Why Does My Knee Hurt When I Sleep on My Side?

Knee pain from side sleeping usually comes from how your legs are stacked and bent for hours, not from your mattress or from damage that happened overnight. The position rarely creates a problem out of nothing. It presses on and strains spots that were already irritated, which is why the pain shows up at night. Where the knee hurts is the best clue to what is irritated, and small changes to your position often bring relief within days.

What Side Sleeping Does to Your Knees

When you lie on your side with nothing between your knees, your top leg drops forward and downward.1Superpower. Why Do My Hips Hurt When I Sleep? Causes & Solutions That twists the pelvis, stretches tissues on the outside of the top leg, and squeezes structures underneath.2Superpower. Why Do My Hips Hurt When I Sleep? Causes & Solutions The same sag bends the top knee inward, which puts strain on its inner side.

The bottom knee has its own problem. The inner surfaces of your two knees often rest directly on each other. There is little padding over the bony inner knee, so hours of contact press on whatever sits there.3Spire Orthopaedic Centre. Knee Pain at Night: Common Reasons and When to Be Concerned Many people also curl up with their knees bent tightly, which loads the front of the knee.

Pain that never bothers you during the day can still appear at night because of how differently the knee is loaded. When you walk, the load keeps shifting. Lying still keeps steady pressure on one spot for hours. Tissue that was a little irritated by the day’s activity gets pressed for longer, and because you don’t notice mild discomfort while asleep, you don’t move until it wakes you. After a still night, the knee may also feel stiff and worse for the first few minutes.

Which knee hurts tells you something. Pain in the top knee usually points to the inward sag and twist. Pain in the bottom knee usually points to pressure from the other leg. Pain in both knees after curling up tightly points to how far the knees are bent. Check which side you were lying on when the pain woke you.

Pain that eases within minutes of changing position is typical of pressure on an irritated spot rather than a serious injury, though it doesn’t rule one out. If the same knee wakes you after several nights on the same side, the position is a likely contributor.

Inner Knee Pain and Pes Anserine Bursitis

Pes anserine bursitis affects the inner knee, where three tendons attach just below the joint.4Spire Orthopaedic Centre. Knee Pain at Night: Common Reasons and When to Be Concerned A bursa is a small fluid-filled sac that cushions tendons where they rub over bone. When this sac is irritated, pain sits just below the inner joint line and can spread down the inner shin.5Spire Orthopaedic Centre. Knee Pain at Night: Common Reasons and When to Be Concerned Side sleeping makes it worse, mainly when the sore knee rests against the other leg.6Spire Orthopaedic Centre. Knee Pain at Night: Common Reasons and When to Be Concerned

The tendons and the cushioning sac sit just under the skin on the inner knee, so the other knee presses almost directly on them. That is why a pillow that keeps the knees from touching often helps more than any change to the mattress.

The condition is common in people with knee arthritis, people carrying extra weight, and runners. Tight hamstrings and knock-kneed alignment add stress to this area.

Arthritis pain is usually felt deep in or around the whole joint, often with stiffness after rest. Bursitis is a more focused spot just below the joint line on the inner side. The two can exist together, which is why an arthritic knee can still have a separate tender patch that flares at night.

You can check for this pattern yourself. Press gently about two to three finger-widths below the inner joint line and see whether it is tender. Bursitis tenderness is a small spot below the joint, not the whole joint. Climbing stairs or getting out of a chair often hurts too. There is often mild puffiness, and less often the area feels warm.

A pillow between your legs while you sleep can reduce pressure on the sac.7Justin M. Lareau, MD. Pes Anserine Bursitis | Justin M. Lareau, Md, Orthopedic Surgeon, Hip & Knee Joint Replacement, Western Springs, Westmont, Il Try a firm pillow that keeps the knees apart and level with the hips.

Daytime care helps your nights. Ice the tender spot for 15 minutes after a day with a lot of activity. Gentle hamstring stretches ease the pull on the tendons. Cut back for a while on the activity that set it off, rather than stopping all movement. Over-the-counter anti-inflammatory pain relievers can help if they are safe for you.

