The anterior cruciate ligament (ACL) stabilises the knee during movement and is commonly injured in sports such as football, basketball, or skiing. Injuries occur when the knee twists, overextends or sustains a direct impact. ACL tears, ranging from partial to complete, can impair mobility and daily function. This guide provides an overview of ACL injuries, including symptoms, treatment options, and prevention strategies.
Recognising the Symptoms of an ACL Injury
ACL injuries are usually accompanied by immediate and noticeable symptoms, signalling damage to the ligament:
Sudden Pain: A sharp, intense pain in the knee, typically making it difficult to bear weight or continue activity.
Popping Sensation: Many individuals feel or hear a distinct “pop” at the moment of injury, indicating possible ligament damage.
Swelling: Swelling develops rapidly within a few hours due to bleeding inside the joint, leading to stiffness and discomfort.
Instability: The knee may feel unstable, giving way or buckling when pressure is applied, especially during walking or standing.
Limited Range of Motion: Pain and swelling can restrict normal movement, making it difficult to fully straighten or bend the knee.
Contributing Factors to ACL Injuries
ACL injuries are often caused by sudden, forceful movements that place excessive stress on the knee joint. Common risk factors include:
Sudden Movements: Quick twists, pivots, or awkward landings can stress the ACL. Strengthening muscles and practising proper movement techniques can help reduce this strain.
Participation in High-Risk Sports: Sports such as football, soccer, and basketball involve rapid direction changes, jumping, and cutting motions, which increase the chance of ACL injuries.
Improper Technique: Poor muscle strength or improper movement patterns, such as the knee collapsing inward during landing, add strain to the ACL.
Previous Injuries: A prior ACL tear increases the risk of reinjury, especially if knee strength, balance, and function are not fully regained through rehabilitation.
Grades of ACL Injuries
ACL injuries are classified into three grades based on the severity of the ligament damage:
Grade 1: Mild Sprain
The ligament is stretched but remains intact, with no tearing. The knee joint stays structurally stable, with only mild swelling and discomfort.
Grade 2: Partial Tear
A partial tear compromises the ligament’s strength, reducing the knee’s structural stability. Swelling and pain are present, and the knee may feel slightly unstable, particularly during sudden movements.
Grade 3: Complete Tear
The ligament is fully torn, leading to a complete loss of structural support. The knee becomes unstable, making it difficult to bear weight or perform normal movements without the joint giving way.
Treatment Options for ACL Injuries
Treatment for ACL injuries depends on the severity of the tear and the patient’s level of physical activity. The goal is to restore knee stability and function, either through conservative management or surgery.
If you experience persistent knee pain, swelling, or instability following an ACL injury, consulting a knee specialist in Singapore can help assess the severity of the injury and determine appropriate treatment options.
Non-Surgical Treatments
Physical Therapy
Physical therapy focuses on strengthening the muscles around the knee, including the quadriceps and hamstrings, to provide stability. It also improves joint flexibility, range of motion, and balance. Physical therapy alone may be sufficient for partial tears, allowing patients to regain knee function without surgery.
Bracing
Knee braces offer additional support by limiting excessive movement and stabilising the joint during physical activities. They are commonly used during recovery to prevent further injury and are often combined with physical therapy.
Medication
Nonsteroidal anti-inflammatory drugs (NSAIDs), such as ibuprofen or naproxen, are used to manage pain and reduce swelling. These medications help make the rehabilitation process more comfortable.
Surgical Treatments
Surgical treatment is typically required for complete ACL tears or cases where the knee remains unstable despite non-surgical interventions.
ACL Reconstruction
This procedure involves replacing the torn ligament with a tendon graft, which can come from the patient’s own tissue or a donor. The new graft functions as a replacement for the damaged ligament, gradually integrating into the knee over time.
Knee Arthroscopy
This is a minimally invasive procedure that allows the orthopaedic surgeon to examine and treat injuries inside the joint using a small camera and surgical instruments. It is often used during ACL reconstruction to confirm the extent of damage and address any other knee injuries, such as meniscus tears. Arthroscopy reduces recovery time and surgical complications compared to traditional open surgery.
Preventing ACL Injuries
Preventing ACL injuries involves strengthening the quadriceps, hamstrings, and surrounding muscles to support the knee. Practising proper techniques for jumping, landing, and pivoting helps minimise strain on the ligament. Regular warm-ups and stretching enhance flexibility, further reducing injury risk. In some cases, a knee brace may provide additional stability during high-impact activities or after a previous injury.
