An odd place that raises eyebrows when experiencing pain in this area is the posterior knee compartment. There are structures in the back of the knee that are frequently associated with posterior knee pain. One of the involved structures is a small muscle called the popliteus. This muscle is triangular in shape and has what is called a ‘reversed orientation’ (1) meaning the muscle belly inserts distally and the tendon originates proximally.
Issues may arise when the popliteus lacks the mechanism of ‘unlocking’ the knee joint. This can become apparent if an individual’s knee is unable to totally extend, particularly to the final 5° (1). An example of how this muscle may be compromised and cause posterior knee pain may be when a bone is formed in the popliteus tendon (called a cyamella) which can be rare, or perhaps from a sporting injury involving the knee twisting while the foot is planted on the ground (2).
Functional stability of the hip, knee and ankle joints are each essential to restore through rehabilitation when the popliteus is injured (2). Such exercises can include standing knee flexion of the injured leg, with the foot aiming to touch the opposing posterior knee of the fixed leg; curtsy split squat; and lateral lunges with an externally rotated leg.
Although the popliteus is rarely injured in isolation and is closely associated with other posterolateral structures of the knee joint, it is still an important stabiliser of the knee, second to the collateral and cruciate ligaments, as its importance is highly regarded (1,2).
References
1. Morgan, Trey; Stevens, Stevie D.; Palmer, Thomas, Athletic Therapy Today Nov2007, Vol. 12 Issue 6, p16 (English Abstract Available)
2. Popliteus: Assessment and rehabilitation. (2018, July 14). Retrieved from https://www.sportsinjurybulletin.com/popliteus-assessment-and-rehabilitation/
