An ACL tear is a tear of the anterior cruciate ligament, which stops the shin bone sliding forward and twisting under the thigh bone. It usually happens when you change direction, land from a jump or stop suddenly. Most people feel a pop, the knee swells within hours, and it may give way afterwards.
ACL injuries are common in football, basketball, netball, badminton and skiing. At Total Orthopaedic, ACL injuries are assessed and treated by Dr Hamid Razak, who was site chief of the SingHealth Sports & Exercise Medicine Centre.
What are the signs of an ACL tear?
The typical signs are a pop at the moment of injury, being unable to carry on playing, swelling within a few hours, and later a feeling that the knee shifts or gives way when you turn.
- A pop or snap felt or heard as the knee twists
- Rapid swelling, usually within 2 to 12 hours, from bleeding inside the joint
- Pain deep in the knee and difficulty putting weight on it at first
- Instability: the knee buckles when you pivot, step off a kerb or come down stairs
- Loss of full straightening or bending, especially if the meniscus is also torn
Pain and swelling often settle in 2 to 3 weeks, so the knee can feel normal walking in a straight line. The instability usually shows when you try to turn or return to sport.
How is an ACL tear diagnosed?
Your knee specialist examines how far the shin moves forward on the thigh (the Lachman and pivot shift tests) and orders an MRI scan. The MRI confirms the tear and shows damage to the meniscus, cartilage or other ligaments, which is found alongside many ACL tears.
Does every ACL tear need surgery?
No. People who do not play pivoting sports and whose knee feels stable after rehabilitation can do well without surgery. Reconstruction is usually advised for those who want to return to pivoting sport, whose knee keeps giving way, or who also have a repairable meniscus tear.
| Rehabilitation without surgery | ACL reconstruction | |
|---|---|---|
| Suits | Lower-demand activity, straight-line sports, stable knee | Pivoting sport, physical jobs, repeated giving way |
| What it involves | 4 to 6 months of guided strengthening and balance training | Keyhole surgery, then 9 to 12 months of rehabilitation |
| Main risk | Further giving way can damage the meniscus and cartilage | Surgical risks, stiffness, graft re-tear |
A partial ACL tear, or a tear of the MCL on the inner side of the knee, often heals without surgery. See knee ligament injuries for the other ligaments.
What is ACL reconstruction surgery?
ACL reconstruction replaces the torn ligament with a tendon graft, usually taken from your own hamstring, kneecap tendon or quadriceps tendon. It is done by keyhole (arthroscopic) surgery through small cuts, typically as day surgery or with one night in hospital.
- The knee is examined through the arthroscope, and any meniscus or cartilage damage is treated
- The graft is taken and prepared
- Tunnels are drilled in the thigh and shin bones where the original ligament attached
- The graft is passed through and fixed in place
- You go home on crutches with a brace if needed, and start exercises the next day
How long is recovery after ACL reconstruction?
Most people walk without crutches by 2 to 4 weeks, jog at about 3 to 4 months, and return to pivoting sport at 9 to 12 months. Going back before 9 months raises the risk of tearing the graft.
| Time after surgery | Typical milestone |
|---|---|
| Weeks 0 to 2 | Crutches, swelling control, getting the knee fully straight |
| Weeks 2 to 6 | Walking normally, cycling on an exercise bike |
| Months 3 to 4 | Jogging in a straight line |
| Months 6 to 9 | Running, jumping and sport-specific drills |
| Months 9 to 12 | Return to pivoting sport once strength and hop tests are passed |
Total Orthopaedic works with a network of physiotherapists and will refer you to one near your home or work for your rehabilitation.
How much does ACL surgery cost in Singapore?
In a private hospital, the typical bill for keyhole ACL reconstruction in 2023 was about S$32,300 (most between S$29,500 and S$36,500) before insurance. The Ministry of Health (MOH) fee benchmark for the surgeon is S$9,156 to S$13,080 including GST.
Total Orthopaedic follows the MOH fee benchmarks closely. These figures are MOH benchmarks and typical bills for a routine case, not a quote: your bill depends on the hospital, ward and complexity of your surgery. Ask the clinic for a written estimate before surgery.
| Fee | MOH benchmark or typical bill (incl. GST) |
|---|---|
| Surgeon’s fee | S$9,156 to S$13,080 |
| Anaesthetist’s fee | S$1,635 to S$2,180 |
| Typical total bill, private hospital inpatient | About S$32,348 (most S$29,514 to S$36,467) |
MOH figures for keyhole ACL or PCL reconstruction (SB701K). Surgery that also repairs the meniscus is billed under a different code. MediSave and MediShield Life or an Integrated Shield Plan can be used.
Your knee surgeon: Dr Hamid Razak
Consultant Orthopaedic Surgeon with over 17 years of experience. MBBS (NUS), MMed (Ortho Surg), FRCSEd (Orth), FRCSGlasg (Tr & Orth), FAMS (Orth Surg). Dr Hamid led the Sports & Joint Preserving Osteotomy Service at Sengkang General Hospital and is an Adjunct Associate Professor at Duke-NUS Medical School. He is a founding member and vice-president of the Singapore Knee Preservation Society, and operates at Mount Elizabeth Novena and Gleneagles Hospitals. Read Dr Hamid’s profile
Frequently asked questions
Can a torn ACL heal on its own?
A completely torn ACL does not grow back together. Partial tears and other knee ligaments often do heal, and many people regain a stable knee with strengthening alone.
Can I walk with a torn ACL?
Usually yes, once the swelling settles. Walking in a straight line is often fine; turning and sport are what make the knee give way.
How soon should I see a doctor after a knee injury?
Within a week or two if the knee swelled quickly, you felt a pop, or it gives way. Go to A&E the same day if the knee looks deformed, you cannot bear any weight, or your foot is cold or numb.
To book a knee consultation, contact Total Orthopaedic. No referral is needed. The clinic sees patients in Novena, Orchard, Gleneagles and Tampines.
Medically reviewed by Dr Hamid Razak. Last updated October 2026. Sources: Ministry of Health fee benchmarks and 2023 bill information for ACL or PCL reconstruction (SB701K). This page is general information and does not replace a consultation.