Ligament Strain on the Inside of the Knee

A ligament on the inner side of the knee keeps it from bending inward. When the top leg sags inward, this ligament gets stretched. Lying on your side with an injured knee unsupported can stress a healing ligament.8Spire Orthopaedic Centre. MCL Injuries: Causes, Symptoms, and When to Seek Treatment So after a twist or sports injury, night pain on the inner side may come from this ligament rather than from bursitis. The pain may feel like pulling or soreness along the inner side that eases when the knee is supported or straightened.

Ligament pain sits along the inner side, at or above the joint line, and usually follows a specific twist, fall, or blow to the knee. The knee may feel unstable or give way. Bursitis usually starts gradually, with no injury.

To protect a healing ligament at night, keep a pillow between the knees so the top knee can’t fall inward. Lying on your back with a pillow under the knee is another option. Wear a brace at night only if your clinician recommended one.

Pain at the Front of the Knee When You Curl Up

Patellofemoral pain is an ache around or behind the kneecap. Sleeping with your knees bent past 90 degrees may make this pain worse.9Exakt Health. Patellofemoral pain syndrome – Treat the cause, not the symptoms The fetal position, with the knees pulled up toward the chest, is a likely trigger. Many people with this problem also hurt on stairs or after sitting for a long time.

The kneecap glides in a groove at the end of the thigh bone, and the more the knee bends, the harder the kneecap is pressed into that groove. Staying tightly bent for hours means hours of that compression on a sensitive area.

To adjust the curl, straighten your legs a little so your knees stay at a right angle or more open. Move the pillow from between the thighs to between the knees and ankles. A body pillow can stop you from curling up again during the night.

Daytime habits feed kneecap pain too. Weak hip and thigh muscles let the kneecap track poorly, and strengthening exercises from a physical therapist help more than rest alone. Squatting a lot or using stairs a lot can flare it up.

When the Pain Is a Burning or Tingling Feeling

Pressure on a nerve that runs along the inner knee is an often-missed cause of pain there and in the upper calf.10PubMed. Saphenous nerve entrapment. A cause of medial knee pain. Nerve pain tends to feel burning, tingling, or numb rather than aching.

Bursitis and ligament pain are usually dull and aching and can be pinpointed with a finger. Nerve pain is often burning, electric, or like pins and needles. It may spread along a line down the inner shin instead of staying at a single tender spot. Light touch or the feel of bedsheets on the skin may be uncomfortable, which a bruise-type ache doesn’t usually cause. Mention numbness, pins and needles, or pain that doesn’t match one tender spot specifically to your doctor.

How to Sleep on Your Side Without Knee Pain

The pillow should be thick enough to keep the knees about hip-width apart. A firm pillow holds its height better than a soft one. Knee pillows or full-length body pillows stay in place during the night, and a folded blanket works for a test night.

To set it up tonight, lie on your side, place the pillow between your knees, and check that your top leg is level with your hip rather than tilted down toward the bed. Put the sore knee on top when possible so the pillow doesn’t press against it from underneath. If you wake with the pillow gone, try a longer body pillow, since a small one often slips out.

If side sleeping still hurts, lie on your back with a pillow under the knees, or try a half-side position leaning on a body pillow. Change positions gradually, because it takes about a week to get used to a new one.

A very soft mattress lets the hips sink and the legs twist, while a medium-firm one keeps the legs more level. A mattress topper is a cheaper fix than a new mattress.

When Knee Pain at Night Needs a Doctor

  • Go urgently if the knee is hot, red, and swollen, especially with a fever, because this can signal infection.
  • Calf swelling and pain can signal a blood clot and need urgent care.
  • Pain that wakes you whatever position you’re in is different from position pain and should be checked.
  • Get it checked if the knee locks, gives way, or you can’t bear weight on it.

Pain that doesn’t improve after a couple of weeks of position changes is also worth a visit. At the appointment, the doctor presses on specific spots to locate the pain and gently stresses the knee to test the ligaments. An X-ray or ultrasound is ordered only if needed. Describe your sleeping position and which knee hurts. Brief notes on which knee hurts, which position, and what helps let a clinician narrow the cause faster, as does mentioning any recent injury, new exercise, or change in weight.

Pressure pain often eases within days of using a pillow. Bursitis can take weeks to settle. Arthritis-related night pain needs longer-term management. Treatment beyond home care can include a physical therapy program, a steroid injection for stubborn bursitis, or treatment aimed at an underlying cause such as arthritis or weight.