Inner knee pain nearly always comes from one of a short list of structures: the medial meniscus, the MCL ligament, the pes anserine tendons and the small sac beneath them, or the cartilage in the inner half of the joint. Hip and lower back problems can send pain to the same spot. What the pain does, and when, usually narrows it down.
What is actually on the inside of your knee
Four structures sit on the inner knee: the medial meniscus (cartilage cushion), the MCL (ligament strap), the pes anserine (tendons on the shin) and the medial compartment (inner joint surface).
Wear in the inner half of the joint
Medial compartment osteoarthritis is thinning cartilage in the inner half of the knee, and the most common cause after 50. Mornings are stiff for about half an hour. See our guide to osteoarthritis in the knee.
A tear in the medial meniscus
In younger knees a tear follows a twist you remember, with swelling in a day or two. After about 40 the meniscus turns brittle, so rising from a deep squat can be enough.
Pes anserine bursitis, the cause that gets missed most often
Pes anserine pain sits about two inches below the joint line on the inner shin, not at the joint itself, and is tender to press.
MCL strain, usually after a specific moment
An MCL strain follows a moment you can name: a blow to the outside of the knee, or a twist that bent it inward. Mild strains settle in a few weeks with rest.
When the problem is not in the knee at all
Hip osteoarthritis and lower back nerve irritation can both send pain to the inner knee, so a proper assessment checks both.
Pain behind the joint is different: see pain behind the knee when straightening the leg.
Pain on the inside of the knee with no swelling
Plenty of people have real inner knee pain with a knee that looks completely normal. The absence of swelling is genuinely useful information.
It makes an acute, significant meniscus tear or a substantial ligament injury less likely, since both usually produce at least some swelling in the first days. It makes an active inflammatory or infected joint much less likely.
It fits comfortably with early medial compartment osteoarthritis, with pes anserine tendon irritation, with a mild MCL strain, and with referred pain from the hip or back. In other words, no swelling does not mean nothing is wrong. It shifts the odds toward the soft tissue and wear-related causes.
Knee pain when bending: what each movement suggests
Knee pain when bending is a broad complaint, so it helps to be specific about which bend hurts.
Squatting or going down stairs. Both load the joint surface heavily. Pain here points toward medial compartment wear or a meniscus problem.
Kneeling. Direct pressure on the front and inner shin. Pain here often points to the pes anserine or the soft tissue in front of the joint.
Getting out of a car or a low chair. A combination of bending and twisting under load. This is a classic pes anserine pattern, and also common in arthritis.
A bend that catches or sticks partway. A mechanical block like this raises the possibility of a meniscus tear.
Inner knee pain causes at a glance
| Cause | What it feels like | Where exactly | What makes it worse |
|---|---|---|---|
| Medial compartment osteoarthritis | Deep, dull ache with morning stiffness | Inner half of the joint itself | Stairs down, standing after sitting, end of day |
| Medial meniscus tear | Sharp, catching, sometimes locking | Right on the inner joint line | Twisting, squatting, pivoting |
| Pes anserine bursitis or tendinopathy | Tender, localised, sometimes burning | About two inches below the joint line | Stairs up, getting out of a car, knees touching in bed |
| MCL strain | Ache along a line, feeling of instability | Down the inside of the knee | Side-to-side movement, pushing off |
| Referred from hip or lower back | Vague, hard to point to with one finger | Inner thigh and knee together | Walking distance, hip movement, back positions |
What can be done about pain on the inside of the knee
Treatment works as a ladder.
Load management and strengthening. Adjust what aggravates the knee, and build strength in the quadriceps, glutes and hips.
Physiotherapy. Targeted exercise, hands-on treatment and gait work help many people. Our physiotherapy and chiropractic teams work alongside our physicians.
What an interventional pain clinic adds. When conservative care has had a fair trial, image-guided injections use ultrasound or fluoroscopy (live x-ray) to place medication precisely.
Hyaluronic acid injections. A gel-like substance similar to the joint’s own fluid, injected for osteoarthritis. Some patients find it eases pain and stiffness for months.
Platelet-rich plasma, or PRP. Your own blood is concentrated and injected to support healing, for some tendon problems and early joint wear.
Genicular nerve radiofrequency ablation. The genicular nerves are small sensory nerves that carry pain signals from the knee to the brain, and they control no muscle. Under image guidance, a physician places fine needles beside them and uses gentle heat from a radio wave to interrupt those pain messages. Nothing is removed and the knee is not operated on. It is used for lasting osteoarthritis pain, often when knee replacement is not an option. Relief often lasts several months to a year or more, and can be repeated.
Warning signs that need urgent care
Most inner knee pain is not an emergency. Some presentations are. Seek same-day medical care if you have:
- A knee that is hot, red and swollen, especially with a fever or feeling unwell
- An inability to put weight on the leg at all
- A knee that gives way repeatedly or buckles under you
- Calf swelling and tenderness along with the pain, which can suggest a blood clot
- Knee pain following significant trauma such as a fall from height or a collision
- Numbness, spreading weakness, or a foot you cannot lift
Questions patients ask about inner knee pain
Can inner knee pain go away on its own?
Often, yes. A mild MCL strain or an irritated pes anserine bursa usually settles over several weeks with rest and strengthening. Pain from joint wear tends to fluctuate rather than disappear. If it has lasted beyond about six weeks, have it assessed.
Why does the inside of my knee hurt when I bend it but not when I walk?
Bending loads the joint surfaces and tendons far more than flat walking does. Pain that appears only with squatting, stairs or kneeling suggests a load-related problem, which fits medial compartment wear, a meniscus tear or pes anserine irritation rather than a whole-joint problem.
Is inner knee pain always arthritis?
No. Arthritis becomes more likely with age, but pes anserine bursitis, meniscus tears, MCL strains and referred pain from the hip or lower back all present in the same place. The pattern and exact location matter more than age alone.
Do I need an MRI for pain on the inside of my knee?
Not usually as a first step. History and examination identify the likely cause in many cases, and x-ray is often the more useful first image for suspected arthritis. MRI helps most when a meniscus tear is suspected or a procedure is planned.
What is the difference between inner knee pain and pain behind the knee?
They usually come from different structures. Inner knee pain points to the medial meniscus, MCL, pes anserine or medial joint surface. Pain behind the knee more often involves a Baker’s cyst, the hamstring or calf attachments, and carries its own warning signs.
This article is general information, not medical advice. It cannot diagnose your pain. If your symptoms are new, worsening, or worrying you, speak with your family doctor or contact us for an assessment.
Getting your knee assessed
If pain on the inside of your knee has lasted more than a few weeks or is limiting what you do, an assessment can identify which structure is involved and which treatments are worth considering. Our pain physicians in Toronto assess the knee, hip and lower back together, because the source is not always where the pain is felt.
Most services are covered by OHIP with a physician referral, which your family doctor can send through our physician referral page. You can also refer yourself directly without waiting for a doctor’s appointment.
