What Causes Pain Behind the Knee with Extension?
Pain behind the knee with extension is not that common. Most posterior knee pain is present with deep knee flexion or kneeling. Therefore, it is important to understand the region of the pain to help delineate what the source of the pain may be coming from.
Back of the Knee Anatomy
The main structures in the back (posterior aspect) of the knee include the menisci and the hamstring tendons across the knee. In addition, pathological swelling of this portion of the knee, which usually occurs due to a leak in the posteromedial joint capsule, is called a Baker’s cyst.
Can Meniscus Tear Cause Pain Behind Knee?
Large meniscal flap tears, meniscal root tears which are displaced and extruded, and a Baker’s cyst all could cause pain behind the knee when extended. In addition, a very swollen Baker’s cyst could get pinched between the hamstring tendons and have posterior knee pain when the knee is out straight. A rare condition called snapping hamstrings could also catch over the posterior aspect of the femoral condyles and have an audible “clunk,” which can lead to behind knee pain.
Is Pain in Back of Knee Common?
Pain in back of the knee with full knee extension is uncommon. If there are any concerns about the severity of pain, one should see a physician to find out the etiology of its cause.