Knee Pain Diagnosis:
Part 1

Accurate knee pain diagnosis is vital in overcoming your knee pain and stopping it from coming back again.

Without knowing the underlying cause of the problem, you can’t accurately treat knee problems. For example, if the knee is swollen, you can treat the swelling, but if you don’t treat the underlying cause of the swelling, it will just keep coming back.

The best way to get an accurate knee pain diagnosis is to see your healthcare professional, but here is a guide to help you find out what your problem might be.  You can search by:

1) Specific symptoms: what are the main symptoms associated with your pain e.g. popping noises, locking
2) Location of the pain: where exactly your knee pain is e.g. inner our outer knee
3) How the pain started: the mechanism of injury e.g. sudden twisting or gradual onset

In part 1 of knee pain diagnosis here, we will concentrate on using specific knee injury symptoms to make a diagnosis. In part 2, we will look at using the location of the pain and how the pain started to make a knee pain diagnosis.

Specific Symptoms

One of the most important parts of diagnosing knee pain is thinking about the specific symptoms that accompany the knee pain. These tend to be the most defining features in knee pain diagnosis, as the presence or absence of them quickly rule conditions/injuries in or out.

1) Knee Makes Unusual Noises

A sudden popping noise at the time of injury usually indicates a ligament injury or sometimes indicates a cartilage tear.
Persistent clicking/grinding when the knee moves usually indicates an ongoing knee problem affecting the joint surfaces or how the bones are moving such as chondromalacia patella

Visit the Noisy Knee Pain Diagnosis section to find out more about specific knee problems that cause strange noises.

2) Pain When Kneeling

Thinking about your specific symptoms helps make an accurate diagnosis eg do you get knee pain when you are kneeling down?

Kneeling puts pressure through the front of the knee and primarily aggravates three conditions:
Housemaids Knee:
inflammation of the prepatellar bursa (fluid filled sac) at the front of the knee. It is a common problem for people who spend long periods kneeling e.g. carpet layers
Osgood Schlatters: common in adolescents, particularly after a growth spurt. Tension on the tendon just below the kneecap damages the bone, often resulting in a hard lump on the front of the shin
Arthritis: changes in the bone caused by wear and tear or sometimes inflammation. Most common over the age of 50

3) Locking (knee gets stuck)

This happens when something gets wedged in the joint, stopping you moving the knee. You generally have to wiggle the knee around before it will then move.
The most common cause of locking is a Meniscus Tear, a tear in the cartilage that lines the joint. It can be caused by sudden twisting or a force through the knee, or can come on gradually due to wear and tear.
A less common cause of locking is Osteochondritis Dissecans, a condition where a poor blood supply causes small bits of bone and cartilage to break off at the joint. 

You can find out more about the different causes and treatment options in the locked knee section.

It is very common to get knee pain from running

4) Running Knee Pain

Knee pain from running is hardly surprising when you think that forces up to 550% body weight go through the joint when running. Running knee pain is usually due to either training errors or poor biomechanics.

Visit the knee pain from running section to find out how to prevent and treat this common problem.

5) Knee Gives Way

This is when the knee buckles underneath you without you being able to control it.  The most common cause of this is a ligament injury, usually an ACL tear or sometimes a PCL injury. They are usually caused by sudden twisting, a force through the knee or the knee bending backwards the wrong way. Only 20% of ACL tears are caused by direct contact.  It may be accompanied by a popping sound, swelling and extreme pain.
Meniscus tears
often make the knee feel unstable and can occasionally cause the knee to give way, but this is much less common.

6) Pain When Bending The Knee

A great deal of force goes through the knee when we do any activities with a bent knee.  For example, squatting down places a force seven times body weight through the knee.  It may be caused by a problem inside the knee, such as a cartilage tear or arthritis, or one of the surrounding structures, such as a ligament tear or inflammation of the bursa.

You can find out about the most common causes and how to treat them in the Knee Pain When Bending section.

7) Pain When Sitting for Long Periods

Knee Pain Diagnosis looks at symptoms like pain when sitting for long periods to help you work out what is causing your knee pain.

It is not just activity which aggravates knee pain. Some conditions tend to get worse with prolonged inactivity e.g. office workers sitting for long periods.  The pain may start while you are sitting or when you first get up. The most common causes are:
Runners Knee: a problem in how the kneecap moves that causes pain and stiffness at the front of the knee
Arthritis: changes in the bone caused by wear and tear or sometimes inflammation
Osgood Schlatters: common in adolescents, particularly after a growth spurt. Tight muscles irritate the bone causing pain just below the knee

8) Pain Going Down Stairs

This usually indicates a problem with the knee cap, as the force going through the knee cap when you come down stairs is 3.5x bodyweight. Find out more about the most common causes of knee pain going down stairs to help with knee pain diagnosis.

9) Swelling

Swelling is a common problem with knee pain.  The location and severity of the swelling helps to make an accurate knee pain diagnosis

Virtually any knee problem may be accompanied by swelling, but different types of swelling lead to different knee pain diagnosis.
If the swelling comes up immediately or within the first 48 hours, it usually indicates a ligament or cartilage injury.
If it comes on gradually with no specific cause, it usually indicates an underlying knee problem such as bursitis. Visit the knee swelling section to find out more on the most common causes of swelling for knee pain diagnosis. If there is moderate to severe swelling, you should see your doctor straight away.

10) Stiffness

Knee stiffness may develop as a result of an injury or a medical condition.  It may develop suddenly or gradually and often fluctuates.  Stiffness when you first wake up that settles once you’re moving about is a classic feature of Osteoarthritis, which is most common in the over 50’s.

Find out more about stiff knee pain diagnosis including the most common causes and the treatment options in the stiff knee section.

11) Bony Lump at Front of Knee

This is a classic sign of Osgood Schlatters, which is common in teenagers/young adults particularly after a growth spurt. Tension on the tendon just below the kneecap damages the bone, often resulting in a hard lump on the front of the shin.

More About Knee Pain Diagnosis

Looking at knee injury symptoms is just one way of making a knee pain diagnosis. In Diagnosis: Part 2 we will look at how to diagnose knee pain from thinking about the location of the pain, and how the pain started.

If you want to know how to get rid of your pain, visit the knee pain treatment section for a variety of treatment options.

Remember, the best way to get an accurate knee pain diagnosis is to see your doctor/physical therapist and it is essential to understand what is causing your pain to be able to treat it.

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See Also

Knee Pain Diagnosis: Part 2

Knee Braces: Would they help?

How can I strengthen my leg?

Test your flexibility - would stretching help you?

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