ACL Tear Surgery: When Arthroscopy Is Needed and What Recovery Looks Like
Symptoms, arthroscopic reconstruction and recovery after an ACL tear, explained simply.
An ACL tear does not always need surgery. Arthroscopic ACL reconstruction, done through small cuts using a thin camera, is usually considered when the knee keeps giving way, when you want to return to pivoting sports such as football, badminton or basketball, or when other parts of the knee are also injured. Many people with less demanding activity levels do well with structured physiotherapy. If surgery is chosen, the torn ligament is replaced with a graft, and returning to sport can take up to a year.
Dr Uday Prakash Reddy is a Senior Consultant Orthopedic Surgeon (registered specialty: Orthopaedics) practising at Continental Hospitals, Financial District, Hyderabad. Continental Hospitals is on Road No. 2 in the Financial District, Gachibowli. This guide explains ACL tears and surgery in plain language so you know what to ask at your consultation.
Key points
- The ACL is a ligament inside the knee that stops the shin bone sliding forward and controls twisting.
- Not every ACL tear needs surgery; physiotherapy is a valid first option for many people.
- Surgery is usually discussed for ongoing instability, pivoting sports or combined injuries.
- Arthroscopic reconstruction replaces the torn ligament with a tendon graft through small cuts.
- Return to sport after reconstruction can take up to a year and is guided by physiotherapy.
What is an ACL tear?
The anterior cruciate ligament (ACL) is a strong band of tissue in the middle of the knee. It stops the shin bone sliding forward under the thigh bone and gives the knee stability when you twist. A tear usually happens when you pivot, stop suddenly, change direction or land awkwardly from a jump, often without any contact with another player.
Ligament injuries are graded from 1 to 3. A grade 1 sprain is a mild stretch, grade 2 is a partial tear, and grade 3 is a complete tear in which the knee becomes unstable. Injury to the meniscus (the knee's C-shaped shock-absorbing cartilage) or to other ligaments often happens at the same time (OrthoInfo, AAOS).
Among the working professionals I see from the IT corridor, many ACL injuries happen during weekend football, badminton or cricket, usually on a sudden turn or landing rather than a collision.
What are the symptoms of an ACL tear?
Many people feel or hear a "pop" at the moment of injury, followed by the knee giving way. The knee usually swells within 24 hours. You may also notice pain, difficulty fully bending or straightening the knee, tenderness along the joint line and discomfort while walking (OrthoInfo, AAOS).
- A pop or tearing feeling at the time of injury
- The knee buckling or giving way
- Swelling within a day
- Loss of full movement
- A sense that the knee cannot be trusted when you turn or change direction
Pain and swelling can settle on their own over a few weeks, but the knee may still feel unstable when you return to activity, which can put other structures inside the joint at risk.
How is an ACL tear diagnosed?
Diagnosis starts with how the injury happened and a careful examination comparing both knees. An X-ray checks for any bone injury. An MRI scan shows the ligament and other soft tissues such as the meniscus and cartilage, which helps plan treatment (OrthoInfo, AAOS).
Does every ACL tear need surgery?
No. Treatment depends on your age, how unstable the knee feels, your activity goals and whether other parts of the knee are damaged. Many people, especially those who do not play pivoting sports, manage well with a structured physiotherapy programme, sometimes using a knee brace during exercise (NHS – alternatives to ACL surgery).
A well-known Swedish trial, the KANON study, followed 121 young, active adults with a fresh ACL tear. One group had early reconstruction plus rehabilitation; the other had rehabilitation with the option of surgery later if needed. At two years, results were similar in both groups, and 36 of the 59 people in the rehabilitation-first group had not needed an operation (Frobell et al., NEJM 2010).
Surgery is more often discussed when:
- the knee keeps giving way or causing problems after a course of physiotherapy
- you play a lot of sport and want to return to activities with cutting, jumping or pivoting
- there is another injury inside the knee, such as a meniscus tear, that also needs treatment
Our page on knee arthroscopy and sports injury care describes the wider range of sports knee treatments.
