Anterior Cruciate Ligament (ACL) Reconstruction
What is an ACL reconstruction?
The anterior cruciate ligament (ACL) has a poor blood supply, and has a low chance of healing by itself or if it is simply stiched back together. The ACL needs to be reconstructed in order to restore knee stability. In an ACL reconstruction operation, the torn ACL ligament is removed and replaced with a new ligament made from tissue from your own body.
Who needs to have an ACL reconstruction?
Click this link to learn more about ACL injuries and who needs surgery.
What does the operation involve?
You will need a general anaesthetic. Arthroscopic (keyhole) surgery is performed initially to inspect the inside of your knee, and repair or remove any areas of damaged cartilage (meniscus). The new ligament (graft) is formed using tissue taken from part of your body. Most commonly this is the hamstring tendons on the inside of your thigh, which can be taken through a small incision on the inside of the knee. Alternatively a portion of the patellar tendon can be used, taken through a slightly longer scar on the front of the knee. Bone tunnels are made through the keyhole scars, and the new ligament is secured to the bone with screws or very strong stitches attached to a device called an endo-button. The skin is stitched together again with dissolving stitches. The operation takes about 90 minutes. You will spend some time in the recovery area before being transferred to a ward.
Graft Choice
The graft is the name for the tissue used to form the new ligament. The two main graft choices for ACL reconstruction are hamstring tendon and patellar tendon. Each have advantages and disadvantages. You will be given personalised advice about which graft is best for you.
Using the hamstring tendon as the graft is the most common type of ACL reconstruction. This can be done through a smaller scar and there is less pain early-on after surgery. There may be a slightly higher rate of re-injury, particularly in young and contact sports athletes.
Using the patellar tendon for the ACL reconstruction gives a bigger graft, which may have less risk of re-injury. It may take longer for the initial pain and swelling to settle after this surgery. Kneeling may be uncomfortable long-term, and there is a very small risk of patella fracture. A patellar tendon graft may not be possible in very young patients who are still growing.
In rare cases where there is no suitable graft available from your own body, a graft can be used from another person. This is called an allograft. Allograft is only needed when there are multiple ligaments that need reconstruction, or for revision surgery.
Prior to surgery
It is important to regain knee motion before ACL reconstruction. If your knee is very stiff before surgery, stiffness may worsen or persist long-term. Increasing knee motion can be achieved by gentle exercise, using a stationary bike (exercycle) at low resistance, or sometimes via supervised physiotherapy. Maintaining strength of the quadriceps muscle will make rehabilitation after surgery easier too. Activities that cause instability such as playing netball, tennis, rugby or other sports should be avoided to prevent further damage to the cartilage inside your knee.
What is the recovery after surgery?
The recovery after ACL surgery comprises of several key stages. It is important to remember that recovery takes time; you need to rebuild your muscle strength and co-ordination, and allow the graft to heal completely before you can return to full activity. If you do not follow a complete rehabilitation plan you risk re-injury. The main phases of recovery are post-operative swelling management, regaining range of motion, strength training and eventually sport-specific rehabilitation. Below is a guide to the standard recovery time-frames.
First 24 hours
You will be given pain relief medication. If a nerve block was used then part of your leg may be numb for 24 hours.
You will be able to walk with the use of crutches and bear weight on your leg as tolerated.
A hospital physiotherapist will teach you how to use crutches and give you some simple exercises to perform at home.
Knee straightening and bending up to 90 degrees is encouraged.
Ice may be applied to help with swelling.
You can go home the day of, or the day after surgery.
First two weeks
Continue to walk using crutches, bearing weight as comfortable.
Use simple pain relief and anti-inflammatories.
Keep doing range of motion exercises every day to work on knee bending and straightening.
Ice and elevate your knee regularly and wear the tubigrip bandage provided to help reduce swelling.
Keep the wounds covered with the waterproof dressings applied in the hospital. You can have a shower and then pat them dry. If the dressings peel off you should replace them.
Call Mr Gormack’s clinic to book an appointment to check the wounds two weeks after surgery. If this is not possible you can arrange to see a nurse at your local GP.
