MOBILIZE 物理治療中心

Common Conditions

Cruciate Ligament Tear

ACL / PCL Tear Symptoms, Common Causes and Treatments

Location and Function of Cruciate Ligament

Anterior Cruciate Ligament (ACL)

The anterior cruciate ligament (ACL) is a strong band of connective tissue located within the knee joint, connecting the femur (thigh bone) and tibia (shin bone). It plays a critical role in maintaining knee stability by resisting excessive forward movement of the tibia, controlling rotational forces, and limiting excessive valgus and varus stresses during dynamic activities such as pivoting, cutting, and landing.

In addition to its mechanical role, the ACL contains mechanoreceptors that contribute to proprioception, providing the brain with information about joint position and movement, which is essential for coordination and neuromuscular control.

Posterior Cruciate Ligament (PCL)

The posterior cruciate ligament (PCL) is located at the back of the knee joint and crosses with the ACL. Its primary function is the opposite of the ACL — it restricts excessive backward movement of the tibia relative to the femur, helping to maintain knee stability during walking, stair climbing, and weight-bearing activities.

Compared to the ACL, the PCL is structurally stronger and injuries are less common, usually requiring a greater external force to cause damage.

Common Causes of Cruciate Ligament Tear

Anterior Cruciate Ligament (ACL)

ACL injuries are among the most commonly reported knee ligament injuries, with an annual incidence of approximately 1 in 3,500 people in the United States alone. The majority of ACL injuries are non-contact injuries, commonly occurring during sports that involve pivoting, sudden deceleration, jumping, or rapid changes in direction.

Sports and activities commonly associated with ACL injuries include football, basketball, badminton, rugby, skiing, and hiking. Due to the crucial role of the ACL in knee function, a comprehensive and individualized rehabilitation programme is essential following injury, regardless of whether surgery is required.

Posterior Cruciate Ligament (PCL)

PCL injuries are less frequent than ACL injuries and are usually associated with high-energy trauma. Common mechanisms include road traffic accidents, where the tibia is forcefully driven backward, or direct impact to the front of the knee during a fall.

These forces can cause excessive posterior tibial translation, leading to partial or complete PCL rupture.

Symptoms of Cruciate Ligament Tear

Anterior Cruciate Ligament (ACL)

Signs and symptoms of an ACL injury may include:

  • A loud “pop” sound or popping sensation at the time of injury
  • Rapid swelling of the knee
  • Severe knee pain and inability to weight-bear
  • Reduced knee range of motion
  • A sensation of the knee “giving way” or instability

Symptoms can vary depending on the severity of the injury and individual pain tolerance.

Posterior Cruciate Ligament (PCL)

Symptoms of a PCL injury are often milder compared to ACL injuries but may still affect daily activities, including:

  • Knee pain when walking long distances or going up and down stairs

  • A feeling of instability, particularly during stair descent

  • Mild to moderate knee swelling

Risk factors

While anyone can sustain a cruciate ligament injury, several factors may increase the risk:

  • Poor physical conditioning, particularly weak quadriceps and hamstrings

  • Fatigue, especially during the later stages of training or competition

  • Female sex, with studies reporting a female-to-male ACL injury ratio of approximately 4.5:1

  • Anatomical factors such as higher body mass index, smaller ACL size, or joint hypermobility

  • Poorly fitted footwear

  • Poor playing surface quality

  • Previous cruciate ligament injury

How Do Physiotherapists Test the Cruciate Ligaments?

Before proceeding with an MRI scan, physiotherapists perform specific clinical special tests to assess ligament integrity and knee stability:

  1. Lachman Test: This is the most sensitive test for detecting an ACL injury. With the knee flexed to approximately 30 degrees, the therapist gently pulls the tibia (shin bone) forward. Increased laxity or the absence of a firm “end-feel” may indicate an anterior cruciate ligament (ACL) tear.

  2. Pivot Shift Test: This test reproduces the sensation of the knee “giving way” and evaluates rotational stability. A positive result may suggest ACL insufficiency.

  3. Anterior Drawer Test: Performed with the knee bent at 90 degrees, this test assesses the degree of forward translation of the tibia. Excessive movement may indicate an ACL injury.

