Knee A to Z

A piriformis stretch is a knee rehabilitation exercise (stretch) to loosen the piriformis muscle and tendon.

The piriformis syndrome is buttock pain due to tightening or irritation of the piriformis muscle where it is crossed by the sciatic nerve.

The pivot shift test is a test to assess the integrity of both the anterior cruciate ligament and and also the other key structures that contribute to the knee's stability. Page updated June 2024 by Dr Sheila Strover (Clinical Editor)

PKR is an abbreviation of 'partial knee replacement'.

A placebo is a dummy drug or dummy surgery used in clinical trials.

Platelet Rich Plasma is a blood preparation where a portion of plasma rich in platelets is extracted from the rest of the blood.

PLC is an abbreviation of 'posterolateral corner', that region at the side of the knee towards the back.

A plica is a ribbon-like fold of joint lining (synovium) which may be present in any knee as an embryological remnant. Page updated June 2024 by Dr Sheila Strover (Clinical Editor)

Plica surgery in the knee is performed to remove a plical fold of joint lining that is being troublesome, perhaps because it is catching in the joint.

Plica syndrome is a collection of symptoms commonly experienced together in the knee, when a fold of joint lining called a plica is irritated, thickened and intermittently catches between other structures in the joint. Page updated May 2024 by Dr Sheila Strover (Clinical Editor)