Conclusion
ACL injuries can impact daily activities and physical function, but early diagnosis and a structured recovery plan can improve outcomes. Knowing what to expect during ACL recovery can also help set realistic expectations for the weeks and months following treatment. For minor injuries, physical therapy may be sufficient, while more severe tears often require surgery. Strengthening knee muscles and using proper movement techniques are key to preventing future injuries. Prompt treatment and dedicated rehabilitation are necessary for maintaining long-term knee health.
If you are experiencing knee pain or instability, schedule a consultation today for an accurate diagnosis and a personalised treatment plan.
Dr. Kau Chung Yuan
MBBS (S’pore)
MRCS (Ireland)
MMed (Ortho)
FRCSEd (Ortho)
Dr Kau (许医生) is a Fellowship trained Orthopaedic Surgeon with a subspecialty interest in Hip and Knee surgery and has been in practice for more than 15 years.
He is experienced in trauma and fracture management, sports injuries, and joint replacement surgery.
Fellow of the Royal College of Surgeons Edinburgh, Orthopaedics (FRCS, Edin) 2014
Master of Medicine (Orthopaedics), Singapore (MMed) 2013
Member of the Royal College of Surgeons Ireland (MRCS, Ire) 2009
Bachelor of Medicine and Surgery (MBBS, Singapore) 2004
Living with knee osteoarthritis, the gradual wearing down of the cartilage that cushions your knee joint, can make even simple daily activities feel like a challenge. Understanding the different types of knee braces for osteoarthritis that patients in Singapore can access is a practical starting point for taking control of your joint health. Understanding the […]
Knee pain that makes you hesitate before climbing stairs, or stiffness that greets you every morning before you have even taken your first step, are experiences many people quietly endure, often assuming they are simply part of getting older. Knee arthritis is a common reason people seek orthopaedic care. Understanding Knee Arthritis Knee discomfort can […]
Not all knee replacement implants are designed identically, and differences between designs can influence how a prosthesis functions over time. An implant typically consists of three main components: a metal cap for the femur (thighbone), a metal plate with a plastic spacer for the tibia (shinbone), and often a plastic button for the patella (kneecap). […]
When patients ask “how long does robotic knee surgery last,” they are usually asking two separate questions: how long the procedure takes on the day, and how long the replacement will hold up over time. This article addresses both. What Is Robotic Knee Surgery? Robotic knee surgery is a surgical technique in which a robotic […]
A robotic knee replacement procedure typically takes between 60 and 120 minutes in the operating theatre. While the core surgical duration is comparable to conventional methods, additional time is allocated for intraoperative system registration and real-time mapping of your unique joint anatomy. Factors such as patient anatomy, surgical complexity, and pre-operative planning workflow can also […]
Robotic knee replacement uses computer-assisted technology to help your surgeon plan implant positioning before bone cuts are made. The ROSA Knee System by Zimmer Biomet can create a three-dimensional model of your knee from standard X-ray images, or can be used with an imageless workflow where your anatomy is mapped during surgery. Real-time intraoperative feedback […]
Partial knee replacement preserves healthy bone and ligaments while replacing only the damaged compartment of the knee, and it may support faster recovery and more natural movement than total knee replacement in suitable candidates. Surgical and Anaesthetic Risks Partial knee replacement is performed under spinal or general anaesthesia, and both the anaesthetic and the surgery […]
Patients considering knee replacement often ask how long the implant will last before needing further attention. Long-term registry data suggest modern implants typically remain functional for 15 to 25 years, with many patients continuing to experience good function well beyond that range. Actual longevity depends on a combination of factors, including implant design, activity level, […]
Knee replacement becomes a consideration when cartilage damage progresses beyond what conservative treatments can manage, replacing damaged joint surfaces with metal and plastic components designed to support smoother movement. Most candidates have tried physiotherapy, medication, and injections for months or years first, and evaluation typically weighs pain severity, functional limitations, and imaging findings rather than […]
Knee replacement surgery involves removing damaged cartilage and bone and replacing them with metal and plastic components designed to support joint function. Robotic-assisted and traditional approaches work toward this goal through different methods: one utilises computer-guided technology to assist with planning and bone preparation, while the other relies on manual instrumentation and surgical technique. […]
