ACL reconstruction

Deciding whether to have knee surgery can feel overwhelming. This guide will help you understand your knee surgery options, benefits, risks, and recovery so you can make an informed decision about the right treatment for your condition.

ACL reconstruction surgery is for patients who have persistent instability of the knee following an ACL rupture. The instability is usually experienced with twisting (pivot) movements, and may be less symptomatic with in-line activities (jogging, cycling, rowing). The surgery aims to restore stability to the knee, and is not a treatment primarily for pain.
Repair of the ACL is not commonly practiced, as outcomes of surgery are unreliable. An exception to this is if the ACL has pulled off (avulsed) from the tibia (shinbone) with a piece of bone attached. This usually occurs in younger patients.
Research has shown that some individuals are able to rehabilitate the knee and strengthen the muscles sufficiently to not need reconstructive surgery. In the absence of coexisting injury within the knee (often meniscal tears), a trial period of physiotherapy may be appropriate. Up to 50% of carefully selected patients may not need surgery with this approach.
The surgery will be explained to you by Mr Smith in clinic, the alternatives, likely recovery period and any associated risks discussed. You will have a pre-operative clinic appointment to ensure that you are safe for surgery, and that there is no aspect of your health that can be optimised prior to having surgery. You will be informed at this stage when to stop any regular medications, and what time you can eat and drink until prior to the surgery.

On the day of surgery you will see Mr Smith and the anaesthetist prior to the surgery, to ensure that all questions have been addressed. The consent form will be checked with you, and the correct leg marked. You will often see a physiotherapist prior to your surgery also.
The procedure is usually performed under a general anaesthetic (fully asleep), with a nerve block in the thigh for pain relief.

You will be given antibiotics into the vein at the time of surgery to reduce the risk of infection.

The surgery is performed with a tourniquet on the thigh, which temporarily stops the blood to the area, increasing surgical visualisation and minimising bleeding. This may leave you with a sore thigh for a couple of days following the surgery.

The ligament is reconstructed using your own tissue taken from elsewhere (graft), with the common donor options being hamstring tendons, patella tendon, and quadriceps tendon. All grafts have individual pros and cons, and so the discussion about which is appropriate for your goals will happen between you and your surgeon.

It is largely arthroscopic (key-hole) surgery, with small cuts to take grafts (donor tissue).

A tunnel is drilled in the femur and tibia in the position of the ruptured ACL, the graft passed through the tunnels, and secured at both ends.

The incisions are then washed with sterile water, and closed with stitch that absorbs. Adherent dressings are applied, with a bandage over the top. Local anaesthetic is injected to help with pain relief.

Surgery takes approximately an hour, and afterwards you will be placed in a heavy bandage. You may have a brace fitted if you have significant meniscal repair surgery performed at the same time.

Discharge is often the same day, or sometimes the next if the procedure is performed later in the afternoon.

An outline of the post operative rehabilitation can be found here. This is a guide, not a programme, and so therapy should be supervised by a qualified physiotherapist.
This will depend upon what time of day the surgery is performed. If your surgery is in the morning, you will usually go home the same day. If later on, you may require a single night stay in hospital.
The first few days can be a bit uncomfortable, but you will be discharged with appropriate pain relief. The quadriceps muscles often go to sleep after the surgery, and the key to the early recovery is getting them contracting again. This will allow you to start weaning off crutches, and returning towards walking unaided. The knee will be swollen, and can remain so for 6-8 weeks. This is normal.

You will be seen for a wound check at two weeks, and a follow-up clinic appointment will be arranged for 6-8 weeks following the surgery.

The key to successful ACL reconstruction recovery is engagement in the post-operative physiotherapy programme. This is a structured, highly evidence-based rehabilitation regimen that ensures that the muscles and knee control are restored after surgery, to allow you to ultimately return to activities of your choosing. This must be guided by a qualified physiotherapist. An outline of the rehabilitation timeline and goals can be found here.
Regards returning to work or studies, I advise to return when ‘no longer distracted by either the pain or pain killers’. If you have an office or home based job, this can be as early as one or two weeks. For more physically demanding jobs, return to work can take longer, but you can be provided with an appropriate fitness to work (sick) note for the period.

What are the risks of ACL reconstruction surgery?

ACL (anterior cruciate ligament) reconstruction is generally safe and effective, but like any surgery, it carries certain risks. Every effort will be made to minimise these risks, but to allow this it is important that you mention any health issues at the pre-operative assessment. Below are common and rare risks along with estimated percentages based on medical literature and clinical studies. Mr Smith will speak to you in detail about these prior to any surgery.

