Dr. Peter McEwen - M.B.B.S. F.R.A.C.S(Ortho).F.A.Ortho.A.DipModLang - Surgery Knee Dr. Peter McEwen - Surgery Knee: (123) 456789
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ACL Reconstruction

Find out more about ACL Reconstruction Hamstring Tendon with the following link

ACL Reconstruction Hamstring Tendon

Find out more about ACL Reconstruction Patellar Tendon with the following link

ACL Reconstruction Patellar Tendon


The Anterior Cruciate Ligament (ACL) joins the femur (thigh bone) to the tibia (shin bone) in the centre of the knee. It is a key stabilizer of the knee without which the femur and tibia translate and rotate excessively with the respect to each other. This instability presents as the knee giving way particularly on uneven surfaces or when changing direction. Each episode of giving way is in fact as dislocation event, every one of which is damaging to both the meniscal and articular cartilages of the joint. The more speed and momentum involved in an instability event, the more force there is in the dislocation and the more damage that is done to the joint.

The ACL can be ruptured (torn) by many different mechanisms but broadly speaking, injury patterns can be divided into contact and non-contact. The non-contact mechanism is by far the most common, even in collision sports. Non-contact ACL rupture results from over rotation or hyperextension of the femur on the tibia and can only occur if the muscles acting across the knee lose control of it. Fatigue, poor coordination, speed and mass (size) all play a role in the loss of muscle control. Contact ACL rupture results from a direct hit to the limb while the foot is fixed to the ground and is a simple case of overwhelming force rather than loss of control. Both contact and non-contact mechanisms of injury can produce multiligament injuries where other key ligaments are ruptured as well as the ACL but this is much more common in contact injuries. Non-contact injuries are preventable to a degree and some rule changes (particularly interchange rules) in the collision codes in Australia have been made specifically to reduce the fatigue component. Strength, fitness and agility training also have a role to play in injury prevention as do boot and playing surface specifications. Contact injuries are much more difficult to prevent. There is an inherent risk in collision sport but who wants to live their life in a bubble?

Indications for Surgery

Not every ACL rupture needs to be reconstructed. The decision to have surgery is based on a balance between an individual's physical requirements for the knee and what the knee will let them do without giving way. For example, a 55 year old office worker who plays no sport and has no giving way is in a very different position to a 22 year old soldier who can't do his job let alone play sport. Age by itself has little to do with the decision to have surgery but arthritis does. In general most young Australians seem to be very bad at living life in straight lines and low speeds and tend to end up doing a great deal of irreversible damage to their ACL deficient knees and are therefore probably better off having early reconstructions (within 3 months of the initial injury). Broadly speaking, the surgery has two aims. The first is to produce a stable knee that allows unrestricted activity without giving way. The second is to prevent an arthritis developing rapidly in a young adult. Producing a stable knee is much more predictable than preventing arthritis. It is becoming increasingly apparent that an ACL rupture is a serious global insult to the knee that by itself may be an independent risk factor for arthritis. If this is combined with meniscal or chondral injury then the tendency to progress to arthritis is dramatically increased. Some meniscal tears can be repaired, particularly in the context of an acute (recent) ACL rupture and every attempt is made to salvage the menisci when doing an ACL reconstruction. Saving a meniscus can prevent arthritis developing or at least substantially slow its onset and as such meniscal preservation in a young person constitutes the strongest indication for an ACL reconstruction. Chondral damage can also be reconstructed. See the Cartilage Reconstruction page in this section for more information on this topic.

Timing of Surgery

As mentioned above, an ACL rupture is a serious global insult to the knee and generally it is best to reconstruct an ACL once pain, weakness, swelling and stiffness has resolved (usually about 6 weeks after the injury). Immediate reconstruction is warranted when delay will adversely affect the outcome of the surgery. ACL ruptures associated with displaced but potentially repairable meniscal tears or other ligament injuries to the knee are examples of this.


ACL rupture is often associated with an audible snap or pop, with a sensation of tearing or shifting in the knee and always with pain and swelling. Early diagnosis is very important. An MRI is not a necessity to make the diagnosis of ACL rupture but is very useful for detecting damage to the meniscal and articular cartilages. Early referral to an orthopaedic surgeon is ideal and awareness of the possibilty of an ACL injury is the first step.


The Anterior Cruciate Ligament (ACL) does not heal once ruptured and the tissue cannot be repaired surgically, at least not in a way that results in a functional ACL. Therefore ACL injury is treated by reconstruction, that is, making an entirely new ligament. The new ligament is called the graft and in the case of ACL reconstruction is a free graft. A free graft is one that has no blood supply and must obtain one by gradual incorporation. There are various graft options but for various reasons Dr McEwen uses autologous (your own) hamstring tendons for primary ACL reconstructions. For detailed information on ACL graft options and placement go to the Which Graft document in the FAQ section.

ACL reconstruction surgery is done through small incisions. The hamstring tendons are harvested through a 3cm incision on the top of the shim and the rest of the procedure is done using an arthroscope through keyholes. Once the graft is fashioned and sized by doubling or tripling the donor tendons the anatomic centres of the native ACL attachments are marked and a fine guide wire is passed through the anatomic centres. A drill that matches exactly the diameter of the graft is then passed over the guide wires to produce a bony socket on each side of the joint. The graft is seated into the sockets, tensioned and fixed in position. The implants that hold the graft in position are small, do not need to be removed and will not set of security equipment at airports.