What happens during arthroscopic ACL reconstruction?
Arthroscopic ACL reconstruction is keyhole surgery. The surgeon works through a few small cuts around the knee using a thin camera called an arthroscope. The torn ligament is not stitched back together; instead it is replaced with a graft, usually a tendon taken from another part of your own leg such as the hamstring, which is fixed into small tunnels in the bone (NHS).
- Anaesthetic — you are given an anaesthetic so that you do not feel the operation.
- Camera check — the surgeon looks inside the knee at the ligament, meniscus and cartilage.
- Graft preparation — a tendon graft is taken and prepared to the right size.
- Tunnels and fixation — small tunnels are made in the thigh bone and shin bone, and the graft is passed through and fixed in place.
- Other repairs — a torn meniscus may be repaired or trimmed in the same operation if needed.
When the ligament has pulled away close to where it attaches to bone, a repair rather than a reconstruction may sometimes be considered, but reconstruction remains the most common operation (OrthoInfo, AAOS).
How long does recovery take after ACL surgery?
Recovery is gradual and guided by physiotherapy rather than fixed dates. Most people start walking with crutches soon after surgery, return to desk-based work in about 4 to 6 weeks, and manage most daily activities within a few months. Returning to sport can take up to a year (NHS – recovering from ACL surgery).
| Stage | What usually happens |
|---|---|
| First 2 weeks | Crutches and possibly a brace; ice and elevation for swelling; early exercises; a follow-up check about 2 to 3 weeks after surgery |
| Weeks 2 to 6 | Regaining full straightening and bending; stopping crutches when the physiotherapist advises; desk-based work often resumes around 4 to 6 weeks, depending on the job |
| Months 2 to 6 | Strength and balance training; gradual return to cycling and later light running when cleared |
| Months 6 to 12 | Agility, jumping and sport-specific drills; return to pivoting sport only after strength and control are checked |
These are typical ranges, not promises. Every knee and every rehabilitation plan is different. Do not drive until your medical team says you are fit to do so.
What are the risks of ACL surgery?
Most people who have ACL surgery have no complications, and those that do occur are usually minor and treatable. Possible risks include blood clots in the leg, wound infection, injury to nerves or tissue, ongoing pain or stiffness, a knee that still feels unstable, problems where the graft was taken, and re-tearing the graft (NHS – complications of ACL surgery).
Contact your surgical team promptly if you notice increasing redness, discharge from the wound, a high temperature, or pain and swelling in the calf after surgery. Sudden breathlessness or chest pain needs emergency care.
When should you see a doctor after a knee injury?
Get your knee assessed if it swelled quickly after a twisting injury, if you heard a pop, if it gives way when you turn, or if you cannot fully straighten it. An early examination checks for an ACL tear and for damage to the meniscus, so treatment can be planned calmly rather than by guesswork.
Sources
- NHS – What is ACL (anterior cruciate ligament) surgery?
- NHS – Alternatives to ACL surgery
- NHS – Recovering from ACL surgery
- NHS – Complications of ACL surgery
- American Academy of Orthopaedic Surgeons (OrthoInfo) – Anterior Cruciate Ligament (ACL) Injuries
- Frobell RB et al. A randomized trial of treatment for acute anterior cruciate ligament tears. N Engl J Med. 2010;363(4):331–342.
Medically reviewed by Dr. Uday Prakash Reddy, MBBS, MS (Orthopedics), Senior Consultant Orthopedic Surgeon, Continental Hospitals. This article is general health information and does not replace a consultation or medical advice. Consult a qualified doctor if knee pain, swelling or instability persists.
About the Author
Dr. Uday Prakash Reddy
Senior Consultant Orthopedic Surgeon at Continental Hospitals, Hyderabad, with over 24 years of experience in orthopedics, arthroscopy and joint replacement.