muscle bulk for strength and control.

Driving: You can drive once you are fully weight-bearing, no longer reliant on crutches and able to safely perform an emergency stop. This depends on the complexity of surgery:-

Simple Arthroscopic procedures – 1 week

ACL reconstructions – 3-4 weeks

Multiple Ligaments, Cartilage & Meniscal repairs – 6-8 weeks

Returning to Work: This depends on the complexity of surgery but also the type of work you do.

Simple Arthroscopic procedures –

  • Desk-based: 1 week (2 weeks when commutes are arduous)
  • Manual Work: 2-3 weeks

ACL Reconstructions –

  • Desk-based: 2 weeks (3-4 weeks when commutes are arduous)
  • Manual Work: 6-8 weeks

Multiple Ligaments, Cartilage & Meniscal Repairs-

  • Desk-based: 2 weeks (3-4 weeks when commutes are arduous)
  • Manual Work: 8-12 weeks depending on your job complexity. Often a period of amended duties will be necessary for heavy manual work.

Returning to Sporting activities

  • Simple arthroscopic procedures: 3-4 weeks
  • Complex knee reconstructions & repairs: 9-12 months (see section above on Return to Sport)

What are the potential complications or risks associated with this surgery?

Bleeding/bruising: Bleeding is typically minimal and occurs in the first couple of days after the surgery. This may necessitate a change of dressings if they come loose. Bruising can be significant, particularly after more complex surgery, and will often track down the leg to the ankle and foot but will settle and does not cause long term problems. Elevating the operated leg when resting (including at night) on a pillow will help to minimise swelling in the first few weeks after surgery. Regular icing should also be used liberally – this improves swelling and pain after surgery. An ice pack for 10 minutes in every hour can be used.

Infection: This is a rare complication and occurs in less than 1% of cases. It is a potentially serious complication when it does happen, however. Usually the infection is superficial involving the skin and will settle with antibiotics but if it is a deeper infection, this will require further surgery to wash out the wound.

Nerve and vascular injury: Damage to the major nerves and blood vessels at the back of the leg are, thankfully, very rare after keyhole surgery (less than 0.1%). The small superficial nerves that supply the area of skin on the front of the leg, known as cutaneous sensory nerves, are commonly in the operative incision line and damage is unavoidable. This results in a numb patch near the scars which may track down the lower leg towards the ankle. The usual course is that the affected numb area will reduce in size during the first year after surgery but may never go away completely.

Blood clots in legs or lungs: We worry about leg vein clots (Deep Vein Thrombosis or DVT) because clots can be dislodged and travel to the lung where they can become a life-threatening problem (1:10,000). For this reason you will be given blood thinning injections until fully mobile and weight bearing normally. For less complicated cases you will be able to fully weightbear straight away and these measures will not usually be required. For complex cases blood thinning injections or Aspirin may be necessary for up to 6 weeks following surgery.

Anaesthetic risks: Modern anaesthesia is usually very safe, but there are small risks associated with general anaesthetics including airway problems and unexpected allergic reactions. There are separate risks associated with receiving a nerve block. The anaesthetist will be able to go through these risks with you prior to the operation. 

Graft re-rupture: By virtue of the fact that you have ruptured your ACL you are at a higher risk of another rupture than the general population. This ranges from between 4-8% in scientific papers and is the same risk in both the knee you have had surgery on and the other side.

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