Woman holding her grazed and cut knee

The signs that suggest your injury resulted in bleeding within the knee joint– and what to do about it.

You’ve suffered a knee injury. Perhaps you’ve slipped and fallen on an icy street. Maybe you’ve been on the receiving end of a nasty (and not very) sporting tackle. It could simply be a case of falling on the ski slope.

For all these, there’s a simple rule of thumb: if the knee swells within an hour, something has bled. There are 4 main reasons why you might have blood on the knee:

  1. You’ve fractured something
  2. You’ve dislocated your knee cap (patella)
  3. You’ve had a very large meniscal or cartilage tear
  4. You’ve torn a ligament

You’ll need swift diagnosis and treatment in respect of each of these injuries.


Precisely what form that treatment takes will depend upon the nature of the injury. In the case of a fracture, you’ll be unable to put weight on the leg and an immediate trip to A&E will be the most sensible course of action.

Some of the other injuries, however, may not be quite so clear cut. Take ligament damage, for example. Over the course of a few days, with rest, ice, compression and elevation (RICE), the swelling often reduces. You may have been advised that the injury was a ‘ligament sprain’ as x-ray results proved ‘normal’. Eventually you may feel able to return activities as normal.

However if a ligament has been torn, such as the ACL, instability can occur. Attempt activities that require twisting or pivoting and the knee can give way or feel unstable.

>  Discover more about ACL injuries and treatment


Ligament damage is one of those conditions that people tend to try and put up with for a while, assuming that, if the swelling reduced over a few weeks, then the rest of the problems will fix themselves over time too.

Ruptured or torn ACLs don’t repair and can lead to long-term problems. Whilst being unable to return to full activities can be frustrating for an individual, the real danger lies in secondary injuries. Every time the knee gives way, further damage to the cartilage can occur and over time result in problems including arthritis.

So, if the knee swells within an hour, the chances are there’s bleeding within the joint. Get the problem checked out by your knee specialist as soon as you can. Establishing an early diagnosis within a couple of weeks is the key to optimal treatment.


If you have experienced a knee injury, talk to the knee consultants at Yorkshire Knee Clinic now.

>  Discover more about arthritis & knee replacements
>  Read more on patient information & FAQs
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