Knee pain describes any discomfort around the knee joint. It is one of the most common complaints seen by physiotherapists in Australia. Depending on the injured structure or condition, many people will report knee pain when bending (also known as knee flexion).
According to the Royal Australasian College of Physicians, 35% of Australians will experience knee pain.[1] The likelihood of developing knee pain will generally increase with age, particularly over the ages of 70.[2]
There are many causes of knee pain when bending. Many actions require the knee to bend, such as walking, squatting, kneeling and sitting. As a result, having knee pain in these positions can affect your quality of life or even being able to live a normal daily routine.
Causes of Knee Pain When Bending
For an injured and healthy person, being able to bend the knee is an afterthought. However, for those who experience discomfort, it can range from being a nuisance to even disabling.
While the action of knee flexion may seem simple, there are many complex actions occurring in the joint. Ranging from the cartilage gliding between each other, to the ligaments stretching to provide support and even the contraction from the surrounding muscles (e.g. hamstring, calf), there are many structures involved.
Top 10 Causes of Knee Pain When Bending
1. Osteoarthritis
Osteoarthritis describes the inflammation and thinning of cartilage between the knee joint. Healthy cartilage is needed for the knees to glide across each other when bending. As the cartilage wears down, there is more effort and friction that occurs when the knee bends.
2. Meniscus tear
The meniscus are two U-shaped pieces of cartilage which sit in between the knee joint. They help lubricate the joint and absorb shock when weight bearing (e.g. running, jumping). Meniscus tears commonly occur when the knee is twisted while the foot is fixed on the ground (e.g. changing directions, landing after jumping).
3. Patellofemoral pain syndrome (PFJ syndrome)
Patellofemoral pain syndrome describes pain around the patella (knee cap) due to its abnormal movement (e.g. excessive side-to-side shifts).
4. Subluxed or dislocated patella
The kneecap can either pop out (patellar dislocation) or temporarily slip away (subluxation) from the groove that it sits in on the knee joint.
5. Knee sprain (e.g. MCL, LCL, PCL and/or ACL tear)
A knee sprain is a tearing or rupture injury to the ligaments that support the knee. An ACL tear is the most common of these injuries.
6. Patellar Tendonitis
Patellar Tendonitis is characterised by swelling or breakdown of the knee tendons, which can lead to pain when the knee is bent and/or loaded. Common tendons that are affected include the patella, hamstring or quadriceps tendon.
7. Baker’s cyst
A baker’s cyst is a collection of fluid that builds up behind the knee.
8. Knee bursitis
Knee bursitis is when inflammation and swelling of fluid-filled sacs called bursa cause knee pain, particularly under the pressure when bending. Bursas are found all around the knee joint that provide cushioning between the bone and soft tissue (e.g. tendons, muscles)
9. Ililiotibial band (ITB) syndrome
The ITB is a long piece of connective tissue that connects the hip to the knee. ITB Sydnrome can occur along the band or the attachment onto the knee when it becomes tight.
10. Fractures
racks or broken bones can also occur through direct trauma or repetitive loading. Bones between the joints and or the knee cap can be involved.
Location of Knee Pain When Bending
The location of your knee pain when bending can help with deciding what could be causing the symptoms. Physiotherapists will routinely use signs and common landmarks around the knee for a diagnosis. Below will be a list of potential conditions and/or injuries depending on the location and other signs connected to the knee pain.
Pain Above the Kneecap
Pain Behind the Knee When Bending
Outer Knee Pain When Bending
Pain Below the Kneecap
Pain in Front of the Knee When Bending
Inner Knee Pain
Knee Pain When Bending with Swelling
Home Treatments for Knee Pain When Bending
Rest
Try to reduce weight and impact on the knee when bending. Rest provides the opportunity for the structures to heal. Activities, such as running and squatting are types of knee bending activities that could be reduced (at least temporarily).
Elevate
Elevating the knee about hip height helps reduce swelling in the knee which can lower pain and stiffness when bending. Elevating the leg allows for any fluid in the knee to flow away from the joint.
Ice and/or Heat
Ice, heat or combination therapies can help ease knee pain depending on the condition. These can be applied in the form of gel packs, creams or through specialised machines.
Ice helps desensitise the area to pain, reduce inflammation and decrease swelling. Whereas, heat helps increase blood flow to encourage healing but should be avoided if the knee is swollen. Some people find combining the treatments also help for certain conditions and situations.
Pain Medications
Over-the-counter medications, such as anti-inflammatories (e.g. Nurofen, Voltaren) or pain relief (e.g. Panadol) can be used to provide short-term pain relief. Please consult your doctor if you are unsure whether these medications are appropriate.
Compression
Compression sleeves or tubigrip around the knee can also be worn to help reduce the swelling through the knee joint. Bringing down the swelling allows the knee to bend without the restriction from the fluid build up.
Braces
For some conditions, braces can be worn to support and take stress away from the injured structures in the knee joint. Specific conditions, such as patella tendinopathy and patellofemoral pain syndrome have specialised braces that can help improve knee movement and pain. Consult your physiotherapist for advice about which type of brace may be more effective.
When to seek physiotherapy
While knee pain can resolve, it can become a consistent problem for many people. Seeking professional help in the form of physiotherapy can be the solution.
Physiotherapists regularly see patients experiencing knee pain when bending. They will be able to perform a physical assessment to determine a potential diagnosis and a treatment plan. Additionally they may recommend investigations (e.g. x-ray, MRI) for further assistance.
Physiotherapists also routinely work with other relevant healthcare professionals, such as doctors, specialists and surgeons to deliver better outcomes for patients.
Knee pain can become a serious problem for many people, ranging from the inability to participate in sports, work or even walk. Seeking physiotherapy early increases the chances of a faster recovery, prevents the condition worsening and reduces the need for surgery.
If you are experiencing any of the problems below, it may be time to seek physiotherapy.
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Swelling in the knee after an injury (e.g. twisting the knee, landing awkwardly)
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Knee pain that is progressively worsening or not improving
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Knee pain that affects your livelihood (e.g. playing sports, working)
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Considering more invasive treatments, such as surgery or injections
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Unsure why you have knee pain when bending
Physiotherapists will be able to provide you with many potential strategies to manage your knee pain, including:
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Exercise and rehabilitation
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Non-medicated pain relief (e.g. massage, dry needling, electrotherapy)
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Lifestyle strategies
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Changing your training and/or exercise patterns
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Use of crutches (if necessary)
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Recommending braces.
Key takeaways
There are a number of reasons why you may be experiencing knee pain when bending. The act of bending the knee is complicated, ranging from gliding cartilage to muscle contractions. As a result, there are many structures in the knee which could be the source of the pain.
Injuries to these structures can develop over time or due to specific incidents. These types of conditions usually improve, remain consistent or worsen overtime.
Although there are home treatments which can help, they may only provide temporary relief. If you’re experiencing knee pain when bending, it’s always best to consult a physiotherapist. They will be able to identify what may be your issue and provide a long-term management plan going forward.