Treatment Options for Cruciate Ligament Injuries

Surgical Treatment – Cruciate Ligament Reconstruction

Cruciate ligament reconstruction surgery aims to replace the torn ligament and restore knee stability. The decision to proceed with surgery depends on factors such as the severity of the injury, knee stability, sporting demands, occupation, and lifestyle.

Non-surgical Treatment

Some individuals may achieve satisfactory outcomes with conservative management, including:

  • Medication to reduce pain and inflammation
  • Physiotherapy to restore knee mobility, strength, and stability
  • Use of knee braces during specific stages of recovery

Prehabilitation (Prehab) Before Surgery – Why Is It Important?

When surgery is indicated, physiotherapy before surgery (prehabilitation) plays a vital role in optimizing post-operative outcomes. Research has shown that individuals who enter surgery with better knee range of motion, strength, and neuromuscular control often experience smoother and faster rehabilitation after reconstruction.

The goals of prehabilitation include:

  • Reducing pain and swelling

  • Restoring full knee extension and functional flexion

  • Strengthening the quadriceps, hamstrings, and hip musculature

  • Improving balance and proprioception

  • Preparing the knee physically and mentally for surgery

Anterior Cruciate Ligament (ACL) Reconstruction Rehabilitation

Acute Stage (Week 1-5)

Early and structured rehabilitation following ACL reconstruction is essential to prevent muscle wasting and restore knee mobility. Treatment may include electrotherapy, ice and compression, soft tissue techniques, and joint mobilization to manage pain and swelling. Physiotherapists will also guide patients through safe and appropriate exercises that form the foundation for later rehabilitation stages.

Three key principles during the early phase: 

  • Early and safe weight-bearing

  • Achieving full terminal knee extension as soon as possible

  • Strengthening the trunk and lower limbs using open and closed kinetic chain exercises as tolerated

Subacute Stage (Week 6-10)

At this stage, rehabilitation focuses on progressive strengthening through both open and closed kinetic chain exercises such as lunges and squats. Exercise intensity typically begins at lower loads (less than 50% of maximal strength) and gradually increases. Proprioceptive and coordination training is introduced as symptoms allow.

Intermediate Stage (Week 11-16)

With adequate range of motion and strength, rehabilitation progresses to higher-level loading, including jogging and hopping exercises. Multi-planar movements are incorporated to prepare individuals for sport-specific training and on-field demands.

Later Stage (Week 17 onwards)

The focus shifts to maximizing knee strength, endurance, and power. Plyometric training, along with deceleration, acceleration, pivoting, and cutting drills, is emphasized to refine movement efficiency and reduce the risk of re-injury.

Return To Sport

Research consistently shows that returning to sport earlier than nine months following ACL reconstruction significantly increases the risk of re-rupture. Therefore, it is strongly recommended that individuals return to sport no earlier than nine months post-surgery, provided all functional criteria are met.

 

Criteria Of Returning To Sport

  • At least 90% quadriceps and hamstrings strength compared to the uninjured side

  • At least 90% performance on hop and functional tests compared to the uninjured side

  • No pain or swelling

  • Psychological readiness to return to sport

Prevention Is Better Than Treatment: FIFA 11+ Injury Prevention Program

For athletes participating in high-risk sports such as football and basketball, a standard warm-up alone is not sufficient. We strongly recommend performing the FIFA 11+ before training sessions. The FIFA 11+ is a structured warm-up program developed and endorsed by FIFA. Research has shown that it can reduce the risk of ACL injuries by approximately 30–50%.

The program consists of three main components:

  1. Running exercises and dynamic stretching

  2. Core strengthening, plyometric training, and balance exercises

  3. High-speed running and cutting drills

Frequently Asked Questions

No, not all ACL injuries require surgical treatment. For some mild, non-complete ACL tears, proper conservative treatment such as physical therapy and functional training can also help restore knee joint function. However, for severe injuries or unstable knees, surgical treatment is usually the better choice. Doctors will assess the best treatment plan for the patient based on the specific situation.

Prehabilitation is a training program aiming to restore range of motion and optimize strength and balance before the surgery. A good prehabilitation directly improves post-operative quadriceps strength, optimizes prognosis of surgery, and allow a faster return to functional activities and sports.

