ACL reconstruction is performed arthroscopically and takes approximately 60-90 minutes. Full recovery and return to pivoting sport takes 9-12 months.
ℹ️ Completing a pre-operative physiotherapy programme before ACL reconstruction significantly improves outcomes. Surgery is not performed on an acutely swollen knee. The knee should be fully straight and have a good range of movement before the operation.
ACL reconstruction replaces the torn ACL with an autograft harvested from your own body (hamstring tendons or bone-patellar tendon-bone). The graft is fixed in bone tunnels in the femur and tibia. Takes approximately 60-90 minutes under general anaesthetic.
The knee must have full extension and minimal swelling before surgery. A pre-operative physiotherapy programme of 4-6 weeks is strongly recommended. Surgery on a stiff, swollen knee significantly increases the risk of post-operative stiffness (arthrofibrosis).
Routine pre-operative assessment for general anaesthetic.
You will use crutches for 2-4 weeks and may use a hinged knee brace for the first 6 weeks. Arrange these before surgery.
Post-operative rehabilitation should be booked before surgery. The 9-12 month rehabilitation programme is as important as the operation itself.
ℹ️ You will be given a specific arrival time. Do not eat or drink (other than clear water up to 2 hours before) from midnight the night before. Bring your medication list and any documents sent by the hospital.
You will be admitted to the ward or day surgery unit, change into a gown, and be seen by the nursing, anaesthetic, and surgical teams before theatre.
Your surgeon will confirm the procedure, mark the operative side, and you will sign a consent form before going to theatre.
You will meet the anaesthetist in the anaesthetic room. Once anaesthesia is established, the procedure will begin.
After surgery you will wake in the recovery room where nurses monitor your vital signs until you are stable and comfortable.
Most patients having arthroscopic or day-case procedures go home on the day of surgery. Those having joint replacement typically stay 1–2 nights. Before discharge, the team will check your pain is controlled, give you wound care instructions, and confirm your follow-up appointment.
You will be given oral pain relief before discharge. Take it regularly for the first 48 hours rather than waiting until pain is severe.
A nurse will check the wound before you leave and explain how to keep it clean and dry.
You will receive a letter for your GP and details of your next outpatient appointment - usually at 2 weeks for a wound check.
Arrange for a family member or friend to collect you. You must not drive on the day of surgery if you have had a general anaesthetic or sedation.
⚠️ Important: If you cannot fully straighten the knee after surgery, contact your physiotherapist or surgical team promptly. Loss of extension after ACL reconstruction (arthrofibrosis) is a serious complication that requires early aggressive physiotherapy.
Avoid getting the wound wet until it is fully healed - usually 10–14 days. Use a waterproof cover or cling film when showering.
Do not wait until pain is severe before taking medication. Regular simple analgesia (paracetamol, ibuprofen if appropriate) is more effective.
This is usually 2 weeks after surgery. Sutures or clips will be removed if used.
Seek urgent advice if you develop increasing redness, warmth, swelling, discharge from the wound, or a temperature above 38°C - these may indicate infection.
60-90 minutes in theatre. Go home same day or next morning with crutches and knee brace.
Maintain full knee extension. Gentle flexion exercises. Quad sets and straight leg raises begin immediately.
Increasing weight-bearing, quadriceps strengthening, proprioception training. Cycling and swimming from 6-8 weeks.
Jogging programme from 3-4 months. Cutting and change-of-direction drills from 5-6 months.
Return to full competitive sport only after meeting LSI criteria (over 90% limb symmetry). Do not rush return.
The graft goes through a biological process called ligamentisation - it gradually transforms from a transplanted tendon into a functioning ACL. The graft is weakest at 6-9 months (the period of rapid remodelling), which is why early return to pivoting sport is dangerous.
Hamstring tendon graft (gracilis and semitendinosus) is the most commonly used. Bone-patellar tendon-bone graft has historically been considered the gold standard for competitive athletes. Your surgeon will discuss the best option for you.
Re-rupture of the ACL graft occurs in 5-25% of patients, particularly young athletes who return to sport early. Revision ACL reconstruction is possible but is technically more complex.
The aim of ACL reconstruction is to restore knee stability and allow return to pivoting and cutting sport. Without reconstruction, the ACL-deficient knee is at risk of giving way episodes and progressive meniscal and cartilage damage.
Under general anaesthetic, the graft (hamstring tendons or bone-patellar tendon-bone) is harvested through a small incision. Bone tunnels are drilled arthroscopically in the femur and tibia at the anatomical ACL attachment points. The graft is passed through the tunnels and fixed with interference screws or buttons. Any associated meniscal tears are addressed at the same time. Takes 60-90 minutes.
Multiple RCTs (KANON, Delaware) demonstrate that structured rehabilitation achieves equivalent outcomes to ACL reconstruction in patients who modify their activity to avoid pivoting sport. Appropriate for patients not wishing to return to pivoting sport.
Avoiding pivoting sport and activities that cause giving way. Reduces the risk of further meniscal damage but does not restore stability.
The most commonly used graft in the UK. Harvested from the semitendinosus and gracilis tendons. Lower donor site morbidity than BPTB.
Historically considered the gold standard for competitive athletes. Higher donor site morbidity (anterior knee pain) but potentially stiffer graft. Comparable outcomes to hamstring graft in high-quality trials.
The reconstructed ACL can re-rupture, particularly in young athletes who return to pivoting sport before meeting functional recovery criteria. Risk is highest in the 6-24 month post-operative period.
Excessive scar tissue formation causing permanent loss of knee movement. Risk is significantly increased by performing surgery on an acutely inflamed, stiff knee. Pre-operative physiotherapy to restore full extension and reduce swelling is essential.
Septic arthritis after ACL reconstruction is rare but serious and may require further surgery.
Blood clot in the leg veins.
Incorrect placement of the bone tunnels can result in graft failure and the need for revision surgery.
Hamstring harvest can cause medial hamstring weakness and scar tenderness. BPTB harvest commonly causes anterior knee pain and difficulty kneeling.
Expected for 2-4 weeks after surgery.
The site where the graft was harvested is sore for several weeks.
Stiffness in the early recovery period. Maintaining full extension from day 1 after surgery is critical.
Without ACL reconstruction, the knee remains unstable with a risk of giving way episodes during pivoting activities. Each episode of giving way risks further meniscal damage and cartilage injury, accelerating the development of knee osteoarthritis. Non-operative management with physiotherapy and activity modification is appropriate for patients willing to permanently avoid pivoting sport.