Everything You Need to Know About a Baker's Cyst

What is a Baker’s Cyst?

00A Baker’s cyst is a fluid-filled swelling that forms behind the knee, usually as a result of knee joint inflammation or injury. It’s not harmful in itself, but it can cause tightness, stiffness, or discomfort, especially when bending or straightening the knee.

An analogy…

Imagine your knee joint like a water balloon. If too much pressure builds up inside, like from inflammation, the balloon bulges out the back, forming a soft lump, which is the cyst.

What causes a Baker’s cyst?

The knee joint produces synovial fluid to lubricate and cushion movement. If the knee is irritated by arthritis, a meniscus tear, or inflammation, extra fluid builds up and can push out into a sac of tissue at the back of the knee, forming a cyst. This sac (the bursa) becomes stretched and swollen, usually in the popliteal space (behind the knee joint).

What are the signs and symptoms of a Baker’s cyst?

Swelling or a lump behind the knee
Tightness or fullness in the back of the knee
Stiffness or limited bending of the knee
Pain with full flexion or extension
Symptoms may worsen after activity or prolonged standing

What tests are used to diagnose a Baker’s cyst?

Palpation: A soft, fluid-filled lump is felt behind the knee.

Ultrasound: Confirms the presence and size of the cyst.

How long does a Baker’s cyst take to heal?

Small or mild Baker’s cysts may settle in 2–6 weeks with conservative treatment. Larger or persistent cysts may take several months to resolve, especially if caused by underlying joint issues.

How does a Baker’s cyst happen?

Knee osteoarthritis or rheumatoid arthritis
Meniscus injuries (especially medial meniscus tears)
Inflammatory conditions like gout or synovitis
Knee overuse or high-impact activity
Poor lower limb biomechanics or muscle imbalances
History of knee trauma or surgery

What treatment can help a Baker’s cyst?

Addressing the underlying cause (e.g. treating arthritis, managing a meniscus tear)
Manual therapy (gentle mobilisation of the knee, massage of tight surrounding tissue)
Ice and compression
Stretching and strengthening exercises for the knee and lower limb
Activity modification
Aspiration (fluid drainage)
Corticosteroid injection

What exercises or stretches can I do for a Baker’s cyst?

Quad and hamstring stretches
Isometric quad sets
Bridges and side-lying hip exercises
Knee extension and flexion
Glute and core strengthening
Gentle cycling or pool-based activity

What products can help with a Baker’s cyst?

- KT Pilates Band Pack

AAROM knee flexion in sit

Sit in a chair and bend your affected knee back as far as you can. Place the ankle of your good leg over the front of your affected leg and use it to bend your knee back further. Hold this position

Passive knee extension stretch sitting

Sit upright in a chair, and place the heel of your affected leg on a stool or table. Make sure there is a gap between your foot and your hip as you try to straighten the affected knee as much as you can. Stay in this position and hold as directed.

Gastrocnemius stretch in standing (holding on)

In a standing position, step your affected leg back behind you. Keep the heel on the floor and the toes pointing forwards. Bend the front knee, moving your body forwards, until you feel a stretch in the back of the calf. Make sure your heel does not come off the floor and your back knee does not bend.

Resisted knee extension in stand

Stand with your feet flat on the floor at hip width apart. Tie a resistance band into a loop around a secure object. Place your affected leg in the loop, with the band behind your knee. Step back so you have some tension in the band. Keeping your body straight, bend both knees a little. As you straighten your knee back up you will pull against the resistance of the band, working the thigh muscle. Relax and then repeat.

Wall squats with stability ball

Hold a stability ball against a wall, placed in the small of your back. Lean firmly back against the ball. Walk your feet forwards, keeping your toes pointing ahead and your legs at hips-width apart. Squat down, dropping your hips towards the floor and bending your knees until they reach 90 degrees. Stand up straight, driving the movement with your buttock muscles. Make sure your body remains straight and knees travel directly forwards over your toes throughout this exercise.

Bridge on the floor

Lie on your back with your knees bent and your feet flat on the floor. Tighten your buttock muscles and lift your hips up into the bridge position. Make sure you keep your hips up and level throughout the movement.

Hamstring stretch in standing

Hold onto a chair or table for support. Move your affected foot one pace in front. Keep your back foot facing forwards and soften the knee. Make sure your hips are square and you maintain a straight back. Gently lean forwards and push your hips out behind you. You will feel a stretch down the back of your front thigh. Hold this position, keeping the heel of your front foot on the floor.