After Surgery

A Cryocuff, which is an ice and pressure dressing, is applied to the knee as the main dressing and if used well dramatically reduces pain and swelling. Dr McEwen will provide the necessary equipment for the Cryocuff to be used at home for the first week after surgery.

ACL reconstruction surgery is done as a day case or overnight stay procedure. Weight bearing is permissible immediately and no splint is required but a pair of crutches is needed for support for two or three weeks postoperatively. If a collateral ligament or meniscus is repaired as well a splint is required and /or weight bearing is restricted for six weeks. Clear instruction regarding weightbearing and splints will be given prior to discharge.

Getting over surgery without any problems requires an active approach to prevent problems rather than reacting to problems once they occur. The rule with prevention is "the sooner the better". Therefore there are a few things the patient should actively take responsibility for:

  1. Ice therapy. Turn over the water in the cryocuff at least hourly unless sleeping.

  2. Blood Clot (DVT) Prevention. Drink plenty of fluids. Do calf pump exercises when lying or sitting. Mobility is the most important factor in DVT prevention. Stand and move a few metres every hour while awake. Moving frequently is the key, not moving long distances.

  3. Pain Control. Don’t let pain ramp up. As soon as you are aware that pain is increasing let the nursing staff know. Much less painkiller is required to keep pain away compared to beating severe pain into submission.

Sleep in whatever position is most comfortable. There is no need to sleep only on your back with the knee straight.

The wound should be clean and dry. Notify Dr McEwen immediately if this is not the case.

You will have a postoperative appointment scheduled for 1week after the surgery. Sutures will be removed at this time. Paul Parker, a very senior and experienced musculoskeletal physiotherapist, will see you at the same time so leave plenty of time for this. There is no need for supervised physiotherapy between discharge from hospital and your appointment with Paul.

Sleep disturbance is very common after ACLR and tends to persist longer than daytime pain. Sleep in whatever position is most comfortable, use ice, and use the provided sleeping tablets and painkillers if needed (as long as they are causing no side effects).

Risks and Complications

As with any major surgery, there are potential risks involved. The decision to proceed with the surgery is made because the advantages of surgery outweigh the potential disadvantages.

It is important that you are informed of these risks before the surgery takes place. Almost without fail those undergoing ACL reconstruction surgery are healthy so complications are very infrequent.

  • Haemarthrosis (bleeding into the knee). Haemarthrosis is part and parcel of ACL reconstruction surgery. It can however be painful and restrict motion and muscle recovery and is very much reduced by using the Cryocuff properly and keeping the knee up. A tense haemarthrosis needs to decompressed by removing blood from the knee through a needle. This is done in rooms at the time of the first postoperative visit if necessary.
  • Infection. Infection can occur with any operation. In the knee this can be superficial or deep. Superficial infections are treated with antibiotics. Deep infections always require surgical treatment as well as antibiotics. Deep infection is an uncommon but very serious complication and many measures are employed during the course of having an ACL reconstruction to prevent it. In most cases of deep infection the joint can be salvaged but in certain circumstances the graft will need to be removed and another implanted after the infection is cured.
  • Blood Clots (Deep Venous Thrombosis).These can form in the calf muscles and can travel to the lung (Pulmonary embolism). These can occasionally be serious and even life threatening. If you get calf pain or shortness of breath at any stage, you should notify your doctor. As with infection, many measures are employed to prevent this complication. These include compression stockings, calf compressors, IV fluids, blood thinning medications but by far the most important is early mobility.
  • Stiffness in the Knee (Arthrofibrosis). This is very uncommon with ACL reconstruction surgery. This is least likely to occur after the knee has settled down from the original injury and is the reason most reconstructions are best done around six weeks after the injury.
  • Neurovascular injury (Damage to nerves and blood vessels). Major nerves and vessels pass behind the knee and are close to the surgical field of an ACL reconstruction. Great care is taken to avoid damage to these important structures.
  • Numbness. The skin on the outside edge of the incision may be numb after the surgery. Most people are very aware of this in the first 6 months after surgery. The sensation of numbness fades with time but sometimes never returns absolutely to normal.
  • Graft failure. The graft is a free graft and has no blood supply for months after the surgery. It is vulnerable to biologic and mechanical insults during this time. Strict adherence the postoperative rehabilitation protocol is critical. Grafts are stressed by people doing too much too soon not by behaving within the limits set out by Dr McEwen. A mature and successful graft can be ruptured by the same mechanism as a native ACL. Completing rehab before going back to a pivoting sport is very important.
Dr. Peter McEwen - Surgery of Knee
Dr. Peter McEwen - Surgery of Knee
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ACL Reconstruction - Dr. Peter McEwen - Surgery of Knee
Arthroscopic Surgery - Dr. Peter McEwen - Surgery of Knee
Cartilage Repair - Dr. Peter McEwen - Surgery of Knee
Partial Knee Replacement - Dr. Peter McEwen - Surgery of Knee
Realignment Surgery - Dr. Peter McEwen - Surgery of Knee
Total Knee Replacement - Dr. Peter McEwen - Surgery of Knee
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Australian Orthopaedic Association Royal Australasian College of Surgeons
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