• Your swollen knee is red and hot - with or without a fever
• You suffer a knee injury and it swells up like a balloon
• Both your knee and ankle are swollen
• Large swollen knee with no history of knee injury or trauma

• Baker's Cyst with pain behind knee
• infection
• bone fracture
• tumor or cancer
• blood clot (Deep Vein Thrombosis) with posterior knee pain
• Osteo-Chondritis Dessicans
• lateral meniscus tear, usually posterior horn
• medial meniscus tear, usually posterior horn
• arthritis (Osteoarthritis)
• inflammatory arthritis
• popliteus tear
• plantaris tear with rupture

A large swollen knee is usually a serious symptom. You should seek help immediately for proper medical treatment. 

Common Pain Behind Knee Symptom #2: Locking

Knee Joint Locking - This is when your knee gets stuck in one position and won't move. If you can't unlock your knee, get to a qualified medical doctor immediately for evaluation and proper treatment. Knee Joint Locking is caused by damaged cartilage, usually from a lateral meniscus tear, medial meniscus tear or a loose body (Osteo-Chondritis Dessicans) getting lodged in between your thigh bone (femur) and your leg bone (tibia). This is why you need to manipulate your knee joint until the cartilage or loose body gets unstuck. Real locking is potentially damaging to your knee joint cartilage and may cause early Osteoarthritis (common wear- and-tear knee arthritis). 


Pain Behind Knee Diagnosis

You may need diagnostic testing for confirmation.
These diagnostic tests should be supplementary. Many doctors today depend on tests - especially MRI Scans - for diagnosis. MRI Scans are often not even 90% accurate and can lead to a misdiagnosis. Your doctor should take a thorough history, perform a complete examination and arrive at a possible diagnosis before testing.

Here are the common diagnostic tests:

X-Ray - Good for common knee arthritis and large fractures. Only visualizes bones and joint space. May miss small and stress fractures

MRI SCAN - Good for cancer and fractures; less accurate for knee ligaments and meniscus cartilage tears. 

Diagnostic Arthroscopy - This is when the orthopedic surgeon uses the scope to visualize your joint. This is extremely accurate for almost all knee conditions but it does involve more risk because of the anesthesia.

Bone Scan - an uncommon test, but needed occasionally to confirm a diagnosis of small or stress fractures - especially in the tibia plateau and, possibly, fibular head.

Ultrasound - used for confirmation of a blood clot (DVT)

Once you know your diagnosis, the next step is to determine the causes. Often, in chronic knee pain, there are hidden pain and inflammation triggers.

Pain Behind Knee Treatment

The treatment depends on the cause of your behind the knee pain:

Baker's Cyst - natural anti-inflammatories like enzymes, needle aspiration

Infection - IV antibiotics, surgery, incision and drainage

Knee Bone Fracture - a cast or walking brace for leg bone (tibia), thigh bone (femur), patellar fracture or fibular head fracture ... followed by aggressive physical therapy and rehabilitation. Some fractures do require knee surgery to correct alignment.

Tumor or cancer - referral to oncologist

Blood clot (Deep Vein Thrombosis) - blood thinners

Osteo-Chondritis Dessicans - knee arthroscopy for removal of loose particle

Lateral and Medial meniscus tear, usually posterior horn - try and avoid surgery by taking natural anti-inflammatories or enzymes, ice with compression, do physical therapy ... may take 4 - 8 weeks to improve. 
If your knee pain does not improve, you may need arthroscopic surgery. 
If your knee locks and you cannot move it; or, it continues to lock off-and-on, then surgery is recommended.

Arthritis (Osteoarthritis) - ice and compression, *natural anti-inflammatories, knee brace, patellar taping (McConnell), knee exercises for joint synovial fluid movement, physical therapy, knee exercises to strengthen weak muscles, foot inserts (orthotics), proper shoes, knee pads, avoiding the seven evil inflammatory foods, strength weight training, cardiovascular fitness training, anti-inflammatory diet, fish oil and Vitamin D3 supplementation to get back to normal levels. Last Resort Options - hyaluronic acid or cortisone injections, knee arthroscopy, knee replacement surgery

Inflammatory arthritis - beyond the scope of this article

Popliteus tear - natural anti-inflammatories, ice, physical therapy and rehabilitation

Plantaris tear - natural anti-inflammatories like enzymes, ice

Please have your knee examined and diagnosed by a qualified medical professional.

Hopefully this information helps your find the right treatment for your Pain Behind Knee.