Carpal hygroma
A hygroma is a fluid-filled swelling over the front of the knee that usually occurs after blunt trauma, e.g. hitting knees when jumping a fence.
Treatment
Hygroma’s are usually non-painful and don’t cause a lameness and, therefore, require no treatment. If the swelling is large enough to cause a lameness or the cosmetic appearance is a problem then the swelling can be treated by either draining the swelling and injecting steroids or removing the lining of the cyst surgically. These treatments do have complications and in some cases may make things worse. There is also a good chance that the swelling will reappear.