Knee pain and instability

Updated July 2023. Photo: mine

September 08, 2015  /  anne brennan

Painful, swollen, stiff, weak,  unsteady  and/or achy knees are common. Although  most only remember the most recent pain, the problem probably  started   young, as 25 % of teenagers have knee pain (KP).

When young it is called  growing pain or a sports injury, as it often hurts/swells or gives way  during or after sport.

Pain can come and go for years despite treatment. KP can be diagnosed as cartilage or ligament damage even though these structures do not have nerves that can keep creating pain.

Problems spike around 50 when muscles weaken, even in athletes.

From 60  onwards knee pain  is diagnosed as osteo arthritis or ‘wear and tear’ or degeneration. There is, however, no evidence that wear and tear causes pain.

Pain can move around, spread OR focus on one spot. It can feel deep or sore to touch. It usually changes. This is NOT weird.

Overall the  symptoms and treatment for all ages and types of KP are more  similar than different. 

NOTE: constant troubling pain or swelling in a child or teenager must always be checked out by a GP. Especially  if sleeping is difficult. This  can indicate a serious medical condition 

What causes pain?

Pain is usually a warning to stop or take care. Ignore warnings and the intensity and duration of pain increases, sometimes to the point where it always seems achy. 

Common garden variety knee pain is, usually, caused by MUSCLE strain. Strain creates inflammation and swelling. Muscles are strained by overuse, or by actions they are not trained or prepared for.  The beginning of a sport season is high risk time: knees  sprain if  not match fit or by sudden unexpected actions, especially if weak or stiff or lacking stability. 

Muscles lose strength, flexibility and stability unless exercised or if in pain.

They can further weaken significantly within 6 weeks  if ‘injured.’ This creates a viscious cycle if  returning  to sport without careful rehab.

Every ache, sharp pain or ‘giving way’ increases unhelpful inflammation and swelling and further decreases muscle strength, flexibility, endurance and agility. Once muscles start giving way or grabbing  they will keep at it, when least expected,  until retrained.

Giving way can lead to a true injuries ( when cartilage or ligaments tear) triggering  even more muscle weakness and instability.

This downward spiral affects all ages including teenagers.

Most pain is NOT due to an injury

Knees frequently swell and ache or give way when there is no injury and /or they can  keep hurting for years after an injury has recovered/healed.  While cartilage and tendon tears can  trigger or coincide with severe pain,  weakened or stiffened muscles /inflammation keeps   up the pain.

 How to tell if it is really damaged?

A true injury involves ‘soft’ tissue or bone trauma. It usually follows a fall or a knock or an awkward twist. It causes deep bruising. Injuries  need  rest to help bones and damaged tissues heal.

Knee damage is a sign that knee muscles are  not up to the job of protecting the joint and bones. However torn cartilage and ligaments do not have nerve endings that can keep on creating pain and muscle weakness. It is not good to lose them, but according to the research, surgery is NOT necessary even for torn cruciate ligaments, so long as dynamic strength, endurance, agility and control is regained using carefully calibrated exercise.

 A dislocating knee cap  is another issue entirely, although even then, carefully calibrated exercise can help

An x-ray or scan?

The medical guidelines (below) recommend X-rays only if a practitioner suspects a recent fracture, dislocation or a medical condition.

Why not? X-rays/scans/joint tests  almost always show wear and tear and damage including torn ligament in athletes which is normal for use but can  lead  to unnecessary worry/surgery.   Over 60, X-rays usually show  ‘bone on bone’, degeneration, narrowed joints, cartilage on cartilage, and bits of bone floating around. These are normal for age and action. They have not been shown to cause pain  

Bones wear in not out. Weight through bones helps keep joint surfaces healthy. However, exercise must be even, with good technique and calibrated. There is no evidence that:  1.Too much exercise wears joints out or  that 2. Exercise takes weight off damaged bones. Instead: calibrated exercise reduces pain and allows MORE weight through bones. Which is good.

Changes in bone called osteoarthritis can be the result of poor biomechanics due to obesity or limping. Knee bones gradually change shape to deal with changed pressure. They might look worn but this is not, in itself, painful.

Frightening diagnoses of torn cruciate ligaments or wear and tear or osteo/arthritis or degeneration or bone on bone can lead to hopelessness, the belief that nothing except surgery will help, and then  surgery. Theses  diagnoses can  discourage exercise: the one treatment proven to help.  

REFERENCES  

NHMRC (2003). "Evidence based management of acute musculoskeletal pain."

ABC RN Thinking about knee surgery? Exercise might be a better bet. 
http://ab.co/2airKwj