It was announced on Wolf's blog this evening that Josh Pinkard will not play against Nebraska because of a deep bone bruise. It was also noted that things seem to be getting murkier in regards to that injury. So lets take a look at it, as it is becoming a more common injury.
From the Sports Injury Blog
Bone bruises are also known as periosteal. The most painful bruises, they can sometimes take months to heal. What happens in a bone bruise is a compressive force pushes the bone in on itself. When this happens the outer layer of the bone, the Periostium which is fibrous, breaks down. This leads to leaking of fluid.
The term knee bone bruise is a misnomer, as the knee isn't a bone. The effected area is actually the tip of the femur where it connects to the knee.
What the symptoms of a knee bone bruise?
You're going to have soreness and pain to the touch as you do with a normal bruise, but a bone bruise will typically not swell. It'll be difficult to walk, and there may be discoloration in the area of the knee bone bruise.
Other reasons for a bone bruise have to do with Ligament Damage such as a tear or an avulsion (rupture). They can also be classified as tiny fractures of the bone underneath the cartilage. X-rays don't often show the bruises on the bone, but MRI scans can.
Diagnosing the Bone Bruise
Once the physician suspects a bone bruise certain diagnostic studies are done to not only confirm the injury but also to look for any other injuries that may have occurred. Diagnosis of bone bruising is essentially based on MRI findings because conventional radiographic techniques are limited in providing accurate bone marrow characterization.
The "murkiness' of Pinkard's injury would lead me to beleive that there may be a torn ligament in the knee which is also a cause of a bone bruise.
MRI of a deep bone bruise.
The white "shading" is actually blood that has collected at the bruise site
Update [2007-9-11 22:37:44 by Paragon SC]: Wolf is reporting on his blog that Pinkard has another ACL injury this time to the other knee, not the one that was repaired last season. This would also explain the bone bruise that was seen probably on an MRI scan, as it is indicative of a ligament tear or rupture. We will probably have an Injury Clinic write-up on ACL injuries next week to look at Pinkard’s injury a little more closely.