Risk	Description
Ongoing pain	Pain may persist due to graft tension, scar tissue, or coexisting pathology (5–10%)
Knee stiffness	Reduced range of motion post-op; may require physiotherapy or manipulation (5–10%)
Swelling	Effusion common early post-op; usually resolves with rehabilitation (5–10%)
Wound infection (superficial)	Local infection around incisions; managed with oral antibiotics (1–5%)
Numbness (around incision)	Sensory changes over anterior knee due to nerve irritation (5–10%)
Donor site pain	Pain at patellar or hamstring tendon harvest site, may persist (1–10%)
Deep joint infection	Requires joint washout and IV antibiotics; may lead to graft loss (0.1–0.5%)
Blood clot (Deep vein thrombosis/Pulmonary embolus/heart attack/stroke)	Risk increased with immobility or travel; prophylaxis considered (0.5–1%). You may be prescribed Aspirin after the surgery to reduce this risk
Graft rupture/failure	May occur months or years later, especially in athletes (1–5% over 5 years)
Hardware irritation	Screws or implants may cause discomfort and require removal (0.5–1%)
Arthrofibrosis	Excessive scarring leading to stiffness; may require further surgery (0.5–1%)
Major nerve or vessel injury	Extremely rare; injury to popliteal artery or saphenous nerve (<0.1%)
Complex Regional Pain Syndrome (CRPS)	Pain and hypersensitivity disproportionate to surgery; difficult to treat (<0.1%)
Anaesthetic complication	Includes severe allergic reaction or cardiorespiratory events (<0.1%)
Fracture during surgery	Fracture of tibia or femur from tunnel placement (<0.1%)
Post-traumatic osteoarthritis	Increased risk of knee arthritis over 10–20 years, especially with meniscal damage (Up to 50% by 15–20 years)
Re-injury or graft rupture	Risk of tearing the graft or opposite ACL; higher in young, active patients (Up to 20% in high-risk groups)
Kneeling discomfort	Especially after patellar tendon graft; may be persistent long term (10–20%)
Loss of performance	Some athletes do not return to pre-injury level, despite physical recovery (up to 30%)
Residual instability	Sensation of giving way may persist despite an intact graft (5–10%)

Please contact the hospital where your surgery was performed, and they will easily be able to get in contact with Mr Smith on your behalf.

ACL reconstruction surgery is for patients who have persistent instability of the knee following an ACL rupture. The instability is usually experienced with twisting (pivot) movements, and may be less symptomatic with in-line activities (jogging, cycling, rowing). The surgery aims to restore stability to the knee, and is not a treatment primarily for pain.
Repair of the ACL is not commonly practiced, as outcomes of surgery are unreliable. An exception to this is if the ACL has pulled off (avulsed) from the tibia (shinbone) with a piece of bone attached. This usually occurs in younger patients.
Research has shown that some individuals are able to rehabilitate the knee and strengthen the muscles sufficiently to not need reconstructive surgery. In the absence of coexisting injury within the knee (often meniscal tears), a trial period of physiotherapy may be appropriate. Up to 50% of carefully selected patients may not need surgery with this approach.
The surgery will be explained to you by Mr Smith in clinic, the alternatives, likely recovery period and any associated risks discussed. You will have a pre-operative clinic appointment to ensure that you are safe for surgery, and that there is no aspect of your health that can be optimised prior to having surgery. You will be informed at this stage when to stop any regular medications, and what time you can eat and drink until prior to the surgery.

On the day of surgery you will see Mr Smith and the anaesthetist prior to the surgery, to ensure that all questions have been addressed. The consent form will be checked with you, and the correct leg marked. You will often see a physiotherapist prior to your surgery also.
The procedure is usually performed under a general anaesthetic (fully asleep), with a nerve block in the thigh for pain relief.

You will be given antibiotics into the vein at the time of surgery to reduce the risk of infection.

The surgery is performed with a tourniquet on the thigh, which temporarily stops the blood to the area, increasing surgical visualisation and minimising bleeding. This may leave you with a sore thigh for a couple of days following the surgery.

The ligament is reconstructed using your own tissue taken from elsewhere (graft), with the common donor options being hamstring tendons, patella tendon, and quadriceps tendon. All grafts have individual pros and cons, and so the discussion about which is appropriate for your goals will happen between you and your surgeon.

It is largely arthroscopic (key-hole) surgery, with small cuts to take grafts (donor tissue).

