Acute Knee Injury

First Aid

First and foremost, what is needed is good first aid:

R

Rest

I

Ice

C

Compression

E

Elevation

R

Referral

*R. - I. - C. to minimise further internal bleeding

E. to reduce swelling

R. to a good physio, sports doctor or orthopaedic surgeon

Often the mechanism of injury is enough to strongly suspect the diagnosis, especially in typical cases of rupture of the ACL (Anterior Cruciate Ligament). It is then important to get the diagnosis confirmed or otherwise, and get expert advice on the best course of action.

The following is a simple, rough guide to what damage may have been done:

How did it happen?

  • Gave way on landing or side-stepping: 90% chance you have torn your ACL (Anterior Cruciate Ligament).

  • ‘Snap’, ‘Crackle’ or ‘Pop’ in the knee when your knee went: 90% chance you have torn your ACL.

  • Rapid swelling after the injury, within hours, indicates bleeding within the knee (haemarthrosis). Sometimes it may be delayed till overnight, especially if the knee was iced after injury, and if the injury was late in the day: 70% chance you have torn your ACL. Alternatively you will usually still have had a significant injury, but very occasionally it may just be bleeding from acute impingement of some joint lining (synovium) with no serious damage.

  • Twisted and felt knee go out of joint: Maybe the patella dislocated and went back in. (Pretty obvious if it didn’t go back in!)

  • Twisted and felt pain on the inner side of the knee: Maybe a torn meniscus (cartilage), or maybe a sprained medial ligament. Or maybe just aggravation of some wear and tear, or impingement of some sensitive joint lining (synovium).

  • Jarred or twisted and felt pain on the outer side of the knee: Maybe a torn meniscus (cartilage), but again, maybe just aggravation of some wear and tear, or impingement of some sensitive joint lining (synovium).

  • Twisted and/or squatted, and haven’t been able to straighten knee properly since then (locked knee): Probably a torn meniscus (cartilage) has jammed out of place in the knee. (Sometimes it can click back in, but come out again from time to time.) Or maybe a loose bit of bone or gristle (articular cartilage), that is floating around like a mouse in the joint, could have jammed between the bones. There is a particular condition called Osteo-Chondritis Dissecans in which a piece of the joint surface can become detached and become a loose body in the knee.

  • Fell on to the knee: Probably painful bruising of the front of the knee, and if that involves the very sensitive pad of fat in the knee under the knee-cap, it can very sore for a long time (eg about 5 months). Maybe a tear of the Posterior Cruciate Ligament.

  • Major injury, like a motor bike accident; not sure of the mechanism exactly: Maybe a dislocation of the whole knee joint with rupture of several ligaments and tendons, with a risk of injury to the main artery that goes down the leg, and/or nerve damage.

To further clarify the possibilities, you should have X-Rays and then you will need an expert to examine your knee, to check if the ligaments are intact, and whether there is tenderness localized to a particular anatomic site, and whether there are signs of meniscus damage, or of the patella having dislocated. Quite often an MRI (Magnetic Resonance Imaging, in a big doughnut shaped electro-magnet) will need to be ordered to further clarify the exact diagnosis, in order to make the best informed decision on the best course of management, for your knee in your circumstances.