The rehabilitation process after surgery is a long and challenging one. Patients need to follow the physiotherapist’s advice and pay attention to the following:

  1. Persist with daily functional and strength training exercises to gradually restore knee joint flexibility and muscle strength.
  2. Undergo regular professional assessments and adjust the training plan accordingly based on the recovery progress.
  3. Be patient during the recovery and do not return to intense physical activities too early to avoid re-injury.
  4. Maintain a positive psychological state and follow the therapist’s guidance to complete the entire rehabilitation process.

If an ACL injury does not receive proper treatment and good rehabilitation, it may lead to some long-term consequences, such as:

  1. Knee instability
  2. Degenerative changes in the joint cartilage, increasing the risk of osteoarthritis
  3. Decreased sports ability, making it difficult to return to the pre-injury level
  4. Psychological impact, causing fear and anxiety towards future physical activities

Therefore, only through professional treatment and systematic rehabilitation training can these long-term consequences be minimized.

Testimonials & Reviews

After suffering years of chronic knee issues after ACL reconstructive surgery I was recommended to this clinic and the results were amazing. The centre does not only focus on pain relief but with an extremely holistic approach, assesses the root cause of pain and focuses on return to sports and performance once the pain diminishes. Most physiotherapy centres in Hong Kong do not even offer this level of attention to detail and service and would highly recommend to anyone having chronic pains or want to have proper post orthopaedic surgery rehabilitation!
Arnold Woo
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I had never been a believer in physio therapy in the past or that my experience with multiple chain medical physiotherapy center had brought me nothing but temporary improvements. Until I had came across mobilize physiotherapy where they take the extra mile to examine your situation and tailor a physiotherapy session. The physiotherapists at mobilize not only identifies the root cause and provide massages for pain relievers but also to provide take home excerises for improvements.

I was never rush out the door for the next session and they ensure that I had receive the right treatment before the session ends. I would highly recommend this physiotherapy center.
Edmond Chan
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I came to them with chronic neck and knee issues, and they didn't just provide massage therapy. They took the time to thoroughly evaluate the source of my problems and develop a comprehensive treatment plan. Through a combination of targeted hands-on therapy, customized strengthening exercises, and patient education, they helped me regain mobility and address the root causes of my pain. I learned the correct ways to strengthen the muscles and improve my posture to prevent future issues.

The staff is incredibly knowledgeable, taking the time to explain everything and ensure I understood how to continue my progress at home. Thanks to their expertise and dedication, I'm now pain-free and able to return to my regular activities without any limitations.
Arthur Liu
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I first found Mobilize Physio through Google after undergoing a two-level microdiscectomy at just 18. The surgery left me with significant leg damage due to severe sciatica and partial paralysis, and I needed to rebuild my strength and confidence to walk and play sports again.

Having Avery as my physiotherapist made a world of difference. He was incredibly patient, knowledgeable, and always took the time to educate me throughout our sessions which meant a lot since I hope to become a physiotherapist myself. Whenever I had extra questions, he was always there to answer them.

Over time, my legs started to feel normal again as I regained strength and mobility, and Avery helped me rebuild not only my body but also my confidence. I’m truly grateful for his help and would highly recommend him to anyone dealing with pain or recovering from surgery.
Nish Hemlani
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Avery’s physiotherapy service has been highly professional and tailored precisely to my pain profile and lifestyle, including the sports I enjoy.

In a cosy, comfortable setting, he has delivered effective, progressive results without unnecessary delays, proactively advancing therapy to drive improvement.

I have also received valuable advice and exercises focused on long-term physical health, with Avery generously sharing expertise to educate and empower me.

The centre also offers a variety of therapies/ activities that help people regain or build physical strength in a holistic way. I would recommend Mobilize 🙂
Man Ki
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Physiotherapist Will is very knowledgeable and professional. I hurt my knee and shoulder, and the physiotherapy treatment include detailed assessment, muscle relax and exercise rehabilitation / strengthening and target my routine sport / exercise. The treatment is 1-on-1 which allow adequate time for interaction with patience of treatment and detailed explanation. The place is clean / tidy (with decent equipment for exercise rehabilitation / strengthening) and the staff are nice and helpful. The treatment give me confidence for recovery. Thank you so much Mobilize Physio!
Ricky Mak
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