About knee pain
Your joints are involved in almost every activity you do. Simple movements such as walking, bending, and turning require the use of your hip and knee joints. Normally, all parts of these joints work together and each joint moves easily and without pain. But when a joint becomes diseased or injured, the resulting pain can severely limit your ability to move and work. Pain in your knee can be debilitating, making it difficult for you to walk, climb stairs, or even pick up an object from the floor. It can limit your freedom of movement and ability to function independently.
There are many treatments that may relieve knee pain, helping you move more freely and rediscover some of the physical activities you once enjoyed. If you’re feeling pain in your knee, the first thing you should do is ask your GP for advice. There are a number of treatment options that he/she may recommend.
How does the knee work?
Your thigh bone (femur) turns on the upper end of the shin bone (tibia), while your kneecap (patella) slides in a groove on the end of the thigh bone. Bands of tissue called ligaments connect these two bones and help keep the knee joint steady. The long muscles on the front of the thigh, called quadriceps, help strengthen the knee.
A smooth substance (called articular cartilage) covers the surface of the bones where they touch each other within the joint, and acts as a cushion between the bones. A thin, smooth tissue liner (called the synovial membrane) covers the rest of the surfaces of the knee joint, and provides fluid that lubricates the joint and prevents your bones from rubbing against
Causes of knee pain
Usually, knee pain and loss of mobility is caused by the joint’s cartilage lining wearing away. When this happens, the bones rub directly against each other, causing pain and swelling. One of the most common causes is osteoarthritis (OA), which often happens following trauma or direct injury to the knee. Without cartilage, there’s no ‘shock absorber’ between the bones in the joint, so stress builds up in the bones and causes pain and discomfort.
How does arthritis affect the knee?
Knee pain is sometimes caused by deformity or injury, but one of the most common causes is osteoarthritis (OA), also known as degenerative joint disease. In a joint that has been damaged by arthritis the cartilage becomes inflamed and wears down, causing bone to rub against bare bone, creating pain, stiffness, deformity and loss of mobility. And since it’s a degenerative disease, it just gets worse over time. Other common causes of joint pain include rheumatoid arthritis or post-traumatic arthritis1.
Osteoarthritis (OA) is the most common form of arthritis in Australia. Over 2.1 million Australians experience OA, which was over half (59%) of all arthritic conditions in the years 2014–15. Although osteoarthritis can affect people of all ages, it mostly affects people over 45, with 1 in 5 Australians (21%) having some degree of osteoarthritis2.
There is currently no cure for OA, but there are many effective treatments to control symptoms3.
Symptoms of OA
If you have OA you may feel discomfort, pain or joint stiffness (which may vary at different times of the day or night) and show signs of swelling and tenderness in one or more joints. You may even hear a crunching sound in your joints as the bones rub directly against each other.
Causes of OA
In many cases, it’s hard to identify a clear cause of OA. But research suggests some things may put certain joints at more risk. For example:
- Knees – a previous knee injury, being overweight or jobs involving kneeling, climbing or squatting3.
- Hips – a previous hip injury, being overweight, or jobs involving heavy lifting, such as farming3.
- Hands – a family history of OA in the family3.
To diagnose you properly and offer the right treatment, your doctor will consider your symptoms and medical history, examine your joints, and arrange one or more diagnostic tests. For example, he or she may suggest blood tests, X-rays, a CT scan, or an MRI scan to get a clear view of your joint’s alignment and general condition3.
Based on the results of these tests, your doctor will then discuss the best treatment options with you. Depending on the severity of your OA and the pain you’re experiencing, treatments may include:
- Pain relief – using medicines such as paracetamol or non-steroidal anti-inflammatory drugs (NSAIDs)3
- Exercise and weight loss – an exercise program designed specifically for you, and a weight loss program if you’re overweight3.
- A surgical procedure or joint replacement surgery – if your OA symptoms and pain levels are no longer controlled with other therapies3.
Always discuss your treatment options with your doctor.
Go to knee treatment options
- How does arthritis affect the knee?
Other causes of knee pain
This section explores several other causes of knee pain, there may however, be reasons not included here, which can cause knee pain. Please consult your health care professional to determine the exact cause of your specific pain
Rheumatoid arthritis (RA) is an autoimmune disease that causes pain and swelling of the joints. This can become very painful, and causes swelling and stiffness that may eventually damage the joint’s cartilage and bone, and weaken the soft tissue around the joint, preventing the joint from working properly4.
For more information about rheumatoid arthritis please visit https://arthritisaustralia.com.au/types-of-arthritis/rheumatoid-arthritis/
Post-traumatic arthritis can develop if, after an injury to the joint, the bone and cartilage don’t heal properly. When this happens, the joint is no longer smooth, which can lead to extra wear on the joint. Post-traumatic arthritis often follows serious injury to the knee, or repeated high impact or force to the joint. Injury to a joint, such as a bad sprain or fracture, can also cause damage to the articular cartilage. Once this cartilage is damaged, it doesn’t normally grow back. Instead, scar tissue replaces it, which doesn’t protect or cushion the bones in the joint as effectively.
Post-traumatic arthritis is treated in a similar way to similarly to osteoarthritis.
Sarcomas are very rare primary bone cancers that have not spread from cancer somewhere else in the body (e.g. from breast tissue)5. It is more common to see cancer in bone that has spread from another part of the body, however, these types of cancer are best treated like the primary cancer from which they spread5. Although a sarcoma can develop at any age, sarcomas most commonly appear in children and young adults5.
Bone cancers form in the cells that make hard bone tissue. Cancers such as leukaemia, multiple myeloma, and lymphoma, which arise in cells produced in bone marrow, are not considered bone cancers, but they do affect the bone and may require orthopaedic management5.
For more information on bone cancers please visit the Australian Cancer Research Foundation https://www.acrf.com.au/support-cancer-research/types-of-cancer/bone-cancer/
Go to knee treatment options
- Rheumatoid arthritis
1. “What is arthritis”, Arthritis Australia website (https://arthritisaustralia.com.au/wordpress/wp-content/uploads/2018/02/ArthAus_WhatisArthritis_1805.pdf) accessed January 2019.
2. Arthritis snapshot: Web report Australain Government Institute of Health and Welfare (Updated 24 July, 2018 Cat.no:PHE 234)
3. “Arthritis Information Sheet: Osteoarthritis”Arthritis Australia website (https://arthritisaustralia.com.au/wordpress/wp-content/uploads/2018/02/Osteoarthritis_New-updated.pdf)
4. “Arthritis Information Sheet: Rheumatiod arthritis”Arthritis Australia website (https://arthritisaustralia.com.au/wordpress/wp-content/uploads/2017/09/ArthAus_RheumatoidArthritis_1805.pdf)
5. Australian Cancer Research Foundation website: (https://www.acrf.com.au/support-cancer-research/types-of-cancer/bone-cancer/)accessed February 2019