Knee Pain
Pain in the knee
The following is a guide to trying to make your own diagnosis, but can’t be relied upon without an expert checking your knee. Also, things don’t always quite fit the usual pattern, or you may have some symptom not listed here. Sometimes even the experts can’t put their finger on the problem right away, and X-rays may have been unhelpful, in which case an MRI is an excellent way of investigating further without harming the knee at all.
Does the knee swell up?
There must be something significantly wrong, even if it is not terribly painful.
Where is the pain?
In the front of the knee: Probably from the kneecap area. See patello-femoral pain.
In the front inner (antero-medial) aspect of the knee: Probably patello-femoral (kneecap) pain rather than a cartilage tear.
On the inner side (medial) of the knee: Probably cartilage tear or breakdown. Maybe the pain comes from the kneecap area.
On the outer side of the knee: Maybe (50-50) a tear or breakdown of the cartilage (lateral meniscus), but could also be pain from the kneecap area.
In the back of the knee: Maybe this comes through to the back of the knee from the kneecap area; maybe there is swelling in the back of the knee (Baker’s cyst), or, unusually, it could be atypical pain from a cartilage tear.
On both sides of the knee: Nearly always patello-femoral pain.
All over the knee; Maybe inflammation of the joint lining (synovitis), and often associated with swelling. Maybe patello-femoral.
Please Note.
pain in or around the knee may also come from somewhere else (referred pain or radiating pain). e.g. thigh, hip, tight muscles, sciatica.
When is the pain noticeable?
Mainly with going up and down steps, and/or with sitting or driving for a long time: Almost certainly this pain comes from the knee-cap area. (Patello-femoral pain)
With twisting or sideways movements: Maybe a torn cartilage, or maybe just joint lining (synovial) pinching.
With squatting down: Pain in the front is almost certainly patello-femoral. Pain on the side may be a cartilage tear, especially if it feels like there is something mechanically not right in there.
With time on my feet, standing and/or walking too long: Probably the pain is from the weight-bearing compartments, and may be due to arthritis.
Just walking along, the knee can suddenly partly give way, maybe with a sharp twinge of pain: This is usually due to some inflamed joint lining pinching between the knee-cap and the bone, causing the quads (the driver/thigh muscle) to quit for a split second. Usually people catch themselves before falling right down, but not always.
With first getting going from rest: This is the typical pain of inflammation, which is usually secondary to an underlying cause such as wear and tear, but can happen by itself for no good reason. This pain also eases when warmed up, but is worse at the end of the day and after activity, and especially at night.
Any time, even in the middle of the night, the knee gets severely painful and I can’t move it: This is usually due to inflamed synovium jamming between the knee-cap and the edge of the groove (femoral trochlea).
Especially at night: Aching is probably inflammatory, probably due to arhritis, but could be referred from higher up the limb, or from the hip or back.
When I rest my knees together: Strongly suggests cartilage damage, or maybe arthritis in the inner half of the knee (medial compartment).
All the time: This may on occasion be a cause for more serious concern, as it may be some sort of nerve pain, or pain referred from further up the leg. On the other hand, it may be inflammation pain, as above.
What kind of pain is it?
Sharp, catching pain: This suggests there is something that is mechanically not right, such as a cartilage (meniscus) tear, but it could just be pinching of inflamed joint lining.
Aching and/or throbbing: Probably this kind of pain is due to inflammation, or arthritis, or both. The question is to sort out what is the underlying cause of the inflammation?
Burning pain: sometimes burning may be due to the heat in an inflamed joint, but often such pain suggests nerve pain, such as can develop in association with disturbance of circulation. If that is the cause, it may be a very difficult problem (eg Chronic Regional Pain Syndrome) needing expert help from a specialist in chronic pain management.
How did the pain start?
Out of the blue, gradually sneaking up on me: Probably some sort of degenerative breakdown process affecting the joint surface and/or a cartilage, even if you are too young for that sort of thing.
Out of the blue, quite suddenly one day: The same underlying degenerative breakdown process, but with a bit of loose cartilage or meniscus spontaneously shifting and getting in the way. In young people there could be a bit of bone that has come loose, especially if the knee is clunking or locking.
With an injury: See “Acute Knee Injuries” also.