There are two types of haemarthrosis – one is a mild one that follows surgery that has approximately 25cc in the joint - that does not need draining.
The moderate haemarthrosis where you have 50cc in the joint definitely needs draining because it will shut down your quadriceps and your hamstrings – they will lose 30-40% of their strength. Those are the haemarthroses that are not mild or not severe. The severe one needs draining because it is very tense and the patient is painful. The moderate one is about 50cc and that does need draining.