Why Does My Knee Lock or Give Way?

Understanding Knee Instability and Common Causes

Have you ever felt your knee suddenly “give way” beneath you, or experience a moment where your knee feels stuck or locked? These symptoms are common in musculoskeletal conditions, especially when there’s an underlying issue affecting the joint stability or mechanics. Knee locking and instability can be alarming, but understanding the causes is the first step toward proper diagnosis and treatment.

At MSK Doctors, we specialise in diagnosing these issues without the need for a GP referral, using advanced motion analysis, open MRI, and regenerative treatments to help you recover and avoid long-term damage.

What Does It Mean When a Knee “Locks” or “Gives Way”?

• Knee locking refers to a situation where your knee gets stuck in a bent or straight position and temporarily cannot move.

• Giving way is when your knee unexpectedly loses stability, often causing you to stumble or feel like you might fall.

These signs usually indicate a mechanical issue within the knee joint—something is disrupting its smooth, stable function.

Common Causes of Knee Locking and Instability

🩺 1. Meniscus Tears

The meniscus is a C-shaped piece of cartilage that cushions the joint. A torn meniscus can catch or flap inside the joint, leading to:

• True locking (when the knee physically cannot straighten)

• Clicking or catching during movement

• Pain along the joint line

Bucket-handle tears in particular are known for causing true mechanical locking, often requiring intervention.

🧠 Diagnosis Tip: If you can’t straighten your leg fully, and it feels physically blocked, an MRI and clinical assessment are vital.

🦵 2. Anterior Cruciate Ligament (ACL) Injuries

The ACL is a critical ligament that controls forward motion and rotational stability of the knee. A partial or complete ACL tear often results in:

• The knee giving way during turning or pivoting

• Instability when walking downhill or changing direction

• Feeling of “looseness” or lack of control

ACL injuries are common in sports and can be non-contact in nature, especially during sudden deceleration or landing awkwardly.

🧠 Motion Analysis Insight: Using MAI-Motion, we can analyse your gait and knee control in real time, identifying hidden instability and mapping personalised rehabilitation.

🦴 3. Patellar Tracking Disorders

Sometimes the issue isn't inside the joint but relates to the alignment of the kneecap (patella) as it moves through its groove. If the patella doesn’t track correctly, it may:

• Shift outwards (subluxation)

• Cause the knee to feel unstable or “give way”

• Be associated with sharp pain during squatting or stair climbing

This is more common in younger individuals, especially females, and may be linked to muscle imbalance or anatomical variation.

🧠 Rehabilitation Focus: Strengthening the vastus medialis oblique (VMO) and addressing hip-knee-ankle alignment can significantly improve stability.

When Should You Seek Help?

If your knee continues to lock or give way, it’s essential to seek a specialist opinion. Ignoring these signs can lead to:

• Worsening joint damage

• Increased risk of cartilage injury

• Early-onset arthritis or chronic instability

At MSK Doctors, we combine onMRI™ imaging, real-time motion analysis, and regenerative orthopaedics to determine the root cause and create a personalised plan—without waiting lists or GP referrals.

Treatment Options for Knee Instability

Depending on the underlying cause, your treatment may include:

We also offer regenerative therapies such as mFAT (micro-fragmented adipose tissue), PRP (platelet-rich plasma), and exosomes to support healing and reduce the need for invasive surgery.

Preventing Knee Locking or Giving Way

• Warm up properly before exercise

• Strengthen surrounding muscles (quads, hamstrings, glutes)

• Use proper technique during movement

• Address early symptoms—don’t “walk it off”

Early intervention can make a dramatic difference in outcomes.

Frequently Asked Questions (FAQs)

Can a locked knee unlock itself?
Sometimes yes, but persistent locking usually indicates a mechanical issue like a meniscus tear and should be assessed.

Is giving way always due to a ligament tear?
No, it could be caused by poor muscle control or patellar instability. Proper assessment is key.

Do I need surgery if my knee gives way?
Not always. Many patients improve with rehabilitation and regenerative therapies, especially if the ligament is partially intact.

Can I prevent my knee from locking again?
Yes—with the right rehab plan, muscle strengthening, and possibly orthobiologics, long-term stability can often be restored.

Final Thoughts

If your knee locks or gives way, don’t ignore it—it’s your body’s way of telling you something isn’t right. At MSK Doctors, we can diagnose the problem quickly using motion capture, open MRI, and regenerative medicine, helping you avoid surgery where possible and return to full confidence in your knee.

🔍 No GP referral needed – Book an assessment directly at mskdoctors.com