Why Knees Hurt

Learn More

Me day after knee surgery 

What better time to write about 'why knees hurt' than a day and a half after knee surgery as I sit here jealously watching joggers bounce along the sea wall on a gorgeous Vancouver day.  I am hiding out from my three little kids today to give my meniscus a chance to calm down.  It was a relatively minor surgery, but my knee is very swollen none the less.  I can add this one to my list of injuries and operations that help me experience empathy for my clients instead of sympathy.  Unfortunately, over the years, I have been way too good at market research for my work as a physiotherapist!  This article will hopefully help prevent you from sitting where I am today, or at very least know when to take the plunge and have surgery on that persistent, nagging knee pain.A little bit of basic anatomy will give you a better context to understand your knees and this article.


Your knees are simply big hinge joints that are built to flex and extend.  They are held together by four major ligaments called your MCL, LCL, ACL & PCL.  Sandwiched in the middle of the joints are two C-shaped cartilage cups called your medial and lateral meniscus; these act as both shock absorbers and stabilizers.  On the front of the joints your knee caps function to protect your knees and act as levers to help strengthen the pull of your thigh muscles.

knee muscular anatomy 

When I assess people complaining of knee pain, my first goal is to determine if one of the above mentioned structures is physically damaged or is something simply disturbing the mechanics of the joint, creating friction and causing pain.  I would say that 90 percent of the time it is the latter.  Your knees and the structures that hold them together allow you to bend and straighten your legs freely, but they really don't appreciate any twisting or torquing forces on them which put your knees at the mercy of your hips and ankles.  Your hips and ankles are built to move in a variety of planes, but are both very prone to tightening up or getting quite weak, either or both situations will have negative effects on your knees.

The most common 'diagnosis' of generalized knee pain is termed Patello-Femoral Syndrome or PFS.  PFS is not something you catch like a virus or a cold, it is simply a name given to pain around the front of the knee, and it happens for a reason.  It typically arises when muscle imbalances in your hip and thigh disturb the mechanics of how your knee cap needs to slide as you bend your knee.  The poor mechanics of the knee cap create friction as you move that can eventually lead to pain and sometimes swelling.  The knee cap pain is a symptom of something that is going wrong, if you want to get rid of it you have to investigate why your hip and thigh muscles may have an imbalance.  The answer is usually hidden in how your foot and hip are working together to load your leg in a stable manner as you walk or run.  If your leg loading is quite good, then the knee pain can even arise from a disconnect in how well your trunk muscles are working to stabilize your upper body on your lower body as you move.  In other words, your knee pain may be coming from any or all of the following: weak feet, tight calves, tight hips, poor alignment, a braced back, or poor core control.  I would encourage you to look deeper than just icing your knee and getting orthotics, if you truly want to get rid of the problem.  A good physiotherapist is the place to start.

In the absence of acute injury, most knee pains develop as a manifestation of something that you do poorly on a regular basis.  It may be how you stand or sit at work all day.  It may be the funny position you like to sleep all night.  It may be how you walk in the shoes that you have chosen.  A physio can help loosen you up and correct your alignment, but when the root cause is something that you are unknowingly doing, you have to learn that change can be good. Take a look at your posture.  How do you sit at work all day?  Are cushy supportive shoes really your best choice? (Click on links to learn more).

Sometimes knees do get structurally damaged.  Plant and twist movements can result in tearing your meniscus or ACL (anterior cruciate ligament).  If you tear your meniscus the knee will usually subtly swell up over a couple days.  It can be painful to weight bear on, or produce intermittent sharp pains and even a feeling of locking.  What you experience will really depend on the nature and location of the tear.  A good physio or sports med doc should be able to diagnose it for you.  If you manage to tear your ACL, there is a good chance you may hear a pop sound and the knee will likely swell up immediately.  The knee will feel unstable and your hamstrings will likely spasm to brace your knee.  When enough torque is put on the knee it is quite common to tear both the ACL and the meniscus at the same time.

What should you do?

  1. RICE: Rest, Ice, Compress, Elevate
  2. See a Physio for proper assessment, diagnosis and treatment
  3. Suspected torn meniscus?
  4. Continue with physio and exercises.  If it is not responding well after a few months, request an MRI from doctor
  5. If MRI confirms tear, continue physio for up to a year
  6. If problem persists up to 9 months, pursue referral to orthopaedic surgeon for a scope
  7. Rehab from surgery is about 6 weeks (you can walk that day though)
  8. Suspected torn ACL?
  9. Continue physio and discuss need for a brace
  10. See doctor about MRI and referral to orthopaedic surgeon
  11. If you are young and active: Get surgery!
  12. If you are older and more sedentary continue with physio and try to avoid surgery
  13. Rehab from surgery is 6-12 months

Other common structural injuries are MCL sprains and dislocated knee caps.  These usually come from direct blows and require immobilization for up to 6 weeks afterward.  You should talk to your doctor and physio about what would be the best brace during the first couple months.  MCL braces will allow some flexion and extension, but dislocated knee caps typically require the leg to stay straight for a month or so.  These injuries are not typically repaired by surgery so it is important to let your body create scar tissue for stability and then work to regain the movement and function after 4-6 weeks.  A physiotherapist will help you build your strength back up and identify all your compensation patterns from being in a brace for so long.

Whether your knee pain arose as a biomechanical issue or a direct trauma, the eventual result can be osteoarthritis (OA).  Poor mechanics over time lead to wear and tear and the joint can slowly start to break down; pain is part of this process.  Injuries that create instability and surgeries that remove parts of your knee that were supposed to be there will also lead to OA.  Arthritis is effectively a structural issue in the knee.  The cartilage wears off, small osteophytes grow and fine cracks in the underlying bone all cause the joint to slowly seize up.  The knee will become much less tolerant to higher impact activities because the shock absorbers have worn out.

The best way to approach knee OA is activity modification and regular maintenance to the muscles around your hip and knee.  The pain and irritation caused by the structural damage inside your knee will cause the surrounding muscles to tense and can result in more unnecessary pain.  I have kept many people with horrific looking knee X-Rays playing tennis at a high level by simply doing Intramuscular Stimulation (IMS) to their hips and thighs every four weeks.  Having muscular tension released every month and ensuring you keep your legs as strong as possible will stave off an inevitable total knee replacement (a topic for another post).No matter how or why your knee hurts, the best approach you can take is to put your knee in a good environment by looking at your body as a whole and not just focussing on your sore knee.  Make sure your alignment is good and learn to move well and most knee pain will take care of itself.

See below for a progression of exercises I recommend to help you learn how to move well.  They start with awareness of your hips and spinal position and progress to more dynamic movements.

Please feel free to leave questions or comments below and I will try my best to answer them.

More Recent Stories.

Sign Up For My Monthly Updates

Stay up to date on my new blog posts, videos, books & courses
Thank you! Your submission has been received!
Oops! Something went wrong while submitting the form.