A tunnel is drilled in the femur and tibia in the position of the ruptured ACL, the graft passed through the tunnels, and secured at both ends.

The incisions are then washed with sterile water, and closed with stitch that absorbs. Adherent dressings are applied, with a bandage over the top. Local anaesthetic is injected to help with pain relief.

Surgery takes approximately an hour, and afterwards you will be placed in a heavy bandage. You may have a brace fitted if you have significant meniscal repair surgery performed at the same time.

Discharge is often the same day, or sometimes the next if the procedure is performed later in the afternoon.

An outline of the post operative rehabilitation can be found here. This is a guide, not a programme, and so therapy should be supervised by a qualified physiotherapist.
This will depend upon what time of day the surgery is performed. If your surgery is in the morning, you will usually go home the same day. If later on, you may require a single night stay in hospital.
The first few days can be a bit uncomfortable, but you will be discharged with appropriate pain relief. The quadriceps muscles often go to sleep after the surgery, and the key to the early recovery is getting them contracting again. This will allow you to start weaning off crutches, and returning towards walking unaided. The knee will be swollen, and can remain so for 6-8 weeks. This is normal.

You will be seen for a wound check at two weeks, and a follow-up clinic appointment will be arranged for 6-8 weeks following the surgery.

The key to successful ACL reconstruction recovery is engagement in the post-operative physiotherapy programme. This is a structured, highly evidence-based rehabilitation regimen that ensures that the muscles and knee control are restored after surgery, to allow you to ultimately return to activities of your choosing. This must be guided by a qualified physiotherapist. An outline of the rehabilitation timeline and goals can be found here.
Regards returning to work or studies, I advise to return when ‘no longer distracted by either the pain or pain killers’. If you have an office or home based job, this can be as early as one or two weeks. For more physically demanding jobs, return to work can take longer, but you can be provided with an appropriate fitness to work (sick) note for the period.

What are the risks of ACL reconstruction surgery?

Risk	Description
Ongoing pain	Pain may persist due to graft tension, scar tissue, or coexisting pathology (5–10%)
Knee stiffness	Reduced range of motion post-op; may require physiotherapy or manipulation (5–10%)
Swelling	Effusion common early post-op; usually resolves with rehabilitation (5–10%)
Wound infection (superficial)	Local infection around incisions; managed with oral antibiotics (1–5%)
Numbness (around incision)	Sensory changes over anterior knee due to nerve irritation (5–10%)
Donor site pain	Pain at patellar or hamstring tendon harvest site, may persist (1–10%)
Deep joint infection	Requires joint washout and IV antibiotics; may lead to graft loss (0.1–0.5%)
Blood clot (Deep vein thrombosis/Pulmonary embolus/heart attack/stroke)	Risk increased with immobility or travel; prophylaxis considered (0.5–1%). You may be prescribed Aspirin after the surgery to reduce this risk
Graft rupture/failure	May occur months or years later, especially in athletes (1–5% over 5 years)
Hardware irritation	Screws or implants may cause discomfort and require removal (0.5–1%)
Arthrofibrosis	Excessive scarring leading to stiffness; may require further surgery (0.5–1%)
Major nerve or vessel injury	Extremely rare; injury to popliteal artery or saphenous nerve (<0.1%)
Complex Regional Pain Syndrome (CRPS)	Pain and hypersensitivity disproportionate to surgery; difficult to treat (<0.1%)
Anaesthetic complication	Includes severe allergic reaction or cardiorespiratory events (<0.1%)
Fracture during surgery	Fracture of tibia or femur from tunnel placement (<0.1%)
Post-traumatic osteoarthritis	Increased risk of knee arthritis over 10–20 years, especially with meniscal damage (Up to 50% by 15–20 years)
Re-injury or graft rupture	Risk of tearing the graft or opposite ACL; higher in young, active patients (Up to 20% in high-risk groups)
Kneeling discomfort	Especially after patellar tendon graft; may be persistent long term (10–20%)
Loss of performance	Some athletes do not return to pre-injury level, despite physical recovery (up to 30%)
Residual instability	Sensation of giving way may persist despite an intact graft (5–10%)

Please contact the hospital where your surgery was performed, and they will easily be able to get in contact with Mr Smith on your behalf.

ACL reconstruction

Deciding whether to have knee surgery can feel overwhelming. This guide will help you understand your knee surgery options, benefits, risks, and recovery so you can make an informed decision about the right treatment for your condition.

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