Your knee is the largest and one of the most complex joints in your body. It connects your thigh bone and your leg bone together.
The knee is vulnerable to injuries like sprains, dislocations, fractures and ligament tears because of its mobility and weight-bearing function. Having pain behind your knee can be very inconveniencing.
What Causes Pain Behind The Knee?
It’s always best to discuss with your doctor to find out what exactly is causing yours but here are some possible conditions that can cause pain at the back of the knee.
1. Hamstring Injury
This can be a strain or tear involving the tendon of your hamstrings- the large group of muscles at the back of your thigh that are responsible for bending your knee. They are very active when you run, climb and jump.
Hamstring injuries are relatively common in athletes who participate in sports like soccer, track events, basketball, and tennis. They can get overstretched during sudden explosive movements like sprinting or jumping.
2. Calf Strain
This occurs when the muscles at the back of your leg get strained. Many times, it happens when the calf is stretched for a prolonged period or when playing any sport that requires you to quickly go from standing to running- like in tennis or squash. The pain may be dull initially but becomes worse after taking a few steps.
It can even become severe enough to prevent you from walking well.
3. Jumper’s Knee:
This results from an injury to the tendon that connects your kneecap to your leg. It can happen when you jump or change direction suddenly, like when playing volleyball or basketball.
You might feel pain when you bend and then straighten your knee. Other symptoms include swelling, weakness, and knee stiffness.
4. Baker’s Cyst
This is a fluid-filled swelling that can occur at the back of the knee in arthritis or torn meniscus. These conditions may cause your knee to produce too much synovial fluid that can build up to form a cyst.
It presents as pain within and behind the knee, swelling, and stiffness. Baker’s cysts sometimes go away on their own but if persistent, may require drainage and other forms of treatment by a doctor.
5. Popliteus Strain
The popliteus is a muscle that extends across the back of the knee. It helps to bend the knee and can get strained during downhill skiing or after a long-distance run. It typically causes pain, redness, and swelling. The pain is worse when the knee is bent against resistance.
6. Meniscus Tear
Each knee has two of these pieces of cartilage. They act as cushions and can get torn when there’s a sudden twist at the knee joint. A meniscus tear is quite common in games like tennis and basketball where you might need to use one leg as a pivot.
When the meniscus cartilage is injured, there could be sudden pain that is worsened by rotating the knee, swelling, and stiffness. There might also be a popping sound. As you grow older, your meniscus weakens and is more likely to tear when a serious amount of force is applied to your knee.
7. Cruciate Ligament Injury
This is one of the most common types of knee injuries.
Injury to the anterior cruciate ligament (ACL) can occur if you suddenly change direction while running, land wrongly after a jump or after a tackle in contact sports like football. There could be a “popping” sound with knee pain and swelling.
A posterior cruciate ligament (PCL) injury can occur from twisting the knee, missing a step while walking or a hard blow to the front of the knee, like in a car accident. Apart from pain, you might notice swelling, weakness, stiffness, and difficulty walking.
This is when cartilage in the knee breaks down from overuse, aging or arthritis. The main symptom is a dull ache behind your kneecap that gets worse when you climb stairs or after you’ve been sitting for a while.
You might also experience a cracking or grinding feeling when you bend and straighten your knee.
This is a degenerative disease that leads to the wearing away of cartilage that covers bones in the knee. This makes the bones rub against each other, causing pain, swelling, and stiffness. It is more common in older adults.
10. Deep Vein Thrombosis (DVT)
DVT is a blood clot that forms in the deep veins of the leg.
Its symptoms include cramping pain at the back of the leg which may radiate to the back of the knee, swelling at the leg, with a reddish or bluish color and warmth of the skin over the affected area.
It is a serious condition that may lead to a pulmonary embolism- a potentially fatal condition, so you need to seek medical attention if you suspect you’re having DVT. Treatment includes using blood thinners and the insertion of a filter into your vein.
11. Leg cramps
This happens when leg muscles tighten due to insufficient blood flow or tiredness. It can cause pain that radiates to the back of your knee.
When you have a cramp, you’ll suddenly feel your muscle contract or spasm. The pain lasts for a few minutes. You are more likely to experience cramps when you are exercising or playing sports.
Other possible causes are:
- Nerve problems in your leg
- Tetanus infection
- Lead or mercury in your blood
- Liver disease
12. Referred Pain
Pain from the lower back can be referred down into the knee through the sciatic nerve. It might be associated with other symptoms like a tingly sensation, numbness, and muscle weakness.
When To See A Doctor
You should see a doctor if the pain is severe, persistent or if you experience the following:
- A swollen leg or knee
- Redness in the affected leg
- Warmth in the affected leg
- Change in the appearance of your knee joint
- Leg weakness
- Difficulty breathing
When you see a doctor, some tests may be requested during your visit. Here are some:
- X-rays of the knee joint
- D-Dimer Test
- Ultrasound scan
Treatment is usually tailored towards the cause of the pain.
Acetaminophen, paracetamol or a non-steroidal anti-inflammatory drug (NSAID) cream or gel, may help relieve the pain. Using over-the-counter NSAIDs like ibuprofen can also help reduce swelling and inflammation.
The PRICE Principle
When you suspect a strain or other knee injuries, you should follow the PRICE principle. Here’s what it means:
- Protection – protect the affected area from further injury – for example, by using a support.
- Rest – avoid physical activity and keep your leg still. Your doctor may recommend the use of crutches in severe cases.
- Ice – apply cold packs to the back of your thigh for 15 to 20 minutes every two to three hours during the day. Don’t apply ice directly to your skin, you can wrap it in a tea towel.
- Compression – compress by wrapping a bandage around the thigh to limit any swelling and movement that could cause further damage.
- Elevation – keep your leg raised and supported on a pillow as much as possible, to help reduce any swelling.
Most times, a doctor will involve a physical therapist in treating knee conditions as they help quicken recovery. They may employ electrotherapy or other special equipment and may suggest some exercises to help in rehabilitation.
If a ligament or tendon is torn, surgery may be the best treatment. This may be preferred in competitive athletes who need to have a full, quick recovery.
Warming up before exercising or playing sports can go a long way in preventing many knee injuries. To prevent other conditions, maintain a healthy weight, eat healthily, and be physically active.