Weeks 2 - 6
Crutches can be discontinued once you are confident walking.
You can start driving short distances.
Work on range of motion exercises at home. Aim to achieve full extension (straightening) and bend to at least 90 degrees.
Rest your knee to allow the swelling to settle. Ice and anti-inflammatory medication will help to control swelling.
You will be reviewed in clinic six weeks after surgery.
Week six onwards
Exercise bike and swimming may be started, at low resistance.
Increase walking distances.
Gym-based exercises under supervision of a physiotherapist can begin.
Avoid free weights until at least three months after surgery.
Do not start running until at least four months after surgery as this can damage the graft.
Initially start running in straight lines on flat even ground.
Introduce gentle curves after six months and slowly progress to tighter turns.
Return to sport 12 months after surgery only if you have regained full muscle strength, and are cleared by your physiotherapist and surgeon.
How does the new ligament heal?
Your new ligament has to heal and regain a normal blood supply before it is strong enough to withstand sporting activity. Healing of the graft to the bone at each end takes approximately eight weeks. Blood supply to the middle of the graft returns over many months, and your body then remodels (replaces) the main structural fibres over the course of 12 -18 months. This means it actually gets weaker before it gets strong; the graft is weakest around eight weeks after surgery. The graft is strong enough to withstand normal walking immediately after surgery, but takes 12 months before it can tolerate the cutting and twisting movements required during sport.
Other information
Bruising and swelling - It is normal to experience some bruising and swelling after surgery. This is usually located around the knee and surgical wounds, but sometimes may track down the leg all the way to the foot. This is normal and the fluid will be reabsorbed with time. Some calf or foot swelling is normal after surgery. This is best treated by elevation and rest. Excessive swelling can be caused by a blood clot in the veins in your leg (DVT). If you are concerned, you should seek medical attention as an ultrasound scan of your leg may be necessary.
Hamstring pain - If a hamstring graft has been used, it is common to experience pain and bruising in the inner thigh region. This may last several weeks after surgery. When you first start physiotherapy you may experience a sharp pulling or tearing sensation in the healing hamstrings. This will settle with a period of rest, ice and anti-inflammatories.
Infection - This is a very uncommon but important complication of ACL surgery. Increasing pain and redness around the surgical site may represent a superficial infection. This must be treated urgently with antibiotics. If in doubt, make an urgent appointment at Mr Gormack’s clinic or see your GP. A deep infection is a very rare but serious problem. If you develop high fevers, pus discharging from the surgical scar, a sudden increase in swelling or an inability to move or take weight on your leg, go to hospital urgently to receive medical care.
Numbness - Most patients will have a small patch of numb skin around the scar, and sometimes on the outer side of the knee. This will generally reduce over time.
Stiffness - It is possible to form scar tissue inside the knee joint (arthrofibrosis) after any surgery. It is important to start your range of motion exercises as soon as you are comfortable after your operation. It is particularly important to regain full straightening of the knee. If you have had a meniscal repair you may be asked to avoid deep bending beyond 90 degrees for the first six weeks. Most stiffness will resolve with time, but in rare cases further surgery may be needed to release scar tissue.
Re-injury - If you are careful re-injury should not occur. The re-rupture rate after ACL reconstruction surgery is about 5%. It is more common in very young patients, and generally happens when patients return to activity sooner than recommended. If you are concerned that you have re-injured your ACL contact the clinic to arrange a review.
When can i drive after surgery?
You can drive again once you no longer need crutches to walk and can safely control your vehicle. After right knee surgery this usually takes between 3 - 6 weeks. After left knee surgery, and with an automatic car, driving is often possible by two weeks post-surgery. You should not drive if you are taking strong pain killers such as tramadol or codeine.
When can i go back to work after surgery?
Every job is different, so returning to work depends on the individual requirements of your position. In general, it is possible to return to office-based work after 1-2 weeks. It may take 6-12 weeks to return to positions that require a lot of standing and walking. If you do a heavy physical job it may take 4 - 6 months to return to full duties, although light duties are generally possible earlier than this.