What is OS fabella?
The fabella is a sesamoid bone in the posterolateral capsule of the human knee joint. The presence of the fabella in humans varies widely and is reported in the literature to range from 20% to 87% [1-7]. The fabella is located in the posterior aspect of the knee where lines of tensile stress intersect.
What is the typical location for an OS fabella?
The fabella is a sesamoid bone that is embedded in the lateral head of the gastrocnemius muscle and often articulates directly with the lateral femoral condyle. It is present in 10-30% of the general population with a higher incidence in Asians.
What type of bone is the fabella?
The fabella is a sesamoid bone, meaning it grows in the tendon of a muscle: the kneecap, for instance, is the largest sesamoid bone in the human body.
How is fabella syndrome treated?
Fabella pain syndrome can be treated with physical therapy, injection of local anesthetics or steroids near the site, radial extracorporeal shock wave therapy (rESWT) or fabellectomy [6]. Physical therapy entails the patient be placed in a prone position with the legs supported at an angle of 30 degrees flexion [15].
Can fabella cause pain?
If it does hurt, it is called fabella syndrome. It is recognized by a sharp pain, local tenderness, and intensification of pain in the area of the fabella by full extension of the knee. It can also cause pain during knee flexion, ascending stairs, cross-legged sitting and athletic activities.
Why do some people have a fabella?
Dr Berthaume said: “The fabella is a sesamoid bone — a tendon-bound bone that grows in response to mechanical forces like friction, tension, pressure, and stress. Larger muscles and longer shin bone in males produce more mechanical force, which explains why men are more likely than women to develop fabellae.”
What causes a fabella?
It is potentially due to less insulation by subcutaneous adipose tissue in individuals with ectomorphic somatotypes. Fabella syndrome has been identified as an uncommon, but relevant, a cause of pain post-TKA due to mechanical irritation of the posterolateral tissues of the knee.
Why do I have a fabella?
How can you tell if you have a fabella?
The symptoms of fabella syndrome are posterolateral pain and a catching sensation (or clicking sound) with knee flexion. Prichett has suggested an association between the presence of fabella and an increased risk of OA of the knee.
How do I know if I have fabella?
Examination. Physical examination may reveal the presence of swelling/tenderness in the posterolateral aspect of the knee. Palpation of the fabella may suggest the presence of a firm nodule in the left posterolateral popliteal fossa, medial to the tendon of the biceps femoris, and approximately 1 cm in diameter.
Why do I have an extra bone on my knee?
Your patella is a triangular-shaped bone in the front of your knee that’s also known as your kneecap. About 1 to 2 percent of people have a bipartite patella, which means their patella is made up of two bones instead of one. You may have a bipartite patella in one or both of your knees.
What is fabella in knee?
The fabella is a sesamoid bone in the posterolateral capsule of the human knee joint. In quadrupedal mammals, the fabella is believed to have a role similar to the patella in redirecting extension forces of the knee joint from one point to another.