What In The World Is A Fabella ?

Those were my words, when I was told I had a Fabella bone in my knee.

A Fabella bone is an extra sesamoid bone, located laterally, behind the knee. Only about 10% of the population has a Fabella bone. It is embeded at the head of the Gastrocnemius tendon. It is about the size of a pea and is very difficult to see on xray. Believe it or not, this little bone is susceptable to arthritis, fracture, dislocation and impingement.

As small as this bone is, it can cause some major problems, which I experienced after my TKR. Six weeks after my TKR, I started experiencing a snapping sensation that was painful , to the posterolateral side of my knee. When I was 3 mos post-op TKR, I had a doctor's appointment with my hometown OS. I told him about the snapping when I walked. He could not feel it when he examined and said, whatever it was, it would probably go away, eventually. Well as time went on, the snapping got worse. It was happening more frequently and became more painful. This went on over the next several months, til it became a very sharp pinching pain. The pain would literally would stop me in my tracks when it occurred.

It was now 6 mos after my TKR and time for my 6 mos post op check with Dr Noyes. I told him about this snapping and pinching to the posterolateral. I was also experiencing problems with lateral pain, stiffness and on and off MCL pain. Besides being diagnosed with scar tissue again. This snapping was a separate problem from the scar tissue. At first we thought it was  possibly the hamstring or popliteal tendon snapping over my prothesis. I got a cortisone shot and did ultra sound to the painful areas. As the ultra sound wand rubbed over this painful area, I could feel it go over something hard. The PT and I thought it might be a ball of scar tissue. When I went back to Cincinnati 4 weeks later, I had an xray taken. There on the xray, very faintly showing up, was the Fabella bone. I could barely see it. It was right where the pain was and what I was feeling during the ultra sound. This Fabella bone was getting impinged in my prothesis when I walked.

I was scheduled for an open surgery, aka an arthrotomy, when I was one year post op from my TKR. I would be having 4 procedures during this open surgery. One of the procedures was the removal of the Fabella bone. This required a very painstaking debridement from the head of the Gastrocnemius tendon. It is suspended in this tendon, much like the patella . After it's removal, the tendon had to be stitched up.

Removal of this bone ended the painful impingement and snapping I had to the posterolateral  part of my knee.

missmyknee's picture